management plan for the derogation of the greek …
TRANSCRIPT
MANAGEMENT PLAN FOR THE
DEROGATION OF THE GREEK PURSE SEINE
FLEET FROM THE PROVISIONS OF ARTICLE
13 OF (EC) 1967/2006
ATHENS 2008
2
Contents 1. MANAGEMENT PLAN OBJECTIVE .......................................................................................................... 3
2. THE PURSE SEINE FISHERY IN GREECE ............................................................................................... 4
2.1. General ........................................................................................................................................................ 4
2.2. The Greek purse seine fleet ......................................................................................................................... 4
2.3. Greek legislation in force ............................................................................................................................ 5
2.4. EU legislation .............................................................................................................................................. 6
2.5. Fishing effort ............................................................................................................................................... 6
2.6. Landings ...................................................................................................................................................... 7
2.7. Discarded catches from the purse seine fishery ........................................................................................... 8
3. MANAGEMENT PLAN FOR THE SUSTAINABLE EXPLOITATION OF THE ANCHOVY
AND SARDINE STOCKS ............................................................................................................................... 10
3.1. Target-species of the management plan .................................................................................................... 10
3.2. Current state of the management plan's target-stocks................................................................................ 11
3.2.1. Landings ................................................................................................................................................. 11
3.2.2. Discards of the target-species ................................................................................................................. 13
3.3. Effects of purse seine operations to the environment ................................................................................ 14
3.3.1. Impact to the demersal stocks ................................................................................................................. 14
3.3.2. Impact to the sea bottom and benthos .................................................................................................... 14
3.4. Financial impact from the application of the Reg. (EC)1967/2006 on the purse seine fishery in
Greece. .............................................................................................................................................................. 16
3.4.1. Significant reduction of the available small pelagic fish available for fishing ....................................... 16
3.4.2. Increase of the fishing trip duration ........................................................................................................ 18
3.4.3. Reduction of the available traditional fishing grounds (by area)............................................................ 19
3.5. Reference points for the application of the management plan................................................................... 20
3.5.1. Anchovies (Engraulis encrasicolus) ....................................................................................................... 20
3.5.2. Sardine (Sardina pilchardus) .................................................................................................................. 22
4. MONITORING PLAN FOR THE TARGET-STOCKS AND THE REFERENCE POINTS ..................... 25
4.1. Eco-sounding and hydroacoustic survey ................................................................................................... 25
4.2. Landing sampling ...................................................................................................................................... 26
4.3. Purse seine segment landings .................................................................................................................... 27
4.4. Study of possible additional measure for the reduction of discards .......................................................... 27
4.5. Time schedule of the monitoring plan for each year ................................................................................. 28
4.6. Administration procedures regarding the special fishing permits ............................................................. 28
5. RESUME ...................................................................................................................................................... 30
6. REFERENCES ............................................................................................................................................. 33
Annexes
3
1. MANAGEMENT PLAN OBJECTIVE
The objective of the present management plan is to support derogation from the provisions of
paragraph 3 of article 13 of the Reg. (EC) 1967/2006 in accordance to paragraph 5 of the same
article in relation to the minimum distances and depths and other measures
Article 13, paragraph 3: minimum distances and depths for the operation of fishing gears
The use of purse seines shall be prohibited within 300 meters of the coast or within the 50 metres
isobath where that depth is reached at a shorter distance from the coast. A purse seine shall not be
deployed at depths less than 70 % of the overall drop of the purse seine itself as measured in Annex
II to this Regulation.
The present management plan provides specific information so that the purse seine vessels operate
under the previous measure regime i.e. allow fishing with purse seines shall be prohibited within
300 meters of the coast or within the 30 meters isobath where that depth is reached at a
shorter distance from the coast regardless the vertical drop size of the nets.
The present management plan provides also for the issuing of special fishing permits in accordance
with Regulation (EC) 1627/94
The present management plan provides:
scientific evidence which prove that derogation of the provisions of article 13, paragraph 3
in relation to the purse seine gear and the traditional way of use in Greece today are
substantiated
information related to the purse seine fishery in Greece so that the negative effects from the
application of the new measures on the fishery production and economics of the sector are
recognized
technical information on the use and operation of the traditional purse seine gear
a detailed management plan for the management of the purse seine target species stocks in
accordance to article 6, of (EC) 2371/2002 on management plans and article 19 of (EC)
1967/2006 and especially:
1. identify the target species and their ranking of priority
2. set reference points and targets for their sustainable exploitation
3. identify the fleet segment
4. elaborate the management plan in accordance to the ecosystem-based approach and
precautionary approach
5. propose management measures for the protection of the stocks in accordance to article
19, (EC) 1967/2006 considering the state of stocks, the biological characteristic of the
target-species, the characteristics of the fishery and the fleet and the economic effects
from the application of the new measures
6. the proposal of technical measures, the technical characteristics of the gears, the areas
and periods for fishing of target-species, the minimum landing sizes
7. the protection of the environment from the use of the gear
8. the proposal of indicators and indicator's monitoring plan for the control of the stocks of
the target-species
9. the definition of an annual monitoring plan of the management plan's control indicators
10. the study of the selectivity of the purse seine nets
11. the procedure for the issuing of special fishing permits in accordance to the Reg (EC)
1627/1994
4
2. THE PURSE SEINE FISHERY IN GREECE
2.1. General
The purse seine fishery is especially important for the Greek fishery sector economy since it is the
only gear which targets small pelagic species and especially anchovy and sardines. The purse seine
is a mobile circular net which is rather selective since its operation is based on the attraction of
small pelagic fish schools using low light intensity and consequently the encirclement of the schools
with the net. This operation is conducted only if the fish school is of the expected size in terms of
number of individuals, species and individual size as reported to the fishermen by the electronic fish
finder systems on board. Another reason which justifies the fact that the gear is selective is that the
net mesh is open through its operation and therefore, under sized fish may escape. The purse seine
segment of the Greek fleet provides the local market with the 90% of the total anchovy and sardines
landed annually since the fishing of such species using pelagic trawls is prohibited in Greece.
2.2. The Greek purse seine fleet
There are 290 purse seine vessels in the Greek fleet in accordance to the Fleet Register of December
31, 2006 (indicative). There are also 121 vessels registered with both purse seine and trawler
licenses and therefore the total number of purse seine vessels in Greece is 425 vessels. The number
of the vessels (as in all other feet segments) is constantly reducing due to the decommissioning
plans enforced by the Ministry of Agricultural Development and Food. The age distribution of the
purse seine fleet is illustrated in Figure 1. The distribution shows that most vessels are old with half
of them constructed before 1985.
4 53 2
13
7 6 69
14
24
42
76
21
36
21
1
0
10
20
30
40
50
60
70
80
90
1930
1935
1940
1945
1950
1955
1960
1965
1970
1975
1980
1985
1990
1995
2000
2005
2006
ΑΡΙΘ
ΜΟ
Σ Σ
ΚΑΦ
ΩΝ
Figure 1. Age distribution of purse seine vessels (primary gear license)
Source: Fleet register December 31, 2006
In accordance to the data in the Greek National Program for Fisheries Data Collection (Data
Collection Regulation) for the year 2006, the number of professional fishermen directly employed
on purse seiners are 4000 and given their family status, the total population which is dependent on
the purse seine segment is estimated to be 16000 persons (average 38 persons per vessel).
5
The main species landed by the purse seines in Greece are Engraulis encracicholus, Sardina
pilchardus, Trachrurus spp, Boops boops, Spicara spp, Sardinela aurita, Scomber japonicus και
Scomber scomber.
The evolution of the Greek purse seine fleet is summarized in Table 1 (Fig. 2).
Table 1. Evolution of purse seine fleet in Ionian and
Aegean Seas
Year Aegean Sea Ionian Sea
1998 301 53
1999 291 50
2000 282 52
2001 283 51
2002 277 50
2003 268 49
2004 265 45
2005 256 42
2006 250 40
Αριθμός ζκαθών Γρι - γρι
R2 = 0.9724
R2 = 0.8507
0
50
100
150
200
250
300
350
1998 1999 2000 2001 2002 2003 2004 2005 2006
Έηος
Αρ
ιθμ
ός
ζκ
αθ
ών
Αιγαίο Ιόνιο
Figure 2. Number of purse seine vessels (- ■ - Aegean Sea; - ▲ - Ionian Sea)
The purse seine fleet has been reducing during the last decade in the Aegean and the Ionia Seas.
Almost 85% of the fleet is operating in the Aegean Sea and its distribution is not uniform since
most of them operate from large harbours like Piraeus and Thessaloniki. From the total vessels,
61% operates in North Aegean Sea, 24% in the South Aegean Sea and 15% in the Ionian Sea. This
reduction is owed to the success of the decommission plans applied since 1994.
2.3. Greek legislation in force
In accordance to today's Greek legislation – not considering the EU legislation applied in Greece –
the management of the purse seine fishery and the management of the small pelagic stocks is
conducted with the following additional local measures (national laws):
Number
Number of purse seine vessels
6
1. Purse seine (night) fishery operation is prohibited for the period December 15 and February
28 every year
2. Purse seine fishery is prohibited for 2 days before and 2 days after each full moon
3. The minimum mesh size is 16 mm for the purse seine vessels operating at night and 40 mm
for the purse seines operating during daytime
4. Purse seine is prohibited within a distance of 100 m from the coastline regardless the depth
5. Purse seine fishery is prohibited in various geographic areas
6. The use of pelagic trawlers is banned while the fishing of small pelagic fish by bottom
trawlers is prohibited.
2.4. EU legislation
According to the new regulation of fishing in Mediterranean [(EC) 1967/2006], Article 13,
paragraph 3: minimum distances and depths for the operation of fishing gears, the use of
purse seines shall be prohibited within 300 meters of the coast or within the 50 meters isobath
where that depth is reached at a shorter distance from the coast. A purse seine shall not be deployed
at depths less than 70 % of the overall drop of the purse seine itself as measured in Annex II to this
Regulation.
2.5. Fishing effort
The evolution of purse seine fishing effort expressed in fishing days per year, day x GT and day x
Kw indicators is summarized in Table 2 (Fig. 3)
Table 2. evolution of purse seine fishing effort in the Aegean and Ionian seas.
Year Fishing Days Days x GT Days x Kw
Aegean Sea
1998 163.5 1,740,457 8,626,653
1999 162.9 1,723,797 8,315,669
2000 162.2 1,681,888 8,070,459
2001 166.3 1,741,079 8,333,390
2002 162.0 1,685,983 7,964,052
2003 176.5 1,851,229 8,400,991
2004 154.4 1,636,404 7,336,972
2005 168.5 1,780,085 7,829,104
2006 163.2 1,718,645 7,548,697
Ionian Sea
1998 139.5 209,534 1,176,532
1999 149.9 215,334 1,211,466
2000 146.8 225,622 1,235,496
2001 140.5 213,053 1,160,748
2002 155.9 234,732 1,251,359
2003 153.3 231,338 1,212,886
2004 162.9 228,194 1,194,799
2005 166.9 222,578 1,188,020
2006 155.9 207,793 1,109,105
7
Σσνολικός αριθμός ημερών αλιείας Γρι - γρι
R2 = 0.705
0
10000
20000
30000
40000
50000
60000
1998 1999 2000 2001 2002 2003 2004 2005 2006
Έηος
Εηή
ζιο
ς α
ριθ
μό
ς η
μερ
ών
αλιε
ίας
Αιγαίο Ιόνιο
Μέζος εηήζιος αριθμός ημερών αλιείας ανά ζκάθος
R2 = 0.6278
120
130
140
150
160
170
180
1998 1999 2000 2001 2002 2003 2004 2005 2006
Έηος
Εηη
ζιο
ς α
ριθ
μός
ημ
ερώ
ν α
λιε
ίας
Αιγαίο Ιόνιο
Αλιεσηική προζπάθεια Γρι - γρι
R2 = 0.6023
0
1000000
2000000
3000000
4000000
5000000
6000000
7000000
8000000
9000000
10000000
1998 1999 2000 2001 2002 2003 2004 2005 2006
Έηος
Ημ
έρες
x K
w
Αιγαίο Ιόνιο
Αλιεσηική προζπάθεια Γρι - γρι
R2 = 0.0315
0
200000
400000
600000
800000
1000000
1200000
1400000
1600000
1800000
2000000
1998 1999 2000 2001 2002 2003 2004 2005 2006
Έηος
Ημ
έρες
x G
RT
Αιγαίο Ιόνιο
Figure 3. Evolution of purse seine vessel fishing effort (- ■ - Aegean Sea; - ▲ - Ionian Sea)
During the last decade, fishing effort has remained stable or slightly declining except the average
per vessel number of fishing days in Ionian Sea. The purse seiners, since they can operate
efficiently only when the sea weather is calm (5-6 Bf maximum) – eventhough they legally
operate for most part of the year - their actual operational period is not more than 5-6
months.
2.6. Landings
The total landings from purse seine fishery range between 30000 and 50000 tonnes from the
Aegean sea (subarea 3.1) and 2000 to 5000 tonnes from the Ionian Sea (subarea 3.2). From these
landings, 92-98% are small pelagic (Engraulis encracicholus, Sardina pilchardus, Trachrurus spp,
Boops boops, Spicara spp, Sardinela aurita, Scomber japonicus και Scomber scomber). Data on the
landings from the Greek National Program for Collection of Fisheries Data in accordance to
EC/1534 and EC/1639 as well as the databases kept by the Institute for Marine Biological
Resources of the Hellenic Centre for Marine Research are summarized in Table 3 (Fig. 4).
Total number of fishing days Annual average number of fishing days per vessel
Fishing effort (days x gt) Fishing effort (days x kw)
8
Table 3. Purse seine fleet landings from Aegean Sea and Ionian Sea (total, pelagic fish segment, demersal fish segment)
LANDINGS Percent of total purse seine landings
Percent of purse seine
landings of demersal
species to the total
national demersal species
landings
YEAR TOTAL PELAGIC
SPECIES
DEMERSAL
SPECIES
PELAGIC SPECIES
(%)
DEMERSAL
SPECIES (%) DEMERSAL SPECIES (%)
Aegean Sea
1998 29,948 28,173 1,776 94.1% 5.9% 9.00%
1999 45,646 44,672 974 97.9% 2.1% 1.91%
2000 42,677 40,882 1,794 95.8% 4.2% 2.86%
2001 42,534 40,813 1,720 96.0% 4.0% 3.01%
2002 34,546 31,757 2,789 91.9% 8.1% 3.71%
2003 36,590 34,896 1,694 95.4% 4.6% 2.2%
2004 41,571 40,901 670 98.4% 1.6% 0.89%
2005 46,298 44,749 1,548 96.7% 3.3% 2.35%
2006 49,780 49,133 648 98.7% 1.3% 1.05%
2007 41,851 41,291 560 98.7% 1.3% 1.09%
Ionian Sea
1998 2,644 2,482 162 93.9% 6.1% 1.82%
1999 2,048 1,868 180 91.2% 8.8% 3.62%
2000 3,198 2,941 258 91.9% 8.1% 1.29%
2001 1,934 1,903 32 98.4% 1.6% 0.19%
2002 3,325 3,185 140 95.8% 4.2% 0.81%
2003 5,045 4,992 52 99.0% 1.0% 0.46%
2004 2,809 2,606 203 92.8% 7.2% 2.08%
2005 4,494 4,080 414 90.8% 9.2% 3.28%
2006 3,927 3,679 248 93.7% 6.3% 1.76%
2007 2,157 2,035 122 94.4% 5.6% 0.85%
The purse seine landings have not shown a declining trend over the last years. The demersal
species landed as by-catch by purse seines is insignificant and 3% of the total purse seine
landings annually or the 2.5% of the total national landed amounts of demersal species (from
all fleet segments).It is therefore justified the fact that the purse seine as a gear does not target
demersal species and does not affect demersal species ecosystems.
Αιγαίο Πέλαγος
Εκθορηώζεις Γρι - γρι
0
10,000
20,000
30,000
40,000
50,000
60,000
1998 1999 2000 2001 2002 2003 2004 2005 2006 2007
Έηος
Εκ
θο
ρηώ
ζει
ς ζ
ε t
Σσνολικές Πελαγικά είδη Βενθοπελαγικά είδη
Ιόνιο Πέλαγος
Εκθορηώζεις Γρι - γρι
0
1,000
2,000
3,000
4,000
5,000
6,000
7,000
8,000
9,000
10,000
1998 1999 2000 2001 2002 2003 2004 2005 2006 2007
Έηος
Εκ
θο
ρηώ
ζει
ς ζ
ε t
Σσνολικές Πελαγικά είδη Βενθοπελαγικά είδη
Figure 4. Annual landings of purse seine vessels (1998-2007) from the Aegean and Ionian Seas
(-■- Total; -▲- Pelagic species; -♦- Demersal species)
2.7. Discarded catches from the purse seine fishery
According to research projects data on purse seine fishery, the discarded catch is a very small
percentage of the total landings of the purse seine fishery. (National Program for Collection of
Fisheries Data in accordance to EC/1534 and EC/1639).
9
Table 4. Percentage of discarded catches to the total landings of the purse seine fishery
in Greece
Year Demersal
Species (%)
Pelagic Species
(%) Total
2003 0.4534 2.3148 2.7683
2004 0.1849 7.7386 7.9235
2005 0.1145 4.1004 4.2149
2006 0.0346 2.5795 2.6141
As summarized in Table 4, the discarded catches range between 3 and 8% with an annual
average of 4.1%. The main amount is small pelagic species while the demersal species are
insignificant with an annual average of 0.2% of the total discards.
10
3. MANAGEMENT PLAN FOR THE SUSTAINABLE EXPLOITATION OF
THE ANCHOVY AND SARDINE STOCKS
According to the regulation (EC)2371/2002, the present management plan refers to the Greek
fishing vessels which have a fishing permit to use the gear 'purse seine'. In accordance to article 6 of
the regulation (EC) 2371/2002, the present management plan:
identifies the target-species for which a special fishing permit system is to be enforced and
which are landed only with the purse seine fishing gear
provides information on the present state of the target-stocks
identify and describe the known effects of the purse seine fishing gear to the environment
identify and describe the known effects of the application of these measures to the purse
seine fishery sector
set reference points for each species based on biomass, fishing mortality and exploitation
rate. The evaluation of these points will be conducted on an annual basis and if the case that
the values of these indicators fall below the reference points then the special fishing permits
will be revoked
describe the details of a monitoring plan for the above reference points which will assess the
state of the stocks of the target-species in relation to the reference points
3.1. Target-species of the management plan
The target species and by priority will be (1) the anchovy (Engraulis encrasicolus) and (2) the
sardine (Sardina pilchardus).
The anchovy and the sardine are the most valuable small pelagic species in Greece. They form the
main amount of small pelagic landings (Table 4). Both these species in Greece are mostly fished
with the purse seine fishing gear.
Both these species have special characteristics which are important and should be carefully
considered for their management. In particular:
1. they exhibit large biomasses due to their low position in the food chain
2. they show considerable horizontal and vertical migrations
3. they exhibit small life span. Most of the landed specimens are not older than 3 years
4. their stock status depends significantly on their annual recruitment due to their small life
span and this results to significant biomass fluctuations depending on the environmental
conditions
5. there exist 2 genetically separate stocks of anchovy, that of the Aegean Sea and that of the
Ionian Sea. On the contrary, the sardine stock is pammictic.
The anchovy and sardine are landed usually close to the areas of high productivity. These species
form almost 80% of the total purse seine segment landings. The production of these species is
illustrated in Figure 5. In particular during the last decade, the purse seine annual landings range
between 9500 and 24000 tn for anchovy and 7000 and 18000 tn for sardines.
11
0
5000
10000
15000
20000
25000
30000
1950
1959
1968
1977
1986
1995
2004
Έηος
Εκθορηώζεις
(t)
Εκθορηώζεις γαύροσ ζύμθωνα με ηην
Εθνική Σηαηιζηική Υπηρεζία
0
5000
10000
15000
20000
25000
30000
1950
1959
1968
1977
1986
1995
2004
Έηος
Εκθορηώζεις
(t)
Εκθορηώζεις γαύροσ ζύμθωνα με ηην
Εθνική Σηαηιζηική ΥπηρεζίαΕκθορηώζεις ζαρδέλας ζύμθωνα με ηην
Εθνική Σηαηιζηική Υπηρεζία
0
5000
10000
15000
20000
25000
1950 1959 1968 1977 1986 1995 2004
Έηος
Εκθορηώζεις
(t)
Εκθορηώζεις ζαρδέλας ζύμθωνα με ηην
Εθνική Σηαηιζηική Υπηρεζία
0
5000
10000
15000
20000
25000
1950 1959 1968 1977 1986 1995 2004
Έηος
Εκθορηώζεις
(t)
Figure 5. Anchovy and sardine landings (tn; National Statistical Service)
3.2. Current state of the management plan's target-stocks
3.2.1. Landings
The total landings from purse seine fishery (all species) range between 30000 and 50000 tonnes
from the Aegean sea (subarea 3.1) and 2000 to 5000 tonnes from the Ionian Sea (subarea 3.2). From
these landings, 92-98% are small pelagic (Engraulis encracicholus, Sardina pilchardus, Trachrurus
spp, Boops boops, Spicara spp, Sardinela aurita, Scomber japonicus και Scomber scomber). Data
on the landings from the Greek National Program for Collection of Fisheries Data in accordance to
EC/1534 and EC/1639 as well as the databases kept by the Institute for Marine Biological
Resources of the Hellenic Centre for Marine Research are summarized in Table 5.
Table 5. Purse seine vessel's landings (total and per target species)
LANDINGS
PERCENTAGE TO THE
TOTAL PURSE SEINE
LANDINGS
Year Total Pelagic species Anchovy and
Sardines
Pelagic Species
(%)
Anchovy and
Sardines (%)
Aegean Sea
1998 29,948 28,173 22,162 94.1% 74.0%
1999 45,646 44,672 28,538 97.9% 62.5%
2000 42,677 40,882 28,872 95.8% 67.7%
2001 42,534 40,813 28,122 96.0% 66.1%
2002 34,546 31,757 21,675 91.9% 62.7%
2003 36,590 34,896 24,403 95.4% 66.7%
2004 41,571 40,901 28,008 98.4% 67.4%
2005 46,298 44,749 33,723 96.7% 72.8%
2006 49,780 49,133 40,624 98.7% 81.6%
2007 41,851 41,291 33,444 98.7% 79.9%
Ionian Sea
1998 2,644 2,482 1,873 93.9% 70.8%
1999 2,048 1,868 1,380 91.2% 67.4%
2000 3,198 2,941 2,055 91.9% 64.2%
2001 1,934 1,903 1,210 98.4% 62.6%
Annual anchovy landings Annual sardine landings
12
LANDINGS
PERCENTAGE TO THE
TOTAL PURSE SEINE
LANDINGS
2002 3,325 3,185 2,129 95.8% 64.0%
2003 5,045 4,992 3,780 99.0% 74.9%
2004 2,809 2,606 2,053 92.8% 73.1%
2005 4,494 4,080 2,897 90.8% 64.5%
2006 3,927 3,679 2,924 93.7% 74.5%
2007 2,157 2,035 1,703 94.4% 78.9%
Αιγαίο Πέλαγος
Εκθορηώζεις Γρι - γρι
0
10,000
20,000
30,000
40,000
50,000
60,000
1998 1999 2000 2001 2002 2003 2004 2005 2006 2007
Έηος
Εκ
θορ
ηώζ
εις
ζε
t
Σσνολικές Πελαγικά είδη Γαύρος - Σαρδέλα
Ιόνιο Πέλαγος
Εκθορηώζεις Γρι - γρι
0
1,000
2,000
3,000
4,000
5,000
6,000
7,000
8,000
9,000
10,000
1998 1999 2000 2001 2002 2003 2004 2005 2006 2007
Έηος
Εκ
θορ
ηώζ
εις
ζε
t
Σσνολικές Πελαγικά είδη Γαύρος - Σαρδέλα
Figure 6. Total purse seine segment landings (in tonnes) in Aegean and Ionian Seas
(-■- Total; -▲- Pelagic species; -●- Anchovy, Sardine)
The main volume of landings is composed of anchovies and sardines alone (63-82% of total purse
seine landings for both species). The distribution of landings in Greece differs from north to south
and from east to west (see also Stergiou 1997). The distribution is summarized in Table 6.
Table 6. Anchovy and sardine landings in the Aegean Sea sub-areas (in tonnes)
Year Aegean Sea North Aegean
Sea
South Aegean
Sea
North Aegean
Sea (%)
South Aegean
Sea (%)
1998 22 162 19 724 2 438 89.00% 11.00%
1999 28 538 25 113 3 425 88.00% 12.00%
2000 28 872 27 224 1 648 94.29% 5.71%
2001 28 122 26 498 1 624 94.23% 5.77%
2002 21 675 19 708 1 967 90.92% 9.08%
2003 24 403 22 836 1 567 93.58% 6.42%
2004 28 008 25 598 2 410 91.40% 8.60%
2005 33 723 30 958 2 765 91.80% 8.20%
2006 40 624 37 052 3 572 91.21% 8.79%
2007 33 444 30 896 2 548 92.38% 7.62%
The landings of both species originate mainly from the Aegean sea (93% annual average) during the
last decade. In addition, landings originating from the North and central Aegean Sea form the 80%
of the total national landings of these species.
Total Landings – Aegean Sea Total Landings – Ionian Sea
13
3.2.2. Discards of the target-species
The amounts of anchovies and sardines discarded during purse seine fishery operations are
insignificant justifying the fact that the gear is highly selective. The estimated percentage of
discards is summarized in Table 7.
Table 7. Percent of discarded anchovies and
sardines over the total landings.
Year Anchovy
(%)
Sardines
(%)
2003 0.06 0.01
2004 0.02 0.61
2005 0.03 0.04
2006 0.01 0.37
The average size of the 50% of the discarded anchovies is 86,2 mm while for the sardine is 106.9
mm. Almost 80% of the discarded anchovies and 60% of the discarded sardines are undersized (Fig.
7).
Ποζοζηά απορριπηομένων αηόμων ζαρδέλας ανά κλάζη μήκοσς
0
10
20
30
40
50
60
70
80
90
100
55 65 75 85 95 105 115 125 135 145 155 165 175 185 195 205 215 225 235 245 255
Ολικό μήκος (mm)
%
Ποζοζηά απορριπηομένων αηόμων γαύροσ ανά κλάζη μήκοσς
0
10
20
30
40
50
60
70
80
90
100
55 65 75 85 95 105 115 125 135 145 155 165 175 185 195
Ολικό μήκος (mm)
%
Figure 7. Percent of discarded anchovies and sardines per length class
Percent of discarded sardines per length class
Percent of discarded anchovies per length class
Total length (mm)
Total length (mm)
14
3.3. Effects of purse seine operations to the environment
The known data indicate that the use of a purse seine does not have any impact to the environment.
The operation of the purse seine fishing gear has minimal impact to the demersal species and the
benthos of the location of fishing as shown from the by-catches described above.
3.3.1. Impact to the demersal stocks
Regarding the demersal stocks, the impact of the purse seine is minimal. According to the data
summarized in Table 4, only 3% of the total landings of the purse seine fleet segment of the Greek
fisheries sector comprises of demersal species. The landings of demersal species from the purse
seine segment also represent only the 2.5% of the total demersal species landings of the Greek
fisheries sector. Also the discards of the demersal species is minimal. According to the existing data
the percentage of discards are below 0.5% with annual average 0.2%.
3.3.2. Impact to the sea bottom and benthos
Regarding the impact of purse seine gear to the sea bottom and benthos, 3 comments need to be
made. All 2 justify the fact that the purse seine gear with the technical characteristics and mode of
use in Greece does not create any impact to the sea bottom and the benthos (details can be found
in Annex IV):
(a) Based on the technical characteristics and method of use of the purse seine in Greece, it is
impossible that it can be used as a trawled gear (like a trawler). When the purse seine net is
deployed from the fishing vessel, its hauling is conducted with the fishing vessel stationary and only
with the use of the hydraulic winches. During the hauling, the operation of the engine is only to
provide hydraulic power to the winches and not to move the vessel. Moreover, if the vessel moves
during the hauling, this will only result to the entanglement of the net. Therefore, the opinion that
the purse seine gear can be used as a mobile gear (trawling) is totally unreal and false. The
hauling of the net can be carried out wither mechanically using automatic winches or by hand in the
case of small fishing vessels. The material from which the net is made as well as the way the
various parts of the net are sawn together does not allow it to be dragged like a trawler along the sea
bottom because it will be significantly damaged. Even in the case that a fisherman would like to use
it as a trawler (illegally) the damages that would be incurred to the net would be difficult to cover
financially (a purse seine net costs around 40,000 € the small version – Central Greece - and around
60,000 € the large version – North Greece).
(b) When a purse seine net has an official height of 120 m (measured according to the official
method set by the EU i.e. stretched and wet) then the operational height of the net (the height of
the net during deployment from a vessel) cannot be more than 60 m and when it closes by the use of
a purse line, its depth cannot be more than 20 m. This justifies the fact that the net cannot have any
impact to the sea bottom at operational depths down to 30 m as it was the limit of the legislation
until today. Obviously the effects of the gear are much less when it operates at depths down to 50 m
as provided by the latest regulation on the Mediterranean fisheries.
(c) The operation of the purse seine net is based on the encirclement of a school of small pelagic
species. The net can have a circumference of 500 m (for example in North Ionian Sea-Corfu) to 800
m (North Aegean Sea-Thermaikos Gulf). The height of the net can be 65 m (for example in North
Ionian Sea-Corfu) to 120 m (North Aegean Sea-Thermaikos Gulf). The detection of the school of
fish is carried out using electronic fish finders and the gathering of the fish is carried out using a
light source. These light sources have special characteristics by means of intensity set by the
15
Ministry of Agricultural Development and Food. This are special technical measures set by
the Greek administration within the framework of stock conservation and such measures are
not existent in other EU member states. The high selectivity of the purse seine net is owed to the
fact that these low intensity light sources attract only the small pelagic fish (which are targeted by
the gear) and not any other species (like demersal etc.). The deployment of the net is carried out
either using a small boat (tender) or the main fishing vessel. The deployment needs to be completed
quickly (normally not more than 10 minutes) so that to avoid losing the fish. Another special
characteristic of the use of the gear is that it cannot be used when the weather is bad and winds
more than 4-5 Bf because the wind-driven waves will cause the entanglement of the net and the loss
of the fish.
There is misunderstanding regarding the use and operation of the purse seine net in Greece. Non
detailed description of the fishing gear from international organizations like F.A.O. indicate that the
purse seine is allowed to be fully deployed in depth and then it is hauled on board using the purse
seine line. In the following picture the use of the purse seine net is illustrated in accordance to
F.A.O. (fishing gear fact-sheets, www.fao.org). Eventhough this image is good to provide a
description of the parts of the net, it does not show the operation of the net and the relationship
between the circumference and height of the net. The height of the net is 6-7 times less than the
circumference (Fig. 8).
Figure 8. Operation of purse seine net according to F.A.O.
Under normal operation conditions the fish are trapped at the side part of the net and NOT the
bottom as it is implied from the above image (Fig. 8; see arrow). In Figure 9, the correct
deployment of the net is illustrated.
During deployment the net is not allowed to be fully extended vertically. When the deployment is
finished, the net is immediately hauled on board the vessel and therefore, the only part of the net
that is extended is the initial part which was first deployed off the vessel. During deployment the net
is fully opened from below and from below the vessel. The small time between the initiation of the
deployment and the hauling is very small so that the encircled fish school does not have time to
escape either from below the net or from below the vessel (see also Annex IV).
16
Figure 9. Position and deployment of the purse seine gear when the hauling is started (by means of a purse line)
The mostly deployed part of the net is shown to the right. The movement of the vessel during the encirclement of the
fish is shown (arrow)
3.4. Financial impact from the application of the Reg. (EC)1967/2006 on the purse seine
fishery in Greece.
The number of people directly employed in the purse seine segment is 4000 while the dependent
population (number of family members) is estimated to be 16000 in Greece. Moreover it should be
noted that the processing industry in Greece is mostly based to the anchovies and sardines landed by
the purse seiners. Also the purse seine segment offers jobs and income to other economic sectors as
well such as transportation, tourism, construction etc.
The main impacts of the Reg. (EC) 1967/2006 on the purse seine segment and the Greek fishery
sector are:
3.4.1. Significant reduction of the available small pelagic fish available for fishing
For the correct and beneficial application of the regulation there are several issues regarding the
distribution of the anchovy and sardine stocks in the Greek seas need to be considered. The
distribution of the stocks depends on the geomorphology of the coastline. According to the existing
research data on the distribution of the stocks and biomass of small pelagic species it is evident that
most of the known fishing grounds will not be available for fishing using the purse seine in the
future. The small pelagic fish like sardines and anchovies are usually gathered at upwelling areas
and areas close to eutrophic coastal waters.
Contrary to what happens in other areas, in Greece the areas with high productivity are located
close to the coastline and are usually connected to areas of river outflow. In addition, the Greek
coastline is exhibits numerous closed gulfs which are interconnected with narrow passages. In
Annex III, the description of such areas is provided for further consideration and which show
extended areas in which fishing with purse seine is prohibited by the new EU regulation.
17
These characteristics of the Greek coastline result to the concentration of the stocks of small pelagic
close to the coastline and not the open sea as in other areas (open sea and oceans). In Table 14, the
percentage of sardine and anchovies distributed by depths is summarized (DCR reports; 2003-
2004).
Table 14. The percent of sardine and anchovy biomass distributed among the depth zones (in m) according to eco-
sounding research data (summer data; 2003-2006)
(a) Distribution of sardines and anchovies in depth zones <15 m, 15-30 m και 30-50 m. (*) estimation (older
legislation)
Year <15 m (*) 15-30 m 30-50 m
Anchovy Sardine Anchovy Sardine Anchovy Sardine
2003 44% 22% 14% 33% 42% 45%
2004 31% 23% 14% 36% 55% 41%
2005 44% 19% 24% 32% 32% 49%
2006 34% 14% 33% 44% 33% 42%
(b) Distribution of biomass in depth zones <50 m, και >50 m (latest legislation)
Year <50 m >50 m
Anchovy Sardine Anchovy Sardine
2003 56% 78% 44% 22%
2004 69% 77% 31% 23%
2005 56% 81% 44% 19%
2006 66% 85% 34% 15%
Moreover the sardine and anchovy populations are concentrated closer to the coastlines
during the winter period (Giannoulaki et al 2003, 2005, 2006).
The percentages presented in Table 14, provide a conservative view of the issue since areas with a
depth less than 15 m have not been studied thoroughly. However, in any case the application of
the new regulation at depths equal and below 50 m as provided by the latest regulation for the
Mediterranean will allow the exploitation only of the 40% of the available stock of the
anchovy and only the 20% of the available stock of the sardine.
The existing legislation and policies on the purse seine fishing in Greece have taken into
consideration the above special characteristics allowing for the protection of more than the 20% of
the existing stock of anchovies and more than 35% of the sardine stock. The application of the
technical measures provided by the Reg. (EC)1967/2006 will eventually have dramatic economic
effects on purse seine fishing sector as well as the processing sector considering that less than 40%
of the available fish biomass will be available for exploitation.
For the above reasons and given the satisfactory state of the sardine and anchovy stocks it is evident
that the technical measures that should be applied for the purse seine fishery in Greece is to be
allowed to operate at depths between 30 and 50 m without any other restriction based on the net
height. In the present management plan, reference points and an annual monitoring plan are
described for the sardine and anchovies. Based on these reference points, the special fishing permits
will be revoked if the monitoring survey shows that the current reference point's values are worse
than the set reference points.
18
3.4.2. Increase of the fishing trip duration
The application of the new regulation will result to the increase of the fishing trip duration since the
new fishing grounds (at depths allowed by the new regulation) are located further away from the
home ports and which in turn results to the increase off the coast of fishing. According to the data
from the National Program for Collection of Fisheries Data in accordance to EC/1534 and EC/1639)
for 2006, the fishing cost structure for the purse seine segment is:
Staff (salaries and social security) 35,73%
Fuel 18,68%
Maintenance (vessel and gears) 10,15%
Other miscellaneous 35,44%
100,00%
Due to the delicate nature of the fish landed by the purse seine, the purse seine vessels cannot
perform long fishing trips away from the main harbours and fish monger markets. This indicates
that any change in the fishing trip and especially its duration will have a negative impact to the
quality of the landed fish – except the cost of fishing – and thus, the economic returns in the sector.
The range of the fishing trips of the purse seine vessels is not longer than 20-30 nm around the
home port. This is estimated considering the maximum speed of a standard vessel (around 10 knots)
and considering that the trip between the fishing ground and the landing port is not more than 2
hours. The range of a fishing trip can reach even 150 nm from the home port when the vessel will
move to adjacent fishing grounds from those close to the hope port. However, in that case the
prerequisite is that the vessel must operate close to a official landing port. In general, the purse
seine vessels operate in fishing grounds which are (a) close to official landing ports in which the
prices are satisfactory and (b) the duration of the trip between the fishing ground and the landing
port is not longer than 2-3 hours due to the sensitive nature of the small pelagic fish (are easily
spoiled).
The change of the fishing isobath which is applied through the new regulation causes the increase of
the fishing trip duration. Based on the known geographic data and the known official home and
landing ports, the distance of the allowed fishing grounds from the main Greek home ports is
changes as follows:
Thessaloniki: from 25 nm to 40; increase by 60% (15 nm)
Nea Michaniona/Moudania, North Greece: from 9 nm to 23 nm; increase by 156% (14 nm)
Chalkida (South Evoikos Gulf): from 15 nm to 41 nm; increase by 173% (26 nm)
Stylida/Oreoi channel: from 11 nm to 27 nm; increase by 145% (16 nm)
Volos: from 3.5 nm to 5 nm; increase by 43% (1.5 nm)
Patra: from 0.8 nm to 4.2 nm; increase by 525% (3.4 nm)
Corfu: from 1 nm to 25 nm; increase by 2500% (25 nm)
The above estimations show that the application of the new regulation will result to the
coincidence of the new purse seine fishing grounds with the trawler fishing grounds.
It should be noted that the increase of the distance between the home ports and the fishing grounds
will result to the prohibition of fishing in the main purse seine fishing grounds ie. the Thermaikos
gulf and Strimonikos Gulf/Gulf of Kavala. The main reasons that the new regulation will affect the
fisheries production and national economy are:
19
the sardine and anchovy stocks are coastal and on a seasonal basis they may gather very
close to the coast
the use of the purse seine gear is traditional and has not been modernized in the recent years.
The purse seiners use light sources of very small intensity up to 10000 candles (regulated by
law) when adjacent countries use light sources with intensities up to 100000 candles. The
Greek Ministry of Agricultural Development and Food has regulated by law the maximum
allowed light intensity for purse seine fishing contrary to other EU member states.
3.4.3. Reduction of the available traditional fishing grounds (by area).
According to the known research data, the traditional purse seine fishing grounds are:
Gulf of Corfu (range 60 nm)
Pagassitikos gulf, Oreoi channel, North Evoikos Gulf to Chalkida
Kavala Gulf, Ierissos, Thasos islands (range 70 nm)
Argolida gulf, outer Saronikos gulf (range 120 nm)
Crete, Kithira sea, central Kyklades Island's area (range 120 nm)
Saronikos gulf, South Evoikos Gulf (range 12 nm)
the coast from south Corfu island to Patraikos gulf (range 30 nm)
Thermaikos gulf to Athos (East) and Pilion mountain (South) (range 150 nm)
The changes in the existing traditional fishing grounds due to the application of the new regulation
are considered significant since the Greek coastline is characterized by shallow depths. These
changes are summarized below:
Strymonikos gulf (Thassos island to Athos): from 2743 km² to 1773 km²; reduction κατά
35,3% (970 km²)
Thermaikos gulf (from Sithonia pen. to Zagora, Pilion) from 4173 km² to 2880 km²;
reduction by 30.9% (1293 km²)
Pagassitikos Gulf: from 480 km² to 240 km²; reduction by 50.0% (240 km²)
Oreoi channel (outer Maliakos gulf to Aegean sea exit channel): from 293 km² to 115 km²;
reduction by 60.8% (178 km²)
North Evoikos Gulf: from 690 km² to 384 km²; reduction by 44.3% (306 km²)
South Evoikos Gulf: (outer limit of 100 m isobath) from 734 km² to 130 km²; reduction by
83.3% (604 km²)
Argolikos Gulf: from 744 km² to 645 km²; reduction by 13,3% (99 km²)
Patraikos Gulf (from Rion-Antirrion bridge to Ionia Sea: from 263 km² to 91.5; reduction by
62,5% (171,5 km²)
Corfu gulf (from north border with Albania to south Corfu island): from 516 km² to 0 km²;
total loss of the fishing ground (516 km²)
The total loss of fishing grounds is estimated to be 4377.5 km² out of a total of 10636 km² i.e.
41,2%.
It should also be noted that due to the morphology of the Greek coastline, the application of
the prohibitions provided in the new regulation will transfer the fishing activities of the purse
seine outside the 6 mile territorial waters limits since Greece is the only EU member state with
such a small limit of territorial waters (other countries have limits of 200 nm and more).
20
3.5. Reference points for the application of the management plan
Within the framework of the present management plan regarding the state of stocks of sardines and
anchovies in the Aegean Sea, the reference points were set based on the National Program for
Collection of Fisheries Data in accordance to EC/1534 and EC/1639 data derived from eco-
sounding research and fish plankton studies. In addition, the present management plan includes also
the description of a monitoring plan of the target species (see Chapter 4).
3.5.1. Anchovies (Engraulis encrasicolus)
The anchovy belongs to the family of Engraulidae. Their maximum length reaches 20 cm and the
average age in the landed amounts is up to 3 years. It feeds on plankton and its spawning period is
between April and November. Reproduction peak is observed between June and July (Somarakis et
al. 2002, 2004, 2006, Stergiou et al 2002). The length at first spawning is 10.5 cm (Somarakis 2004,
2006, Stergiou et al 2002). The minimum landing size is 9 cm. The anchovy stock in the Greek
territorial waters is composed of 2 genetically distinct groups: the Aegean Sea group and the Ionian
Sea group.
3.5.1.1. Total biomass
The total biomass of the anchovy was estimated with acoustic surveys during the period June and
July for the years 2003 to 2006 within the National Program for Collection of Fisheries Data in
accordance to EC/1534 and EC/1639. These surveys cover the North and Central Aegean Sea in
which the 90% of the anchovy biomass is located and from which the 80% of the landed amounts is
derived. The methodology of estimation is provided in detail in Annex I. The results are
summarized in Table 7.
Table 7. Total biomass for the anchovy stock in the Aegean Sea based on eco-
sounding surveys
Year Biomass (t) CV
2003 47838 0.230
2004 46508 0.149
2005 31852 0.109
2006 62685 0.162
3.5.1.2. Spawning biomass
The spawning biomass was estimated using the Daily Egg Production Method – DEPM from
plankton research surveys during the period June-July of the years 2003-2006 within the National
Program for Collection of Fisheries Data in accordance to EC/1534 and EC/1639; see details in
Annex II). The results are summarized in Table 8.
Table 8. Spawning biomass of anchovy stock in Aegean Sea (DEPM method)
Year Spawning Biomass (t) CV
2003 40042 0.202
2004 22799 0.242
2005 20533 0.170
2006 48700 0.180
21
0
10000
20000
30000
40000
50000
60000
70000
2003 2004 2005 2006
Έτος
Βιο
μά
ζα (
t)
Γαύρος: Αναπαραγ. Βιομάζα Γαύρος: Ολική Βιομάζα
Figure 10. Anchovy biomass estimates based on eco-sounding and plankton research data
3.5.1.3. Fishing mortality
The estimation of the fishing mortality and the exploitation ratio was based on the Integrated Catch
Analysis-ICA method (Patterson 1998). For the application of the method, the following data are
required (National Program for Collection of Fisheries Data in accordance to EC/1534 and
EC/1639) (Table 9):
a) total biomass
b) number at age in the stock
c) spawning biomass
d) number at age in the spawning stock
e) landings
f) landings per age
Table 9. Annual fishing mortalities per age of anchovy
Age 2000 2001 2002 2003 2004 2005 2006
1 0.0082 0.2021 0.1516 0.2115 0.1206 0.1475 0.0729
2 1.3372 0.0245 1.2571 2.0008 1.1404 1.3951 0.6895
3 1.097 0.7824 0.0062 1.796 1.0236 1.2523 0.6189
4 0.4177 0.4899 0.4089 0.8673 0.5221 0.4383 0.3741
Average (Ages 1-3+) 0.8752 0.3547 0.4588 1.228 0.7962 0.6684 0.5705
3.5.1.4. Exploitation rate
The data on exploitation rate are summarized in Table 10.
Biomass, t
-■- Total Biomass, -♦- Spawning Biomass
22
Table 10. Exploitation rate of anchovy
Age 2000 2001 2002 2003 2004 2005 2006
0 0.0028 0.0016 0.0015 0.0000 0.0000 0.0000 0.0000
1 0.0068 0.1441 0.1122 0.1490 0.0913 0.1094 0.0573
2 0.5270 0.0200 0.5116 0.6251 0.4872 0.5375 0.3649
3 0.4777 0.3947 0.0051 0.5995 0.4603 0.5106 0.3402
Average (ages 1-3+) 0.4042 0.2189 0.2821 0.5268 0.3882 0.3570 0.2772
3.4.1.5. Reference points for the management of anchovy
Based on the above the initial reference points for the management of the anchovy will be:
Minimum total biomass (June): 35.000 tonnes
Minimum spawning biomass (June): 26.000 tonnes
Maximum fishing mortality: 1.2
Maximum exploitation rate: 0.4
The reference point regarding the total biomass and spawning biomass were based on estimated
minimum amounts from eco-sounding surveys in the Aegean Sea since 2003 increased by 10% to
cover the areas and landings not yet covered by research.
The maximum fishing mortality and exploitation rate values are slightly lower from the values
derived from the application of the ICA methodology. Its must be noted that the proposed
exploitation rate is in accordance to the standard exploitation rate for small pelagic species proposed
by Petterson (2002).
The reference points will be reviewed on an annual basis based on the results of the monitoring
survey for the target stocks. The monitoring survey will cover the whole geographic area in which
the target species are fished and the data of these surveys will lead to more accurate estimated of the
reference points.
3.5.2. Sardine (Sardina pilchardus)
The sardine belongs to the family of Clupeidae. The maximum length reaches 25 cm and the age in
the landed amounts is up to 4 years. It is a pelagic species with a high commercial value. The
spawning period in the eastern Mediterranean extends between October and April with a peak
during December-February. The length at first spawning is 11.5 cm (Stergiou et al 2002, Somarakis
et al 2006). The minimum landing size is 11 cm. It is sold as fresh or processed (canned etc.)
3.5.2.1. Total Biomass
The total biomass of the sardine was estimated through acoustic surveys during the period June and
July for the years 2003 έφς 2006 within the National Program for Collection of Fisheries Data in
accordance to EC/1534 and EC/1639. These surveys cover the North and Central Aegean Sea in
which the 85% of the sardine biomass is located and from which the 75% of the landed amounts is
derived. The methodology of estimation is provided in detail in Annex I. The results are
summarized in Table 11.
23
Table 11 Total biomass for the sardine stock in the Aegean Sea based on eco-
sounding surveys
Year Biomass (t) CV
2003 19281 0.183
2004 13848 0.354
2005 20464 0.368
2006 42856 0.47
Σαρδέλα: Ολική Βιομάζα
0
5000
10000
15000
20000
25000
30000
35000
40000
45000
2003 2004 2005 2006
Έτος
Βιο
μά
ζα (
t)
Σαρδέλα: Ολική Βιομάζα
Figure 11. The state of biomass of sardines in Aegean Sea (eco-sounding surveys)
3.5.2.2. Fishing Mortality
The estimation of the fishing mortality and the exploitation ratio was based on the Integrated Catch
Analysis-ICA method (Patterson 1998). For the application of the method, the following data are
required (National Program for Collection of Fisheries Data in accordance to EC/1534 and
EC/1639) (Table 9):
a) total biomass
b) number at age in the stock
c) number at age in the spawning stock
d) landings
e) landings per age
Table 12. Fishing mortality per age for sardine stock.
Age 2000 2001 2002 2003 2004 2005 2006
1 0.071 0.2773 0.263 0.1632 0.0807 0.0929 0.0819
2 1.6998 0.8088 1.7011 1.8923 0.9357 1.0776 0.9498
3 1.7854 1.9079 0.1197 1.1217 0.5547 0.6388 0.563
4 0.738 0.9657 0.6604 0.7569 0.3743 0.431 0.3799
Average ( Ages 1-3+) 1.1854 0.998 0.6946 1.009 0.5237 0.6031 0.5316
3.5.2.3. Exploitation Rate
-▲- Sardine: Total Biomass (t)
24
The data on exploitation rate are summarized in Table 13.
Table 13. Exploitation rate of sardine
Ages 2000 2001 2002 2003 2004 2005 2006
0 0.0002 0.0005 0.0014 0.0005 0.0002 0.0002 0.0002
1 0.0815 0.2574 0.2474 0.1694 0.0916 0.1040 0.0929
2 0.6800 0.5027 0.6801 0.7029 0.5391 0.5739 0.5428
3 0.6906 0.7046 0.1302 0.5837 0.4095 0.4440 0.4131
Average (Ages 1-3+) 0.5970 0.5550 0.46474 0.5696 0.3956 0.4198 0.3992
3.5.2.4. Reference points for the management of sardine
Based on the above the initial reference points for the management of the sardine will be:
Minimum Total biomass: 15.000 tonnes
Maximum fishing mortality: 1.1
Maximum exploitation rate: 0.4
The reference point regarding the total biomass were based on estimated minimum amounts from
eco-sounding surveys in the Aegean Sea since 2003 increased by 10% to cover the areas and
landings not yet covered by research.
The maximum fishing mortality and exploitation rate values are slightly lower from the values
derived from the application of the ICA methodology. Its must be noted that the proposed
exploitation rate is in accordance to the standard exploitation rate for small pelagic species proposed
by Petterson (2002).
The reference points will be reviewed on an annual basis based on the results of the monitoring
survey for the target stocks. The monitoring survey will cover the whole geographic area in which
the target species are fished and the data of these surveys will lead to more accurate estimated of the
reference points.
25
4. MONITORING PLAN FOR THE TARGET-STOCKS AND THE
REFERENCE POINTS
According to the present plan, the monitoring of the state of the stocks in relation to the reference
points will be conducted on an annual basis. In the case that the current values of the reference
points exceeds from above or below the maximum or minimum values set above, the special fishing
permits will be revoked. The monitoring plan includes eco-sounding surveys for anchovy and
sardine and monthly monitoring of the landings and the biological characteristics of the landed
individuals.
The proposed monitoring plan covers both the 2 genetically different stocks of anchovy (Magoulas
et al 2006) existing in the Greek waters (Aegean Sea stock and Ionian Sea stock) as well as the
whole stock of sardines
4.1. Eco-sounding and hydroacoustic survey
The stocks of both target species will be estimated through annual hydroacoustic surveys during the
2nd
and 3rd
quarter of every year in 2 phases: the Aegean Sea survey and the Ionian Sea survey (fig.
12 and 13)
338o
39o
40o
41o
22o 23o 24o 25o 26o
3338o
39o
40o
41o
22o 23o 24o 25o 26o
Figure 12. Illustration of hydroacoustic survey transects in Aegean Sea
20 21 22 23
38
39
40
20 21 22 23
38
39
40
Figure 13. Illustration of hydroacoustic survey transects in Ionian Sea
26
The survey transects will be perpendicular to the coastline and the inter-transect distance will be10
miles. The hydroacoustic surveys will provide the following data:
a) Total biomass of anchovies and sardines
b) Age structure of the populations
c) Average length at age keys
d) Weight and length relationships
In addition spawning biomass of anchovy will be estimated in Aegean Sea, through ichthyoplankton
survey based on the DEPM, and since the survey period coincides with the peak of the reproduction
period of the species. The detailed methodology is provided in Annex I. The methodology and
survey protocol will be the same used in the National Fisheries Data Collection program.
4.2. Landing sampling
Within the framework of the monitoring plan the systematic sampling of landings is planned. The
sampling will be conducted on a monthly basis at the 4 main geographic regions where the purse
seine fishery is focused:
1. Thracean Sea – Strymonikos Gulf (Kavala region)
2. Thermaikos Gulf (Michaniona region)
3. Evoikos Gulfs – Saronikos Gulf (Chalkida region)
4. Ionion Sea (Paatra region)
The sampling will be conducted on a monthly basis and will cover 1 sample of 50 fish per 200 kg of
landed amount in accordance to the protocol followed for the DCR regulation. In every sample a
length frequency analysis and age determination will be preformed. Every month 5 samples will be
taken from the landings derived from 5 different vessels. The profile of the annual landings will be
determined after integration of the data from every station and year quarter in accordance to the
protocol proposed by ICES (2005).
The above data will aid the determination of the state of sardines and anchovies. The hydroacoustic
surveys will result to the collection of the following data:
1. Total biomass
2. Length distribution of stocks
3. Number at Age of stocks
From the landing samples, the following data will be derived:
1. Length distribution of landings
2. Number at Age of landings
With the integration of the data from both samplings and the application of the ICA method and/or
other integration methods, the evaluation of the state of the stocks and the reference point values
will be estimated. In particular, the estimation of the spawning biomass of the anchovy will be
conducted in the Aegean Sea using the Daily Egg Production Method during the peak of the stock
spawning (See Annex II).
27
4.3. Purse seine segment landings
In order to fulfill the objectives of the present monitoring plan other data will be required. These data
will be derived from the National Program for Collection of Fisheries Data in accordance to
EC/1534 and EC/1639) which covers 30 landing ports (Fig. 14).
Moudania
IerisosMihaniona
Porto Lagos
Igoumenitsa
Mesologi
Perveza
Kerkira
Volos Alonisos
Katerini
Mytilini
Fanari
Alexandroupolis
Kavala
HiosChalkida
Kalamata
Piraias
Lamia
Patra
Korinthos
Iraklion
Naxos
Kythnos
Samos
Chania
Sitia
Rhodos
Lefkada
Nafplion
Figure 14. Sampling stations (ports)
The exploitation of the existing network of data collection will aid the collection of the following
information:
1. estimation of monthly fishing effort (days at sea, days at sea x kW, days at sea x gt)
2. daily landings
3. annual landings in Aegean and Ionian Sea
4. social and economic parameters
The above are required to estimate the mortality levels and the exploitation rates.
4.4. Study of possible additional measure for the reduction of discards
28
The target small pelagic species exhibit significant population fluctuations which depend on the
environmental conditions which affect the recruitment of the species. The fact that the small
pelagics depend on their recruitment is owed to their small life span (almost all landed fish are 1 or
2 years of age with older fish very rare). The fish landed by purse seiners are usually only 2 years
old – uniform production)
One of the aims of the present monitoring plan is to study the possibility to propose additional
technical measures to reduce catches of undersized fish which usually are discarded.
4.5. Time schedule of the monitoring plan for each year
According to the management plan, one survey will be carried out every year between June and
September. Additionally, the monitoring of the amount and composition of the landings will be
carried out from March to December 15 i.e. during the period which the fishing with purse seine is
allowed by law.
The results on the state of stocks of anchovy and sardine in relation to the reference points will be
submitted to the Ministry of Agricultural Development and Food until February 15 of every year.
In the case that the state of stocks is out of the limits set by the reference points, the special fishing
permits will be revoked before the start of the purse seine fishing period (March 1st).
The annual time schedule of the monitoring plan and administrations procedures is illustrated in the
following figure:
4.6. Administration procedures regarding the special fishing permits
Within the present management plan, the issuing of special fishing permits is planned for fishing
vessels that carry professional license for purse seine fishing and at the same time, satisfy the
provisions of Reg. (EC)1967/2006 i.e. they have a proven record in fishing with this particular year
of more than 5 years.
29
Immediately after the approval of the management plan, the following administration procedure
will be followed on behalf of the Ministry of Agricultural Development and Food:
1. Issuing of a Minsterial Decree, following an approval by the Fisheries Council, for the
adoption of the derogation within the framework of the following clauses:
a. paragraph 2, of the article 9 of the Law 2732/1999 regarding the professional unions
and jurisdiction issues of the Ministry of Agriculture (O.J. 154 A)
b. article 90 of the Legislation Codex for the Government and the Government
Agencies as ratified with article 1 of P.D. 63/2005 regarding the codification of
legislation for the Government and the Government Agencies
The Misterial Decree will also provide for the issuing od special fishing permits for the
derogations
2. Issuing of a special fishing permit for the fishing vessels willing to apply the derogation and
which will allow fishing with a purse seine gear from the 30 m isobath and further or from a
distance of 300 m and further regardless the height of the net. These permits will be valied
for 1 fishing period (1 year)
3. At the same time, the Ministry of Agricultural Development and Food will select a suitable
research Institute or agency which will undertake the scientific monitoring of the stocks in
order to fulfill the requirements of the Regulation for the submission of reports every 3 years
with the first report's deadline not after July 31, 2009.
The monitoring plan will have an annual duration and will provide all the required scientific
information for the assessment of the state of the target-species stocks for the issuing or revocation
of the special fishing permits which will be applied in the next fishing period.
30
5. RESUME
With the present management plan the need for the issuing of special fishing permits for the Greek
purse seine is justified, considering that due to the provisions of article 13 par. 3, of the Reg.
(EC)1967/2006, as well as the special characteristics of the Greek coastline (ch. 3), most of the
traditional purse seine fishing grounds are excluded from fishing. In addition, the fact that purse
seine fishery is targeting sardines and anchovies and, based on the current Greek legislation, the
fishing of small pelagic with trawls is strictly prohibited, this will lead to the dramatic reduction of
the production of sardines and anchovies increasing at the same time the needs for imports.
The present management plan is in accordance to the Reg. (EC)2371/2002 and refers to the purse
seine fishing vessels only. Within the present management plan and in accordance to the provisions
of article 6, Reg. EC)2371/2002:
1. the defined target species are the anchovy and the sardine. These species are the almost 80%
of the species landed by purse seiners and 95% of the amounts landed by the purse seiners
2. the state of the stocks is evaluated
3. reference points are set for every species. If the estimated values exceed the reference points
then the special fishing permits will be revoked. The reference points are based on 4
different biological criteria: the total biomass (anchovy and sardine), the spawning stock
biomass (anchovy), the fishing mortality (anchovy and sardine) and the exploitation rate
(anchovy and sardine) in accordance to Reg. (EC)2371/2002, article 5.2
4. the impact of the purse seine gear to the environment is analysed. In accordance to the
known data the Greek purse seine does not have any impact to the demersal species, exhibits
low discards and it does not affect the sea bottom
5. the economic impacts from the application of the regulation is described
In addition and in accordance to the regulation, an annual monitoring plan of the state of the stocks
and the levels of the reference points is described.
31
TABLE OF CORRESPONDENCE BETWEEN THE
REGULATION'S REQUIREMENTS AND CLAUSES AND THE
PRESENT MANAGEMENT AND MONITORING PLAN
Provision/clause in
Regulations Reference in present management plan
Information proving that a
derogation from Reg.
(EC)1967/2006 is justified
1. The stocks of anchovy and sardine does not show a reduction which would justify
the application of more strict technical measures and prohibitions (chapter 2)
2. The reduction n of the traditional fishing grounds and the increase of fishing trips
creates increased fishing costs (chapter 3.4.)
3. The geographical distribution of the stocks does not coincide with the new fishing
grounds leaving almost 80% of their biomass unexploited (Annex ΙΙΙ)
Description of the state of
the purse seine segment
and the impacts of the new
measures to the sector
Chapters 2, 3.3., 3.4. and ΑNNEX ΙΙΙ
Technical information on
the use and operation of
the purse seine gear
ANNEX IV
Target species
Chapter 3.1.
The species are the anchovy and sardine with the same ranking order of priority
Reference pints for the
sustainable management of
the target stocks
Chapter 3.5.
ANCHOVY
Minimum total biomass (June): 35.000 tonnes
Minimum spawning biomass (June): 26.000 tonnes
Maximum fishing mortality: 1.2
Maximum exploitation rate: 0.4
SARDINE
Minimum total biomass (June): 15.000 tonnes
Maximum fishing mortality: 1.1
Maximum exploitation rate: 0.4
Fleet and distribution Chapter 2
Application of the
precautionary approach Chapter 4
Technical description and
characteristics of the gear
Annex ΙΙΙ
Biological characteristics
of target species Chapter 3.1.
Characteristics of the
fishery Chapter 2
Characteristics of the fleet Chapter 2
32
Economic impact from the
application of the
regulations
Chapter 3.4.
Reduction of discards Chapters 2.7, 3.2.
Control of fishing effort The present management and monitoring plan aims to the control of fishing
effort by means of special fishing permits
Definition of fishing areas
and seasons Annex III
Minimum landing size Covered by the Reg. (EC)1967/2006. No changes are included in the present
management plan
Environmental protection
Chapter 3.3.
1. It is proved that the use of the current gear does not affect the demersal stocks
2. The use of the gear at the designated depth limits – with its current technical
specifications – does not have an impact to the sea bottom and the benthos
Monitoring plan Chapter 4
Time period until the
successful completion of
the monitoring plan and
time schedule
Chapter 4.5
Annual
33
6. REFERENCES
Draper N.R. and H. Smith, 1966. Applied regression analysis. Ed. John Wiley and Sons, N.Y., 407
p.
Giannoulaki M, Machias A, Somarakis S, Tsimenides N. 2005. The spatial distribution of anchovy
and sardine in the northern Aegean Sea in relation to hydrographic regimes. Belgian Journal of
Zoology 135 (2): 151-156
Giannoulaki M., A. Machias, C. Koutsikopoulos, J. Haralabous, S. Somarakis, N. Tsimenides.
2003. The effect of coastal topography on the spatial structure of the populations of small
pelagic fish. Marine Ecology Progress Series. 265: 243-253.
Giannoulaki M., Machias A., Koutsikopoulos C. and Somarakis S. 2006. The effect of coastal
topography on the spatial structure of anchovy and sardine. ICES Journal of Marine Science,
ICES Journal of Marine Science, 63(4): 650-662.
Hunter J.R. and B. Macewitz, 1985. Measurement of spawning frequency in multiple spawning
fishes. In: Lasker R. (Ed.). An Egg Production Method for Estimating Spawning Biomass of
Pelagic Fish: Application to the Northern Anchovy, Engraulis mordax. NOAA Technical Rep.
NMFS 36: 79-93.
Hunter J.R., 1985. Preservation of Northern Anchovy in Formaldehyde Solution. In: Lasker R.
(Ed.). An Egg Production Method for Estimating Spawning Biomass of Pelagic Fish:
Application to the Northern Anchovy, Engraulis mordax. NOAA Technical Rep. NMFS 36:
63-65.
ICES, 2005. Workshop on Sampling Design for Fisheries Data (WKSDFD), ICES CM 2005/ACFM
11
MacLennan D. and Simmonds E.J. 1992. Fisheries acoustics. Chapman & Hall, London, 325p.
Magoulas, A., Castilho, R., Caetano, S., Marcato, S. and Patarnello, T., 2006. Mitochondrial DNA
reveals a mosaic pattern of phylogeographical structure in Atlantic and Mediterranean
populations of anchovy (Engraulis encrasicolus). Mol. Phylogenet Evol 39 (3): 734-746.
Patterson K., 1992. Fisheries for small pelagic species: an empirical approach to management
targets. Reviews in Fish Biology and Fisheries, 2, 321-338.
Patterson K.R. 1998. Integrated catch-at-age analysis, v.1.4. Aberdeen, Marine Laboratory.
Somarakis S., Palomera I., Garcia A., Quintanilla L., Koutsikopoulos C., Uriarte A., Motos L.,
2004. Daily egg production of anchovy in European waters. ICES Journal of Marine Science
61: 944-958
Somarakis, S, C. Koutsikopoulos, A. Machias and N. Tsimenides- 2002. Applying the Daily Egg
Production Method to small stocks in highly heterogeneous seas. Fish. Res., 55: 193-204.
Somarakis, S., Ganias, K., Siapatis, A. Koutsikopoulos, C., Machias, A., and Papaconstantinou, C.
2006. Spawning habitat and daily egg production of sardine in the eastern Mediterranean.
Fisheries Oceanography 15 (4): 281-292
Spanakis, E., Tsimenides, N. and Zouros, E., 1989. Genetic differences between populations of
sardine, Sardina pilchardus, and anchovy, Engraulis encrasicolus, in the Aegean and Ionian
seas. J. Fish. Biol., 35: 417-437.
Stergiou KI, Somarakis S and Machias A. 2002. Anchovy and Sardine in Greek waters: a review of
biological, ecological and fisheries aspects related to environmental variability. Environmental
variability and small pelagic fisheries in the Mediterranean Sea. Copemed: 66-68.
34
ANNEX Ι
Stock assessment of the anchovy and sardine stocks using hydroacoustic methods
Acoustic echoes will be registered continuously along 70 pre-defined transects in the study area
with a Biosonics Split Beam 38 kHz DT-X. The partitioning of integrated deflection will be done
by comparing the echogram at corresponding times. Echograms will be examined in order to
identify school marks that characterize anchovy and sardine (MacLennan and Simmonds, 1992).
Acoustic survey will cover a total area of 31000 Km2 of echo-integration acquisition.
338o
39o
40o
41o
22o 23o 24o 25o 26o
3338o
39o
40o
41o
22o 23o 24o 25o 26o
338o
39o
40o
41o
22o 23o 24o 25o 26o
3338o
39o
40o
41o
22o 23o 24o 25o 26o
Figure Ι.1. The preselected profiles in the Aegean Sea.
In order to estimate anchovy and sardine’s biomass, the weight-length relationship is
required as well as species length frequency distribution per area. Therefore, a number of pelagic
trawls (at least 30) will be held along transects in the positions of high fish concentrations.
The density of targets (F) from the observed echo integrals will be estimated according to
the equation F= (K/<σ>)E, were K is the calibration factor, <σ> is the mean cross-section and E is
the Echo integral after partitioning (MacLennan and Simmonds 1992). The <σ> will be calculated
for the mean total fish length of each area according to the equations <σ>= 104π TS/10
ιif , where fI
is the corresponding length frequency as deduced from the fishing samples.
The abundance Q will be estimated separately for the eastern and the western part of the
study area. The abundance Q in each elementary statistical sampling area will be calculated from
the average density within each sub-area according to the equation:
NFA ki
ik/Q ,
where FI is the I sample; Ak is the area of each elementary statistical sampling area and Nk is
transects in Ak. The variance V will be estimated as
V=
i
(AFI-Q)2/[Nr(Nr-1-1)]
The data will be log transformed and the means and variances of F will be estimated
according to the following equations:
F=exp(m)GN[0.5 S/(n-1); V=F2-exp(2m) GN[S(n-2)/(n-1)
2];
where m = average (lnF); S= variance (lnF) and n = independent observations of F
The total abundance Qt and its variance will be obtained by summing the results for each region
Qt=Q1+Q2+… , and Vt=V1+V2+…. Standard error of Qt is the square root of V (MacLennan and
Simmonds 1992).
35
ANNEX ΙΙ
Eggs and larvae sampling and the application of the Daily Egg Production Method for the
estimation of anchovy spawning stock biomass
Ichthyoplankton samples will be obtained over a grid of 205 sampling stations with a WP2 sampler
(mouth opening: 0.255 m2, mesh-size: 0.200-mm). Tows will be made from within 5 m of the
bottom to surface or from 200 m depth to surface at deep stations. All samples will be preserved,
immediately after collection, in 10 % borax-buffered formalin. Anchovy eggs and yolk sac larvae,
at each developmental stage (Somarakis et al. 2002) will be counted and their abundance
standardised to number per square meter.
Adult samples will be collected onboard of the research vessel "PHILIA" by means of a pelagic
trawl. Additional samples will be obtained onboard the commercial purse seine fleet. Fish will be
fixed immediately after collection with 10% buffered formalin (Hunter, 1985) for laboratory
analysis.
Spawning frequency (S), i.e. the fraction of mature females spawning per night will be estimated
using the postovulatory follicles (POFs) method (Hunter and Macewicz 1985) Parameter estimation
generally will follow procedures described in Picquelle & Stauffer (1985) and Somarakis et al.
(2002). Age of eggs will be calculated based on a temperature dependent model of European
anchovy developmental rate, the station surface temperature (5m), peak spawning time (midnight),
and time of tow (Somarakis et al. 2002). The survey area will be post-stratified into positive and
negative area. The estimate of daily production of eggs in the positive area will be derived by
regressing the counts of embryos (eggs and yolk sac larvae) on their age using the exponential
mortality model:
Ρt = Pe-Ζt
where Ρt = number of embryos (eggs or yolk-sac larvae) at age t produced per day per m
2
t = age in days.
P = daily egg production per m2
Ζ = daily rate of instantaneous embryonic mortality
We will use two yolk-sac larvae stages (YSI and YSII) and will calculate their duration and their
age from fertilization from laboratory derived temperature dependent curves, assuming station
surface temperatures (5m) as the yolk-sac larvae incubation temperatures. Stage durations will be
used to calculate the daily production of YSI and YSII larvae (Somarakis et al. 2002).
The technique to estimate P and Z will be weighted non-linear least squares regression. Station
weighting factors will be proportional to the station representative area. The sum of weighting
factors will equal the total number of stations in the corresponding stratum.
We will use the ratio estimator (Picquelle & Stauffer, 1985) for adult parameters W, R, F, and S:
y
m y
m
i ii
n
ii
n
1
1
(1)
with sample variance
36
Var y
m y y
m
nn n
i ii
n
i
i
n ( )
( )2 2
1
1
2
1
where y = estimate of the population mean,
n = number of stations,
yy
mi
ij
ij
mi
1
= mean of the ith station, and
mi = number of fish sampled from the ith catch.
ijy = value for the jth female in the ith sample
Data on the number of eggs per batch ( Fij ) and the ovary free weight (Wij
*) recorded for the
hydrated females will be used to fit a linear model: *
ijij bWaF (2)
The variance estimator of the batch fecundity will be:
Var F
mF F
n
s
nW W Var b
m
nn
i
i
ni h
h
i h
i
i
n( )
( )( ) ( )
* *2
1
2 2
1
2
1 (Draper & Smith, 1966)
where F : the estimate of batch fecundity for the whole population of mature females,
F i : average batch fecundity of the ith sample,
F i : F mijj
m
i
i
1
/ where F ij is the estimated batch fecundity for the jth female in the ith
sample,
sh
2 : variance about the regression (Equation (2),
nh : number of hydrated females used to fit the regression (Equation (2),
W i
* : average ovary-free weight of the ith sample,
W h
* : average ovary-free weight of the nh
hydrated females, and
Var b( ) : variance of the slope of the regression (Equation (2).
The results of the DEPM as well as information on plankton and adult samples will be estimated
separately for the eastern and the western part of the surveyed area. The total stratified biomass
estimate (eastern + western part), will be the sum of the regional biomass estimates.
37
ANNEX III
Geographic areas excluded from fishing with purse seine
1. Gulf of Corfu
According to bathymetry, all area between Corfu and mainland Greece is not available for purse
seine fishing
38
2. Patraikos Gulf
According to bathymetry, only a small part is available for purse seine fishing
39
3. Thermaikos Gulf
This is the most important and traditional fishing ground for small pelagic fish.
The internal Thermaikos gulf is not available for fishing and the average fishing trip for the isobath
of 84 m has tripled
40
4. Saronikos Gulf
Saronikos Gulf has a special geomorphology. Eventhough the depths are enough for the legal use of
purse seines, fishing is prohibited in various regions of the gulf due to special measures (shipping
lines, Naval weapons testing sites etc.).
41
5. Pagassitikos Gulf, Maliakos Gulf and Oreoi channel
A large part of Pagassitikos gulf and almost all Of the Oreoi channel is not available for purse seine
fishing. Also the available regions are not areas in which anchovies and sardines can be found.
42
6. Strymonikos Gulf, Gulf of Ierissos and gulf of Kavala
The shelf at this area is steep close to the coastline but after that the sea bottom is almost level.
Therefore, the isobath of 50 m is very close to the coastline while again the distance until the
isobath of 84-85 m is long and the reduction of the available fishing ground significant.
43
ANNEX IV
Technical and geometrical description of the use and operation of the purse seine gear
IV.1. General
On November 25, 2007 an experimental use of the purse seine net was carried out in the area of
Pagassitikos gulf and at the GPS fix location Ν39°18.346 Ε23°04.311. The duration of the haul was
33 minutes in total. During the haul the net deployment was recorded as well as several geometric
and mechanical observations regarding the operational use of the gear were made.
IV.2. Net deployment procedure – use of purse seine net
The fish school is located by the use of electronic echosounder and fish finder instruments which
are among the standard electronic equipment of a purse seine vessel. The identification species, the
size of the individuals and the size of the school are all based on the vessel captain experience.
If the size of the school is big enough to attempt the initiation of the fishing procedure, the vessel
crew immediately deploys a floating light source (robot, see Figure IV.1) which will aid the
gathering of the school close to the sea surface as well as mark the spot where the fish schools is
located . This is the only way that a purse seine vessel can catch fish – by attracting them close to
the sea surface and around the light source. In addition, only the small pelagic fish are attracted to
the light while all the other species are repelled by the light and move away.
At the same time the crew deploys a small tender boat with one crew member. The small boat
remains always close to the floating light source so that he can check whether the fish school still
remains in the area using his own fish finder device. In addition, by using VHF communications he
is in constant contact with the purse seine vessel captain in order to provide him with information
regarding the state of the fish school and the surface water currents. Thisway the purse seine captain
can position his vessel correctly in relation to the fish school and the net when the hauling begins.
If the fish are still in the area of the light source, then the deployment of the net is initiated with the
purse seine vessel performing a cyclical move around the light source (Fig. IV.2.). The hauling of
the net using a purse line starts immediately when the purse seine vessels completes its cyclical
movement around the fish school. This results to the fact that (a) at the end of this maneuver the
purse seine net is not deployed vertically in full and (b) the fishing vessel remains adrift. For these
reasons, the net needs to be hauled immediately after the cyclical maneuver because the opening of
the net below is so great that the fish may escape very easily. This proves that because of
operational restrictions the net cannot be deployed vertically in full and reach 120 m depth.
The hauling of the net on board is carried out by simultaneous hauling of the purse line using the
mid-section hydraulic winch and the surface line by means of the front and aft hydraulic winches.
The hauling is conducted carefully so that the fish are trapped at the upper right or left part of the
net (Fig. IV.8).
44
Fish attraction device using light source (robot)
Figure IV1. Fish attraction device
1: switchbox
2: fuse and batteries, 200V rectifier
3: floats
4: common household light bulbs 220 V (4 lamps, ~ 1000-1500 candles)
5: buoy for lifting the robot out of the water
6: ‘sampani, a piece of rope which is attached to the robot. Its free end shows the fishermen the
direction and strength of the surface currrents
45
Figure IV.2. The deployment of the purse seine net at the point of the initiation of the hauling (arrows: direction of
surface currents)
46
IV.3. Geometry and technical characteristics of the purse seine nets
Technical specifications for the construction of the net
A typical purse seine net exhibits a length 500-800 m and a height 100-120 m. These dimensions
are measured in accordance to the EU regulations as stretched and wet. In order the net to reach
these dimensions it needs to be composed of 14-19 net sheets with a length of 500-800 m each and
a height of 400 m each and a rhomboidal mesh of 16 mm.
Operational dimensions (during the operation; Fig. IV.3)
The length of the purse seine net depends on the length of the float line (a thick rope without any
elongation tolerance). The net sheets - which are used for trapping the fish (16 mm mesh) – are
sawn on the float line so that the length of the sheet is 1.15 times longer from the float line. Thisway
the mesh of the fishing net is always open and there is no possibility to be stretched and close.
The height of the net also depends on the side net sheets ('fani'). These sheets are made of thick line
and exhibit a mesh of 44 mm. Every net has 2 side sheets from both sides if its height is around 100
m and 3 sheets if the height is 120 m. The total height of the 2 side sheets is 400 mesh x 44 mm per
mesh x 2 sheets = 35.20 m or in the case of 3 side sheets, it is 52.80 m. The meshes of the fishing
net part (central; Fig. IV.3.) are sawn on the side sheet meshes with a ration of 1:8 (8 fishing net
meshes on 1 side sheet mesh; Fig. IV. 5). Therefore, even if the net has a height of 100 or 120 m, its
actual height during its use cannot be more than 35.20 m or 52.80 m. From the operational point of
view this way of constructing the net is required so that the fishing net mesh (central part) is always
open.
Moreover, due to the surface currents and the positioning of the purse seine vessel the net is
'inflated' outwards creating an upward movement of the net (Fig. IV.4). When the hauling of the net
with the purse line is started then the shape of the net takes the profile shown in Figure IV.4.
FOR ALL THE ABOVE REASONS IT IS PROVED THAT THE PURSE SEINE NET CANNOT
BE DEPLOYED VERTICALLY IN FULL AND DURING ITS OPERATION IT MAY REACH A
DEPTH (IF ALLOWED THE TIME TO DEPLOY) WHICH IS ALMOST HALF THE ACTUAL
HEIGHT OF THE NET.
Figure IV.3. Overall purse seine net layout
side net ('fani')
44 mm
400 mesh in height
2 sheets fishing net - part of the net that traps the fish
float line
lead line – rope with weights
47
Figure IV.4. Profilee of the net during hauling
ΓΙΦΤΥ
FISHING NET – CENTRAL PART
ΦΑΝΙ
SIDE NET
Figure IV.5. Detail of the sawing of the fishing net and the side net
Another way to prove that the purse seine net CANNOT reach in size during the operation of the
height of 100-120 m is the following: the fishing net is sawn on the float line with a ration of 1:1.15
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so that the mesh is always open. Since the mesh of the fishing net (wet and stretched is 16 mm, then
its actual horizontal dimension is 16 mm/1.15 = 13.9 mm when the net is used (Fig. IV.6). Then by
simply using the Pythagorean theorem, the vertical half dimension is (8²-6,95²) = 3,96 mm or the
mesh is 7,92 mm vertically. (Fig. IV.6).
13.9 mm
3.9
6 m
m6.95 mm
8.00 mm
7.9
2 m
m
Figure IV.6. True mesh dimensions of the purse seine net
It is obvious that the vertical dimension of the mesh is 7.92 mm and NOT 16 mm (wet and
stretched) i.e. on the vertical scale it is always the 7.92/16=49.53% of the official net height.
Therefore, a net with 100 m height (wet and stretched) has a height of 49.53 m during operation or
59.44 m when the net exhibit a height of 120 m.
During the hauling, the angles of the purse line are 100-110° as seen from above and 18-20° on the
vertical scale. The hauling speed of the purse line is 0.3-0.4 m./sec (Fig. IV. 7).
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Eικόνα IV.7. Όυη από το κατάστρφμα και πλάγια όυη θέσης σσρματόστοινοσ στίγγας κατά την ανάσσρση τοσ διττσού
Figure IV.8.
Purse seine net parts
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IV.4. Timing of the net hauling
The timing of the purse seine hauling procedure is summarized in the following table.
Time
Diameter of
float line
around the
fish school
(Df)
Diameter of the
purse line around
the fish school
(Dps)
Comments
0 min 180 m 170 m Start of purse line hauling
5 min 120 m 80 m
10 min 55 m 0 m The first lead weights appear by the
vessel
28 min 30 m 0 m All lead weights are on board
33 min 0 m 0 m
Most of the net is on the deck while
the part of the net which traps the
fish is by the boat – the fishermen are
ready to start fishing the fish using
hand nets
50-60 min 0 m 0 m
All gears and nets are on board and
ready for the next hauling. The vessel
moves to the next fishing location.
90-120 min 0 m 0 m
The selection of the fish, their
grading and the packing of the fish in
iceboxes is finished.
Legend
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PHOTO GALLERY
1. Lead weight line's rings. The purse line passes through those rings. Blue net: parts of the lead
weight line
2. Side net ('fani')
3. Aft winch
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4. Side winch for the purse line
5. Fishing line (center) and float line (up and right)
The capacity of the fishing net to stretch horizontally is shown
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6. Connection (stitch) between the side nets ('fani') and the fishing net
The stitching ratio of 1:8 is visible