May-June /978

Lobster, Homarusamericanus, Trap Design

and Ghost Fishing

Ronald Joel Smolowitz(Editor and Project Leader)

LCDR NOAA CorpsNorthwest Fisheries Center

Woods Hole, MA 02543

INTRODUCTION

The Northeast Fisheries Center of the National Marine Fisheries Service hasconducted research on the American lobster, Homarus americanus, for manyyears. Recently, research efforts have been directed toward forming a data baseupon which recommendations for management of the inshore and offshore stocks inwaters off the New England and Mid-Atlantic coasts can be based. The Center isassembling information on population, size, stock separation and mixing, growthrates, mortality rates, and recruitment indices.

To understand the effects of fishing on the resource, fisheries managers need notonly catch/effort statistics and total weight and size composition of removals, butalso data on the effects of non-selective and destructive fishing methods. Fisheriesengineers and diver/biologists of the Center conducted a series ot studies into theselatter two factors; the results of this research are contained herein.

Trap Design and Ghost Fishing:An Overview

Table 1.-Lobster fishery statistics for 1969 and 1970.

MFR PAPER 1306

RONALD JOEL SMOLOWITZ

INTRODUCTION

This paper presents necessarybackground information for the sub­sequent papers on lobster trap designand ghost fishing in this issue of MarineFisheries Review. A brief review of thelobster fishery and management is fol­lowed by a discussion of ghost fishingand escape vents.

England this represented a 2 percentincrease in volume and a 13 percentincrease in value over the 1968 land­ings. A 2 percent decline in catch byinshore pot lobstermen was more thanoffset by a 29 percent increase in catchby offshore otter trawlers. New York

and New Jersey's share of the harvestincreased by 20 percent in volume and24 percent in value over 1968 levels.These increases were due to a moreintensive inshore pot fishery which re­sulted when fishermen di verted their ef­fort from black sea bass, Cel1tropristisstriata. to lobsters (National MarineFisheries Service. 1969).

By 1972 the lobster landings weredown to 32.3 million pounds, but thevalue of the catch was in excess of $39million (Table 2). The inshore potfishery landed 23 million pounds-asignificant drop from the 27 millionpounds caught inshore in 1969. How­ever, the offshore landings had in­creased by nearly 2 million pounds dueto increased effort in the offshore pot

TOTAL LANDINGS POT FISHHtG fTER TRAWL -Lobue REMARKS(PGOlA4~)

rlsher-v~lncl~tli

1,000 lbs 1,000 S Traps lfftdl"'Jl- 'II""... t.ftdl"9l- O.T..., Boots (1,0001/1.1) .. hlU" I.OOOlhl t"'''''''ll

r1Of: 19.835 16,047 5,814 .:;..--r:669 819.375 19,835

35 ~esse1s ~ 402 gross leInslot,ll

H.H 731 652 261 ~93 17,160 732

MA 4.965 4,141 1,211 ~1 131.30) 3,455 152 Z4 1,249 220.5007 pOt vesseh - 1,010 gran

<D tons t014!

(1l'.1 4.246 3.787 228 ~8S 22.400 892 198 '1 3,]23 31.200

\'"CT 9JJ 945 445 ~4 20,7'14 ac. 12 3 12' 2,TOO

",... 30,711 26.172 1,965~ 1,012.022 25.718 362 68 4.698 254,400(·u.) 7,432

H.Y 1,416 1.415 261~ 37,195 883 72 18 461193 69.100

H.J 1.434 l,1l2 53 ~24 12,590 9" 198 .) 329 125,800

'" ------"'~ 2,850 2,"'1 31' ~ 49,785 1,857 270 65 790 194,900(IU.) 217

III 26 21

------21,700

4.800 Ib~ C4uqht in (hhtraps

VA 181 123

-------37 ) 181

TO' .... 207 144

------37 7 181 21,700",,,.

TOTA 33,768 28,964 8.279 ~ 1,061. 17 27.575 '" 140 5.6691.649 471.000

ME 18,172 1,,202 6,326~6,289 1,180.000 18.172

N.H. 688 722 J2J ~37 17.800 '88

'/0

\ MA 5.685 5,853 1.334 ~92 138.646 4,206 10' l' 1.039 397.200r--(1l R.I. 5.195 5,212 307 ~1 30.257 1,62"0 185 38 3,561 12.800

5 pot vessels· 396 gross

'\) tons total

~59 POt vessels - 87 gross

Cl 673 m 670 25.719 671 1.800 tons total

TOUl 30,413 29,704 8.960~ 1,392,422 25.357 287 54 4.600(u.) 8,364 411.800

H. Y. 1,647 1,847 375 ~ 47,070 '" 78 21 647 55.90025 pot vessels· 409 gross

266 tons tot<!ll

N.J. L,836 1,739 '3 ~ 15.450 70' '11 52 1,035 50.50017 pot vessels - 171 grass

'8 ton}j!-OUI. 43,800 lbs caught

D£ ~lOlA\.

~ ,~.q3 3,566 '38 ~;,: 62,520 289 73111.'.129. 1,649 1.682 106,400

MO 22 20 ~ 10 , 13 5f .O7,500 lbs caught 1n ftshtraps

VA 229 149 ~ 47 9 98 130,600

TOT ....

~tli(U 251 169 57 11 III 131 100

OTAl 34.147 33.459 9,398 ~ 1,454,942 27,006 63J 138 ,393 1649.3~18,658

RANGE

The American lobster, Homarusamericanus, is found naturally on theeast coast of North America, fromNorth Carolina to Labrador, and is mostabundant from Nova Scotia to NewYork. While most lobster fishing oc­curs in inshore waters, defined in thispaper as all coastal waters extending 30nautical miles seaward, since the early1950's the offshore lobster stocks(along the edge of the continental shelf)have been increasingly fished.

THE FISHERY

Lobsters in the inshore fishery arecaught mostly in traps or pots (the twoterms are used interchangeably) as de­scribed by Everett (1972). Offshorelobsters have been harvested using oltertrawl nets that are specifically riggedfor lobster fishing or that catch lobstersincidentally to fishing groundfish. In1968 an offshore pot fishery developedusing a larger version of the inshore pot(Doli bel', 1973:63).

The lobster fishery is the most valu­able fishery on the east coast of theUnited States. In 1969 lobster landingswere a record 33.8 million pounds­worth $29 million (Table 1). In New

Ronald Joel Smolowitz is with theNortheast Fisheries Center, NationalMarine Fisheries Service, NOAA,Woods Hole, MA 02543.

2

Vessel· oyerS tons Boat - under 5 tons 511I1I11 catches by dredges, gill nets. by nand, dip nets,

anddtvtng not lncludeil"

Marine Fisheries Review

TOTAL LANDINGS POT FISHING TT£R TR}Wl-lobster(,-,)

~ 11'lC'ldefttal REHA.RkS1.000 Ibs 1.000 I hher- Y~ Traps L,.tM'''f'- fl'P\otr. Urodh"lll- O.T.

"'. Bolts (1.0001'.' - VII"" {LOCOl". l!ft4I ...1

AME 17,568 17,481 6,670 ~s

34 vessels· 394 gron tons1.278,226 17.558

N.H. 667 741 345 ~o 18,600 667

... ~~ 6,146 6.894 1,099873 110,672 890,60(I'- 4,816 60 10 408

m ;;.-;;, 22 pOt vessels - 8.817 gross

\ A.. I. 5.389 6.03S 319 202 40,701 2,930 loo 41 2,458 ,....CT 5lJ 657 609~ 25,929 m I,OOC

10:41.~'J ,31.3 JI,811 9.042 ~ 1,474.128 26,492 260 891,60((~.[. ) 8,377 51 2.866

NY 1,790 l,OM 474~ 55.325 1,039 79 II m ll,IOC

NJ 1.323 1,460 IlJ~ 31.640 479 179 47 769 J5,4()()

J)[ JO 41 II .----; 475 JO

TOT.&L 3,143 ),555 618~ 87,440 1,548 l58I'..... ) )64 58 1.496 58,500

I() l8 l8

-------4,600 lbs caught In fish

23,500 tr"ps

VA l34 loo 19~ ),loo III 122.300

'"'' m n8 19~ ),loo III0<" 145,800

33.718 35-.594 9,619~ 1,564.768 518 mTOTAL .131 28.151 4,361 1j)95,900

ME 16,257 18,588 7,039~ l,A48,Jfi5 16.256

If."PC.H, 674 809 l77~ 15,958 673

... 8,032 10.216 l,lO4~ 145.127 1.017 604 ,138 offshor~ trips cau9htN 10 410 511,700

I'- 9)1 2.8 .. ill ion lbsm R, I. 3,361 4.319 418~

14.615 offshore trips caught

1\) l41 47,361 2,475 104 n 8n 13,400 1.6 Iltl1l0fl Ibs

CT 640 777 768 ~ 33,761 5)9 400

'"'' 28.664 34,769 9,696 ~ 1.690,518 21.020 164 32(U.) l,l8l 525,500

NY 1.145 1,825 506 ~ 53.1SO 1.011 6l 17 III)5J 11,400

NJ 1,308 1,828 171~ 42.010 838 IlO 3l31 447 15,100

J)[ l2 )6 19~ 615 l2

'"'' 2,475 3,689 696~ 95.175 1.871 18l 49 568 l6,500(1.... ,1

NO II l6 4 ~ 500 IS5,400 Ib'it cauqht In fishtraps

VA 884 1.028 J) ~ 6,000 877 6.100

10T,\4 90S 1.054 J7~ 6.500 892 6.100Ott"

TOTAL 32,244 39,512 10,429 1:/;;'; 1,792,65] 29,783 346 81 1,850 SS6.l00

Table 2.-Lobsler fishery slalls11cs for 1971 and 1972.

Since then government regulationhas taken many forms. There are lawsgoverning minimum and maximumsizes. Fishing seasons are regulated.There are also many regulations regard­ing the marketing of lobsters. Egg­bearing females are protected. Evenlimited entry has been used to restrictthe number of Canadian canneries inthe last century (Collins, 1904:22).

Other forms of regulations have dealtmainly with the gear used. Many statesrequire that pots and buoys have meansof identification as an aid for law en­forcement. Some types of gear are ban­ned outright, such as scuba gear inMaine. Otter trawlers are not allowed tooperate in certain areas.

Most of these regulations have been

fishery. The 1972 offshore pot landingswere 6.3 million pounds compared with115,000 pounds in 1969. Otter-trawlcatch declined from 6.8 million poundsin 1969 to 2.4 million pounds in 1972.

The average annual landings be­tween 1971 and 1975 were 30.4 millionpounds. In 1976, lobster landings were31.7 million pounds, worth a record$52.7 million (Robinson, 1977).

Tables 1-3 present an overall reviewof the lobster fi shery, by state, from1969 to 1974. The data were extractedfrom Fishery Statistics of the UnitedStates for the corresponding years, ex­cept for 1974 which is unpublished pre­liminary data.

MANAGEMENT

Because of the rapid decline of theinshore lobster catch and the increasingexploitation of the offshore stocks,methods to manage the resource arebeing discussed. Such discussions arenot new. For over a century, concernfor the protection of the American lob­ster has been shown by both industryand government. Calls for the protec­tion of lobsters are usually stimulatedby fear of overfishing to the point ofcommercial extinction.

Fishermen and researchers alikehave considered government regulationof lobster fishing one way to protect thelobster resource since the earliest yearsC)f the fishery (Herrick, 1911; Field,19 I I). One of the first restricti ve piecesof legislation on lobster fishing wasenacted in in Sweden in 1686. The firstprotective legislation for lobsters in thiscountry was formulated in Province­town in 1812. The Provincetown lawrequired permits for lobster fishing andwas actually more concerned with thepredator, man, than with the prey. By1874, overfishing, due to the rapidlyrising demand of the canning industry,caused Massachusetts to make it illegalto sell any lobster less than 10.5 inchesin overall length. Maine's first lobsterlaws, like those of Massachusetts, wereconcerned with residency require­ments. In the 1870's, coincidentallywith Massachusetts, laws were enactedthat restricted canning, but it was notuntil 1895 that the 10. 5-inch lobsterregulation terminated canning in Maineentirely.

May-June /978

V~ssel - over S tons Boats - under 5 tons

attempts to deal with the obvious situa­tions that may cause resource deple­tion. However, there are some less ob­vious problems. One of these is "ghostfishing. "

GHOST FISHING

Ghost fishing is defined as the abilityof fishing gear to continue fishing afterall control of that gear is lost by thefisherman. This problem was first rec­ognized in gillnet fisheries and was amajor topic of discussion at a Food andAgriculture Organization (FAa) meet­ing in Rome in 1960.

The chief of the Fishing Gear Sectionof FAa's Fisheries Division stated thatbottom-set cod gi II nets that were re­covered months or years after being lost

S,NIl catches by dredges. gill nets. by hand. dip neh.andd;yir.g not included.

J

~TOTAl LAHOUtGS POl FISHING n£R TRAWL-Lobster R[MAR,K$

('0\in6I)

Fisher-~

lllCjclen~l

1,000 lb$ 1.000 I Traps l~~\'Q!' rll,..r_ l~l'Mlt"91' O.T.

"'" BOAts (U)OCl 1M) w. Ytlul, {1,OOOlbt L'"cl!"9t

~p£ 17.044 Z3,Z70 8,151~ 1,822.490 17.044

N.H. 497 '80 468~ 22,299 4.7

HA 5,624 8.527 1,093~ 159,773 5,120 " 10 260 219,400 6.150 offshore traps co!ugl'lt.57 1. 7 million lbs

(J)R.l. 402~ 74 15

20.375 offshore traps caught

\/2.773 4,235 52.204 2.627 459 1.7 million lbs

CT 544 841 514~ 27,523 543

TOl"" 26,482 17 ,553 10,628~ 2.084,289 25.831 136 2S 719 219.4001~.[.1 9.728

NY 892 1,428 4.4~ 52.450 798 56 16 93800 3.400 offshore trd:ps caught

365 0.4 mill Ion lbs

NJ 1.363 2,234 115~ 40.565 '26 73 11 420 7.900 12.965 Offshon! traps caught0.4 million lbs

D' 2. 51 41~ 764 2. 400 offshore traps caughtI 500 lbs

101"l. 2.284 3,713 710~ 93,779 1.753 12' 38 Sl3 8,700(1\••• )

MO 24 33 3~ 800 20 3.700 lbs caught in (I!.htraps

VA I" 285 3' :---- 6.400 182 5 1 7 10.200

fOUl. 223 318 39~ 7.2Q0 202 5 1 7 10,200,..".28,989 41.584 11,377~ 2.185,268 27,786 270 64 1,239 238,300

TOTAl 0.141

p£ 16,457 2l,2lZ 10.628~ 1,789.900 16.457

(N.H. 4'8 702 '02 ~6 23.105 4.8

~24.100 offshore traps caught

~ HA 5.943 9,103 1,4711.062

170,100 4,993 60 11 950 1.1 million lbsr--(J)

R.1. 3.129 5.201 544 ~ 56.500 2.650 S2 16 S7923.500 offshore traps caught

\) 230 l.8 III 1lion lbs

CT 647 1,095 715 ~5 23.925 '47·)1~. 26.674 39,313 13,760 8~ 2,063.530 25.245 142 27 1.529(ll.e! 9.672

NY 730 1.395 554~ 56,200 661 4' 14 ,. 5,800 offshore traps cauClht0.3 million lbs

NJ l,l9l 1.9lS 107~ 32 .700 716 .0 18 m 9.700 offshOre tra.ps caught55 O.3,111Hon lbs

D' 2S 45 43~ 1.500 25

101"1,946 3,355 704 2':'----::: 90,400 1.402 13' 32 544pu.) .4.

"" 3' 65 , ~o 2.000 3' till Cdught offshOre

VA 274 504 20 ~o 3,000 274 all c.tught offshore

TOT.l.l 310 56' 2? ~ 5,OCJ 310"....TOTAL 28,930 43,237 14.49] 1~ 2.158,930 26,957 281 5' 2,073

10,116

Table 3.-Lobster fishery statistics for 1973 and 1974.

contained numerous fish skeletons andlive fish. He referred specifically to anintensive fishery around Iceland thatemployed synthetic fiber nets fittedwith plastic and metal floats-fishinggear that could continue to fish withoutrotting for long periods (U. S. Depart­ment of Interior, 1968).

The solution devised to counter theproblem was to hang the nets from thefloats with natural fiber twine. If thenets were lost, this twine would rotcausing the nets to separate from thefloats and sink; thus the gear would nolonger be an effective fishing unit (YonBrandt, 1964: 168).

The threat of ghost fishing in a potfishery became a concern in the west

4

Vessel - over 5 tons 8o.tt - under 5 tons

coast king crab, Paralilhodescamlschalica, fishery in the early/960's. When this fishery began in the1950's, the first pots were large ver­sions of those used for Dungenesscrabs, Cancer magisler. These potswere covered by natural fiber twineswhich usually rotted out in less than aseason (Rietze, pers. commun. I

). Dur­ing the 1960's, pot design evolved;king crab pots are now constructed withsteel frames covered with syntheticfiber web, making them highly durable.This durability made it more urgent to

'Harry L. Rietze, Director. Alaska Region. Na­lional Marine Fisheries Service, NOAA, P.O.Box 1668, Juneau, AK 99802.

~1I c.ttches by dredges, gill nets, by h.tnd, dip nets,.tnd diving not included.

answer the question of whether or notlost pots continued to fish and for howlong, especially when gear-loss rateswere estimated at over 3,000 pots an­nually (Meyer, pers. commun. 2

).

The National Marine Fisheries Ser­vice (NMFS) began in 1970 to study theproblem of lost king crab pots to deter­mine if they did continue to fish and iftrapped crabs could escape. In addition,information was gathered on deteriora­tion rates of different pot web hangingmaterials (Meyer, footnote 2). The pre­liminary results of the experiment indi­cated that king crabs could escape fromlost pots. However, the same study re­ported that lost pots that were recoveredoften contained as many as 100 livemarketable king crabs.

Some observations that gave impetusto the above research were made byMcNeely (NMFS, pers. commun. 3 ) ona cruise aboard the John N. Cobb inJanuary 1970. On this cruise nine ex­perimental sablefish (blackcod), Anop­lopoma fimbria. pots were recoveredwhich had been lost for I month. Sixof the pots contained snow crabs(Chionoeceles) , as many as 32 per pot,and the average catch of sablefish was12 fish per pot. There were also numer­ous remains of sablefish in the pots.

Hipkins and Beardsley4, in a prog­ress report on the development ofsablefish pots, felt that ghost fishing ofthese pots might be a serious problem:"It appears then that blackcod (sable­fish) pots (and probably most other potgear) will continue to fish with dead fishserving as bait to attract new fish whicheventually die to attract more fish andso ad infinitum until the pot deterioratesto the point where fish can escape. Thisprocess of deterioration is slow and

2Robert Meyer, National Marine Fisheries Ser­vice. NOAA, P.O. Box 1638, Kodiak. AK99615.

'Richard McNeeley, Northwest and AlaskaFisheries Center, National Marine Fisheries Ser­vice, NOAA, 2725 Monllake Boulevard East,Seallle, WA 98112.

'Hipkins, F. W., and A. J. Beardsley. 1970.Development of a pOl system for harveslingblackcod (Anoplopoma fimbria). A progress re­port. U.S. Dep. Commer., NOAA, Natl. Mar.Fish. Serv., Sealtle, 31 p. Available at the'\ionhwest & Alaska Fisheries Cenler, NMFS,NOAA, 2725 Monllake Boulevard Easl, Seattle,WA 98112.

Marine Fisheries Review

could take years depending upon thematerials employed in constructing thepot. The consequence of large numbersof ghost pots fishing in an unregulatedmanner in competition with fishermencould be catastrophic to the blackcodfishery. The lost pots will continue tofish long after the fishery is uneconomicfor the commercial fishermen."

They recommended, as a solution.that a cotton web destruct panel be bui Itinto each pot. Subsequently the State ofWashington issued a regulation onbottom-fish pots that requires: "A sec­tion of one vertical wall must be con­structed of cotton fiber or one of thewalls of synthetic fiber must be attachedto the frame with cotton hangings topermit escapement of fish if thebottom-fish pot is lost (Wash. Dep.Fish. Regs., WAC 220-16-J45. 1971).

Canadian fisheries managers, evenwithout experimental evidence,thought it prudent to lake action to pre­vent ghost fishing. Proposed regula­tions for the developing snow crab,Chionoecetes opilio, fishery containedprovision that would have required allpots to be fitted with a 12-inch longsection of netting laced with degradablematerial (Cormier, pers. commun ..').

Regulations of the State of Floridarequire that all spiny lobster, Panulirusargus, pots be constructed of wood sothe pot, when lost, will eventuallybreak and not continue to fish.Sixteen-gauge, I-inch poultry-wirereinforcement is allowed on the pot sidebut not on the top or bottom. This rein­forcement protects the pot from the"ravages of turtles." Escapable pots,e.g., ice cans and drums, are also per­mitted in the fishery (Seaman and Aska,1974:58).

Though preventive regulations exist,the controversy on ghost fishing is farfrom settled. At a pot fishing and arti­ficial baits symposium held at the Uni­versity of Washington in March 1972,there was much debate on whether potscan fi sh un bai ted. One ki ng crabfisherman felt that lost unbaited pots donot continue to fish. He thought that agreater problem was lost gill nets

"Fisheries and Environment Canada, Onawa, On­tario, Canada K JA OE6.

May-June /978

(tangle nets) which he has found attimes to contain the remains of manyking crabs (Jaeger, 1972).

Atthe same symposium il was Slatedthat Dungeness crab fishermen in theHumboldt Bay, Calif., area were con­cerned with ghost fishing. Here, too,there was" ... no sound experimen­tal data as to the catch rate in such ghostpots" (Jaeger, pers. commun. 6 ).

An analogous situation existed inAustralia in a snapper (Chrysophrysunicolor) fishery. Local fishermen wereafraid of the deleterious effect potsmight have on the fishery and researchwas undertaken to identify problems.Continued fishing by lost pots was con­sidered a possible problem, but hereagain no information was available onthe many factors related to ghost fishing(Bowen. 1964). (This pot fishery waseventually banned in 1966, mainly dueto the fact that the pots scraped alongthe sea bottom, when hauled, killinglarge areas of coral.)

In one of the most thorough researchprojects on pot fishing accomplished todate, factors affecting the performanceof the "Antillean" fish trap (Munro etaI., 1971) were studied. Many observa­tions were made on catch rates, es­capement, and mortality of a variety ofspecies of reef fishes. The researchersfound that although up to 50 percent ofthe entrapped fish eventually escaped,many others died due to physical de­terioration, starvation, and predation.This last factor, predation of entrappedanimals. has also been reported in theNew Zealand rock lobster, Jasusedwardsii and J. verreauxi, fishery,the predator in this case being Octopusmaorum (Ritchie, 1972).

The threat of ghost fishing in the NewEngland lobster fishery became a pointof concern during the development ofthe offshore pot fishery. The cruise re­port of the M V Delaware (Cruise68-05, July 1968) documents the re­covery of lost pots:

"Nineteen pots were recovered inMay 26. These pots had been lost onMarch 17 when all the bu oy Jines

"Sig Jaeger, North Pacific Fishing Vessel Own­er's Association, Fishermen's Terminal, Seattle,Wash.

had parted at faulty swaged splicesin the wires. The pots had been set in175- to 21 O-fathom depths. One ofthe recovered pots was damaged bythe grapnel-an entire side panelwas missing. The remaining 18 potscontained a total of 24 lobsterswhich weighed 156.5 pounds-thisis a catch rate of about 8.7 poundsper pot. All of the lobsters were quitelarge and they undoubtedly wouldhave exceeded the 6.5-pound aver­age weight if it had been possible toweigh them when they were firstcaught instead of after the extendedperiod of starvation through whichthey had passed. The volume ofmeat within the lobster shells wasexceedingly small for the size ofeach shell; one very large lobster hadthrown both claws-the blackenedremnant of the crushing claw wasstill in the pot with the lobster."

Experiences such as this, by both re­searchers and commercial fishermen,became more common as the fisherydeveloped.

In November of 1971, McRae pre­pared material for an InternationalCommission for the Northwest AtlanticFisheries (ICNAF) advisory committeemeeting that recommended action betaken to prevent the possibility of aghost-fishing problem in the offshorelobster fishery (McRae, NMFS, pers.commun. 7

). In March of 1972, theNortheast Fisheries Center undertookthe task of developing methods to pre­vent ghost fishing. Concurrently withNMFS research, Sheldon and Dow(1975) conducted a ghost trap experi­ment in Maine. They concluded thatunbuoyed traps continued to fish, andthat cannibalism resulted in the deathsof at least 15 percent of the lobstersentering the traps.

Factors AffectingGhost Fishing

Initial research by the Center, con­sisting mostly of a literature review,concerned itself with identifying thefactors affecting ghost fishing in the

7Ernest McRae, Southeast Fisheries Center, Na­tional Marine Fisheries Service, NOAA, 75 Vir­ginia Beach Drive, Miami, FL 33149.

5

Figure I.-A photo taken from a submersible at 100 m in Veatch Canyon ofa lost trap thatwas no longer an effective fishing unit. A red hake surveys the scene.

offshore lobster fishery. Theseparameters were grouped as follows.

Number of pots lost.

By definition, the first criterion that apot must meet to be considered a ghostpot is that it is lost. A lost pot is not aghost pot unless it continues to fish afterall control is lost. Pot loss in theoffshore lobster fishery is caused byvessels inadvertently severing trawlstrings, trawl strings become fouled,storms, and gear mechanical failure.

POf type

The ghost-fishing catch rate is a di­rect function of how long the pot re­mains physically intact as an effectivefishing unit (Fig. I). While the offshorelobster fishery had a high pot-loss rate,it used the cheaper, less durable,wood-framed pot. As the loss rate de­creases, fishermen tend to switch tohighly durable pots.

The size of a pot is also important inassessing ghost fishing. Larger potsusually have higher catch rates.

Other key parameters affecting catchare pot selectivity (size range andspecies) and the effectiveness of the potdesign in preventing escapement. Themortality caused by ghost fishing is di-

6

rectly related to the retention capabilityof the pot and the pot's selectivity.

Location where lost

The forces acting to destroy a pot asan effective fishing unit vary geo­graphically and with depth. Corrosionrates are a function of interrelated vari­ables such as temperature, depth, oxy­gen, salinity, and velocity. Biologicaldeterioration varies at different loca­tions and with temperature, velocity,and substrate. A pot can also be de­stroyed by storm surge or by being bur­ied in the substrate.

The ghost-fishing catch rate varieswith the target-species availability atdifferent locations. Ghost-fishing mor­tality is probably related to the avail­ability of predators and to hydrographicconditions; these two factors are alsolocation dependent.

Target-species behavior

A ghost-pot's catch rate depends onwhy the target species enters the pot,e.g., bait and/or shelter-seeking be­havior. It follows that the pot's reten­tion rate is a function of this behavior aswell as of pot design; some pots aredesigned to be inescapable, whileothers are hauled before the targetspecies wants to leave.

Ghost-fishing mortality depends on

the target species' endurance of the ad­verse conditions of the pot. There canbe self- or conspecific-inflicted injuriescaused by behavioral response to theconditions of crowding, starvation, andenvironmental change.

Preventing and DecreasingGhost Fishing

Two of the controllable factors af­fecting ghost fishing are rate of pot lossand pot type.

In the offshore lobster fishery.fishermen have placed much effort intodecreasing their pot losses. Thesefishermen set trawl strings with up to 90attached pots, sometimes extendingover 1.5 km in length, on the oceanbottom. Foreign and domestic trawlfishermen, dragging midwater or bot­tom trawl nets, often work the sameareas as the fixed-gear lobstermen.They sometimes inadvertently towacross the lobster-trawl strings and fre­quently sever the connections to surfacebuoys.

A partial solution to this problem hasbeen to concentrate the pots in "potfields" and report their positions to theCoast Guard. This solution has beenfurther refined by dividing offshorewaters into dragging and fixed-gearareas. The concentration of pot fieldshas led to lobster-trawl strings becom­ing fouled with each other and beinglost. This problem has been reduced bythe lobstermen setting their stringsparallel to the bottom depth contours.

The above practices by the fisher­men, along with experience gained inthis new offshore lobster fishery, havedecreased the annual pot-loss rate fromas high as 100 percent to about 25 per­cent. This latter figure is comparable tothe loss rate in the inshore lobsterfishery.

The fishermen's immediate concernfor decreasing gear loss is based on thedirect economic costs and not a fear of aghost-fishing problem. Their choice ofpots is also based on direct economiccosts, the primary variables beingdurability, handling, and catch rates. Itcan be assumed that a fisherman willuse the most economically efficient potavailable. The problem is to design thispot to prevent or reduce ghost fishing ifthe pot is lost, without introducing in-

Marine Fisheries Review

efficiencies into the fisherman's opera­tion. One approach would be to designthe pot to selectively retain only legal­sized lobsters. Much research has beenaccomplished in this area in regard toprotecting short lobsters.

Enforcement of size limits has al­ways been a problem (Collins, 1904;Herrick, 1911; Field, 1911). Even to­day, by conservative estimates, thelanded number of short lobsters ex­ceeds 10 percent of legal landings.Though this illegality is difficult todocument, it is not necessarily difficultto solve. Solutions available include: I)increased enforcement pressure, 2) bet­ter education of the fishermen on thevalues of size limits, and 3) sublegalescape vents.

Escape Vents

Pots that contain escape vents couldconceivably decrease ghost fishing re­lated injuries and mortality. The wordvent is defi ned here as an opening in alobster pot, such as the space betweenthe laths. An escape vent is an openingdesigned into the pot to allow lobstersto escape. The head ring in a pot is theentrance vent, though lobsters may alsoescape through it.

Sublegal escape vents allow lobstersunder the legal minimum size to es­cape. A legal minimum size require­ment is considered an effective biologi­cal and economic tool (Wilder, 1954;Thomas, 1973). While there is no con­sensus of what the optimum minimumsize should be, few challenge the factthat size limits are necessary for protec­tion of the lobster stocks.

Sublegal escape vents on lobster potsare not a new idea. The effects of lathspacing on the size composition of thecatch has been recognized by fishermenever since they began building pots.

Some of the earliest recorded scien­tific experiments on lath spacing wereconducted by Adolph Neilsen, Superin­tendent of Fisheries in Newfoundland,in the 1890's (Templeman, 1958). Heestablished the concept of using lathspacing as a means of regulating thecatch of sublegal lobsters.

Newfoundland eventually enacted alaw requiring 13M-inch spacing in pots,but many fishermen were critical of thevalue of this law. They thought it did

May-June /978

not affect the catch of sublegals, thatthe bait was used up faster, and thatlegals could escape. In 1938 Temple­man conducted experiments demon­strating that pots with the 13M-inch spac­ing not only caught 80 percent fewershorts (9-inch overall length), but werealso able to catch more legal-sizedlobsters than pots of smaller lath spac­ing (Templeman, 1939).

Wilder conducted similar experi­ments between 1943 and 1946 (Wilder,1943, 1945, 1949). In areas where thelegal size of the lobster was 7 inchesoverall, Wilder found that pots withI J.4-inch lath spacing decreased thecatch of sublegals by 60 percent andincreased the catch of legals whencompared with pots of I-inch spacing.Where the legal size was 3 VB inches onthe carapace, 13M-inch lath spaces al­lowed 7S percent of the shorts to escapewithout reducing the legal catch. Wild­er states that pots with sublegal ventsallowed the greatest increase in legalcatch where the average size of lobsterscaught was large. Where the averagesize was small, the greatest reduction incaptured shorts occurred. In addition,wider-lath pots retained fewer crabs.

Experiments in Western Australiaand Tasmania, testing the effectivenessof sublegal escape gaps (vents) onrock-lobster pots, provide results simi­lar to that of the Canadians. Again, potswith escape vents decreased the amountof undersized lobsters caught and in­creased the catch of legal-sized lobsters(Winstanley, 1970, 1973; Bowen,1963).

The crab fishermen of California,Oregon, Washington, and Alaska havea self-imposed regulation requiring es­cape vents in pots (Hipkins, 1972).These vents allow the smaller femalecrabs to escape. In California, a regula­tion regarding crab-pot escape-ventsize became law effective January1975.

In August of 1975 the State-FederalLobster Management Program made upof representatives from New Englandand the Mid-Atlantic states, recom­mended that sublegal escape vents berequired in all lobster traps. The re­commendations, based in part on un­published data from this study, andfrom Krouse and Thomas ( 1975), were

subsequently promulgated as regula­tions by Massachusetts and Maine.

The advantages of sublegal escapevents in the northern lobster fisheryhave been summed up by Templeman(1958) as follows:

"(a) the lessening of the temptationto sell illegal small lobsters and thereduction of the number of shortsavailable to fishermen who illegallyretain these lobsters; (b) the savingof considerable time in picking shortlobsters and crabs out of traps; (c) adecrease in injuries to short lobstersby rough handling and from encoun­ters with larger lobsters in theconfined space of the traps; (d) aprobable reduction in the loss ofsmall lobsters which may be eatenby cod and other fishes, either ontheir way down from the surfaceafter being discarded, or becausethey have been distributed on thebottom, in daylight, in unfamiliarterritory without shelter; and (e) ifthe traps were built with wide spacesall over them, an increase in haulingefficiency, since traps with fewerlaths and less ballast, and with widerspacing all over the trap, would bemore stable and survive better underturbulent conditions. It is very likelyalso that this greater stabil ity wouldincrease the catch when the traps arefished in wave-disturbed shallowwater. "

Sublegal escape vents may effec­tively decrease ghost-fishing mortalityamong short lobsters, especially wherethe catch ratio of shorts to keepers is 10to 15: I (Thomas, 1973:4), but do notsolve the problem within the legalrange. Most of the offshore lobsterscaught are of legal size. The approachhere may be to have a "catch-escapevent" on each pot that is kept shut bysome degradable mechanism. After aspecified period of time this mechanismwould deteriorate, opening the vent andrendering the pot ineffective, e.g., thecotton panel required on Washingtonbottom-fish pots.

Another approach to the problem ofpreventing ghost fishing might be todesign an entirely different type of potthat does not depend on the escape­proof trapping of the lobsters. Pots of

7

Figure 2. -An offshore lobster using a discarded 55-gallon drum as a shelter. Photo taken from asubmersible at 200 m in Veatch Canyon.

this variety are used in a number offisheries where the target animal dem­onstrates positive thigmotactic re­sponse, e.g., eels, octopus, and spinylobsters (Von Brandt, 1964:58). In thespiny lobster, Panulirus argus, fisheryof Florida, Ihis type of pot is sometimesconstructed out of discarded gasolinedrums (Smith, 1958:26).

We coined the name "habipot" for atype of pot that does not depend primar­ily upon bait attraction or escape-prooftrapping of the lobsters but instead cap­tures lobsters by offering an attractiveshelter (Fig. 2). Pots of this conceptualdesign would not ghost fish, and couldpossibly fish selectively since dif­ferent-size lobsters apparently preferdifferent shelters (Cobb, 1971). Unfor­tunately we were not able to test thisconcept adequately because of timeconstraints.

The papers that follow present theresults of our field and laboratory exper­iments.

LITERATURE CITED

Ihe lobster. Homal'lls americanus. Ecology52: 108-11 5.

Collins, J. W. 1904. Report of a convention heldin Boslon. 1903, to secure better protection ofthe lobster. Mass. Comm. Inland Fish. GameRep. 1903.51 p.

Doliber. E. 1973. Lobslering/inshore andoffshore. Assoc. Press. N. Y., 108 p.

Everett, J. T. 1972. Inshore lobster fishing. U.S.Dep. Commer., NOAA, Natl. Mar. Fish.Serv., Fish. Facts-4, 26 p.

Field, G. W. 191 I . The lobster fishery: A specialreport including suggestions for uniform lawsmade to the Legislalure of Massachusetts bythe Commissioners on Fisheries and Game.Boslon. Mass., 59 p.

Herrick, r. H. 191 I. Natural history of theAmerican lobster. Bull. U.S. Bur. Fish.29: 149-408.

Hipkins. F. W. 1972. Dungenesscrabpots. U.S.Dep. Commer., NOAA, Natl. Mar. Fish.Serv., Fish. FaCIS-3, 13 p.

Jaeger, S. 1972. Potfishing and artificial baitssymposium proceedings. Wash. Sea GrantAdvis. Program, Univ. Wash., Seattle,WSG-AS-72-2, 32 p.

Krouse, 1. S., and J. C. Thomas. 1975. Effects oftrap selectivity and some population param­eters on size composition of Ihe American lob­ster, Homarus americanlls. catch along theMaine coast. Fish. Bull., U.S. 73:862-871.

Munro, J. L., P. H. Reeson, and V. C. Gaul.197 I. Dynamic factors affecting the perfor­mance of the Antillean fish trap. Gulf Caribb.Fish. lnst. Proc. 23:184-194.

National Marine Fisheries Service. 1972. Fisherystatistics of the United States 1969. U.S. Dep.Commer.. NOAA, Natl. Mar. Fish. Serv.,Stat. Dig. 63,474 p.

Ritchie, L. D. 1972. Octopus predalion on pot­caught rock lobster-Hokianga area, N.L.,September-October 1970. N.Z. Mar. Dep.,Fish. Tech. Rep. 81,40 p.

Robinson, L. A. (editor). 1977. Fisheries of theUnited States, 1976. U.S. Dep. Commer.,NOAA, NaIl. Mar. Fish. Serv., Curr. Fish.Stat. 7200, 96 p.

Seaman, W .. Jr.,andD. Y. Aska(editors). 1974.Research and information needs of the Floridaspiny lobster fishery. Proceedings of confer­ence held March 12, 1974, Miami. Mar. Ad­vis. Program, Univ. Fla., Gainesville, SUSF­SG-74-20 I, 64 p.

Sheldon, W. W., and R. L. Dow. 1975. Trapcontributions to losses in the American lobsterfishery. Fish. Bull., U.S. 73:449-45 I.

Smith, F. G. w. 1958. The spiny lobster industryof Florida. Fla. Board Conserv., Educ. Ser.11,36 p.

Templeman, W. 1939. Investigations into the lifehistory of the lobster (Homarus americanus)on the west coast of Newfoundland, 1938.Newfoundland Dep. Nat. Resour., Fish. Bull.7, 52 p.

____. 1958. Lath-spacing in lobster traps.Fish. Res. Board Can., Prog. Rep. Atl. CoastStn. 69:22-28.

Thomas, J. C. 1973. An analysis of the commer­cial lobster (Homarus americanus) fisheryalong the coast of Maine, August 1966 throughDecember 1970. U.S. Dep. Commer., NOAATech. Rep. NMFS SSRF-667, 57 p.

U.S. Department of the Interior. 1968. Explora­tory fishing and gear research base. Lobsterexplorations with pot (trap) gear. Cruise Rep.,M/V Delaware 68-05. U.S. Dep. Inter., Bur.Comm. Fish., Gloucester, Mass., 7 p.

Von Brandt, A. 1964. Fish catching methods ofthe world. Fish. News Ltd., Lond., 19\ p.

Wilder, D. G. 1943. The effect of lath spacingand size of fishing ring on the catch of lobstertraps. Fish. Res. Board Can., Prog. Rep. Atl.Coast Stn. 34:22-24.

____. 1945. Wider lath spaces protectshort lobsters. Fish. Res. Board Can., Atl.BioI. Stn. Circ. 4, I p.

1949. Protect short lobsters bywidening lath spaces. Fish. Res. Board Can.,Atl. BioI. Stn. Circ. 14, I p.

____. 1954. The lobster fishery of thesoulhern Gulf of St. Lawrence. Fish. Res.Board Can., Atl. BioI. Stn., Gen. Ser. Circ.24, 16 p.

Winstanley, R. H. 1970. Escape gap commercialcrayfishing trials. Professional Fisherman'sAssociation of Tasmania (Magazine), April1970, p. 118.

- . 1973. Tasmanian rock lobsterfishery-past and future. Aust. Fish.32(7): 15-20.

Bowen, B. K. 1963. Effectiveness of escape gapsin crayfish pots. Fish. Rep. 2, Fish. Dep ..West. Aust., 13 p.

____. 1964. The Shark Bay fishery onsnapper, Chrysophrys lInicolor. Rep. I. Fis.h.Dep., West. Aust., 13 p.

Cobb. S. 1. 1971. The sheller related behavior of

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MFR Paper 1306. From Marine Fisheries Review, Vol. 40, No. 5-6, May-June1978. Copies of this paper, in limited numbers, are available from 0822, UserServices Branch, Environmental Science Information Center, NOAA, Rockville,MD 20852. Copies of Marine Fisheries Review are available from the Superin­tendent of Documents, U.S. Government Printing Office, Washington, DC20402 for $1.10 each.

Marine Fisheries Review