Non-indigenous species - knowledge base and

pilot study results

Solvita Strake, Henn Ojaveer

Latvian Institute of Aquatic Ecology Estonian Marine Institute, University of Tartu

GES-REG final seminar 3-4 December 2013, Tallinn

AquaNIS front page

Baltic module on invasion events is freely accessible

Some of the potential uses of AquaNIS

Identify taxonomic composition of non-indigenous species (NIS);

Identify similarity of cumulative composition of NIS in different regional seas and countries, as well as its dynamics over time;

Identify similarity of new NIS by regional seas and by countries, as well as dynamics over time;

Identify NIS invasion pathways and vectors, both by regional seas and countries, and reveal temporal dynamics;

Identify IAS, their spread and invasion pathways/vectors; Use data for risk assessments.

Methodology used for monitoring The capability to correctly identify the species either using traditional ID methods or DNA analysis The traits of introduced species Risk assessment The impact that non-indigenous species will have on Good Environmental Status Control and management procedures

Gaps in knowledge

Pilot studies on non-indigenous species

The impact of the round goby (Neogobius melanostomus) on the benthic environment -To increase knowledge about the impacts of the invasive fish species on the environment; -To support development of new indicator for non-indigenous species

Port biological survey in Muuga harbour, port of Tallinn -To test, develop further and assist in finalising the HELCOM port survey guidelines

Round goby Neogobius melanostomus

• Round goby is an invasive species of Ponto-Caspian origin

• First finding reported from the Gulf of Gdansk in 1990

• Arrived via ship ballast water

• In Latvian waters first findings reported from coastal fishermen catches at open Baltic Sea coast near Liepaja in 2004

• In the southern part of the Gulf of Riga in 2005

• Currently Round goby has been found or established in the southern and eastern Baltic Sea, Bothnian Sea, Gulf of Finland, Archipelago Sea, Kattegat and Belt Sea and southern Sweden

Figure 1. Presence of Round goby in the Baltic Sea.

Source: HELCOM List of non-indigenous species.

Material and methods

• Fish samples were collected at three different depths (5, 10, 15m) by Nordic Coastal survey net, coastal gillnet

• Fish density determined visually by SCUBA divers in 9 transects at constant depth

• Round goby age, length, body weight

• Digestive tract analysis

• Soft bottom fauna sampling

• Hard bottom fauna and flora sampling

• Macrobenthos species distribution and coverage using a drop video camera

Sampling site: MPA “Nida-Perkone” located at open Baltic Sea coast, July (25-27) and August (4-6) 2012

Total number of Round goby in scientific surveys using Coastal net series

Site 2006 2007 2008 2009 2010 2011 2012 Total

Bernati 5 110 115

Liepaja 8 53 280 254 1323 1125 2381 5424

Pape 46 195 539 780

Total 8 53 280 254 1374 1430 2920 6319

Fish population structure in different depths

Percentage of fish caught by Nordic coastal survey nets in 5, 10 and 15 meter depth

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

5 10 15 Total

Nu

mb

er

wit

h P

erc

en

tage

Depth, m

Great Sandeel

Sprat

Eelpout

Small sandeel

Twaite shad

Cod

Roach

White bream

Herring

Turbot

Pike-perch

Vimba

Smelt

Flounder

Pearch

Round goby

Digestive tract analysis

Relative proportion of different prey items in competing benthic fish stomachs: Round goby, flounder and vimba

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Round goby Flounder Vimba

Pe

rce

nta

ge o

f d

iet

Fish species

Other

Zooplancton

Mysids+Decapoda

Amphipoda

Pisces

Polychaeta

M. trossulus

M.balthica

Age structure of round gobies

Age 2+ 3+ 4+ 5+

Lenght group

8,0-8,9 3

9,0-9,9 4

10,0-10,9 4

11,0-11,9 12

12,0-12,9 14 5 1

13,0-13,9 1 8

14,0-14,9 1 18

15,0-15,9 27

16,0-16,9 19 1

17,0-17,9 28 5

18,0-18,9 12 10 2

19,0-19,9 2 10 2

20,0-20,9 11 1

21,0-23,5 1 6 4

n=39 n=120 n=44 n=9

Age structure and diet composition of Round goby

Relative proportion of different prey items in stomachs of 2+, 3+, 4+ and 5+ year round gobies.

0%

20%

40%

60%

80%

100%

2+n=39

3+n=120

4+n=44

5+n=9

Pe

rce

nta

ge o

f d

iet

Age and number of fish

Other

Zooplankton

Pisces

Mysids+Decapoda

Amphipoda

Polychaeta

Mytulis trossulus

Macoma balthica

The most common food items of Round gobies: Mytilus trossulus and Macoma balthica

Size of consumed Macoma balthica and Mytilus trossulus for different length groups of Round gobies

0

2

4

6

8

10

12

3,4

-7,9

8,0

-8,9

9,0

-9,9

10

,0-1

0,9

11

,0-1

1,9

12

,0-1

2,9

13

,0-1

3,9

14

,0-1

4,9

15

,0-1

5,9

16

,0-1

6,9

17

,0-1

7,9

18

,0-1

8,9

19

,0-1

9,9

20

,0-2

0,9

21

,0-2

3,5A

vera

ge le

ngh

t o

f b

ival

ves,

mm

Lenght group

M.trossulus

M.balthica

Conclusions

In the study area round goby was the third most abundant fish species and the main part of population consists from 3+ years old specimens

Conclusions

Benthic fauna has changed – in the study area M. trossulus coverage was less than half of what it was six years previously

Round goby competes with the native species (flounder and vimba), since considerable shares of the diets of all three species consist of Macoma balthica

Conclusions

Indicator: Abundance and impact of non-native fish species (Round goby example)

• The indicator describes relative abundance of particular non-native species within area of concern and its impact on the biodiversity and food web at habitat/ecosystem level

• The values for this indicator are obtained from coastal fish monitoring using „coastal net series“ survey nets. WPUE (mean biomass per one sampling station) of Round Goby and native benthic fish species (in this case: flounder) are calculated

• Reference coditions for this indicator is a state of coastal ecosystem before formation of round goby population. In Latvian case it is the natural state of coastal fish community before 2007

In the current example we can see significant increase of round goby biomass in both areas – Liepaja and Pape. There is also clear decrease of flounder biomass within the period of round goby invasion and most possibly feeding competition can be behind these changes. Thus we cannot consider both areas in GES.

Geographical applicability

This indicator could be used in various geographical regions. However for calculation of this indicator it is important to use only those native species that are historically characteristic and abundant in the habitat/ecosystem of concern and which occupy the same or similar ecological niche as the invasive fish species.

Thank you!