AQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS

Aquatic Conserv: Mar. Freshw. Ecosyst. 17: 111–132 (2007)

Published online 14 July 2006 in Wiley InterScience(www.interscience.wiley.com) DOI: 10.1002/aqc.784

Effects of trap fishing on reef fish communities

JULIE P. HAWKINSa,*, CALLUM M. ROBERTSa, FIONA R. GELLa,1

and CALVIN DYTHAMb

aEnvironment Department, University of York, Heslington, York, UKbDepartment of Biology, University of York, Heslington, York, UK

ABSTRACT

1. Trap fishing is widespread on coral reefs but the sustainability of this practice is causing concernbecause it is efficient and unselective. The effects of trap fishing were investigated by comparing fishassemblages among six Caribbean islands subject to different trapping pressures. These ranged fromnone in Bonaire and Saba increasing through Puerto Rico, St Lucia, Dominica and Jamaicarespectively.2. Fish were censused at depths of 5m and 15m on fore-reef slopes by counting the numbers within

replicate 10m diameter areas for 15min. Between 64 and 1375 counts were made in each country.3. In St Lucia and Jamaica abundance of fish censused on the reef was compared to representation

in traps which were visually sampled underwater in the area of fish counts. Twenty-three traps weresampled in Jamaica and 75 in St Lucia. For some comparisons between these islands, St Luciansampling effort was reduced to that of Jamaica (23 traps and 112 counts) by randomly sub-sampling10 times.4. Traps contained 54 different species in St Lucia and 22 in Jamaica, while there were 90 and 57

respectively in counts. After reducing St Lucian sampling effort to Jamaican levels, an average of 35species were found in traps and 70 seen in counts. Of these, 76% in St Lucia and 73% in Jamaicawere relatively more abundant in traps than they were on the reef.5. Species were considered to be highly susceptible to trapping if the ratio of their abundance in

traps compared to that on the reef exceeded 3:1. Trapping pressure was approximately three and ahalf times greater in Jamaica than St Lucia. After equalizing sampling effort, there was an average of16 highly trappable species in St Lucia compared to 13 in Jamaica. Species did not always appearhighly trappable in both countries. Eleven of St Lucia’s highly trappable species were absent fromJamaica (falling to 8.5 on average after equalizing sampling effort), but none vice versa, suggestingthat trapping may have contributed to their absence or rarity on Jamaican reefs.6. The Tetraodontiformes, which include many non-target species, were particularly susceptible to

trapping in both countries. Their abundance in the six islands censused was inversely related to trapfishing pressure, as was that of two other non-target families, butterflyfish (Chaetodontidae) andangelfish (Pomacanthidae).

*Correspondence to: Julie P. Hawkins, Environment Department, University of York, Heslington, York, Y010 5DD, UK. E-mail:jph7@york.ac.uk1Present address: Wildlife and Conservation Division, Department of Agriculture, Fisheries and Forestry, Knockaloe Farm, Peel, Isleof Man IM5 3AJ, UK.

Copyright # 2006 John Wiley & Sons, Ltd.

7. To determine whether fish that are common in traps in St Lucia are reaching sexual maturitybefore capture, size frequency data for 23 species from a sample of trap catches were gathered andexamined for their state of maturity. In seven species, more than a third of 705 trapped fish wereimmature, indicating that trap fishing causes growth over-fishing (premature removal of fish), andcalling into question the sustainability of yields for these species.8. In conclusion, at the intensities seen in this study, trap fisheries cause serious over-fishing,

reduce biodiversity, and alter ecosystem structure. While commonly perceived as low impact, coralreef trap fisheries in the Caribbean and further afield, need tighter regulation and control.Copyright # 2006 John Wiley & Sons, Ltd.

Received 2 December 2003; Revised 1 February 2006; Accepted 15 February 2006

KEY WORDS: coral reef; fish pot; overfishing; marine reserves

INTRODUCTION

Trap fishing is one of the oldest fishing methods and is widely practised throughout the world in bothtropical and temperate regions (Recksiek et al., 1991; Slack-Smith, 2002). It is the most common fishingtechnique used on Caribbean coral reefs (Gobert, 1998). In this region traps typically consist of a bamboo,wooden, or steel frame covered with chicken wire with a mesh size ranging from 2–5 cm (Stevenson andStuart-Sharkey, 1980). Depending on their design, traps may have one or two funnel-shaped openingsthrough which fish can enter. Fish can also escape from these openings or by squeezing through the mesh(Gobert, 1998). Trap retention rates vary between locations and depend on how long a trap has beensoaked for, and the trap’s internal structure (Whitelaw et al., 1991; Sheaves, 1995).

There are many reasons why traps are popular with reef fishers. They are easy to deploy (Ferry andKohler, 1987), relatively inexpensive to make (Garrison et al., 1998), and can be used in areas with ruggedsubstrata (Miller and Hunte, 1987). If the weather is bad, fishers can leave their traps out until conditionsimprove. Traps are also effective at catching a wide variety of species (Stevenson and Stuart-Sharkey, 1980).

Robichaud et al. (2000) reported there to be little quantitative information on what factors influence thecatchability of reef species. Their own study concluded that mobility was important because it increased therate at which fish encountered traps and hence their likelihood to enter them. While they found that preytended to avoid entering traps containing predators, they suggest that prey might also enter traps in aneffort to avoid predation. On balance, they found that the presence of prey in traps increased thecatchability of piscivores by reducing their escape rates. The study also noted that behaviouralcharacteristics such as schooling species following each other into traps and solitary species avoidingthem may influence catchability, while Wolff et al. (1999) have suggested that some species could beattracted into traps merely by the structure they provide.

Some of the factors that make trapping popular with fishers can also cause problems. As a fishingmethod that is effective but unselective it produces much unwanted bycatch which is commercially wastefuland could be threatening to biodiversity (Dayton et al., 1995; Alverson and Hughes, 1996; Boehlert, 1996).Around Florida about 100 different species are caught in traps with levels of bycatch ranging from 38% to54% (Sutherland and Harper, 1983; Taylor and McMichael, 1983). Taylor and McMichael (1983) foundthat unwanted angelfish (Pomacanthidae) constituted 17% of catches, trunkfish (Ostraciidae) 9%, andbutterflyfish (Chaetodontidae) and wrasse (Labridae) 5–6% each. In the Gulf of Mexico levels of bycatchfrom trap fishing are reported to have reached 65% (NMFS, 1995).

What counts as bycatch varies between regions depending on local traditions, income levels and intensityof exploitation. In parts of the Caribbean, such as Jamaica and Haiti, where many people are very poor andfisheries intense, almost nothing is discarded and fish are used either for food or for bait (Ferry and Kohler,1987; Sary, 1995). However, even if all the catch is used, the potential threat to biodiversity remains.

J.P. HAWKINS ET AL.112

Copyright # 2006 John Wiley & Sons, Ltd. Aquatic Conserv: Mar. Freshw. Ecosyst. 17: 111–132 (2007)

DOI: 10.1002/aqc

As desirable food fish become increasingly rare, even people from wealthy nations resort to eating speciesthat were once considered ‘trash’ such as squirrelfish (Holocentridae) and angelfish. This has happened inBermuda, where, by the 1980s, trap fisheries had decimated the grouper (Serranidae) and snapper(Lutjanidae) populations (Butler et al., 1993).

Although trapping is a multi-species fishing technique, it has more serious impacts on some species thanothers. For example, in the US Virgin Islands trapping, together with hook and line fishing, has virtuallyeliminated the Nassau grouper (Epinephelus striatus) (Garrison et al., 1998). Over a 6-year period duringthe 1970s, a spawning aggregation which consisted of tens of thousands of fish was wiped out (Olsen andLaPlace, 1978). Trap fishing also poses a threat to juvenile fish because of the small mesh sizes used (Saryet al., 1997), particularly to high-bodied species such as surgeonfish (Acanthuridae). In areas with highlevels of trapping, juveniles can represent a significant proportion of the catch (Robichaud et al., 1999) andtrapping can lead to reduced productivity through growth over-fishing, i.e. premature removal of fishleading to lower catches.

A further problem associated with trap fishing is the damage it causes to corals and other bottom-livingorganisms when traps are dropped onto the reef (Yoshikawa and Asoh, 2004). In St Lucia we observedfishers breaking corals with grappling hooks while retrieving their traps (pers. obs.). If traps are lost (theseare often called ‘ghost traps’), they can continue catching fish for weeks, or even months, until they fallapart. Biodegradable panels, which give way sooner than traps, help reduce this waste (Stewart and Ferrell,2002). Despite the problems associated with trap fishing it has received little regulation other than mesh sizerestrictions and limits on numbers and not much is known about how such management measures willimprove sustainability. Fishers have been reluctant to install biodegradable panels into their traps, evenwhen required to by law (Blott, 1978; Garrison et al., 1998; pers. obs.). In Bermuda, the problemsassociated with trapping led to the fishery being closed down in 1990 (Butler et al., 1993) and plans areunder way to phase it out in the Gulf of Mexico by 2007 (http://www.reefguardian.org/Campaigns/FishTrapGOM/MoreInfoFTrapGOM.html).

In this study, we investigate questions relating to the sustainability and biodiversity impacts of trapfishing in the Caribbean by examining the sensitivity of a broad range of species to trapping and looking atthe incidence of capture of juvenile fish of commercially valuable species.

METHODS

Coral reef fish assemblages were censused during single visits to the islands of Bonaire, Saba, Puerto Rico,Dominica and Jamaica between 1994 and 1998 (Figure 1), and on five visits to St Lucia, either annually orbiennially, between 1994 and 2000. Fish were counted over sections of coast covering ca 5–20 km,depending on island size, using an adaptation of the stationary point visual census method developed byBohnsack and Bannerot (1986). For each 15-min count a 10-m tape was laid on the reef to indicate thediameter of a cylinder extending 5m upwards. The location for the first count was the point of entry for thedive and subsequent counts were made along the same depth contour. Approximately equal numbers ofcounts were performed at depths of 5m and 15m and each was separated by at least 10m. The number ofcounts performed in each country was: 72 in Bonaire, 78 in Saba, 98 in Puerto Rico, 64 in Dominica and112 in Jamaica. In St Lucia, we used a sample of 275 counts in 1995 for an inter-island comparison of fishassemblages. For comparisons between fish caught in traps and counted on the reef we used a sample of1375 counts taken between 1995 and 2000.

Comparable measures of the absolute fishing intensity for these islands were not possible, because datahave been reported at different levels of detail, and the types of fishing gear used vary between islands.However, using estimates of number of fishers per kilometre of reef, it is possible to rank fishing pressureamong the islands. Data from published studies, information from fisheries departments and marine parks,

TRAP FISHING EFFECTS ON REEF FISH 113

Copyright # 2006 John Wiley & Sons, Ltd. Aquatic Conserv: Mar. Freshw. Ecosyst. 17: 111–132 (2007)

DOI: 10.1002/aqc

and personal observations on numbers of active fishers and gear types used were combined for the purpose(Table 1). On this basis fishing pressure was low in Bonaire (0.06 fishers km�1 of reef), light in Saba(0.12 fishers km�1) and higher in Puerto Rico (0.83 fishers km�1). Fishing pressure was intense in St Lucia(3.23 fishers km�1) and Dominica (3.03 fishers km�1) and extremely intense in Jamaica (7.14 fishers km�1).These measures include all methods of fishing. If trapping is considered independently, then Bonaire andSaba have none, levels were moderate in Puerto Rico, high in St Lucia and Dominica, and extremely high inJamaica. One other way of comparing fishing pressure is from trap counts. We counted traps during fishcounts in Jamaica and St Lucia only. Twenty-three traps were observed during 112 fish counts in Jamaicawhile in St Lucia 80 traps were observed during 1375 counts, implying that trapping pressure isapproximately three and a half times greater in Jamaica.

Effects of trap fishing pressure on non-target species throughout the Caribbean

The vulnerability of families containing species that are not generally popular food fish, but which do getcaught in traps, was investigated by comparing fish abundance on the reef among the six Caribbean islandsof a superfamily, the Tetraodontiformes (pufferfish (Tetraodontidae), boxfish and trunkfish (Ostraciidae),triggerfish and filefish (Balistidae)), butterflyfish (Chaetodontidae) and angelfish (Pomacanthidae). Theabundances of soldierfish (Holocentridae) which have no commercial value in Saba and Bonaire, are low-value food in Puerto Rico, and are commonly eaten in the other three countries where they make up a largeproportion of trap catches were also compared. Species from these families are predominantly taken bytrap fishing but some are also caught by spearfishing. Mean abundance per count of each family wasanalysed with one-way ANOVAs and post hoc LSD tests. To avoid any possibility of pseudoreplication, wereduced the degrees of freedom in the test to one for each island, i.e. treating islands as samples rather thanreplicates within islands. Data for St Lucia were taken from the 1995 survey prior to implementation ofmarine reserves there (Roberts et al., 2001).

Fish abundance on the reef versus that in traps

In St Lucia and Jamaica species’ abundances on the reef were compared to that inside traps. Trap contentswere recorded during dives to census fish after the fish counts were complete. On a single diveapproximately 100–120m linear distance of reef was searched for traps within the area of the fish counts.The number of traps counted per dive ranged from 0 to 5 in both countries. The numbers of each speciespresent were recorded for each trap. The contents of 23 traps in Jamaica and 75 traps in St Lucia were

Figure 1. Location of the islands studied.

J.P. HAWKINS ET AL.114

Copyright # 2006 John Wiley & Sons, Ltd. Aquatic Conserv: Mar. Freshw. Ecosyst. 17: 111–132 (2007)

DOI: 10.1002/aqc

sampled. In order to compare results between the two countries it was necessary to reduce the level ofsampling intensity in St Lucia to that in Jamaica. This was done by selecting 10 random samples of 112 fishcounts from the 1375 performed in St Lucia, and ten random samples of the contents of 23 traps from the75 traps sampled in St Lucia. Average values obtained from these two sets of 10 random samples are used inthe results to make direct comparisons possible with Jamaica.

Analysis of fish trappability

The trappability of a species is expressed as the ratio of its proportional abundance in traps (i.e. the fractionthat each species represented of the total sample of trapped fish) compared to its proportional abundance inall fish counts. This provides a measure of vulnerability to trapping. Data were pooled across depth andobserver and, from counts in St Lucia, for all the years that were sampled. Species with a trappability valueof one were equally represented in traps and fish counts, those scoring higher were more represented intraps and those scoring lower were more represented in counts. Species were considered highly trappable iftheir trappability ratio was greater than 3 and highly untrappable if it was less than 0.33 (i.e. if a species wasthree times less represented in traps than on the reef). Trappability at the family level was also assessed.

Prior to analyses all species shown in the Appendix were removed from the dataset. These were generallyeither too small (maximum cross-sectional body dimension less than 3 cm) or too big (maximum cross-sectional body dimension greater than 10 cm) to be caught by traps, or could not be counted effectivelyusing visual census because they were cryptic. Cryptic species would tend to be under-represented in counts,thereby giving misleading trappability ratios. Small juveniles of some species included in the analysis couldpass freely through the traps and large numbers of such fish on the reef could lead to underestimates oftrappability for such species.

Size at maturity of fish caught within traps in St Lucia

Between September 2000 and February 2001, the contents of 530 traps landed from 134 fishing trips thathad taken place within the study area in St Lucia were sampled. Size frequency distributions for 23commercially important species were compiled and the gonads of 705 fish bought from trap fishers over atwo-day period in September 2002 were examined and the minimum size at maturity calculated, and wherepossible the size at which 50% and 100% were mature.

RESULTS

Effects of trapping on non-target species throughout the Caribbean

Abundances of Tetraodontiformes, butterflyfish and angelfish on the reef, were all inversely related tofishing pressure (Figure 2) (one-way ANOVAs: F5;6 ¼ 33:5; p50:001 (Tetraodontiformes); F5;6 ¼ 48:0;p50:001 (butterflyfish); F5;6 ¼ 38:6; p50:001 (angelfish)). Tetraodontiformes abundance was much greaterin Bonaire and Saba, where there was no trap fishing, compared to those islands where trapping did occur.Butterflyfish, abundance declined steadily over the fishing pressure gradient. However, the difference inabundance between the most- and the least-fished countries was great, with only 6% as many fish presentin Jamaica as Bonaire. Angelfish were the least abundant of the families sampled. They were most commonin Bonaire and Saba, less so in Puerto Rico and were uncommon to absent in the most heavily fished islandsof St Lucia, Dominica and Jamaica. Soldierfish abundance initially increased with increasing fishingpressure but fell abruptly in intensively fished Jamaica (one-way ANOVA: F5;6 ¼ 42:7; p50:001).

TRAP FISHING EFFECTS ON REEF FISH 115

Copyright # 2006 John Wiley & Sons, Ltd. Aquatic Conserv: Mar. Freshw. Ecosyst. 17: 111–132 (2007)

DOI: 10.1002/aqc

Table1.Characteristics

offisheriesandrelativefishingintensities

ateach

ofthesixstudylocations

Location

No.ofactive

fishers

Length

of

reef

fished

(km)

Gears

used

Speciestargeted

Fishing

intensity

(fishers/

km

reef)

Reference

Bonaire

}leew

ard

coast

from

Klein

Bonairenorth

toSlagbaai

4full-tim

e61.8

hookand

line

nearreef

pelagics(e.g.

jacks,rainbow

runners)

0.06

K.DeMeyer

(Bonaire

MarinePark

Manager),

personalcommunication,

andpersonalobservations

Saba

}leew

ard

coast

from

SEto

Nofisland

10part-tim

e¼

0:83f.t.e.a

6.9

spear

mainly

predatory

fish

such

aslargesnappersand

groupers

0.12

David

Kooistra(Saba

MarinePark

Manager),

personalcommunication,

andpersonalobservations

Puerto

Rico

}reefsaround

LaParguerain

SW

ofisland

64full-tim

e2

part-tim

e¼

65

f.t.e.a

78.3

lines,trap,

nets,spear

predominantlysnappers,

butgrunts

andnear-reef

pelagicsim

portant;awide

varietyofreef

associated

speciesalsotargeted

0.83

Matos-Caraballo,1997

Morelock

etal.,1994

StLucia

}reefsoftheSW

coast

around

Soufriere

25full-tim

e4

part-tim

e¼

27

f.t.e.a

8.4

traps,hook

andline,

limited

spearing,

few

gillnets

widerangeofspecies

includingmanysm

all-

bodiedplanktivores,

invertivores,omnivores

andherbivores;predators

are

highly

desirable

but

only

limited

numbers

caught;inedible

species

are

usedforbait

3.23b

Gellet

al.,2001

Goodridge,

1996

J.P. HAWKINS ET AL.116

Copyright # 2006 John Wiley & Sons, Ltd. Aquatic Conserv: Mar. Freshw. Ecosyst. 17: 111–132 (2007)

DOI: 10.1002/aqc

Dominica

}reefsofthe

NW

coast

around

Portsm

outh

32full-tim

e47part-tim

e=

56f.t.e.a

18.5

traps,hook

andline,

extensive

spearand

nets

widerangeofspecies

includingmanysm

all-

bodiedplanktivores,

invertivores,omnivores

andherbivores;predators

are

highly

desirable

but

only

limited

numbers

caught;inedible

species

are

usedforbait

3.03b

H.Guiste,(C

hiefFisheries

Officer,Dominica),

personalcommunication

Roberts

andHawkins,1996

Jamaica

}reefsofthe

Northcoast

around

DiscoveryBay

58full-tim

e24

part-tim

e¼

70

f.t.e.a

9.9

traps,hook

andline,

extensive

spearand

nets

virtuallyeverythinglarger

than10cm

istargeted.

Majority

ofcatchissm

all-

bodied;largepredators

desirable

butextrem

ely

uncommon

7.14

Sary,1995

Sandem

anandWoodley,

1994

Allison,1992

aThef.t.e.isfull-tim

eequivalents.In

Sabaweassumed

thateach

fisher

fished

for1dayevery2weeks(assuminga6-dayworkingweek)because

allfishingonthisislandis

recreational.Hence,each

fisher

isconsidered

one-tw

elfthafull-tim

eequivalent.In

allother

countries,wherefishingisdoneonacommercialorsubsistence

basis,we

assumed

thatpart-tim

efishersfished

forhalfoftheirtime.

bTheamountofreef

availableto

fishersin

StLuciaandDominicaisvirtuallyidentical.However,because

therangeofgears

usedin

StLuciawasmore

limited

(i.e.less

spearandnet

fishing),weconsidered

thisislandto

beslightlyless

heavilyfished

thanDominica.

TRAP FISHING EFFECTS ON REEF FISH 117

Copyright # 2006 John Wiley & Sons, Ltd. Aquatic Conserv: Mar. Freshw. Ecosyst. 17: 111–132 (2007)

DOI: 10.1002/aqc

Trappability of species

Figures 3 and 4 compare species abundance in traps to that on the reef in Jamaica and St Lucia respectively.Species are listed in rank order of their abundance in counts. In Jamaica, Haemulon plumieri, Holacanthusciliaris, Lutjanus apodus, Lutjanus synagris, Lactophrys polygonia and Chilomycterus antillarum were absentfrom counts but present in traps, while the same was true for C. antillarum and Haemulon striatum inSt Lucia. The most abundant species in both countries was the wrasse, Clepticus parrae, which has beenomitted from all graphs and tables since its dominance obscures results for other species. When C. parraewas included in the analysis it comprised 67.6% of the fish population in Jamaica and 66.5% in St Lucia,but only 0.6% and 3.3% respectively in traps, showing that this schooling, mid-water, planktivorousspecies, not preferable for eating, is not readily trappable.

Catches were generally diverse. In both countries Stegastes planifrons, Acanthurus bahianus, Sparisomaaurofrenatum and Scarus taeniopterus were among the six most numerous in counts. In Jamaica, 22 specieswere recorded in traps and 57 in counts (Figure 3), while in St Lucia there were 54 in traps and 90 in counts(Figure 4). Reducing the sampling intensity of St Lucia to that of Jamaica gave average figures of 35 speciesin traps and 70 in counts, for 10 randomly picked sub-samples of 23 traps and 112 counts.

0 2 4 6 8

Mea

n nu

mbe

r pe

r re

ef c

ensu

sM

ean

num

ber

per

reef

cen

sus

0

1

2

3

4

BonaireSabaPuerto RicoSt LuciaDominicaJamaica

Tetradontiformes

0 2 4 6 80

1

2

Fishers / km reef Fishers / km reef

0 2 4 6 80

1

2

3

4

0 2 4 6 80

5

10

15

20

25

Angelfish

Butterflyfish Soldierfish

Spearman's rho = - 0.45 Spearman's rho = - 0.36

Spearman's rho = 0.17Spearman's rho = - 0.57

Figure 2. Mean abundance ð�s:e:Þ of Tetraodontiformes, butterflyfish, angelfish and soldierfish versus fishing pressure.

J.P. HAWKINS ET AL.118

Copyright # 2006 John Wiley & Sons, Ltd. Aquatic Conserv: Mar. Freshw. Ecosyst. 17: 111–132 (2007)

DOI: 10.1002/aqc

Table 2 shows the trappability ratios of species in Jamaica and St Lucia. These represent the ratioof abundance of species in traps compared to that on the reef in counts. All data for trappability ratioswere taken from underwater observations since data from trap landings may have come from differenthabitats or depths to our fish counts. In Jamaica 73% of species caught in traps were proportionallymore common in traps than they were on the reef, and 35% of those potentially trappable had beencaught. In St Lucia these figures were 76% and 59% respectively for the full sample of 75 traps. Reducingthe sampling intensity to that of Jamaica gave average figures of 76% and 39% respectively, for 10randomly picked sub-samples of 23 traps and 112 counts. These figures are virtually the same as those forJamaica.

Including species caught in traps but not seen in counts there were 13 highly trappable and 43 highlyuntrappable species in Jamaica. St Lucia contained over twice as many highly trappable species (29) asJamaica, and virtually the same number of highly untrappable (44), suggesting that the higher fishingpressure in Jamaica could have eliminated species that are susceptible to trapping. However, reducing theSt Lucia sample size to that of Jamaica (23 traps and 112 counts) produces means of 16 highly trappablespecies and 43 highly untrappable species, showing that the difference was simply a sampling effect. Only sixspecies were considered highly trappable in both countries; three Tetraodontiformes, C. antillarum,

Species

Spa

risom

a au

rofr

enat

umS

caru

s is

erti

Ste

gast

es d

ienc

aeus

Aca

nthu

rus

bahi

anus

Ste

gast

es p

lani

fron

sS

caru

s ta

enio

pter

usS

tega

stes

leuc

ostic

tus

Myr

ipris

tis ja

cobu

sH

oloc

entr

us r

ufus

Aca

nthu

rus

coer

uleu

sC

epha

loph

olis

cru

enta

taS

paris

oma

viri

deH

ypop

lect

rus

puel

laC

epha

loph

olis

ful

vaH

oloc

entr

us m

aria

nus

Mic

rosp

atho

don

chry

suru

sH

aem

ulon

chr

ysar

gyre

umP

seud

open

eus

mac

ulat

usB

odia

nus

rufu

sH

aem

ulon

flav

olin

eatu

mH

oloc

entr

us v

exi

Hol

acan

thus

tric

olor

Ste

gast

es v

aria

bilis

Hyp

ople

ctru

s in

digo

Hyp

ople

ctru

s gu

ttava

rius

Mul

loid

icht

hys

mar

tinic

usC

anth

erhi

nes

pullu

sH

ypop

lect

rus

unic

olor

Hal

icho

eres

rad

iatu

sS

tega

stes

dor

sopu

nicu

sC

haet

odon

cap

istr

atus

Lutja

nus

anal

isS

paris

oma

chry

suru

sH

aem

ulon

sci

urus

Cha

etod

on s

tria

tus

Hyp

ople

ctru

s ni

gric

ans

Hyp

ople

ctru

s ch

loru

rus

Bot

hus

luna

tus

Aca

nthu

rus

chiru

gus

Mel

icht

hys

nige

rD

iodo

n ho

laca

nthu

sS

paris

oma

rubr

ipin

neR

yptic

us s

apon

aceu

sP

rican

thus

cru

enta

tus

Sph

oero

ides

spe

ngle

riLu

tjanu

s m

ahog

oni

Epi

neph

elus

gut

tatu

sLa

coph

rys

triq

uete

rC

haet

odon

oce

llatu

sLu

tjanu

s jo

cuH

oloc

entr

us a

dsce

nsio

nis

Ple

ctry

pops

ret

rosp

inis

Dio

don

hyst

rixS

corp

aena

plu

mie

riX

anth

icht

hys

ringe

nsH

aem

ulon

car

bona

rium

Hae

mul

on a

urol

inea

tum

Hae

mul

on p

lum

ieri

Hol

acan

thus

cili

aris

Lutja

nus

apod

usLu

tjanu

s sy

nagr

isLa

ctop

hrys

pol

ygon

iaC

hilo

myc

teru

s an

tilla

rium

30

20

10

0

10

20

TrapsCounts

% in

cou

nts

% in

trap

s

Figure 3. Proportional representation of species in traps compared to on the reef in Jamaica.

TRAP FISHING EFFECTS ON REEF FISH 119

Copyright # 2006 John Wiley & Sons, Ltd. Aquatic Conserv: Mar. Freshw. Ecosyst. 17: 111–132 (2007)

DOI: 10.1002/aqc

L. polygonia, Diodon holocanthus; one snapper, L. synagris and two grunts, H. plumieri and Haemulonflavolineatum. Of species that were highly trappable in St Lucia, 38% (11) were absent from both traps andcounts in Jamaica: H. striatum, Calamus calamus, Balistes vetula, Mycteroperca interstitialis, Aluterusscriptus, Haemulon melanurum, Kyphosus sectatrix, Lactophrys bicaudalis, Cantherhines macrocerus,Pomacanthus paru, and Ocyurus chrysurus. All occur throughout the Caribbean and so were expected tooccur in Jamaica (Humann, 1996). A third (4) of these highly trappable species were Tetraodontiformeswith most other families represented by just one species. No species trapped in Jamaica were absent fromSt Lucia. To explore the possibility that this difference is an artefact of the greater sampling intensity inSt Lucia compared to Jamaica, we randomly reduced the St Lucia sample size to that of Jamaica, repeated10 times, and counted the number of these vulnerable species that remained in the sample. On average, thereduced samples retained 8.5 of the 11 highly trappable species.

Only the Tetraodontiformes and snappers appear highly trappable in both St Lucia and Jamaica(Table 3). Of the four other families that were highly trappable in St Lucia, no butterflyfish or groupers(Serranidae not including Epinephelinae) were trapped in Jamaica while chub (Kyphosidae) and porgies(Sparidae) were not seen there. No family appeared to be highly untrappable in both countries.

Catch composition and size at maturity

Several commercially important species in St Lucia are commonly caught before they reach maturity(Figure 5, Table 4). For seven of the 23 species sampled, over one-third of the catch taken was immature,

Species

Myr

ipris

tis ja

cobu

sS

tega

stes

pla

nifr

ons

Sca

rus

taen

iopt

erus

Spa

risom

a au

rofr

enat

umA

cant

huru

s ba

hian

usH

oloc

entr

us r

ufus

Spa

risom

a vi

ride

Abu

defd

uf s

axat

ilis

Hae

mul

on c

hrys

argy

reum

Mul

loid

icht

hys

mar

tinic

usA

cant

huru

s co

erul

eus

Cep

halo

phol

is c

ruen

tata

Mic

rosp

atho

don

chry

suru

sS

caru

s ve

tula

Hol

ocen

trus

mar

ianu

sH

aem

ulon

aur

olin

eatu

mS

tega

stes

die

ncae

usS

tega

stes

dor

sopu

nnic

usH

aem

ulon

flav

olin

eatu

mLu

tjanu

s m

ahog

oni

Cha

etod

on c

apis

trat

usP

aran

thiu

s fu

rcife

rH

ypop

lect

rus

puel

laO

cyur

us c

hrys

urus

Aca

nthu

rus

chiru

gus

Sca

rus

iser

tiC

haet

odon

str

iatu

sC

epha

loph

olis

ful

vaB

odia

nus

rufu

sK

ypho

sus

sect

atrix

Lact

ophr

ys tr

ique

ter

Hol

acan

thus

tric

olor

Can

ther

hine

s pu

llus

Pse

udop

eneu

s m

acul

atus

Pria

cant

hus

crue

ntat

usS

paris

oma

rubr

ipin

neC

haet

odon

acu

leat

usH

ypop

lect

rus

chlo

ruru

sLu

tjani

s gr

iseu

sM

elic

hthy

s ni

ger

Hal

icho

eres

rad

iatu

sH

aem

ulon

car

bona

rium

Hol

ocen

trus

vex

illar

ius

Bot

hus

luna

tus

Hyp

ople

ctru

s sp

.H

ypop

lect

rus

nigr

ican

sX

anth

icht

hys

ringe

nsS

tega

stes

leuc

ostic

tus

Hae

mul

on p

lum

ieri

Lact

ophr

ys b

icau

dalis

Lutja

nus

apod

usS

corp

aena

plu

mie

riP

omac

anth

us p

aru

Spa

risom

chr

ysop

teru

mH

ypop

lect

rus

gutta

variu

sLa

ctop

hrys

pol

ygon

iaD

iodo

n ho

laca

nthu

sP

lect

rypo

ps r

etro

spin

isB

alis

tes

vetu

laLu

tjanu

s bu

ccan

ella

Can

ther

hine

s m

acro

ceru

sH

aem

ulon

par

raR

yptic

us s

apon

aceu

sH

oloc

entr

us a

dsce

nsio

nis

Lutja

nus

jocu

Hol

acan

thus

cili

aris

Cha

etod

on o

cella

tus

Lutja

nus

anal

isH

aem

ulon

mel

anur

umE

pine

phel

us a

dsce

nsio

nis

Epi

neph

elus

gut

tatu

sA

lute

rus

scrip

tus

Ani

sotr

emus

sur

inam

ensi

sH

aem

ulon

mac

rost

omum

Bot

hus

ocel

latu

sH

aem

ullo

n sc

iuru

sM

ycte

rope

rca

inte

rstit

ialis

Ste

gast

es v

aria

bilis

Ger

res

cine

reus

Hol

ocen

trus

cor

uscu

mC

alam

us c

alam

usD

iodo

n hy

strix

Bai

rdie

lla s

anct

aelu

ciae

Ryp

ticus

sub

bifr

enat

usR

hom

bopl

ites

auro

rube

nsS

caru

s co

erul

eus

Myc

tero

perc

a ve

neno

saS

phoe

roid

es s

peng

leri

Cal

amus

baj

onad

oLu

tjanu

s sy

nagr

isC

hilo

myc

teru

s an

tilla

rum

Hae

mul

on s

tria

tum

% in

cou

nts

10

0

10

20

Traps

Counts

% in

trap

s

Figure 4. Proportional representation of species in traps compared to on the reef in St Lucia.

J.P. HAWKINS ET AL.120

Copyright # 2006 John Wiley & Sons, Ltd. Aquatic Conserv: Mar. Freshw. Ecosyst. 17: 111–132 (2007)

DOI: 10.1002/aqc

Table 2. Trappability of species in Jamaica and St Lucia calculated as the ratio of their proportional abundance in traps compared tothat in fish counts. Species with an asterisk (*) were found in traps but not seen in counts. A trappability of zero indicates that the

species was seen in counts but not in traps

Species Family Jamaicatrappability

St Luciatrappability

Bothus ocellatus Bothidae not present 0Chaetodon aculeatus Chaetodontidae not present 0.8Epinephelus adscensionis Epinephelinae not present 0Mycteroperca interstitialis Epinephelinae not present 11.2Mycteroperca venenosa Epinephelinae not present 0Gerres cinereus Gerreidae not present 0Anisotremus surianamensis Haemulidae not present 0Haemulon melanurum Haemulidae not present 7.7Haemulon parrai Haemulidae not present 0Haemulon striatum Haemulidae not present *Holocentrus coruscum Holocentridae not present 0Kyphosus sectatrix Kyphosidae not present 6.2Lutjanus buccanella Lutjanidae not present 0Lutjanus griseus Lutjanidae not present 1.1Ocyurus chrysurus Lutjanidae not present 3.3Rhomboplites aurorubens Lutjanidae not present 0Pomacanthus paru Pomacanthidae not present 3.6Abudefduf saxatilis Pomacentridae not present 1.6Scarus coelestinus Scaridae not present 0Scarus vetula Scaridae not present 0.1Bairdiella sanctaeluciae Sciaenidae not present 0Hypoplectrus sp. Serranidae not present 0Paranthius furcifer Serranidae not present 1.2Rypticus subbifrenatus Serranidae not present 0Calamus bajonado Sparidae not present 0Calamus calamus Sparidae not present 14.7Aluterus scriptus Tetraodontiformes not present 9.2Balistes vetula Tetraodontiformes not present 14Cantherhines macrocerus Tetraodontiformes not present 4.1Lactophrys bicaudalis Tetraodontiformes not present 4.9Haemulon plumieri Haemulidae * 13.3Lutjanus apodus Lutjanidae * 0Lutjanus synagris Lutjanidae * 438.6Holacanthus ciliaris Pomacanthidae * 0Chilomycterus antillarum Tetraodontiformes * *Lactophrys polygonia Tetraodontiformes * 18.3Haemulon aurolineatum Haemulidae 210.3 0.2Acanthurus chirurgus Acanthuridae 112.2 2.3Diodon holocanthus Tetraodontiformes 42.1 18.3Sparisoma chrysopterum Scaridae 18 0Acanthurus coeruleus Acanthuridae 12 2.6Acanthurus bahianus Acanthuridae 3.6 2Haemulon flavolineatum Haemulidae 3.5 7.7Holacanthus tricolour Pomacanthidae 1.3 0.3Scarus taeniopterus Scaridae 1.2 0.2Sparisoma viride Scaridae 1.1 1.6Bodianus rufus Labridae 0.5 0Microspathodon chrysurus Pomacentridae 0.5 0.8Sparisoma aurofrenatum Scaridae 0.4 1.3Cephalopholis cruentata Epinephelinae 0.3 0.3

continued over

TRAP FISHING EFFECTS ON REEF FISH 121

Copyright # 2006 John Wiley & Sons, Ltd. Aquatic Conserv: Mar. Freshw. Ecosyst. 17: 111–132 (2007)

DOI: 10.1002/aqc

indicating that serious growth over-fishing is occurring. These include the snappers O. chrysurus (71%immature) and Lutjanus mahogoni (36% immature), surgeonfish Acanthurus coeruleus (45% immature),parrotfish Sparisoma viride (85% immature), grunts Haemulon flavolineatum (38% immature), Haemulonchrysargyreum (43% immature) and the goatfish Mulloidichthys martinicus (50% immature). In 12 species,for example Pseudopeneus maculatus and C. parrae, most fish (>85%) were sexually mature when theywere caught.

Table 2 continued

Species Family Jamaicatrappability

St Luciatrappability

Stegastes leucostictus Pomacentridae 0.2 1.4Scarus iserti Scaridae 0.04 0Bothus lunatus Bothidae 0 0Chaetodon capistratus Chaetodontidae 0 2.3Chaetodon ocellatus Chaetodontidae 0 7.3Chaetodon striatus Chaetodontidae 0 9.8Cephalopholis fulva Epinephelinae 0 0Epinephelus guttatus Epinephelinae 0 9.1Haemulon carbonarium Haemulidae 0 7.3Haemulon chrysargyreum Haemulidae 0 0.3Haemulon sciurus Haemulidae 0 0Holocentrus adscensionis Holocentridae 0 14.7Holocentrus marianus Holocentridae 0 0Holocentrus rufus Holocentridae 0 0.6Holocentrus vexillarius Holocentridae 0 0Myripristis jacobus Holocentridae 0 0.3Plectrypops retrospinis Holocentridae 0 0Halichoeres radiatus Labridae 0 1.1Lutjanus analis Lutjanidae 0 0Lutjanus jocu Lutjanidae 0 0Lutjanus mahogoni Lutjanidae 0 3.3Mulloidichthys martinicus Mullidae 0 0.7Pseudupeneus maculatus Mullidae 0 7Stegastes diencaeus Pomacentridae 0 0Stegastes dorsopunnicus Pomacentridae 0 0Stegastes planifrons Pomacentridae 0 0.02Stegastes variabilis Pomacentridae 0 0Priacanthus cruentatus Priacanthidae 0 0.6Sparisoma rubripinne Scaridae 0 3.6Scorpaena plumieri Scorpaenidae 0 0Hypoplectrus chlorurus Serranidae 0 0Hypoplectrus guttavarius Serranidae 0 0Hypoplectrus indigo Serranidae 0 not presentHypoplectrus nigricans Serranidae 0 0Hypoplectrus puella Serranidae 0 0Hypoplectrus unicolor Serranidae 0 not presentRypticus saponaceus Serranidae 0 4.6Cantherhines pullus Tetraodontiformes 0 8.6Diodon hystrix Tetraodontiformes 0 0Lactophrys triqueter Tetraodontiformes 0 2Melichthys niger Tetraodontiformes 0 7Sphoeroides spengleri Tetraodontiformes 0 0Xanthichthys ringens Tetraodontiformes 0 4.8

J.P. HAWKINS ET AL.122

Copyright # 2006 John Wiley & Sons, Ltd. Aquatic Conserv: Mar. Freshw. Ecosyst. 17: 111–132 (2007)

DOI: 10.1002/aqc

DISCUSSION

This study confirms that fish traps are highly unselective fishing gears, catching a wide variety of speciesfrom many different families. Some families and species are particularly vulnerable to being caught,including many that have traditionally been of little or no commercial value. Measures of abundance ofhighly trappable families across the Caribbean showed steep declines as fishing pressure increased.A comparison of trap catches between St Lucia and Jamaica showed that 11 species that were highlyvulnerable to trapping in St Lucia appeared to be absent from Jamaica. Since current levels of trap fishingin Jamaica were approximately three and a half times higher than in St Lucia, and fishing there has beenintense for over 100 years (Jackson, 1997), it seems that the absence of these species is due to long-termintensive trap fishing.

Examination of 705 fish gonads in St Lucia revealed that in 23 species constituting an importantcomponent of fish catches, there were seven where over a third of the fish caught were immature.Severe growth over-fishing is occurring and suggests that St Lucia’s trap fishery is wasteful and maybe unsustainable. Studies of trap fisheries in other parts of the world have reached similar conclusions.For example, work in Kenya showed that on average 39% of the fish caught in small traps and 49% of thosein big traps were juveniles (Mangi, 2006). For one of these species (Lethrinus xanthochilus) juveniles comprised100% of the catch while in five others, the figure was 75% or more. From St John in the US Virgin Islands,Garrison et al. (2004) reported that most of the commercially important Balistes vetula found in traps areimmature and concluded that the island’s trap fishery had been severely over-exploited. Similarly in the

Table 3. Trappability at the family level in St Lucia and Jamaica calculated as a ratio of a family’s abundance in traps compared tothat in fish counts. The Serranidae (*) have been split into four groups representing species of more similar life history characteristic.

Species denoted as ** were found in traps but not seen in counts

Family Trappability ratios

St Lucia Jamaica

Sparidae (porgies) 12.19 **Kyphosidae (chub) 6.18 **Tetraodontiformes (includes triggerfish, pufferfish, boxfish, filefish) 5.95 7.75Chaetodontidae (butterflyfish) 4.67 0Serranidae* } Grammistinae (soapfish) 4.07 0Lutjanidae (snappers) 3.14 12.94Haemulidae (grunts) 2.28 3.5Acanthuridae (surgeonfish) 2.18 6.12Mullidae (goatfish) 1.5 0Serranidae* } Paranthias furcifer (creole fish) 1.19 **Scaridae (parrotfish) 0.84 0.46Pomacanthidae (angelfish) 0.74 2.55Priacanthidae (cardinalfish) 0.65 0Holocentridae (soldierfish) 0.36 0Serranidae* } Epinephilinae (groupers) 0.36 0.18Pomacentridae (damselfish) 0.35 0.05Labridae (wrasse) 0.34 0.45Bothidae (flounders) 0 0Serranidae* } Hypoplectrus (hamlets) 0 0Gerreidae (mojarras) 0 **Sciaenidae (croakers) 0 **Scorpaenidae (scorpionfish) 0 0

TRAP FISHING EFFECTS ON REEF FISH 123

Copyright # 2006 John Wiley & Sons, Ltd. Aquatic Conserv: Mar. Freshw. Ecosyst. 17: 111–132 (2007)

DOI: 10.1002/aqc

Acanthurus bahianus

8 10 12 14 16 18 20 22 24 26 28

Num

ber

of fi

sh

0

20

40

60

80

100

120

140

160

180

Acanthurus coeruleus

6 8 10 12 14 16 18 20 22 24 26 280

5

10

15

20

25

30

35

Sparisoma viride

10 12 14 16 18 20 22 24 26 28 30

Num

ber

of fi

sh

0

2

4

6

8

10

12

14Sparisoma aurofrenatum

5 10 15 20 25 30 350

10

20

30

40

50

60

Scarus taeniopterus

12 14 16 18 20 22 24 26 28 30

Num

ber

of fi

sh

0

5

10

15

20

25

30

35 Sparisoma rubripinne

14 16 18 20 22 24 260

2

4

6

8

Mulloidichthys martinicus

Size (cm)5 10 15 20 25 30 35

Num

ber

of fi

sh

Num

ber

of fi

shN

umbe

r of

fish

Num

ber

of fi

shN

umbe

r of

fish

0

20

40

60

80

100 Pseudopeneus maculatus

Size (cm)

14 16 18 20 22 24 26 28 300

2

4

6

8

10

12

14

Min. size = 14

Min. size = 17

30.2%

n = 514

45.1%

n = 193

85.2%

n = 89

3.8%

n = 235

0.8%

n = 124

7.1%

n = 14

50%

n = 510

0%

n = 47

Figure 5. Size frequency distributions of species commonly caught in traps in St Lucia, from a sample of 530 fish catches. Arrows markfish size at first maturity. Data for maturity were obtained from a sample of 705 fish catches that were not included in the size frequencydistributions. ‘Min. size’ also describes fish size at first maturity and is indicated on graphs where individuals of this length wereabsent from catches analysed for size frequency distributions. Percentages shown indicate the fraction of fish landed below the size

at first maturity.

J.P. HAWKINS ET AL.124

Copyright # 2006 John Wiley & Sons, Ltd. Aquatic Conserv: Mar. Freshw. Ecosyst. 17: 111–132 (2007)

DOI: 10.1002/aqc

Haemulon carbonarium

14 16 18 20 22 24

Nu

mb

er

of fish

0

1

2

3

4Haemulon chrysargyreum

10 12 14 16 18 20

0

5

10

15

20

25

30

35

Haemulon flavolineatum

8 10 12 14 16 18 20 22

Nu

mb

er

of

fish

0

10

20

30

40

50Haemulon parrai

18 19 20 21 22 23 24 25 26

0

1

2

3

4

Haemulon plumieri

12 14 16 18 20 22 24 26 28 30 32 34

Nu

mb

er

of

fish

0

2

4

6

8Haemulon aurolineatum

6 8 10 12 14 16 18 20 22 24

0

20

40

60

80

100

Ocyurus chrysurus

Size (cm)

15 20 25 30 35 40 45 50 55

Nu

mb

er

of

fish

Nu

mb

er

of fish

Nu

mb

er

of

fish

Nu

mb

er

of

fish

Nu

mb

er

of

fish

0

5

10

15

20

25Lutjanus mahogoni

Size (cm)

10 15 20 25 30 35

0

2

4

6

8

10

12

14

16

Min. size = 16

6.6%

n = 15

43.4%

n = 83

38.2%

n = 136

0%

n = 11

10.3%

n = 29

25%

n = 436

70.9%

n = 179

36%

n = 114

Figure 5. continued

TRAP FISHING EFFECTS ON REEF FISH 125

Copyright # 2006 John Wiley & Sons, Ltd. Aquatic Conserv: Mar. Freshw. Ecosyst. 17: 111–132 (2007)

DOI: 10.1002/aqc

Clepticus parrae

16 18 20 22 24 26

Num

ber

of fi

sh

0

5

10

15

20

Cephalopholis cruentata

10 15 20 25 30 35 40

Num

ber

of fi

sh

0

2

4

6

8 Cephalopholis fulva

12 14 16 18 20 22 24 26

Num

ber

of fi

sh

0

2

4

6

8

10

12

Holocentrus rufus

8 10 12 14 16 18 20 22 24

Num

ber

of fi

sh

0

20

40

60

80

100

120

140

160

180 Holocentrus adscensionis

10 15 20 25 30 35

Num

ber

of fi

sh

0

1

2

3

4

5

6

7

Size (cm)

Myripristis jacobus

Size (cm)8 10 12 14 16 18

Num

ber

of fi

sh

0

50

100

150

200

250

Cantherhines pullus

10 15 20 25 30 35

Num

ber

of fi

sh

0

2

4

6

8

10

12

144.7%

n = 43

0%

n = 49

12.2%

n = 82

20%

n = 25

4.9%

n = 597

20%

n = 30

4.7%

n = 701

Figure 5. continued

J.P. HAWKINS ET AL.126

Copyright # 2006 John Wiley & Sons, Ltd. Aquatic Conserv: Mar. Freshw. Ecosyst. 17: 111–132 (2007)

DOI: 10.1002/aqc

Arabian Gulf the high incidence of juvenile catch in traps has led to a call for fishery reform (Grandcourtet al., 2004).

Comparing the species that were most susceptible to trapping in St Lucia and Jamaica revealeddifferences between these islands. Trappability ratios indicated that the Tetraodontiformes were highlysusceptible to trapping in both Jamaica and St Lucia, and butterflyfish were highly susceptible in St Lucia,but not in Jamaica. Long-term intensive exploitation could eliminate species susceptible to trapping, andthis has probably happened to butterflyfish and several of the Tetraodontiformes that were highly trappablein St Lucia but rare or absent from Jamaica. Although, the results from Jamaica are based on a relativelysmall sample size of 23 traps and 112 counts, a study by Sary (1995) in the same area a year earlier involvedsampling 886 traps. Comparing our list of highly trappable species in St Lucia, with the species that Saryfound in traps in Jamaica reveals that two-thirds of St Lucia’s highly trappable species were missing fromtraps in Sary’s study. This suggests that these species: H. striatum, C. calamus, M. interstitialis, A. scriptus,H. melanurum and K. sectatrix, really could have been fished out from this part of northern Jamaica andthat our findings are not simply an artefact of under-sampling. It is already acknowledged that once-abundant species of snappers, groupers and large parrotfish are virtually absent on Jamaica’s reefs (Koslowet al., 1994). Furthermore, reducing St Lucia samples to Jamaican levels left 8.5 of 11 highly trappablespecies still represented in St Lucia.

Soldierfish had low trappability ratios in both Jamaica and St Lucia, but were much more abundant in StLucia than in Jamaica. Since this study showed trapping pressure in Jamaica to be around three and a halftimes greater than in St Lucia, it is possible that even families which can usually withstand intensive fishingwill become over-exploited if trapping reaches extremely high levels.

Table 4. Catch composition from fish traps in St Lucia showing fish size at first maturity and where possible the size at 50% and 100%maturity

Species Sample size Minimum sizeat maturity

Range Size at which50% mature

Size at which100% mature

Acanthurus bahianus 38 14 12–19 16Acanthurus coeruleus 20 15 11–21 15 15Scarus taeniopterus 38 15 14–24Sparisoma aurofrenatum 67 14 14–23Sparisoma rubripinne 43 17 17–31 22Sparisoma viride 10 25 15–25Cephalopholis cruentata 50 16 12–29 26 26Cephalopholis fulva 23 19 12–25Lutjanus mahogoni 14 20 18–34Ocyurus chrysurus 19 32 17–43 32 32Haemulon aurolineatum 24 14 14–17 16 17Haemulon carbonarium 22 16 15–22Haemulon chrysargyreum 21 15 15–18Haemulon flavolineatum 42 15 13–19 19Haemulon parrai 55 16 13–20Haemulon plumieri 23 17 14–28 25 25Holocentrus adscensionis 46 17 13–24 19 20Holocentrus rufus 34 13 13–17 14 15Myripristis jacobus 29 11 10–15 11 14Pseudupeneus maculatus 19 14 13–21Mulloidichthys martinicus 23 20 13–25Cantherhines pullus 17 13 13–20Clepticus parrae 21 17 17–24 17 17

TRAP FISHING EFFECTS ON REEF FISH 127

Copyright # 2006 John Wiley & Sons, Ltd. Aquatic Conserv: Mar. Freshw. Ecosyst. 17: 111–132 (2007)

DOI: 10.1002/aqc

It is important to be cautious in attributing among-island differences in fish assemblages to differences infishing pressure. There are other factors among islands besides fishing that could have played a role. Forexample, islands differ in size, relief, human population densities and level of development, and thesemay influence processes on adjacent reefs. They also differ in terms of scale and history of human andother impacts, including coral disease outbreaks, hurricanes, watershed clearance and nutrient input, toname a few (e.g. see Gardner et al., 2003). However, findings from the study uphold many predictedeffects of fishing (Polunin and Roberts, 1996). Other factors, such as degree of watershed development,although not tested statistically, do not appear to relate in obvious ways to inter-island differencesin fish abundance or assemblage composition, nor are mechanisms by which they might exert theseeffects clear. One possible exception is that coral cover and habitat structural complexity decrease on thestudy reefs as fishing pressure increases (Hawkins and Roberts, 2004), which may affect reef carryingcapacity and favour some species over others. Hawkins and Roberts (2003) argue that this habitat shift is initself partly a consequence of overfishing of herbivores. Biomass of herbivores decreases 10-fold over thisfishing pressure gradient, from Bonaire to Jamaica, with a consequent reduction in grazing pressure onalgae. Without undertaking experimental manipulations of fishing pressure it is not possible to rule outinfluences other than exploitation, but our findings clearly show that trap fishing has the capacity to alterfish assemblage composition, and historical fishery data suggest that it already has in Jamaica (Koslowet al., 1994).

Some species may be highly trappable because of behavioural traits. For example, most butterflyfishform strong pair bonds (Roberts and Ormond, 1992), so if one member of a pair goes into a trap itspartner is likely to follow. Such behaviour would double the likelihood of a species getting trappedand indeed Chaetodon striatus (trappability ratio 9.8) and Chaetodon ocellatus (trappability ratio 7.3)were highly trappable in St Lucia. Similarly, species which move around in groups or schools mightfollow each other into traps. Highly trappable species which this might apply to in Jamaica includeAcanthurus chirugus (trappability ratio 112), Acanthurus coeruleus (trappability ratio 12) A. bahianus(trappability ratio 3.6) and Sparisoma chrysopterum (trappability ratio 18), and, in St Lucia, Melichthysniger (trappability ratio 7), K. sectatrix (trappability ratio 6.2) and Sparisoma rubripinne (trappability ratio3.6). Other species may be highly trappable simply because they are curious and readily enter enclosedspaces.

Differences in fish behaviour between St Lucia and Jamaica could also help explain why trappabilityratios differed between these countries. In Jamaica, species such as Balistes vetula and Calamus calamus,tended to avoid our counting area but were less timid in St Lucia. Wary behaviour towards people is oftenencountered in places that are intensively spear-fished and, from personal observations, spear-fishers weremuch more common in Jamaica than St Lucia.

Species that grow slowly and reproduce late may be extirpated by trapping even when trapping pressureis relatively light. Groupers and snappers contain species that are prime examples of animals whose lifehistory characteristics (e.g. late maturity) render them particularly vulnerable to over-exploitation(Reynolds, 2003). In St Lucia such species with high trappability ratios were the groupers M. interstitialis(trappability ratio: 11.2) and Epinephelus guttatus (trappability ratio: 9.1) and the snappers L. synagris(trappability ratio: 439), O. chrysurus (trappability ratio: 3.3) and L. mahogoni (trappability ratio: 3.3).L. synagris had the highest trappability ratio of any species in St Lucia. This species was rare in counts andmay have moved into traps at night after coming up from deeper water (www.fishbase.org). Thetrappability ratio of L. synagris thus probably represents an overestimate of the difference in abundancebetween reef and traps for this species.

Trap fishing is widely perceived as a relatively benign method whereby small-scale fishers canobtain a living from coral reefs. However, it is clear from the steep gradients in fish abundance acrossour inter-island fishing pressure gradient that fishing, particularly with traps, has greatly affected Caribbeanfish assemblages. Historical data from the region place this inter-island comparison in a different

J.P. HAWKINS ET AL.128

Copyright # 2006 John Wiley & Sons, Ltd. Aquatic Conserv: Mar. Freshw. Ecosyst. 17: 111–132 (2007)

DOI: 10.1002/aqc

perspective, showing steep declines in high-value, vulnerable species over time. In Puerto Rico, forexample, there were 1403 fishers in 1931, setting 4239 traps and catching 1400 tonnes of reef fish(Appeldoorn et al., 1992). By 1990, trap numbers climbed to 13 555, while catches fell to 854 tonnes.Most of the catch in 1931 was composed of Nassau groupers, Epinephelus striatus and other high-valuesnappers and groupers. By 1990, more than half of the catch was composed of low-value species such asgrunts, surgeonfish and parrotfish. Similar trends of increasing fishing effort, falling catches anddisappearance of high-value species have been seen over much of the region, including the US VirginIslands (Rogers and Beets, 2001), Florida (Ault et al., 1998) and Jamaica (Jackson, 1997). The perceptionthat trap fishing is a benign fishing method has perhaps permitted these fisheries to operate withlittle regulation or control. There is an urgent need for reappraisal, such as that under way in Floridawhere traps are due to be phased out by 2007 (http://www.reefguardian.org/Campaigns/FishTrapGOM/MoreInfoFTrapGOM.html).

Species with high trappability ratios may not necessarily be highly threatened by fishing, even in placeswhere trap fishing is intense. Species which are small at maturity, have short life-cycles and high turnoverrates might be able to withstand being highly trappable because their life history characteristics enable themto persist despite high rates of fishing mortality. In countries where levels of trap fishing are high thesespecies may constitute the majority of catches. However, intensive fishing may threaten sustainability ofeven these species eventually. Mesh size limits help reduce the impact of trapping on fish populations byallowing juvenile fish to escape capture until after they reach maturity (Hunte and Mahon, 1994). They canalso increase catches by reducing growth over-fishing. Work by Sary et al. (1997), done at the same place inJamaica as this study and at a similar time, showed that fishery yields increased when traps with 2.5 cmand 3.2 cm meshes were replaced with ones of a larger size of 3.8 cm mesh. However, meshes will needto be bigger than this if large species with late maturity and a susceptibility to trapping are to gain anyprotection. One way round this problem could be to introduce slots, known as ‘escape gaps’, into traps thatare larger than the mesh size. These help provide an opportunity for juveniles to escape (Stewart andFerrell, 2002).

In summary, certain taxa such as the Tetraodontiformes appear to be particularly vulnerable totrapping. Whatever reasons lure fish into traps and regardless of the fact that some species appear moretrappable than others, trapping is a highly non-selective form of fishing. If populations of vulnerablespecies are to be maintained on reefs, and more resilient species are to support productive and sustainablefisheries, then trapping needs to be regulated. This can include measures such as limiting numbers of trapfishers and how many traps each can use, increasing mesh sizes and introducing escape gaps to traps.Education could also help reduce waste from trap fisheries. For example, fishers could be encouraged tothrow back the small fish they catch from shallow water. Given that fisheries regulations are often difficultto enforce in areas with trap fisheries, marine reserves that are off-limits to fishing probably provide theeasiest and most effective way to tackle the problems associated with trap fishing, particularly if used inassociation with the other forms of management discussed (Murray et al., 1999; Roberts and Hawkins,2000; Russ, 2002; Gell and Roberts 2003). Even in areas where trapping pressure is fairly low, marinereserves will provide essential refuges for species that are particularly vulnerable to over-exploitation(Roberts, 2005).

ACKNOWLEDGEMENTS

We would like to thank the UK Natural Environmental Research Council, UK Department for InternationalDevelopment, University of Puerto Rico Seagrant and USAID for funding this work. Special thanks to the BonaireMarine Park, Saba Marine Park and Scuba St Lucia for generous use of their facilities during field trips. Erkki Siirila,Harold Guiste, Daniel Matos, Graciela Garcia-Moliner, Michelet Fontaine and John Clark helped us track downinformation on fishing pressure. Thanks to John Baxter and two reviewers whose comments greatly improved themanuscript.

TRAP FISHING EFFECTS ON REEF FISH 129

Copyright # 2006 John Wiley & Sons, Ltd. Aquatic Conserv: Mar. Freshw. Ecosyst. 17: 111–132 (2007)

DOI: 10.1002/aqc

REFERENCES

Allison WR. 1992. The Discovery Bay fisheries improvement project: status report. Proceedings of the Gulf andCaribbean Fisheries Institute 42: 331–337.

Alverson DL, Hughes SE. 1996. Bycatch: from emotive to effective natural resource management. Reviews in FishBiology and Fisheries 6: 443–462.

Appeldoorn R, Beets J, Bohnsack JA, Bolden S, Matos D, Meyers S, Rosario A, Sadovy Y, Tobias W. 1992. Shallowwater reef fish stock assessment for the US Caribbean. NOAA Technical Memorandum NMFS-SEFSC-304,National Oceanic and Atmospheric Administration, Miami, FL.

Ault JS, Bohnsack JA, Meester GA. 1998. A retrospective (1979–1996) multispecies assessment of coral reef fish stocksin the Florida Keys. Fishery Bulletin 96: 395–414.

Blott AJ. 1978. A preliminary study of timed release mechanisms for lobster traps. Marine Fisheries Review 40:44–49.

Boehlert GW. 1996. Biodiversity and the sustainability of marine fisheries. Oceanography 9: 28–35.Bohnsack JA, Bannerot SA. 1986. A stationary visual census technique for quantitatively assessing communitystructures of coral reef fishes. Technical report NMFS: 41. National Oceanic and Atmospheric Administration,Miami, FL.

Butler JN, Burnett-Herkes J, Barnes JA, Ward J. 1993. The Bermuda fisheries: a tragedy of the commons averted?Environment 35: 6–15 and 25–33.

Dayton PK, Thrush SF, Agardy MT, Hofman RJ. 1995. Environmental effects of marine fishing. Aquatic Conservation:Marine and Freshwater Ecosystems 5: 1–28.

Ferry RE, Kohler CC. 1987. Effects of trap fishing on fish populations inhabiting a fringing coral reef. North AmericanJournal of Fisheries Management 7: 580–588.

Gardner TA, Cote IM, Gill JA, Grant A, Watkinson AR. 2003. Long-term region-wide declines in Caribbean corals.Science 301: 958–960.

Garrison VH, Rogers CS, Beets J. 1998. Of reef fishes, overfishing and in situ observations of fish traps in St John, U.S.Virgin Islands. Revista de Biologia Tropical 5: 41–59.

Garrison VH, Rogers CS, Beets J, Friedlander AM. 2004. The habitats exploited and the species trapped in a Caribbeanisland trap fishery. Environmental Biology of Fishes 71: 247–260.

Gell FR, Roberts CM, Goodridge R. 2001. The fishery effects of the Soufriere Marine Management Area 1995/6 to2000/1. University of York, York.

Gell FR, Roberts CM. 2003. Benefits beyond boundaries: the fishery effects of marine reserves. Trends in Ecology andEvolution 18: 448–455.

Gobert B. 1998. Density-dependent size selectivity in Antillean fish traps. Fisheries Research 38: 159–167.Goodridge R. 1996. Changes in the coral reef fishery in Soufriere, St Lucia associated with implementation of a systemof fishing priority and marine reserves. MS thesis, University of the West Indies, Barbados.

Grandcourt EM, Al Abdessalaam TZ, Francis F, Al Shamsi A. 2004. Population biology and assessment ofrepresentatives of the family Carangidae } Carangoides bajad and Gnathanodon speciosus (Forsskal, 1775), in theSouthern Arabian Gulf. Fisheries Research 69: 331–341.

Hawkins JP, Roberts CM. 2003. Effects of fishing on sex-changing Caribbean parrotfishes. Biological Conservation 115:213–226.

Hawkins JP, Roberts CM. 2004. Effects of artisanal fishing on Caribbean coral reefs. Conservation Biology 18:215–226.

Humann P. 1996. Reef Fish Identification. New World Publications: Jacksonville, FL.Hunte W, Mahon R. 1994. Size selection of fish by the mesh of fish traps. Document no. LPRSF SSW/WP/21,CARICOM Fisheries Resource Assessment and Management Project, Kingstown, St Vincent.

Jackson JBC. 1997. Reefs since Columbus. Coral Reefs 16: S23–S32.Koslow JA, Aiken K, Auil S, Clementson A. 1994. Catch and effort analysis of the reef fisheries of Jamaica and Belize.Fishery Bulletin 92: 737–747.

Mangi SC. 2006. Gear management in Kenya’s coastal fisheries. PhD thesis, University of York, York.Matos-Caraballo D. 1997. Puerto Rico fisheries census, 1995–1996. Puerto Rico Department of Natural andEnvironmental Resources, Mayaguez.

Miller RJ, Hunte W. 1987. Effective area fished by Antillean fish traps. Bulletin of Marine Science 40: 484–493.Morelock J, Winget EA, Goenaga C. 1994. Geologic maps of the southwestern Puerto Rico Parguera to Guanicainsular reef. Miscellaneous investigations series. US Geological Survey.

Murray SN, Ambrose RF, Bohnsack JA, Botsford LW, Carr MH, Davis GE, Dayton PK, Gotshall D, Gunderson DR,Hixon MA, Lubchenco J, Mangel M, MacCall A, McArdle DA, Ogden JC, Roughgarden J, Starr RM, Tegner MJ,

J.P. HAWKINS ET AL.130

Copyright # 2006 John Wiley & Sons, Ltd. Aquatic Conserv: Mar. Freshw. Ecosyst. 17: 111–132 (2007)

DOI: 10.1002/aqc

Yoklarich MM. 1999. No-take reserve networks: sustaining fishery populations and marine ecosystems. Fisheries24: 11–25.

NMFS (National Marine Fisheries Service). 1995. Characterization of the reef fish fishery of the eastern U.S. Gulf ofMexico. NMFS Memo, Report prepared for the GMFMC.

Olsen DA, LaPlace JA. 1978. A study of a Virgin Islands grouper fishery based on a breeding aggregation. Proceedingsof the Gulf and Fisheries Institute 31: 130–144.

Polunin NVC, Roberts CM (eds). 1996. Reef Fisheries. Chapman & Hall: London.Recksiek CW, Appeldoorn RS, Turingan RG. 1991. Studies of fish traps as stock assessment devices on a shallow reefin south-western Puerto Rico. Fisheries Research 10: 177–197.

Reynolds JD. 2003. Life histories and extinction risk. In Macroecology, Gaston KJ, Blackburn TM (eds). Blackwell:Oxford.

Roberts CM. 2005. Marine protected areas and biodiversity conservation. In Marine Conservation Biology, Norse EA,Crowder LB (eds). Island Press: Washington, DC.

Roberts CM, Hawkins JP. 1996. Status of reef fish and coral communities of the Cabrits National Park. University ofYork, York.

Roberts CM, Hawkins JP. 2000. Fully-protected marine reserves: a guide. WWF Endangered Seas Campaign,Washington, DC, and Environment Department, University of York, York.

Roberts CM, Ormond RFG. 1992. Butterflyfish social behaviour, with special reference to the incidence ofterritoriality: a review. Environmental Biology of Fishes 34: 79–93.

Roberts CM, Bohnsack JA, Gell F, Hawkins JP, Goodridge R. 2001. Effects of marine reserves on adjacent fisheries.Science 294: 1920–1923.

Robichaud D, Hunte W, Oxenford HA. 1999. Effects of increased mesh size on catch and fishing power of coral reef fishtraps. Fisheries Research 39: 275–294.

Robichaud D, Hunte W, Chapman MR. 2000. Factors affecting the catchability of reef fishes in Antillean fish traps.Bulletin of Marine Science 67: 831–844.

Rogers CS, Beets J. 2001. Degradation of marine ecosystems and decline of fishery resources in marine protected areasin the US Virgin Islands. Environmental Conservation 28: 312–322.

Russ GR. 2002. Yet another review of marine reserves as reef fishery management tools. In Coral Reef Fishes, Sale PF(ed.). Academic Press: San Diego, CA; 421–443.

Sandeman IM, Woodley JD. 1994. Jamaica north coast fisheries improvement project } final report to the CanadianInternational Development Agency. 504/13778. Canadian International Development Agency, Hull, Quebec.

Sary Z. 1995. Responses of an over-exploited Caribbean trap fishery to the introduction of a larger mesh size inDiscovery Bay, Jamaica. MSc thesis, University of the West Indies.

Sary Z, Oxenford HA, Woodley JD. 1997. Effects of an increase in trap mesh size on an overexploited coral reef fisheryat Discovery Bay Jamaica. Marine Ecology Progress Series 154: 107–120.

Sheaves MJ. 1995. Effect of design modification and soak time variations on Antillean-Z fish trap performance in atropical estuary. Bulletin of Marine Science 56: 475–489.

Slack-Smith RJ. 2002. Fishing with traps and pots. http://www.fao.org/DOCREP/004/X2590E/x2590e04.htm#TopOfPage

Stevenson DK, Stuart-Sharkey P. 1980. Performance of wire fish traps on the western cost of Puerto Rico. InProceedings of the 32nd Annual Gulf and Caribbean Fisheries Institute; 173–193.

Stewart J, Ferrell DJ. 2002. Escape panels to reduce by-catch in the New South Wales demersal trap fishery.Marine andFreshwater Research 53: 1179–1188.

Sutherland DL, Harper DE. 1983. The wire fish trap fishery of Dade and Broward counties. Florida Marine ResearchPublication no. 40.

Taylor RG, McMichael RH. 1983. The wire fish-trap fishery in Monroe and Collier counties. Florida Marine ResearchPublication no. 39.

Yoshikawa T, Asoh K. 2004. Entanglement of monofilament fishing lines and coral death. Biological Conservation 117:557–560.

Whitelaw AW, Sainsbury KJ, Dews GJ, Campbell RA. 1991. Catching characteristics of four fish-trap types on thenorth west shelf of Australia. Australian Journal of Marine and Freshwater Research 42: 369–382.

Wolff N, Grober-Dunsmore R, Rogers C, Beets J. 1999. Management implications of fish trap effectiveness in adjacentcoral reef and gorgonian habitats. Environmental Biology of Fishes 55: 81–90.

TRAP FISHING EFFECTS ON REEF FISH 131

Copyright # 2006 John Wiley & Sons, Ltd. Aquatic Conserv: Mar. Freshw. Ecosyst. 17: 111–132 (2007)

DOI: 10.1002/aqc

APPENDIX: SPECIES REMOVED FROM TRAPPABILITY ANALYSIS (ARRANGED IN

ALPHABETICAL ORDER)

Species Size (cm) Cryptic

Amblycirrhitus pinos 9 YesApogon maculates 9 YesAulostomus maculatus 75 NoBairdiella sanctaeluciae 15 YesCanthigaster rostrata 9 NoCentropyge argi 6 YesCentropyge aurantonotus 6 YesChannomuraena vittata 120 YesChromis cyanea 10 NoChromis insolata 9 NoChromis multilineata 14 NoCryptotomus roseus 9 YesEchidna catenata 45 YesEnchelycore carychroa 25 YesEnchelycore nigricans 60 YesEquetus acuminatus 20 YesEquetus lanceolatus 20 YesEquetus punctatus 23 YesFistularia tabacaria 120 NoGinglymostoma cirratum 270 NoGramma loreto 6 YesGymnothorax funebris 150 YesGymnothorax miliaris 45 YesGymnothorax moringa 90 YesHalichoeres bivittatus 18 NoHalichoeres cyanocephalus 11 NoHalichoeres garnoti 15 NoHalichoeres maculipinna 13 NoHalichoeres pictus 14 NoHalichoeres poeyi 14 NoHemiemblemaria simulus 9 YesHemipteronotus martinicensis 9 YesHeteroconger halis 38 YesHippocampus erectus 10 YesInermia vittata 18 NoLiopropoma carmabi 4 YesLiopropoma rubre 8 YesLucayablennius zingaro 4 YesMalacanthus plumieri 45 NoMegalops atlanticus 120 NoMonacanthus tuckeri 9 YesMyrichthys breviceps 75 YesMyrichthys ocellatus 75 YesNarcine brasiliensis 38 NoOdontoscion dentax 19 YesOphichthus ophis 75 YesOpistognathus aurifrons 8 YesPempheris schomburgki 13 YesScorpaenodes caribbaeus 10 YesSerranus baldwini 5 YesSerranus tabacarius 11 NoSerranus tigrinus 9 NoSparisoma atomarium 10 YesSparisoma radians 13 YesStegastes partitus 9 NoSynodus intermedius 35 NoSynodus saurus 18 NoThalisoma bifasciatum 13 NoUrolophus jamaicensis 30 No

J.P. HAWKINS ET AL.132

Copyright # 2006 John Wiley & Sons, Ltd. Aquatic Conserv: Mar. Freshw. Ecosyst. 17: 111–132 (2007)

DOI: 10.1002/aqc