Participation of U. S. Trawlersin the Offshore Shrimp Fisheries of

French Guiana, Surinam, and Guyana, 1978-79

ALEXANDER DRAGOVICH and ESSIE M. COLEMAN

The authors are with the Miami Laboratory,Southeast Fisheries Center, National MarineFisheries Service, NOAA, 75 Virginia BeachDrive, Miami, FL 33149-1099. This paper isContribution No. 83-27M.

ed its state of exploitation. The samegroup reviewed and discussed suitablemanagement measures and researchneeds and priorities. The proceedings

western hemisphere, emerged in thelate 1950's. The fishery's history isreviewed by Naidu and Boerema(1972) and Dragovich (1981). Underthe auspices of WECAFC (WesternCentral Atlantic Fishery Commis­sion), an international working groupmet in Panama in 1979 and reviewedthe existing knowledge of the Gui­anas-Brazil shrimp fishery and assess-

100.1"'--.,f--"""'T--T""-"'"T--y---t--y--"'"T--r--"'"T--......,

The waters overlaying the continen­tal shelf area of northeastern Brazil,French Guiana, Surinam, and Guy­ana, known as the Guianas-Brazilshrimp grounds (Fig. 1), harbor fourcommercial species of shrimp: Brownshrimp, Penaeus subti/is; pink-spot­ted shrimp, P. brasiliensis; pinkshrimp, P. notia/is; and white shrimp,P. schmitti. The Guianas-Brazilshrimp fishery, a multimillion dollarinternational fishery known as one ofthe most productive fisheries in the

Introduction

Figure I.-The Guianas-Brazil shrimping grounds, showing the fish ing zonesand their common names.

MIDDLEGROUNDS

~ .....

7776

EAST

.~~OUNDS ROCK

74 7S737271. ·~9 70

A BSTRA CT- The offshore shrimp fisheryof French Guiana, Surinam, and Guyana isknown as one of the richest fISheries in thewestern hemisphere. The four principal speciesharvested are brown shrimp, Penaeus subtilis;pink-spotted shrimp, P. brasiliensis; pinkshrimp, P. notialis; and white shrimp, P.schmitti. Brown and pink-spotted shrimpmade up the bulk of landings. In 1978 and1979, the U.S. catch off the three Guianas was7.0 and 8.9 million pounds ofshrimp or38 and39 percent, respectively, of the total landingsby all fleets operating in this fIShery duringthese years. The average annual catches perU.S. trawler in thousands ofpounds were 52.1(1978) and 67.5 (1979), and the annual catchrates were 13.1 (1978) and 15.4 (1979) poundsper hour. Most fishing was done at night atdepths between 21 and 35 fm offFrench Gui­ana and Surinam and between 11 and 25 fmoff Guyana. Large shrimp «10 to 26-30 perpound) were prevalent in the landings duringthe first halfofthe year, while the smaller sizes(41-50 and >50 per pound) were prevalent dur­ing the second half of Ihe year.

In the absence of data for realistic estimatesof maximum sustainable yield, our assessmentof this fishery was based on trends (1961-79) intotal catch of all nations fishing the area andthe number of trawlers. The shrimp catchesduring 1966-79 remained fairly constant with arange of 15,000 to 20,000 t whole weight, asthe number oftrawlers variedfrom 281 to 658.

April-May-June 1983,45(4-6) 1

of the Panama meeting were pub­lished in February 1980 (Jones andVillegas, 1980a, b). The literature re­lated to the Guianas-Brazil shrimpfishery includes a large number ofpublications listed by Tashiro andDragovich (1980).

In this paper we discuss catch andeffort statistics for 1978-79 from theU.S. flag trawlers operating off theshores of French Guiana, Surinam,and Guyana, and landing informationobtained from processing plant rec­ords. In previous reports on this fish­ery (Jones and Dragovich, 1973;Dragovich and Coleman, 1980), wediscussed the catch and effort statis­tics from the Guianas-Brazil shrimpfishery for 1972-77. During thoseyears, U.S. trawlers fished off Brazil,and relevant statistics on their activitywere collected under the terms of theU.S.-Brazil bilateral fishery agree­ment. The last of these agreements ex­pired in December 1977, and no fish­ing by U.S. vessels has occurred offBrazil since then.

Sources of Dataand Methods Used

Data were obtained on a voluntary

basis from 1) logbooks completed bythe captains of U.S. trawlers operat­ing out of the ports of Cayenne,French Guiana; Paramaribo, Suri­nam; and Georgetown, Guyana, and2) from landing statistics of proces­sing plants from the same ports.

Captains' logbook records includeddaily entries on area fished, numberof hours fished, number of haulsmade, night or day fishing, estimatedshrimp catch (pounds, heads-offweight), and most abundant species.Only the retained catch was reportedand no estimates were made of thediscarded by-catch. We also receivedmonthly and annual landings fromU.S. and other-than-U.S. boats thatfished the fishing grounds off theGuianas. Each landing record de­noted a fishing trip and included thetotal weight of shrimp in each com­mercial weight category. Based on themarket price of shrimp, landings werelisted either as mixed shrimp (pink­spotted, brown, and pink) and/or aswhite shrimp. In our treatment of thelanding's data, the mixed and whiteshrimp were combined in one cate­gory. Landing records did not containinformation according to the statisti-

cal zones, as shown in Figure 1. Dur­ing 1978-79, the fleets based in Cay­enne, French Guiana; Paramaribo,Surinam; and Georgetown, Guyana,fished only off these three countries.Thus, the information on the arealorigin of landings during 1978-79 ismore precise than prior to 1978 whenthe fleets were fishing anywhere be­tween the Amazon and OrinocoRivers.

U.S. Catch and Effort Statistics

Annual and Monthly Landings

Prior to the implementation of off­shore jurisdiction, licensing require­ments, and landing quotas (Table 1),trawlers operating out of Guyana,Surinam, and French Guiana werenot subject to regulations. Starting in1977 and thereafter shrimp trawlershave been licensed and their numbershave been regulated by each country.The present Guianas shrimp fleet ismodern, fairly uniform in size, anduses Florida-type shrimp trawlers. Ex­cept for a slight increase in size andengine power and predominance ofsteel over wooden or fiberglass ves­sels, characteristics of the present fleet

Table 1.-Coastal countries' regulations affecting shrimp flshertes In the Gulanas·Brazll area'.

Extended fishery jurisdictionCountry and licensing requirements

Guyana Jurisdiction extended to 200 mileson 14/10177. License fees for for­eign-owned Guyana~based vessels(US$5,000); foreign-based vessels(US$39,200) and Guyana-<lwned Guy­ana-based vessels (US$2,000); 12­mile territorial sea,

Surinam Jurisdiction extended to 200 mileson 10/12/78. No license scheme; 3­mile territorial sea.

French Jurisdiction extended to 200 milesGuiana in January 1977 by European Econom­

ic Council (EEC). Licensing fromFrance, no fee required at present;12-mile territorial sea.

Brazil Jurisdiction extended to 200 milesin 1970. Foreign fishing under li­censing scheme permitted until31/12/77. Since 1/1178, only jointventures and leasing arrangementspermitted.

Closedseason

None

None

None

None (closedseason forfo re ign boatsenforced in1972-77).

Area restriction

None, except foreign ves­sels must fish outside 12miles.

None

None. except no shrimp­ing permitted in lagoonsor lagoon outlets; notrawling inside 3 miles.From 30 April to 1 Jan­uary, no shrimping atdepths less than 16'/2 fm.

None

Catch or effortlimitations

None

None

Total annual quota of 3.000 tset for 1978. Permanent li­censes issued to French Gui­ana-based vessels. Temporarylicenses. based on fishingdays, issued to foreign-basedvessels until total quota isreached.

Limned entry, only 250 ves­sels allowed in the regionTutoia-Amapa.

Shrimp sizelimitations

None

None

None

None

By-catchlandings

Shrimp vesselsrequired to land2,000 lb. of by­catch per trip;not strictly en­forced.

No regulations,food fish landedaccording to mar­ket demand.

No regulations,food fish landedaccording to mar·ket demand.

No regulations,food fish landedaccording to mar­ket demand.

IAII countries appear to have plans for implementing stricter regulations.

2 April-May-June 1983,45(4-6)

Figure 2.-U .S. monthly shrimp landings fishing off Guyana and FrenchGuiana, 1978-79.

Guyana 19781979

1979

o..LJ1L..I~~L--. a..JIL..I~L..A...

J F M A M J J A SON DMonths

o J F M A M J J A SON D

Months

100

200

300

400

500

100

200

300

500

400

pounds/hour; 1977 =9.6 pounds/hour). This increase was particularlynoticeable in the 15-20 pounds/hourcategory for which the values morethan doubled off Guyana and offSurinam during 1979 (Fig. 3). Catchrates in the categories exceeding 25pounds/hour were reported only in1979 off Surinam.

The average annual catches by U.S.trawlers in thousands of pounds were52.1 and 67.5 for 1978 and 1979, re­spectively. Except for 1973, the yearof the bumper crop, the annual catchper trawler for 1979 was higher thanthe corresponding values for the pre­viously reported years (Table 1). Therelatively high catches by U.S. trawl­ers in 1978 and 1979 were coincidentalwith the facts that 1) the fleets wererestricted to fishing only off countriesof their registry, and 2) the adjoiningBrazilian fishing grounds off themouth of the Amazon were shrimpedby 160 instead of 250 trawlers, themaximum allowable number of trawl­ers for this area.

French Guiana

400

300

200

100

500

o...l...IL..JI~L& a..J~~~L

300

400

200 I100

"'~ O--UJUFUM~A..JML..IJIJJ~AUS~O~N~D

~ Months

"'-grn::>,g 500e-

year, landings in Guyana peaked inMay and thereafter declined. In 1978,French Guiana landings peaked inMay and June and in 1979 in Janu­ary, March, and July. The number ofboats varied only slightly during the2-year period; French Guiana had 60boats in 1978 and 56 in 1979, whileGuyana had 74 boats in 1978 and 79in 1979.

Catch Per Unitof Effort (CPUE)

To express CPUE we used 1) catchper hour of fishing and 2) annualaverage catch per trawler, the latterbeing a popular method in the Gui­anas as a measure of fleet efficiency.The average catch per hour of trawl­ing was calculated from the captain'slogbooks while the annual averagecatch rates per trawler are based onlanding records.

Average hourly catch rates for 1978(13.1 pounds) and 1979 (15.4 pounds)were higher than the values for thetwo previous years (1976 = 11.8

U.S Number Weight landedYear catch of trawlers per trawler

1972' 50 153 3271973 13.6 188 72.31974 9.0 207 43.51975 6.8 157 43.41976 5.9 134 44.21977 8.2 141 58.61978' 7.0 135 52.11979' 8.9 132 67.5

'One·half year2No fishing in Brazilian waters by U.S. vessels.

Table 2.-Annual shrimp landings (millionpounds, heads-off). number of trawlers, andweight landed by U.S. flag vessels in the Gui·anaa-Brazll fishery (1972-79). The mean catchvalues per trawler were computed by usingthe actual landing figures instead of rounded­off values as shown.

are similar to those presented byJones and Dragovich (1973).

The total landings by U.S. vesselsfor 1978 and 1979 were 7.03 and 8.9million pounds, respectively. Theserepresent 38.2 and 38.8 percent of thetotal landings by vessels from allcountries participating in those years.We assembled data on annual land­ings, number of trawlers, and averageannual landings per trawler for theperiod 1972-79 (Table 2) to demon­strate trends in shrimping activity bythe U.S. fleet operating off the Gui­anas. The average catch per U.S.trawler in 1979 was 23 percent higherthan that of 1978.

The year 1972 is used as a startingpoint because in July of that year thefirst U.S.-Brazil bilateral agreementwas signed. Our data for 1972 repre­sents only the second half of the yearand should not be used in compari­sons with data from other years.

Monthly landings of shrimp forFrench Guiana and Guyana for 1978and 1979 are shown in Figure 2. In­sufficient data were available fromtrawlers fishing off Surinam to in­clude their landing information inFigure 2.

Pronounced differences occurred inmonthly shrimp landings from Guy­ana and French Guiana (Fig. 2).Whereas the Guyana landings hadsimilar monthly trends in both years,monthly landings in French Guianawere irregular. Following an annuallow during the early months of the

April-May-June /983,45(4-6) 3

FRENCH

GUIANA

1978 _

19791111I1

GUYANA

10

30

40

30

10

% 20

% 20

"D

~ % 20OJ

52'0C(j)()

QiIl.

FrenchGuiana

5 10 15 2025

Surinam

1978

5 101520253035 40 5 10 15 20

5 10 15 205 10 15 20

Guyana

5 10 15 2025

20

30

20

10

o

Cf)c

.Q 10+-'co>~

Q)Cf)

..Q 0o

'+-

o 25~

Q)..Q

E::JZ

Pounds/hourFigure 3.-Frequency distribution of mean catch per hour of trawling by U.S.shrimpers off the coast of Guyana, Surinam, and French Guiana, 1978-79.

Depth in fathoms

Figure 4.-Distribution of fishingeffort by depth interval for Guy­ana, Surinam, and French Guiana,1978-79.

Distribution of FishingEffort and Catch Ratesin Relation to Depth

and Fishing Zone

Knowledge of areal and depth dis­tribution of fishing effort and relatedcatch rates is very important in theecological studies of commercially im­portant species of shrimp and is alsoof practical value to commercial fish­ermen (Jones and Dragovich, 1977).Based on captains' logbooks, ourtrawlers fished depths from about 5 to60 fm. We plotted the distribution offishing effort in relation to depth (Fig.4); 98 percent of U.S. shrimpersfished off French Guiana and Guy­ana. Off French Guiana, more than80 percent of fishing effort was at the

intermediate depths between 21 and35 fm during both 1978 and 1979; offGuyana the pattern of effort differedfrom that off French Guiana as trawl­ers spread their effort over a muchwider range of depths than off FrenchGuiana (Fig. 4).

To observe the spatial and temporaldistribution of catch rates, we plottedthe mean monthly hourly rates foreach fishing zone (Fig. 5). The ratesvaried slightly during 1978 and 1979in all fishing zones and at all depths(Fig. 6); their coefficient of variationsfor French Guiana and Guyana com­bined for 1978 and 1979 were 20.6and 17.9 percent, respectively. Therelatively high frequency of occur­rence of low catch rates off FrenchGuiana (Fig. 3) might be related to the

fact that shallow depths (21-35 fm)off French Guiana are fished morefrequently than the same depths offGuyana (Fig. 4).

Distribution of Catchand Effort in Relation

to Day and Night Fishing

The chief determining factor in thedaily distribution of effort on the partof shrimp fishermen is the quantity ofmarketable shrimp that they cancatch. Catch and effort statistics inrelation to day and night were col­lected from captains' logbooks.Catches made between sunrise andsunset were recorded by shrimp cap­tains as day catches, those made be­tween sunset and sunrise as night

4 April-May-June 1983,45(4-6)

1978

Guyana

AVERAGE WEIGHT/HOUR

LB KG

•

•

••••

•••

•

••

•••• •

• • •••• • •• ••• ••• • •

• • • •• • • • •• • • • •• • • • •• • • • •

6-10

41-45

46-60

Surinam

III 36-40

~ 31-35

XI- 26-30

~Z 21-25 • •••X 16-20 ••••I- r--r--t----l-~..~ 11-15 • •••

Q •

•••••• •••

46-60 •• ••

1979

• 40-49 18.1-22.2• 30-39 13.6-17.7• 20-29 9.1-13.1• 10-19 4.5-8.6• < 10 < 4.5

41-45 • • • • •• •III 36-40 • • • • •~ • • •031-35 • • • •• •% • • •I- 26-30 • • •• •~ • •21-25 • • • • • •z •• •% 16-20 • • • • •l- • • • 0."-• ~ ,0~ 11-15 • • • • Q:O"-' ro"''':-"Iol • • •Q • • "."6-10 • • ° ~'"• .' ... "':.• yb " .• • • b' b• • ". ""..0. "69 70 71 • .." ".0 ~q;.7]

73 ..' .. ~

7" • ::;"'b" ~~75'>(5 ,~ .. ~:-; ~

" ",a. "» ",0 ~

0." :--",'> ~'\Guyana/ ". ,0 ~<.;

t- '"

Figure 5.-Distribution of the annual catch rate of shrimp by fishing zoneand depth for U.S. vessels fishing off Guyana, Surinam, and French Guiana,1978-79.

April-May-June 1983,45(4-6) 5

PERCENTAGE OF LOGGED CATCH

PERCENTAGE OF LOGGED CATCH

Figure 6.-Distribution of fishing effort by time of day and fishing zone inthe Guianas shrimp fishery, 1978-79.

Figure 7.-Percentage distribution of fishing effort by U.S. vessels accordingto time of day and water depths in the Guianas-Brazil shrimp fishery,1978-79.

\:--1 DAY

_NIGHT

...... DA Y AND NIGHT

c::J DA Y_ NIGHT

........ OA Y AND NIGHT

1979

1919

r I I 1 IiI I 1 I10 20 30 40 50 60 70 80 90 tOO

c. IIil!~

o 10 20 30 40 50 60 70 80 90

c::::::. ~"""""""~C= ~""""'~

C=- ~"""'~

~ ~s.,

CI ~""""""""~..~

c==::::::.__~~~~~,~,~~

CI__~~~~~~,~,~"'~

C=- ~~"""""'~D .m~~""""'~

Cl ~""""~

CII ~~~~

D ~s.~"""~

D .~""""""'~

CI__~""""""""""'~C::::JI .~""""""~

--------~"~"'~

EFFORT (~) BY TIME OF FISHING

EFFORT (\) BY TIME Of FISHING

1978

1978

I I I I I I I Iii10 20 30 40 50 60 70 80 90 100

74 III ~~

7J [II .~~

69 [I:=::J .~"""""'~

70 L:I:=::J .....~""'~

" CI::::JI Iil!~""""'''''il

I , j

Ib 20 ~ 40 so 60 ro 80 90 100

72 III .-::

1S [II .~""~

'6 []I .~""""""~

" [I=-__~....~"""""""""'''''il!zo:~ CI::::JI .~""""""""il

catches, and those that included day­time and nighttime trawling werelabeled as both. Resulting data wereshown for each fishing zone in Figure6 and for the 10 selected depth inter­vals for all fishing zones combined inFigure 7.

If we exclude the effort reported asboth day and nighttime combined,then most of the fishing effort oc­curred during night hours. The night­time effort in 1978 and 1979 repre­sented 85 and 77 percent of the totaldaily effort, respectively. The distri­bution of fishing effort as related tothe time of the day further shows theexistence of geographic differences, asmore time was spent in day fishing offGuyana than off Surinam and FrenchGuiana and the least time was spentoff Surinam. Off French Guiana,proceeding from zone 75 to 77, duringboth years, there was less time spentin night fishing and more in day andnight fishing combined (Fig. 6). Infishing zone 77, over 70 percent of thereported fishing effort was in day andnight fishing combined.

The distribution of daily fishing ef­fort in relation to depth showed thatat shallow depths, particularly at thedepth range 6-15 fm, more effort wasat daytime than at nighttime (Fig. 7).At the depths exceeding 16 fm, mostof the fishing effort occurred duringnight hours. Fishing at depths up to10 fm was mostly for white shrimpand was conducted primarily offGuyana. It is probable that the day­time shrimping in the shallow coastalwaters is related to greater turbidity.

The distribution of the catch as re-

Table 3.-The mean annual catch rates (poundlhour)of shrtmp for day (0), night (N), and both day and night(8) of fishing In the flahlng zones of Guiana fishery.

Zones

697071727374757677

1978

D N B

17.7 13.3 11.718.4 14.1 11.316.1 12.2 11.19.7 9.9 11.4

13.5 10.6 9.818.8 11.0 10.121.8 13.8 12.113.9 12.6 12.819.4 17.9 14.5

1979

D N B

19.7 15.4 13.920.4 14.8 14.620.4 15.4 13.8

17.6250 16.3 27.818.1 15.0 11.618.7 16.7 14.825.3 15.5 14.725.7 15.7 14.4

lated to the time of the day was verysimilar to the distribution of effort(Fig. 8). Even though the total quanti­ty of shrimp caught during nighthours exceeded the daytime catchesby a substantial margin, the daytimecatch rates were much higher thanthose found at night throughout thefishery (Table 3).

Species Composition andGeographic Distribution

of the Catch

Information on species composi­tion of shrimp catches was obtainedfrom boat captains' logbooks. Cap­tains recorded the most abundant spe­cies in their catch, although this meth-

6 April-May-June 1983,45(4-6)

PERCENTAGE Of LOGGED CATCH

Furthermore, brown and pink-spottedshrimp are caught in large quantitiesthroughout the fishery while pinkshrimp are found in small numbersonly and only off western FrenchGuiana, off Surinam, and offGuyana.

In approximately three quarters ofthe logbook records (72 percent in1978; 76 percent in 1979) the catchwas recorded as mixed and in the re­mainder, brown shrimp and pink­spotted shrimp were recorded assingle species (Fig. 9). The geographicdistribution showed prevalance ofbrown shrimp off French Guiana andpink-spotted shrimp off Surinam(Fig. 9). Off Guyana, pink-spottedshrimp were dominant during 1978,but in 1979 there was an increase inproportion of brown shrimp whichwere more abundant than pink-spot­ted shrimp in fishing zones 69 and 70.Pink shrimp were recorded in smallquantities (1.3 percent of recordedcatches) and they were present in allfishing zones except 77. White shrimpwere noted in catches off all threeGuianas, but were present even inlesser quantities than pink shrimp.Pink and white shrimp were not in­cluded in Figure 9 because they werepresent in such small quantities. Thereported catches of white shrimp inthis paper are not representative ofthis species, because U.S. fishermendo not fish intensively in the shallowdepths where this species is mostabundant.

Brown shrimp were dominant offFrench Guiana and pink-spottedshrimp off Surinam in 1978-79 andGuyana in 1978. In 1979 the catchesoff Guyana, fishing zones 69 and 70,had more brown shrimp than pink­spotted shrimp, while in fishing zone71, pink-spotted shrimp were pre­dominant. Our data on species com­position and their distribution for the1978-79 period is in general agreementwith our observations for the previousyears (Jones and Dragovich, 1977;Dragovich and Coleman, 1980).

Size Composition ofShrimp in the Landings

Knowledge of temporal and spatial

I100

I i'0 90 100

I80

I60

o DAY_ NIGHT

~~ DAY AND NIGHT

~~

~

1979

1979

I I20 40

Io

I

o 10 20 30 40 50

~

L-J_....~C::-.__.~

shrimp are easily distinguishable fromeach other; the fourth species, pinkshrimp, presents problems in identifi­cation because pink and brownshrimp are similar in appearance.

I100

= BROWN= PINK - SPOTTEO_ MIXEO

PERCENTAGE OF LOGGED CATCH

I I60 80

1978

I40

I20

I /'///~

Figure 8.-Percentage distribution of catch by U.S. vessels according to timeof day and statistical fishing zones in the Guianas fishery, 1978-79.

"z

~76§5::::~771 ~

All ~lONES

Figure 9.-Species composition of the shrimp catches of U.S. vessels off thethree Guianas by statistical fishing zones. Catches were recorded as mixed iftwo or more species were present in about equal proportions.

(I to 20 30 40 SO 60 70 80 90 100

1978

CATCH U;) BY TIME Of FISHING

!~~~~~1Z!!~1Z!!i~i~i~i1Z!!~~WDA

;::1 ~s 14

69

90 I71

<fl 72wz0 73N

74

75

76 I77

ALLZONES

I0

od tends to overestimate the domi­nant species. The catch was recordedas mixed if two or more species werepresent in about equal proportions.The brown, pink-spotted, and white

April-May-June 1983,45(4-6) 7

:>50 41/50 36/40 31/35 26/30 21125 16120 11115 ... 10

SIZE CATERGORIES (NUMBER OF SHRIMP PER POUND)

Figure 11.-Numerical size composition of shrimplanded in the three Guianas, 1978-79.

._._-- 1978

__ 1979

150

'25

I

'00 I

I

I

15I

I

I

I

50 1-

25

"t~97B----1979

20 <1010 --_ ......... --- ..... _- - ..... __ ..... _..............

o ~ I I I I I I ! r -, ! r

~~~20t26/30.-- - -/'-'--

10~o J ' I I ! I I I I I I I

20t ----31/35 ........-·- ... - ... ... ...10 ' ~~0,,17-~

,0L~oL I I I I I I , , ! I I

10C~o I I I I , II! I I I

~~ tL~_~:LO-_-L--l-_''-l-_--l--_--l--_--l-_--..J.-_-..J.--_-..J.----J--

"~ ,20 >50 ~JO~""'" -

o J I ' I I I I I I I I I

JAN FEB MAR APR MAY JUN JUl AUG SEPT OCT NCN DEC

MONTH

Figure 1O.-Monthly distribu­tion of size categories of shrimpfrom landings in Guyana, Suri­nam, and French Guiana com­bined, 1978-79.

occurrence of different sizes ofpenaeid species may help us to under­stand the area and time of recruitmentand their subsequent availability tothe fishermen. Our information onshrimp sizes from captains' logbooksis biased. As during the past years(Jones and Dragovich, 1977; Drago­vich and Coleman, 1980) the majorityof the catch recorded in the captains'logbooks for 1978 and 1979 wasmedium sized shrimp (16-35 headlessshrimp per pound). In some instancesthe size of shrimp in landings may re­flect selective fishing as influenced bymarket price of shrimp, fuel prices,feasibility of operation, skill of thecrew, condition of the boat, and en­vironmental conditions.

The majority of shrimp landed dur­ing 1978 and 1979 were in the 26-30,21-25, and 16-20 tails per pound sizecategories and a large quantity ofshrimp was in the smallest size cate­gory (>50) (Fig. 10). When the dataon sizes are presented on a numericalbasis (Fig. 11), it becomes apparentthat the major portion of shrimpcaught are in the smallest size cate­gory. If these small shrimp were al­lowed to grow another 2-3 months,the economic return to the commer­cial fisherman probably would havebeen considerably higher.

Based on landing records, monthlydistribution of shrimp sizes in thepresent study was very similar duringboth reported years (Fig. 10). Therewere two modal peaks, one represent­ed the smallest size category (>50) andthe other the larger sizes (26-30 and16-20). The principal difference in thedistribution of shrimp sizes between1978 and 1979 was that both peakswere more pronounced during 1978than during 1979. During 1979 thevariations between the size categories(16-20 to >50)were very slighLLargershrimp (from <10 through 26-30)were landed in greater quantities dur­ing the first half of the years than dur­ing the second half of the years, whilethe smallest sizes (41-50 and >50) werelanded in greater quantities during the

second half of the years; the monthlydistribution of intermediate sizes didnot follow a pattern. If we assumethat these data are accurate and notreflective of selective fishing, then wecan deduce that the major portion ofshrimp were recruited to the fisheryfrom June to December.

We also examined separately theareal distribution of shrimp sizestaken by fleets fishing off French Gui­ana and off Guyana. Landings offFrench Guiana had more larger sizesof shrimp than the landings off Guy­ana, while the smallest sizes (41-50and >50) were much more abundantoff Guyana than off French Guiana.The size data from Surinam were un­available to us.

Based on our data, the sizes ofbrown, pink-spotted, and pinkshrimp generally increase progres­sively with increasing depth. Our ex­amination of the fishing effort offGuyana and French Guiana in rela­tion to the depth of fishing (Fig. 4)showed that the trawlers fish moreshallower depths off Guyana andconsequently catch more small sizesof shrimp than off French Guiana.

Trends in the Fishery

Due to the lack of information onthe inshore shrimp fishery for juve­niles and inadequate species data for

8 April-May-June 1983,45(4-6)

o-4----.------,------,---.....---y------,--..,.

Figure 13.-Trends in catch per unit of effort of shrimp fleets based in FrenchGuiana, Guyana, and Surinam, 1961-79.

1979

700600

1975

500400

Tashiro, J., and A. Dragovich. 1980. Biblio­graphy on the offshore shrimp fishery ofnortheastern South America. WECAFRep. 35, 35 p.

1970

300

NUMBER OF VESSELS

200

1965

100o

FRENCH GUIANAtlvessel

.........,., ... /~-Y

/--/-./' ~ .~ -..

GUYANAIlvessel

1960

30

20

/\\ ....\.' . '.

••• \. • -. : : I

, ;.-- ~. .'. I

'- : .>~::~- %w··... ~J/" / .:, /

~ SURINAM .,

': ~I--r--~---.--.I_Ive-.ss_el-,----,--.----,---r--l-----,----,-----,-~--,__,______,_-----,--_,_-

40

20000

Figure 12.-F1eet size and landings from the offshore Guianas-Brazilshrimp fishery, 1961-79.

~

E~ 15000~(j)(5c~::;; 10000

UlOJcDcCIl-l 5000

Naidu, K. S., and L. K. Boerema. 1972. Thehigh-seas shrimp resources off the Guyanasand northern Brazil. FAO Fish. Circ. 141,18 p.

Literature Cited

Dragovich, A. 1981. Guianas-Brazil shrimpfishery and related U.S. research activity.Mar. Fish. Rev. 43(2):9-18.

____, and E. M. Coleman. 1980. TheUnited States shrimp fishery off the coastsof northeastern Brazil, French Guiana,Suriname and Guyana (1975-77). In A. C.Jones and L. Villegas (Editors). Proceed­ings of the working group on shrimpfisheries of the northeastern South Ameri­ca. Cont. 4.3 WECAF Rep. (28):77-98.

Jones, A. c., and A. Dragovich. 1973. Investi­gations and management of the Guianasshrimp fishery under the U.S.-Brazil agree­ment. Proc. Gulf Carib. Fish. Inst. 25thAnnu. Sess., p. 26-33.

____, and .1977. The UnitedStates shrimp fishery off northeasternSouth America (1972-74). Fish. Bull., U.S.75:703-16.

--,----c-' and L. Villegas. 1980a. Proceed­ings of the working group on shrimp fish­eries of northeastern South America,Panama City, Panama, 23-27 April 1979.WECAF Rep. 27, 89 p.

____, and . 1980b. Proceed-ings of the working group on shrimp fish­eries of northeastern South America, Pan­ama City, Panama, 23-27 April 1979.WECAF Rep. 28, 232 p.

the offshore shrimp fishery, estimatesof maximum sustainable yield (MSY)would not be realistic. Thus, we haveconsidered the status of this fisheryonly in general terms showing thetotal catch versus the number of boats(Fig. 12) and on the basis of gross sta­tistics related to the fishing trends(Fig. 13). For this purpose we haveviewed the fishery as supported byone stock with all species combined.Following the period of expansion ofthis fishery (1960-65), commerciallandings by the participating nationshave remained fairly constant within arange of 15,000 to 20,000 t wholeweight for the period 1966-79 (Fig.12), while the number of trawlersvaried from 281 to 658. From Figure12, it is apparent that the number oftrawlers has considerably increased inrecent years and that the total catchhas not increased concomitantly. Asin past analyses on this fishery (Jonesand Villegas, 1980a), Figure 12 in­cludes data from all other fleets thatfish the Guianas-Brazil shrimpgrounds.

April-May-June 1983, 45(4-6) 9