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Fisheries (and Wildlife)

Fisheries and Wildlife are a Renewable Resource Forests are also renewable Extinction (depletion) is possible if use too much of the

resource, but can enjo continued use if use some !epletable Resources are those which cannot be

renewed, oil, coal, copper, diamonds, etc" Focus on fish in this discussion ### most discussion

would also appl to other wildlife $odern fishin% technolo%, coupled with increased

demand and open#access exploitation of fisheries, hasdri&en man fish stoc's to low le&els some arethreatened with extinction"

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FAO State of the WorldFisheries, 2006

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Collapse: End of Global FishStock by 2050? (source: Globalization0!or"# the $e%in &nstitute' .ccordin% Food and .%riculture /r%ani0ation

(F./), o&er 2 percent of fish species arecurrentl in dan%er of collapse" $onitorin%

-22 %roups of fish species, the F./ deems percent to be full exploited, 1 percento&erexploited, percent depleted, and 1

percent reco&erin%"

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Collapse: End of Global FishStock by 2050? (source: Globalization0!or"# the $e%in &nstitute' 3tud published in Science usin% historical analsis projects the

collapse of all fish stoc's worldwide b 2+4" 5he four#ear stud was conducted b ecolo%ists and

economists at the 6ational 7enter of Ecolo%ical .nalsis and3nthesis, 8739"

3cientists examined fish catch reports from 1:2#22* for -+ocean#wide re%ions that represented 4* percent of fish species inthe world" 5he biodi&ersit of +4 marine reser&es and areas nearfishin% %rounds were then examined"

5he results show that the collapse, a decline of o&er :2 percentof stoc', of one fish species can threaten an entire marinesstem" 5he reduction of biodi&ersit impairs an ecosstem;sabilit to reco&er from en&ironmental stresses and promotesinstabilit"
http://www.sciencemag.org/cgi/content/summary/314/5800/745http://www.sciencemag.org/cgi/content/summary/314/5800/745

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Projections of

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US NOAA Fish StockSstaina!ilit" #nde$

Overfishing< =ar&est rate is abo&e a prescribed fishin% mortalitthreshold"

Overfished # 3toc' si0e is below a prescribed biomass threshold"

Approaching Overfished Condition # 9ased on trends inhar&estin% effort, fisher resource si0e, and other appropriatefactors, it is estimated that the fisher will become o&erfishedwithin ears"

MSY # $aximum 3ustainable >ield # 5he lar%est lon%#terma&era%e catch or ield that can be ta'en from a stoc' or stoc'complex under pre&ailin% ecolo%ical and en&ironmentalconditions"

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US %ecreational Fishin&

Recreational fishin% is also &er important inthe 8nited 3tates"

.ccordin% to the 8"3" Fish and Wildlife

3er&ice, approximatel *+ million adult.mericans (o&er a%e 1-) participated inrecreational fishin% in 221"

5hese an%lers accounted for 22,222 das offishin% and ?* billion on fishin%#relatedexpenses"

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Fisheries 'iolo&"

5he reproducti&e potential of a fish population is afunction of both the si0e of the fish population and thecharacteristics of its habitat"

9oth the %rowth of the population and the population

itself are measured in biomass (wei%ht) units" 9iomass does not distin%uish between number of

indi&iduals and mass of indi&iduals" Fi%ure 11"1 depicts a lo%istic %rowth function which

illustrates the relationship between the fish population

and the %rowth rate of the population" @nitiall, there is no %rowth, then o&er some ran%e of

population (up to A), population %rowth is increasin%"9eond A, the %rowth of the population is decreasin%"

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Fisheries 'iolo&"

5he ecosstemBs abilit to support the fish populationis the most si%nificant reason for the chan%in%relationship between population %rowth andpopulation"

With a low population, the resources will supportincreasin% %rowth" .s the population %rows, there is a %rowin%

competition for those resources and the %rowth in thepopulation slows"

E&entuall, the amount of %rowth falls to 0ero, whichoccurs at the maximum population C"

5his point is also referred to as the carrying capacityof the en&ironment and is a biolo%ical eDuilibrium"

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Fisheries 'iolo&"

5he %rowth function represented in Fi%ure 11"1represents a a compensated %rowth function"

Fi%ure 11" contains a depensated %rowth function, wherethe %rowth rate initiall increases and then decreases"

Fi%ure 11"* contains a criticall depensated %rowthfunction where, A2represents the minimum &iablepopulation"

@f population falls below this le&el, %rowth becomesne%ati&e and population becomes irre&ersibl headed

towards 0ero" 5he implication is that if mana%ers ma'e a mista'e andallow too much har&est, the ma doom the population toextinction"

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he Oti*al +arest

@n order to determine how har&estin% affects a fishpopulation, consider the %rowth function in Fi%ure11"+"

6ote that 71represents the le&el of har&est (har&estand %rowth are measured on the &ertical axis)"

When a har&est of 71units per ear is remo&ed from

the fisher, the fish population declines because

har&estin% is remo&in% a portion of the population" opulation will continue to fall until natural %rowth is

eDual to the har&est, which occurs at A1"

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he Oti*al +arest

@n Fi%ure 11" a har&est le&el of 71is associated

with two eDuilibrium populations (A1B and A1)"

5his means that %rowth is exactl eDual to har&est

and the population will remain unchan%ed at eitherof these le&els"

7msrepresents the har&est le&el associated with

maximum sustainable ield for the fisher"

5his is the onl har&est le&el associated with oneeDuilibrium point"

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he Oti*al +arest

@n the earl discussions of fishermana%ement, maximum sustainable ieldwas the theoretical %oal of mana%ement

policies" Recent polic tar%ets a more precautionar

%oal of a population between the carrin%

capacit and the le&el associated withmaximum sustainable ield"

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he -ordon .odel and #ts/oltion @n a 1: article, =" 3cott Gordon made the point that

uncontrolled access to fisher resources would result in a %reaterthan optimal le&el of fishin% effort"

Gordon deri&ed a catch function that represented a bionomiceDuilibrium"

5his catch function considered the relationship between fishin%effort, catch, and fish population"

Gordon;s analsis be%an b assumin% that, holdin% e&erthin%else constant, catch is proportional to the fish population"

Fi%ure 11"- illustrates a set of ield functions, where each cur&erepresents a different le&el of fishin% effort"

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he -ordon .odel and #ts/oltion 9 superimposin% the eDuilibrium catch function on

the ield functions (Fi%ure 11") it is possible toidentif the effort and ield function associated withmaximum sustainable ield in the fisher"

5his is 'nown as the sustainable ield function(Fi%ure 11"4)"

6otice the sustainable ield function examines the

relationship between effort and catch" .s effort increases, sustainable ield increases and

then decreases"

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he -ordon .odel and #ts/oltion . sustainable total re&enue function can be deri&ed

from a sustainable ield function" rice is assumed to be constant, based on the

additional assumption that catch from that particularpopulation will be small relati&e to the total mar'et"

Gi&en a constant price, a sustainable total re&enuefunction can be deri&ed simpl b rescalin% Fi%ure11"4"

@n Fi%ure 11":, the sustainable total re&enue functionis labeled 5R and an additional cur&e representin%total costs (57) is also %i&en"

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/icient se of the 1sher"

Economic %oal is to maximi0e net benefits(also called economic rent)

5his occurs where 69 H 5R#57 is the

%reatest (also where $RH$7)" Economic rent ori%inates from the

producti&it of the fish stoc', where more fishimplies %reater catch with less effort (cost)"

Where is economicall efficient le&el of effortand har&estI

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/icient se of the 1sher"?

benefits,costs

Effort

57 HcE

EJ E$3>

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/cono*ic /icienc"

.ssumptions in dia%ram rice of fishin% is fixed and constant 7ost of effort (c) is fixed and constant 7atchKunit effort increases with lar%er population

/ptimal effort, that effort which maximi0es economicrent, occurs at EJ

=ow does efficienc compare to $3>I 3mallerhar&est and lar%er fish population

WhI 9ecause hi%her fish population means lowercostKunit effort, when consider both costs andbenefits, efficient to use less than $3>

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/cono*ic /icienc"

Extra benefit of fishin% not worth extra effort past EJso more conser&ation than $3>

5his is economicall efficient le&el, will pri&atemar'et achie&e this resultI

3uppose there is a sin%le owner of the fisher (not amonopol, i"e", competes with other fisheries forprice of fish, but onl 1 decision ma'er concernin%how much to fish this location)

What E will a sin%le owner choose to maximi0eprofitsI

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Sin&le Oner soltion

rofits H total re&enue < total costs H pE < cE,same as net benefits

7an also see this in $R and $7 cur&es

($7Hc, shape of $R comes from 5R cur&e) 5able 11" illustrates the relationship between

total catch, mar%inal catch, and a&era%e

catch" rofits are maximi0ed when $R H $7

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/cono*ic /icienc", OenAccess 3in%le owner would choose economicall

efficient le&el, will open accessI

/pen access H e&erone can access thefisher,

7ommon propert H e&erone within a subsetof the population can access the fisher (open

access, but onl to a subset of the population)

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Soltion nder Oen Access

@n an open#access fisher, when economic rent isearned in the fisher, entrance b new firms occursuntil economic rent falls to 0ero, effort le&el of E1inFi%ure 11":"

5he entrance of firms in response to economic rent

and the resultin% increase in effort to E1results in .RH $7 rather than the optimal effort le&el of Ewhere$RH$7"

/pen access results in o&er exploitation of theresource

5otal profits from fisher are reduced compared tosin%le owner, more effort than necessar is bein%expended to %et a %i&en har&est

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Oere$loitation and OenAccess Each indi&idual fisher compares their a&era%e catch

and associated re&enue with the &alue of the hi%hestalternati&e to fishin%"

@f the hi%hest alternati&e a&ailable is ?2 per da, then

the fisher will compare a&era%e catch (.) multipliedb rice a%ainst the alternati&e of ?2"

5he result is that there are a %reater number of fishersin the fisher than would be if the decision to enter

was based on a comparison of mar%inal productJrice, rather than a&era%e productJ rice"

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+o to &et eicient soltion3

1" ri&ati0e Fisher ### often hard to do, not popularwith man

" @mpost tax on effort ### would wor', but not donemuch

*" Raise real cost of fishin% #### common, but notefficient, end up usin% more resources to catchsame number of fish

1" Gear restrictions

" 3horten season*" 7lose certain fisheries,

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4rrent Fisher" Polic" Example of %ear restriction, in $arlandBs share of the 7hesapea'e,

it is ille%al to dred%e for osters under motori0ed power" 5his meanssails, smaller dred%in% eDuipment, and slower mo&ement across theoster beds"

Re%ulation which re&ol&es around restrictions on the minimum si0eof fish that are le%al to har&est are desi%ned to lea&e a portion of thefish stoc' in the water to pro&ide a sufficient breedin% stoc' to

ensure future populations" Fishers %enerall implement this restriction b choosin% a mesh si0e

for their nets that allows smaller, ille%al fish, to escape" 9ecause fishin% acti&it ma disrupt the spawnin% process, often the

fishin% season is closed for a certain period on an annual basis,

%enerall durin% spawnin% season" .lso, some species become so extremel con%re%ated durin%

spawnin% that fishin% effort could capture &irtuall the entirepopulation"

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4rrent Fishin& Polic"

Re%ulations on where fish ma be cau%ht are desi%nedto protect fish stoc's when the are con%re%ated and&ulnerable to o&erhar&estin%" 5hese tpes of re%ulations also protect &ulnerable fishin%

habitats from destruction b the fishin% process"

5here can be limits on how man fish ma be capturedin a %i&en time period" 5hese limits ma be in the form of wei%ht cau%ht, number of

fish, or &olume of catch"

Example, the catch limit on %iant bluefin tuna is 1 fish per boat". fish can often wei%h as much as 1222 pounds and themar'et price has been ?14 per pound"

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#ndiidal transfera!le5otas @ndi&idual transferable Duotas (@5Ls) would wor' in a fashion

similar to mar'etable pollution permits" 9 limitin% the number of catch Duota which are issued, biddin%

for the Duotas will occur until the price of the Duota is exactleDual to the di&er%ence between a&era%e cost and price

(a&era%e rent)" Mimited entr techniDues structured to direct effort rather than

catch can also be de&eloped" =ere onl a fixed number of boats would be allowed to operate in

the fisher"

5he method of permit allocation could be b auction or historicalpresence in the fisher"

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i*ited /ntr" echni5es

@f these @5Ls are transferable, it will be possible toha&e onl the most efficient fisherman in the fisher" Enforcement of effort#based limits, that is &essel

permits, would be much easier than that associatedwith the catch limits"

6o measurin% or wei%hin% is necessar a poster si0edcertificate of operation would allow eas identificationof le%al &essels"

7atch#based @5Ls are subject to se&eral problems" eople mi%ht cheat on their Duota b sellin% to forei%n

&essels or in an under%round mar'et" .nother problem is associated with the differin% mar'et

&alues of different si0e fish"

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i*ited /ntr" echni5es .lthou%h most fisher re%ulation relies on open#access

techniDues, an important example of a limited entr techniDue isthe Nir%inia oster fisher, where oster beds are treated aspri&ate propert"

@t %i&es oster bed operators incenti&e to in&est in their propertsuch as seedin% with lar&al osters and creatin% more structures

to which the osters can attach" .n additional example of the limited entr re%ulation is the

economic exclusion 0one, established under the authorit of the8nited 6ations 7on&ention of the Maw of the 3ea"

5his re%ulation established a 22 mile limit alon% the coast of a

countr where each countr has the ri%ht to limit access to theirwaters" 5his is a partial limited access re%ulation"

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Other #sses in Fisher".ana&e*ent

/ther problems associated with fishermana%ement includeO incidental catch destruction of habitat throu%h fishin% acti&ities

destruction of wetlands and related habitat throu%hnon#fishin% acti&ities

pollution of fisher habitat conflicts between user %roups and international cooperation concernin% the har&estin%

of mi%rator species"

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A5acltre .Duaculture, the culti&ation of fish in artificial

en&ironments or in contained natural en&ironments, isoften su%%ested as a means of dealin% with the open#access problem"

6ot all species can be culti&ated"

3hellfish are ideal because of their inherent immobilit"

Wildfish will benefit indirectl from aDuaculture if thefarmed species usurps part of the mar'et demand forthe wildfish and therefore reduces the fishin% pressureon the species"

.Duaculture creates its own set of problems"

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A5acltre

.Duaculture can dama%e the en&ironment, e"%", 3hrimp aDuaculture in 7entral and 3outh

.merica has resulted in a loss of man%ro&e

forests, excess nutrient loadin% into estuaries andse&erel reduced dissol&ed ox%en in areasborderin% estuaries"

5here are also potential problems associated

with hbridi0ed fish escapin% and dama%in%the %ene pool of existin% species"

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-ill Nets and on& ines

/ften the fisher will catch not onl the species thatthe see' but also other species, referred to asincidental catch"

$an tpes of fishin% %ear do not discriminate amon%

fish species, and both the desired species and aspectrum of untar%eted species are cau%ht b this%ear"

.mon% the most notorious of these are the %ill nets,

whose len%ths often measured in miles" 5hese nets are &erticall suspended in the water, li'eunderwater fences, ensnarin% the %ill co&ers of fish asthe attempt to bac' out"

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.nother indiscriminate fishin% method is lon%#linin%"

. lon%#line consists of line that ma be 12 'ilometers

in len%th or lon%er, with baited hoo's e&er se&eralmeters"

5hese lines are emploed off the .tlantic coast inpursuit of hi%hl profitable swordfish"

9ecause shar's are often cau%ht, these lon%#linesha&e been an important factor in the decline of theshar' populations"

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!ue to the difficulties of monitorin%, restrictions on fishin%methods ma be preferential to policies based on economicincenti&es"

.n example of this tpe of polic is the reDuirement thatshrimpers install a 5urtle Excluder !e&ice (5E!) in their nets to

allow endan%ered sea turtles to escape" @n addition to the turtles which are 'ic'ed out of the shrimp net,

non#tar%eted fish are also allowed to escape" Whether polic ma'ers should implement the restrictions on %ill

nets and lon%#line operations needs to be determined on a case#

b#case basis for each potential restriction" 5he benefits of protectin% untar%eted species are spread out

o&er a lar%e number of people, but the costs are concentratedupon a &er few"

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7estrction of +a!itat hro&hFishin& Actiities 3ome fishin% techniDues can cause dama%e to the

ecosstem in which the fish exist, diminishin% theproducti&it of the fisher and ecolo%ical ser&ices"

!ama%e can occur when contact of fishin% %ear with

the floor of the estuar or ocean uproots aDuaticplants, brea's coral, dislod%es shell fish, and so on" /ne particularl sensiti&e ecosstem is that

associated with a coral reef, where anchors and boatbottoms dra%%in% across the coral can 'ill it"

E&en more destructi&e is the practice of fishin% usin%explosions or the use of canide in the coral to stunand collect fish for consumption and aDuariums"

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7estrction of Wetlands and%elated +a!itat /ther habitats such as upland and coastal wetlands,

temperate forests and free flowin% ri&ers arecriticall important to fisheries"

5he temperate rainforests of the acific 6orthwestare criticall important to maintainin% the ri&erinehabitat, which is essential to anadromous fish, suchas salmon and steelhead"

.n acti&it which impacts the Dualit of theseecosstems can impact the Dualit of the ri&erinesstem and the salmon and steelhead"

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Polltion of Fisher" +a!itat

@n the 8nited 3tates, man fisheries are in declinebecause pollution has diminished habitat"

5his pollution and loss of habitat has affected &irtualle&er freshwater species, and man saltwater species,

where saltwater species are affected b estuarinepollution" .nadromous species such as salmon, steelhead,

shad, and striped bass are particularl &ulnerable tori&erine pollution"

@n de&elopin% countries, soil erosion from deforestationand intensi&e culti&ation of hillside lands has se&erelimpacted water Dualit not onl in the ri&ers, but inreser&oirs, estuaries, la%oons, and coral reefs"

f i l

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.ana&e*ent of %ecreationalFisher" %esorces @n most 6orth .merican recreational fisheries, there is

unrestricted access to the resource, leadin% to open#accessexploitation"

Recreational policies ta'e the form of limits on the number of fishthat ma be 'ept, restricted seasons, and si0e limits"

9 stoc'in% fish, where a &er lar%e number of fish are hatched,%rown to si0e, and released into the wild, the problem of open#access is addressed b increasin% resource base"

Recreational fisheries often ha&e closed seasons timed tocoincide with spawnin% periods in the fisher"

.ccess impro&ements such as launchin% ramps, fishin% piers,par'in% areas, and artificial reefs can be desi%ned to reducecon%estion in the fisher, althou%h the ma also lead toincreased use"

. f % i l

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.ana&e*ent of %ecreationalFisher" %esorces 7atch and release pro%rams are based on the idea that a

recreational an%ler does not ha&e to 'ill his or her catch toproduce utilit from fishin%"

5hese re%ulations allow fish to be cau%ht, released, and left to%row, reproduce, and be cau%ht a%ain"

7atch and release re%ulations %enerall ta'e the form of moralsuasion and command and control"

3i0e limits place restrictions on the minimum (and sometimesmaximum) si0e of fish that are le%al to 'eep"

7reel limits place restrictions on the maximum number of fish perda that ma be 'ept"

9oth restrictions are desi%ned to protect the reproducti&e &iabilitof the fish stoc's"

S

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S**ar"

Fisher resources are renewable but destructible"

5he destructibilit problem is amplified b the open#access nature of man of the world;s fisher resources"

For commercial fishin%, optimal mana%ement strate%reDuires the limitation of effort to a le&el that maximi0esthe sum of consumers; surplus, producers; surplus,and fisher rent"

.ctual fisher mana%ement seldom achie&es this %oaland is based on de&elopin% restrictions on how, when,where, and how much fish can be cau%ht"

ch11 ckling

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