COMPARATIVE STUDY OF FOOD OF SKIPJACK AND YELLOWFIN

TUNAS OFF THE COAST OF WEST AFRICA'

ALEXANDER DRAGOVICH AND THOMAS POTTHOFF"

ABSTRACT

Stomach contents of 711 skipjack tuna (Katsuwonus pelmnis) and 132 yellowfin tuna(Thunnus albacares) captured in 1968 by live bait and trolling off the coast of WestAfrica were examined. A marked taxonomic similarity was noted between the organismsin the diets of the two tunas. Frequency of occurrence, displacement volume, and num­bers of each food item identified are vresented for each species of tuna. Fishes, mollusks,and crustaceans were the principal foods with fishes generally dominant. The mostprominent fish families were Acanthuridae, Carangidae, Dactylopteridae, Gempylidae,Gonostomatidae, Lutjanidae, Mullidae, Priacanthidae, Scombridae, Serranidae, andTrichiuridaej mollusks were chiefly cephalopods (squids), and crustaceans consistedmostly of macrozooplankton. Juvenile tunas were present in the diet of both speciesof tunas.

Estimates of the size of forage organisms were primarily based on displacement vol·urnes. In the majority of observations, food organisms displaced less than 1.0 ml andthe displacement volumes of stomach contents varied for skipjack tuna from 0.1 to 20.0 mland for yellowfin tuna from 0.1 to 60.0 ml.

Spearman's rank correlation analysis was used to test for a relation between the foodtype (in volume and frequency of occurrence) and the lengths of skipjack and yellowfintunas. Significant correlations were noted between the size of skipjack tuna and boththe volume and the frequency of occurrence of forage fish.

A comparison between the findings of our study and that of other food studies offthe coast of West Africa showed greater taxonomic similarity in tuna forage when thestudies were made in the same general area and that only several types of food were ofprimary importance in each given area. Seasonal changes in taxonomic compositionof forage organisms were also discussed.

The method used to evaluate food organisms consisted of ranking the organisms ac­cording to their dispersal indices, abundance indices, and biomass contribution. Stomato­pods, the amphipod Phrosina semilunata, Teuthoidea, Carangidae, Serranidae, andmegalopal stages were most important constituents of food throughout the investigationarea.

The principal surface tuna fishery in the trop­ical Atlantic Ocean is located off the coast ofWest Africa (Jones, 1969). One of the majortasks of the Southeast Fisheries Center, MiamiLaboratory, has been the study of the biologyand ecology of tunas and tunalike fishes in the

1 Contribution No. 218, National Marine FisheriesService, Southeast Fisheries Center, Miami Laboratory,Miami, Fla.

" National Marine Fisheries Service, Southeast Fish·eries Center, Miami Laboratory, 75 Virginia BeachDrive. Miami, FL 33149.

Manuscript accepted February 1972.nSHERY BuLLETIN: VOL. 70, NO.4. 1972.

tropical Atlantic Ocean. In view of the recog­nized importance of food as an ecological factorin the life history of tunas, one project of thisinvestigation consisted of a study of the foodand feeding habits of skipjack (Katsuwonuspelamis) and yellowfin (Thunnus albacares)tunas - the two predominant species in com­mercial catches in those waters.

We describe and compare the food of skipjackand yellowfin tunas and discuss the relative im­portance of different forage organisms. Wecompare our findings with those of other investi­gators working in the same general area. This

1087

information may be used to study the relation­ship between the distribution of food organismsand occurrence of tuna schools.

Most of the information up to 1969 on foodof various tunas off the west coast of Africamay be found in the review of studies of tunafood in the Atlantic Ocean by Dragovich (1969).Dragovich (1970) also reported on the food ofskipjack and yellowfin tunas off the west coastof Africa.

FISHERY BULLETIN: VOL. 70, NO. ~

MATERIALS AND METHODS

Samples on which the present report is basedwere collected during February, March, Apriland September, October, November of 1968 ontwo cruises (UN6801 and UN6802) of the re­search vessel Undaunted of the Bureau of Com­mercial Fisheries (now National Marine Fisher­ies Service) (Figure 1). All tunas sampled for

10°'..,..----.,..---------------,

10"

200.....----~----.,..--.....-..,.----_i

1088

FIGURE I.-Shaded area shows 10.

calities where stomachs of skipjackand yellowfin tunas were collected.

DRAGOVICH and POTTHOFF: FOOD OF SKIPJACK AND YELLOWFIN TUNAS

this study were caught by pole and line or bytrolling (Table 1). A total of 711 stomachs fromskipjack tuna and 132 from yellowfin tuna wereexamined. The skipjack tuna studied varied infork length from 36 to 63 cm and the yellowfintuna from 52 to 94 cm (Figure 2).

Sampling of catches for stomach samples was

carried out as other requirements of the programand circumstances permitted. Immediatelyafter completion of the morphometric workaboard the ship the stomachs were removed byopening the abdominal cavity and by severingthem from the intestine and the esophagus. Eachstomach was pierced in several places to allow

TABLE l.-Distribution of skipjack and yellowfin tuna stomachs collected during 1968 from the eastern tropicalAtlantic Ocean, identified by month, cruise, and method of capture.

February March April September October NovemberUN680P UN6801 UN6801 UN6802· UN6802 UN6802 Total_._----

With With With With With With Wilh Melhod offood Empty food Empty food Empty food Empty food Emply food Empty food Empty capture

Skipiack tuna

20 28 292 36 70 4 104 69 25 5 511 142 Live bait41 8 3 3 3 47 11 Trolling

Yellowfin tuna

67 24 4 18 109 5 Live bait4 9 3 17 1 Trolling

1 UN68Ql RV Undaun.ted 68(J1 cruise.• UNOOCl2 = RV Undaunted 6802 cruise.

SKIPJACK

YELLOWFIN

UN-6602N=48..........

77 79 II 13 .5 ';;,,=-.....-,,;;---;."',--..

57 5'

UN-6801N=431..

'0

..

""10

50

~ 20

W~ 10

~rJ)

LL.o 10

a:W '0m~ 10::::lZ ..

FORK LENGTH (em)

FIGURE 2.-Length-frequency distribution of skipjack tuna and yellowfin tunas from which stomachs were collected.

1089

penetration of Formalin' and placed in a labeledpolyethelene bag containing 10'/r Formalin.

In the laboratory the stomachs were first clas­sified into those containing food and those thatwere empty. The stomach contents were thenidentified to the lowest possible taxonomic unitswhich were subsequently sorted, counted, andtheir displacement volumes measured. Lengthmeasurements were taken of many forage or­ganisms, particularly fishes. Bait fishes werefound in some of the stomachs, but they werenot considered as part of the regular diet ofskipjack and yellowfin tunas; therefore, stom­achs which contained only bait were consideredempty. Stomachs that contained parasitic trem­atodes were also considered empty.

This study was no exception in regard to dif­ficulties encountered in the identification of for­age organisms (Dragovich, 1969). In numerousinstances the identification of ingested fishes,particularly juvenile tunas, was made from ver­tebrae using methods employed by Potthoff andRichards (1970). Cephalopod identification wasparticularly difficult since many diagnostic ex­ternal characters usually are the first destroyedduring digestion.

The following methods of analysis were used:1) the volumetric method-the individual vol­ume of each taxon and the total aggregate vol­ume of broad taxonomic groups, 2) frequencyof occurrence method-the frequency of occur­rence of a food item and of broad taxonomicgroups, and 3) numerical method-number ofindividuals in the same taxonomic group.

Spearman's rank correlation test, X2 test ofhomogeneity, and paired t-test of difference be­tween the means were used. A method consist­ing of ranking of food organisms according totheir geographic distribution, relative abun­dance, and biomass was also employed.

COMPOSITION OF FOOD

Fishes, crustaceans, and cephalopods were thethree principal food categories found in stom-

• Use of trade names does not imply endorsement bythe National Marine Fisheries Service.

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FISHERY BULLETIN: VOL. 70, NO.4

achs of both skipjack and yellowfin tunas (Fig­ure 3). Food items that do not fall into thesethree categories consisted of mollusks other thancephalopods, salps, polychaetes, and siphono­phores. Other mollusks and saIps were foundin both species of tunas; polychaetes and siphono­phores were present only in stomachs of skip­jack tunas. A checklist of all food items, num­ber of organisms, frequency of occurrence, dis­placement volumes, and length measurements ofsome organisms are presented according to thecruises in Appendix Tables 1 to 4. Fishes wererepresented in the diet of skipjack and yellow­fin tunas by 90 different taxa, crustaceans by 45,and mollusks by 24.

The percentage composition of five food cat­egories in terms of number, volume, and fre­quency of occurrence is shown in Figure 3. Fishwas the dominant food item by volume for bothspecies of tunas, except for yellowfin tuna cap­tured during UN6802, when cephalopods weredominant. Fish occurred most frequently in thediet of both species of tunas sampled duringUN6801; however, crustaceans occurred mostoften in the collections from UN6802. In thediet of yellowfin tuna, fishes were numericallythe most important food items during both cruis­es; in the diet of skipjack tuna, fishes were themost important by numbers during UN6801, butcrustaceans were most numerous duringUN6802.

The group of forage organisms classed asother mollusks consisted primarily of pteropodsand heteropods. Salps, polychaetes, and siphono­phares were the principal components of thegroup of forage organisms classed as miscella­neous-this group was not prominent by vol­ume, frequency of occurrence, or by numbers.

FISHES

Fishes utilized as food consisted mainly ofpostlarval and juvenile forms of pelagic and reeffishes. Some adult fishes, primarily Vinciguerrianimbaria, were also present in the diet of bothspecies of tuna. Although fishes were repre­sented by a larger number of families, only a fewfamilies were important in terms of volume,frequency of occurrence, and numbers.

DRAGOVICH and POTTHOFF: FOOD OF SKIPJACK AND YELLOWFIN TCNAS

SKIPJACK TUNA

UN ·6801

NUMBER VOLUME FREQUENCY OF OCCURRENCE

fishesCrusteceans • •Cephalopods I • -Other mollusks • I IMiscellaneous I I -

UN -6802

fishes -Crustaceans -Cephalopods • -Other mollusks I •Miscellaneous I I

YELLOWFIN TUNA

UN- 6801

NUMBER VOLUME FREQUENCY OF OCCURRENCE

fishesCrustaceans - •Cephalopods • -Other mollusks I I IMiscellaneous I I -

UN-6802

fishes -Crustaceans - •Cephalopods I - -Other mollusksMiscellaneous •

i i i50 'DO 50 'DO 50 'DO

PERCENT PERCENT PERCENT

FIGURE 3.-Percentage of total food (by five categories) in stomachs of skipjackand yellowfin tunas captured during cruises UN6801 and UN6802 off the westcoast of Africa. Food items are represented in terms of numbers, volumes, andfrequency of occurrence.

For UN6801, fish families Acanthuridae, Ca­rangidae, Dactylopteridae, Gempylidae, Gonos­tomatidae, Lutjanidae, Mullidae, Priacanthidae,Scombridae, and Serranidae ranked high interms of volume and frequency of occurrence

for both species of tunas. Owing to the largenumbers of V. nimbal'ia in the diet of both spe­cies of tunas, the family Gonostomatidae wasthe most important forage item for both speciesin terms of volume. In the diet of skipjack tuna,

1091

important contributors by volume were Gonosto­matidae, 44.7/(; Engraulidae, 8.9/(; Mullidae,7.9%; Gempylidae, 2.7%; Serranidae, 2.57<;Lutjanidae, 2.0%; Scombridae, 1.6%; Carangi­dae, 1.6%; and Priacanthidae, 1.5%. Importantcontributors by volume to the diet of yelJowfintuna were Gonostomatidae, 22.1%; Mullidae,14.87<; Tetragonuridae, 6.3%; Carangidae,3.8%; Paralepididae, 1.5%; Priacanthidae,1.2%; and Scombridae, 1.0%. The remainingfish families contributed less than 17< per fam­ily for both species of tunas. The high volumet­ric contribution by the family Tetragonuridaewas due to the large size of only four Tetl'ago­nurus cuvieri, which were found in a singlestomach of a yellowfm tuna.

During UN6802 most important fish familiesby volume and by frequency of occurrence wereCarangidae, Gempylidae, Paralepididae, Scom­bridae, and Trichiuridae. Serranidae and Scor­paenidae were prominent in the diet of skip­jack tuna, but entirely absent in the diet ofyellowfin tuna. Important contributors by vol­ume in the diet of skipjack tuna were Paralep­ididae, 28.4 7<; Percoidei, 8.6 %; Carangidae,3.1'ir; Serranidae, 1.5,/;; Trichiuridae,l.4%,;Gempylidae, 1.3'lr; and Scombridae, 1.2 %. Inthe diet of yellowfin tuna important contributorsby volume were Exocoetidae, 9.6/;; Alepisauri­dae, 5.67<; Carangidae, 2.7/1,; Trachypteridae,2.6'lr; Scombridae, 2.5/;; and Percoidei, 1.4%.The remaining fish families and suborders inthe diet of both species of tunas contributed lessthan 17< per taxon in terms of volume. The rel­atively high contribution by the families Exo­coetidae and Alepisauridae was due to the largevolumes of only three forage fish (AppendixTable 4). From our data we see that some ofthe prominent forage fish families for both spe­cies of tunas were common to both cruises andthat others were important during only onecruise (Appendix Tables 1-4).

CRUSTACEANS

As shown in previous publications (Drago­vich, 1969, 1970), crustaceans, because of theirhigh numbers and high frequency of occurrence,were important components of tuna food. Crus-

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FISHERY BULLETIN: VOL. 70, NO. 4

taceans found in tuna stomachs during bothcruises were similar. The majority were larvalstomatopods, hyperiid amphipods, and differenttypes of megalopae or their equivalents. Thehighest number (32) of taxa was noted in thediet of skipjack tuna during UN6801, while inthe diet of yellowfin tuna for the same cruise,20 different taxa were identified-16 of thesewere common in the diet of both species of tunas.During UN6802, 22 different taxa were identi­fied in the diet of skipjack tuna and 10 in thediet of yellowfin tuna-7 were common to bothspecies of tuna. Stomatopods were not iden­tified further than order. Phronima sedentaria,Phrosina semilunata, and Brachyscellus spp.were the most common amphipods in both tunasfor both cruises. Megalopal stages probably con­sisted of many species, but due to the lack oftaxonomic literature, they were not identifiedfurther than class or family.

A variety of anomurans and caridean shrimpwere consumed by both species of tunas. Dar­danus pectinatus (Glaucothoe) was the most im­pOl'tant anomuran for both tunas during bothcruises. Carideans were more prominent duringUN6801 than during UN6802.

Euphausia hansem: was eaten by both tunasduring UN6801. During UN6802, E. hansenioccurred in high numbers in the diet of skipjacktuna but was entirely absent in the food of yeI­lowfin tuna. Since E. hanseni are of minutesize, they were probably accidentally ingestedor the skipjack tuna were filter feeding. Thesame explanation may be applied to other or­g.wisms of similar size found in the stomachsof both species of tunas, for example, copepodsand isopods. Another explanation is that someof the euphausiids, copepods, or isopods could bethe remains of stomach contents of other fishesingested by tunas.

Phyllosoma occurred in low numbers in thediet of both species during both cruises. Theidentified forms were Panulirus rissoni, Scyl­larus arctus, Scyllarus sp., and Scyllaridea sp.

MOLLUSKS

Cephalopods formed the bulk of the molluscanfood of both species of tunas during both cruises.

DRAGOVICH and POITHOFF: FOOD OF SKIPJACK AND YELLOWFIN TUNAS

Teuthoidea (squid) were the most important byvolume and by frequency of occurrence in thediet of both species. Most of the squid belongto the family Ommastrephidae. Among iden­tified omasterphids, Ornithoteuthis antillarumwas most frequently encountered. This specieswas especially numerous in the food of skiY'jacktuna during UN6802. Octopoda were less nu­merous and occurred with less frequency thanTeuthoidea. The displacement volume of someof the Octopocla (Argonauta argo and A. sp.)was very large. Five specimens of A. argo con­sumed by yellowfin tuna during UN6802 dis­placed 165.5 ml-more than all other molluskscombined for that cruise or all the fishes forthat cruise (Appendix Table 4).

Among other mollusks, pteropods and hetero­pods were found in the stomachs of skipjacktuna during both cruises. They were absentin the food of yellowfin tuna during UN6802and occurred only in two stomachs duringUN6801. A heteropod, CavoUm:a longirostris,occurred in high numbers in the diet of skipjacktuna during UN6801. In terms of volume, bothof these mollusks were of minor importance.

JUVENILE TUNAS AS FOOD OFSKIPJACK AND YELLOWFIN TUNAS

Knowledge on the distribution and abundanceof juvenile tunas and tunalike fishes is very lim­ited because existing collection methods forjuveniles are inadequate. This information isvery important, however, as an aid in identifyingspawning seasons and areas of tunas. One ofthe major sources of juvenile tunas is fromstomachs of adult tunas. Juvenile tunas andtunalike fishes were present in the diet of bothspecies of tunas sampled on both cruises. Asmany as 20 juvenile tunas were found in asingle tuna stomach. The most frequently en­countered and the most numerous juvenile tunaswere Auxis spp. and little tunny (Euthynnusalletteratus) (Table 2). Specimens of Auxisspp. were found in both species of tunas duringboth crui~es. Specimens of E. alletteratus werepresent in the diet of both species of tunas, butonly during UN6801. All the remaining speciesof juvenile tunas occurred infrequently in smallnumbers. Katsuwonus pelamis and Thunnus

TABLE 2.-0ccurrence of juvenile scombrids in the stomachs of skipjack and yellowfin tunas during cruises UN6801and UN6802.

Tota,1 Standard length (mm) Number of Freq uency of Displacementoccurrence volumes

number juveniles inRange Mean a single stomach Number Percent ml Percent

Skipjack tuna UN6801

Unidentified Scombridae 4 1,2 3 0.8 0.5 <0.1Auxis spp. 53 12-37 29 1.2,3,4,9 29 8.1 9.5 0.3EuthynnuJ a[JttttratuJ 120 10-68 29 1,2,3,4, 5, 10 66 18.5 28.1 1.0Katsuwonur pI/ami! 2 :20-32 26 1 2 0.6 0.3 0.3Thu-nffUJ spp. 2 34-47 41 1 2 0.6 1.4 <0..,1

Skipiack tuna UN6802

AuxL' spp. 33 15-63 31 1,6,16 10 5-0 8.6 0.9Sardll sarda 4 25-43 34 1 4 2.0 2.3 0.2Scomhtf ;aponicuJ 1 40 1 1 0.5 1.3 0.1

Yellowfin tuna UN6801

Auxis spp. 7 12-50 22 1,2 5 6.0 1.4 <0.1EuthYftflUJ allttttratul 58 11·70 33 1. 2. 3, 4, 5, 6, 8 21 25.3 16.0 0.7Katruwonus ptlamis 1 38 38 1 I 1.2 O.tZ <0.1Thunnus spp. 3 29-40 36 1 3 3.6 0.8 <0.1

Yellowfin tuna UN6800

Unidentified Scombridae 15 1,3,8 6 14.0 0.8 0.2Auxis spp. 53 15.;34 2a 1,2,4,7,20 11 25.6 7.4 2.1Sarda sardo 4 15..21 ,18 1,3 2 4.7 0.5 0.1Scotnber japofJicus 1 .28 1 1 2.3 0.1 <0. 1

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FISHERY BULLETIN, YOLo 70. NO.4

COMPARISON OF FOOD OFSKIPJACK AND YELLOWFIN TUNAS

TABLE 3.-The distribution of displacement volumes ofindividual forage organisms collected during the cruisesof UN6801 and UN6802.

As in a previous study by Dragovich (1'970),our data show a marked taxonomic similarity ofitems in the diet of skipjack and yellowfin tunasfor the investigation area as a whole (AppendixTables 1-4). We also compared the taxonomiccomposition of forage organisms at the two lo­cations where skipjack and yellowfin tunas were

spp. were found in the stomachs of both speciesof tunas, but only during UN6801. Sarda sardaand Scomber japonicus were also found in bothskipjack and yellowfin tunas, but only duringUN6802.

The presence of juvenile tunas in the diet ofskipjack and yellowfin tunas in various parts ofthe Atlantic Ocean has been reported by Drago­vich (1969, 1970). Presence of Auxis spp. andScomber sp. in the diet of yellowfin tuna fromeast African waters was noted by Williams(1966). Suarez Caabro and Duarte Bello (1961)noted juvenile blackfin tuna (Thunnus atlan­ticus) (5-150 mm fork length) and skipjack tuna(35-145 mm fork length) in the stomachs ofskipjack tuna from the Caribbean Sea. Pres­ence of juvenile tunas in the diet of adult tunashas been frequently observed in food studies inthe Pacific Ocean (Reintjes and King, 1953;King and Ikehara, 1956; Alverson, 1963; Naka­mura, 1965).

caught together in a mixed school. For thoselocations we performed X2 tests of homogeneityon the ratio of fish to total volume of food. Thefirst test indicated that the percentage of fishconsumed differs between the two locations(X2 = 6.74; 1 dt; p < 0.1) possibly reflectingdifferences in forage-at-Iarge composition, timesof day, size frequency of tuna, etc. Within-areadifference in percent fish between yellowfin andskipjack tunas was significant in only one area(X2 = 62.51; 1 dt; p < 0.01).

VARIATION IN FOOD AS RELATED TOSIZE OF TUNAS AND VOLUME OF

STOMACH CONTENTS

The foods of skipjack and yellowfin tunas inthe present study consisted principally of rel­atively small organisms, based on their displace­ment volumes (Table 3). The consumption oforganisms of comparable size in similar propor­tions by skipjack and yellowfin tunas has alsobeen observed by other investigators (Reintjesand King, 1953; King and Ikehara, 1956; Naka­mura, 1965; Williams, 1966; Dragovich, 1970).

To observe the differences in consumption offood by volume and frequency of occurrence ofthe three major food categories as related to sizeof tunas, skipjack and yellowfin tunas were sep­arated into 20 mm and 30 mm length intervalsrespectively (Figure 4). Spearman's rank cor­relation analysis (Steel and Torrie, 1960: 409)was used to see if the volumes and frequency ofoccurrence of the two dominant forage fooditems (fishes and crustaceans) in the diet ofskipjack and yellowfin tunas were correlatedwith the size of tunas. Significant correlationsin the length-food data were noted between thesize of skipjack tuna and percentage volume offish forage (r. 0.576, 11 dt, P < 0.05) and per­centage of occurrence of forage fish (r. 0.565,11 dl, P < 0.05), suggesting that as the sizeof tuna increased, the percentage consumptionof fish by volume and by frequency of occurrenceincreased.

It is generally recognized that the amount andquality of food found in the stomach of tunas

0.1-0.50.1

0.1-0.70.1

O.I.Q.30.1

0.1-1.60.1

0,1-0]

Disploocementvolumes in 900.4of observations

Skipjock tuna

Yellowfin tuna

0.1-55.00,1· 1.00.1-50.5

0.1

0.1·8.20.1· 1.20.1- 6.5OJ1· 0.40.1· 3.5

Toto I range ofdisplacementvolumes (ml)

Fish

CrustaceansCephalopod.Solp•.

Fooditem

Fis~

CrustaceansCeop\lo lopodsOt~er mollusksSalps

1094

DRAGOVICH and POTTHOFF: FOOD OF SKIPJACK AND YELLOWFIN TUNAS

YELLOWFIN TUNA SKIPJACK TUNAiii FII" D.'LWIUo CIUIlIDWI • DT"EI

_U.U FlEtulle' ., ICc•••nct:1" • •

, , I , , I , • , t

WlLUliU FIEOUEIICY If leCU"EHE1" • ....

.......-L...L-.1.-.>' , ,

'.rcut Pete.,.t

...I __...L.JII L-I--'- _

••, 101 1liilL--.L.--J L...---'---------'-_ ..<~

_mil _B--'---------"

-,11. I I ~)~(

flf+I.[]11 _.~~I ..)~~I I

____I~I .-__--'-__1 >,".ci i~'-->(- "T---.....::: .. __ ''\.

_.IIlL.-~1 •

II B I I I-.:-.co'-<'1__ /~

-;;;f'-~~~

II I I ~ \,I~:-~-:~:'--~"'<'1 .""

~)~,~(I I •'I I I r_~,

~~! i"2..- _ -~'\-"""i '-.. - "

I <:'t/"~l...-;('-'< "l.' -",,-r-~

I

• '_""".( 'f

~l~'~:C·\~

II

FIGURE 4.-The distribution of volumes and frequencies of occurrence of the major food categories (fish, crusta­ceans, mollusks, and miscellaneous) at various sizes of skipjack and yellowfin tunas off the west coast of Africa,The sizes of skipjack range from 370 mm to 610 mm (intervals 20 mm); the sizes of yellowfin tuna range from520 mm to 910 mm (intervals 30 mm).

1095

are important in studies concerned with energythat is converted into caloric equivalents of en­ergy utilized for growth. We have the infor­mation only on the volumes of the stomach con­tents. This information may be of interest tothe investigators concerned with energy budgetsof tunas and with studies on transfers of energywithin the food web. In our study, in the ma­jority of observations, the displacement vol­umes of the total stomach contents of skipjackand yellowfin tunas varied from 0.1 to 20.0 mland from 0.1 to 60.0 ml, respectively (Table 4).Information on the volumes of stomach contentsof tunas in the Atlantic Ocean is found only ina limited number of investigations, as cited inthe review of studies of tuna food in the AtlanticOcean by Dragovich (1969). Dragovich (1970)noted volumes of stomachs of less than 20 mlin 75% of skipjack tuna sampled and in 85o/t}of yellowfm tuna. Volumes of stomach contentsof yellowfm tuna caught by longline off the coastof east Africa (Williams, 1966) were generallyhigher than those in our study. The majority ofthe volumes measured by Williams fell within arange of 3.0 to 499.9 cc. Higher volumes ofstomach contents observed by Williams may bepartially explained by the fact that tunas caughton longline are usually larger than fishes caughtby surface methods.

To determine the relation between the volumeof stomach contents and body weight of skip­jack and yellowfin tunas, we have assumed that

FISHERY BULLETIN: VOL. 70, NO.4

1.0 ml of stomach contents is equivalent to 1.0 g.Comparisons on this basis were made betweenthe estimated weight of the stomach contentsand the body weights of tunas. Our calculationshave shown that the total volume of stomachcontents for both species of tunas in almost allobservations was well below 1.0 % of the bodyweight. This observation is in agreement withthe findings by Dragovich (1970). The resultsof these calculations suggest that there was littledifference in the total amount of food found inthe stomachs of both species of tunas as relatedto the body weight. Possible explanations forsuch low volumes of stomach contents may berapid digestion of food, long periods betweenthe feedings, scarcity of food, and the fact thatmost of the forage organisms are very smallmacrozooplankton.

SEASONAL CHANGES INTAXONOMIC COMPOSITION OF

FORAGE ORGANISMS

Cruise UN6801 took place in the Gulf ofGuinea during what is sometimes called the"warm" season (February, March, and April)and UN6802 during the "cool" season (Septem­ber, October, and November). Berrit (1961)in his study on seasonal variations of oceano­graphic conditions introduced these terms. Re­sults on studies by Sund and Richards (1967)

TABLE 4.-Distribution of the volumes of total stomach contents in 711 skipjack tuna and 132 yeUowfin tunastomachs. The (lata were collected during cruises UN6801 and UN6802.

Volume ofSkipjack tuna Ye~lowfin tuna

stomach Number of Percentage Accumulated Number of Accumulatedcontents (mil stomachs percentage stomachs Percenfoge percentage

Empt1 153 21.5 21.5 6 4.5 4.50.1-0.5 127 17.9 39.4 8 6.1 10.60.6-1.D 70 9.B 49.2 7 5.3 15.91.1-1.9 69 9.7 58.9 9 6.8 2f1..72.0-2.9 46 6.5 65.4 10 7.6 30.33.Q.3.9 37 5.2 70.6 5 3.8 34.14.0.4.9 32 4.5 75.1 10 7.6 41.75.0-10.0 80 11.2 86.3 15 IIA 53.1

10.1./20.0 63 8.9 95.2 15 11.4 64.520.1-60.0 24 3.4 98.6 34 25.7 90.260.1-100.0 6 0.8 99.4 12 9.1 99.3

100.1·200.0 4 0.6 100.0 I 0.7 100.0

1096

DRAGOVICH and POTTHOFF: FOOD OF SKIPJACK AND YELLOWFIN TUNAS

on the differences in the occurrence of forageorganisms of skipjack and yellowfin tunas in theGulf of Guinea between these two seasons arecompared with ours.

In our study, the fish families present in thediet of both species of tunas only during the"warm" period were Mullidae, Dactylopteridae,Gonostomatidae, and Engraulidae. In the studyof Sund and Richards (1967), Dactylopteridaewere also present during the "warm" seasononly. A number of crustacean taxa were presentin our study only during the "warm" seasonand absent during the "cool" season. Grapsidae(megalopal stages), Petrochirus sp. and Streetiachallengeri, were found only during the "warm"period and absent during the "cool" period.Other prominent crustaceans observed by us instomachs of both species of tunas only duringthe "cool" period were Vibilia armata, Scyllar­ides sp., Scyllarus sp., and S. aretus. Some ofthe crustaceans (Phronima sedentaria, Phrosinasemilunata, Euphausia sp.) occurred only in oneseason in the observations of Sund and Richards(1'967), whereas we observed them in both sea­sons. More extensive collections are needed be­fore any final evaluation is made in regard to thesignificance of the occurrence of these organismsduring different seasons.

EVALUATION OF FOOD ORGANISMS

In selecting the most important food organ­isms in a given area, many variables have to beconsidered. Reintjes and King (1953) statedthat food items that rank high in number, highin volume, and high in frequency of occurrenceare important foods-at the time and in the areasampled. Using these criteria plus the geo­graphic distribution in evaluation of food or­ganisms of both species of tunas, we have cal­culated dispersal and abundance indices andmean displacement volumes for each food taxonand ranked them accordingly.

The entire investigation area was divided into27 one-degree squares. If a taxon was presentin one square it was assigned a value of one.Using the data from both cruises and for bothspecies of tunas combined, the number of oc-

currences of each taxon in 27 squares was divid­ed by the number of squares-the quotient wascalled the dispersal index. An abundance indexwas calculated by dividing the total number ofindividuals in each taxon by the total numberof all organisms. An approximation of biomassof each food item was represented by the meandisplacement volume. The mean displacementvolume of food items represented in Figure 5varied from 0.1 to 0.7 m!.

Since a large number of taxa are represented,we have selected the 32 taxa with the highestdispersal and abundance indices and presentedthem in a descending order of magnitude (Fig­ure 5). Vinciguerl'ia nimbaria and AnchoviellagUl~neensis, although with low dispersal indices,were included in the diagram because of theirhigh abundance indices. From Figure 5 it isobvious that Stomatopoda, Phrosina semilunata,Teuthoidea, Carangidae, Serranidae, and meg­alopal stages were the most important identifi­able food items throughout the investigationarea while V. nimbaria, Euphausia hanseni, andA. guineensis were of great local importance.

In the evaluation of forage organisms by thepresent method we consider the geographic dis­persal of food organisms to be the most impor­tant criterion for the survival of skipjack andyellowfin tunas, particularly since these tunasare migratory and widely distributed. In ourstudy the tuna forage organisms were bothwidely distributed and abundant in the area ofsampling as indicated in Figure 5. High abun­dance indices were usually associated with highdispersal indices. Thus these food organismsmay be considered to be important in the foodchain of skipjack and yellowfin tunas for thegiven time and area.

The disadvantage of the method is that theestimated geographic distribution of foragetaxa as calculated from stomach contents maynot represent the true distribution. The onlyother information nearest to the natural distri­bution of certain forage organisms found in ourstudy was obtained from zooplankton doubleoblique tows which were made at about the sametime of the capture of tunas from which stomachsamples were taken. The preliminary analysisof the composition of zooplankton from these

1097

....oc:.o00

Unidentified FiShn__ _·_..··..b;;;;;;;;;~======:::::Jlli·~

Stomatopoda· _nn.._..nr II*~- ::-@:J

~identlfled Crustacea £ I i-......_.._~

Phrosina semi/unata··..n· ··i 'I~Teutholdea n·..• ••••••• _·-6 'I~.....~~~

carangldae···· ····· · ·..· -b II"~~ ,"

"" 1 ~7'~"'"::::e (~·~:-I:~::;:::~ I::·.~~· ..·..·..··~~~~c= 1 .~Salpldae n..nn EJ i..·..n · ·· ···· ··

Brachysl:eIlus spp._..._..n ~ 1:__~ /

Ranlnnldae (Megalopae}p ': __ n ~.Acanthurldae ...........nn........b 1:.••.J~

b I. ~~::==~1 ::,~!~~_~~~Ommastrephldae i:D . .~ '~

Scorpaenidae- nb====::::J':·· _~ ~Lutjanidae _ ~ 'I ··· ·· _..···_· ···n.~

Gempylidae _._-_ n n-6 'Iu~

Phronima sedentaria ···..b 'i·· ··· ·..···· ···__ ······u•••n.~

Dactylopterus vo/itansn6 '1 __nc1!~~paralepldldae n n.._b Ii'--' _ _ nnn un..~Y~

=~ ::~="===--~Brotulldaen _n n _b] 1i n~.:~

Carldea · · ·.._ · · _···6 'i _ ··_ · ~n~

Cephalopoda · · ····b:] 'I··.._·_~

Octopoda- nn ···· ·b '1"'-' _ n _~

Carol/nia /ongirostl'is'--~I" (~ .. -_.~

=.=~r=,:~i;~~---"~ill~-...j

Gempy/us serpens..···· ·~I ·····_ nn =!:i'~--$~

Euphausia hansen;..·_.·.·.---,.....i···_··.1~::\Vinciguerria nimbaria·..1¥ : n n n n~

~ ~.~Anchtwiella guineensis --'~I"'--- ~j;:::;:;:::;r:

LEGENDK&US. I'ftmn

i==~"'==~~'DISPllSlL INDEX........'O_IIIIii

20ABUNDANCE INDEX

o • 10= IIOMASS (MIAN DISPLACEMENT VOLUME)

FIGURE 5.-The dispersal and abundance indices and biomass of forage organisms of skipjack and yellowfin tunas off the west coast of Africa.Dispersal and abundance indices expressed in percent. The biomass expressed in milliliters. ~

DRAGOVICH and POTIHOFF: FOOD OF SKIPJACK AND YELLOWFIN TCNAS

plankton samples showed that the major con­stituents were copepods and arrowworms. Ar­rowworms were entirely absent in the diet ofboth species of tunas. Although copepods werepresent in the stomachs of a few skipjack tunas,they may have been remains of the stomachcontents of the ingested fishes. Among theminor constituents of zooplankton, 60 speciesand 10 genera of amphipods and 20 species and3 genera of euphausiids were present in theplankton tows. Although all of the amphipodsand euphausiids found in the tuna stomachswere also present in the plankton tows, theirnumber represented only a small fraction of thenumber of taxa found in the plankton tows, thussuggesting selectivity in feeding of skipjack andyellowfin tunas. Our findings support those ofBlackburn (1965), who stated that no speciesof tuna consumes all the species of net-caughtmicronekton or zooplankton.

COMPARISONS WITH RESULTS OFOTHER INVESTIGATORS

Investigations concerned with the food ofskipjack and yellowfin tunas off the west coastof Africa are numerous (Postel, 1954, 1955a,1955b; Marchal, 1959; de Jager, de V. Nepgen,and van Wyk, 1963; Penrith, 1963; Sund andRichards, 1967; de V. Nepgen, 1970; andDragovich, 1970). Reliable qualitative compar­isons of tuna forage between different studiesare difficult because identification of organismsis usually incomplete. Quantitative compari­sons between various studies of tuna forageUsually consist of comparisons between themajor food categories (fishes, crustaceans, andcephalopods). The nearest areas of the AtlanticOcean to our investigation area for which validcomparisons can be made were investigated byMarchal (1959), Sund and Richards (1967),and Dragovich (1970).

The diet of yellowfin and skipjack tunas in theGulf of Guinea was studied by Marchal (1959)and Sund and Richards (1967), respectively.From a long list of forage organisms presentedby Marchal only several fishes (Vomer setapin­nis, Enthynnus alletteratus, Sternoptyx diaph­ana, Hyppocampus sp., Qphidion barbatum,

Brotulidae, Chiasmodontidae), a few crusta­ceans (Stomatopoda, Heterocarpus ensifer,Glaucothoe, megalopae (Brachyura», and salpswere common to both studies. All fish familiesin the diet of yellowfin tuna and skipjack tunaobserved by Sund and Richards (1967) were alsoobserved by us. The differences in the compo­sition of tuna food between our study and thatof Sund and Richards were on generic and spe­cific levels except for cephalopods, where ourfindings differed entirely.

A strikillg similarity in the food of skipjackand yellowfin tunas was observed between ourstudy and that of Dragovich (1970). Skipjackand yellowfin tunas in the study by Dragovichwere captured off the coast of West Africa fromSierra Leone to Angola. All forage-fish families(21) in the diet of skipjack tuna noted by Drag­ovich were also observed by us. The most prom­inent fish families (Carangidae, Scombridae,Gempylidae) in terms of volume of frequencyof occurrence observed by Dragovich were equal­ly important in our study. We found the samegroups of crustaceans as Dragovich. In thecephalopod diet ommastrephids were the prin­cipal food in both studies.

Postel (1955a) examined contents of stomachsof yellowfin tuna caught off the coast of Senegal.Of 30 species and 7 genera of fish and 12 ceph­alopod taxa listed by Postel, only Euthynnusalletteratus, Katsuwonus pelamis, Sphyraenasp., Cranchia scabra, and Argonauta sp. wereobserved by us. None of the identified speciesand genera of crustaceans by Postel was ob­served by us. The pronounced taxonomic dif­ferences of forage between our study and thatof Postel may be partially explained by the dif­ferent oceanographic regime off the coast ofSenegal.

Postel (1955b), in his report on Katsuwonuspelamis off Cape Verde Islands, identified Sar­dinella am,an, S. sp., Myctophidae, Hemiram­phus sp., Hyporamphus sp., Gephyroberyx dar­wini, Scomber colias, Aphanopus sp., and Mul­lidae in the diet of this tuna. Myctophidae andMullidae were also observed by us in the dietof skipjack tuna. From cephalopods, only Illexillecebrosus coindeti was listed; this species wasnot identified in the diet of skipjack by us.

1099

De Jager, de V. Nepgen, and van Wyk (1963),de V. Nepgen (1970), and Penrith (1963) re­ported that the food of yellowfin tuna caught offSouth Africa consisted mainly of fish. De Jager,de V. Nepgen, and van Wyk stated that lantern­fish and anchovies occurred more frequently inthe diet of yellowfin tuna than in the diet of otherspecies of tunas; crab megalopae were by farthe highest ranking crustaceans. Fish in de V.Nepgen's (1970) study consisted chiefly of gar­fish, lanternfish, and mackerel (Scomber japon­icus) . Most of the forage fishes reported byPenrith (1963) were surface fishes (Scombere­sox sam'us, Corypkaena kippurus, juvenileBramidae). Among crustaceans Penrith (1963)found that yellowfin tuna fed chiefly on the deep­living prawn, Funchalia woodwardii. Megalo­pae also played an important role in the foodof yellowfin tuna and were more important thanamphipods. Mollusks consisted of unidentifiedcephalopods (squid), heteropods, and pteropods.In our study lanternfish and mackerel were un­important as forage for yellowfm and skipjacktunas, and anchovies were not eaten by yellowfintuna but occurred in great numbers in the dietof skipjack tuna; megalopae were among thehighest ranking crustaceans. From a high num­ber of forage fishes listed by Penrith (1963) onlyunidentified Carangidae, Naucrates ductor, uni­dentified Priacanthidae, Priacanthus sp., Acan­thuridae, Scombridae, Balistidae, Blennidae,Bramidae, Coryphaenidae, Coryphaena hippllr­us, and Syngnathidae were also observed by us.Crustaceans common to Penrith's and our studywere stomatopods, amphipods (Phronima seden­taria, Phrosina semilllnata) , and megalopae(Brachyura). Molluscan food for the most partwas different between our study and that ofPenrith (1963).

On the basis of the studies discussed in thissection, it is evident that skipjack and yellowfintunas consume a great variety of forage organ­isms. Fish, cephalopods, and crustaceans werethe principal foods of both species of tunas inall investigations. The similarity in regard tothe taxonomic composition of forage betweendifferent studies was greater when the investi­gations were made in the same general area.In each given area, only several types of food

1100

FISHERY BULLETIN: VOL. 70, NO.4

were important. Although occasionally bottomorganisms were found in the diet of a skipjackand particularly yellowfin tunas, both of thesespecies primarily feed on juvenile pelagic or­ganisms.

ACKNOWLEDGMENTS

We wish to express sincere thanks to the fol­lowing people for their assistance in the identi­fication and verification of specimens: ThomasE. Bowman, Raymond B. Manning, and ClydeF. E. Roper of the Smithsonian Institution,Washington, D.C.; L. B. Holthuis of the Rijks­museum van Naturlijke Historie, Leiden, Hol­land; Donald Moore, Anthony J. Provenzano,Philip B. Robertson, Gilbert L. Voss, and WonTack Yang of the Rosenstiel School of Marineand Atmospheric Sciences, University of Miami,Miami, Fla.

We also thank William W. Fox, Jr. ofthe Uni­versity of Washington, Seattle, Wash., for ad­vice on statistical procedures. Dr. George A.Rounsefell of the University of Alabama re­viewed the manuscript.

LITERATURE CITED

ALVERSON, F. G.1963. The food of yellowfin and skipjack tunas in

the eastern tropical Pacific Ocean. [In Englishand Spanish.] Inter-Am. Trop. Tuna Comm..Bull. 7: 293-396.

BERRIT, G. R.1961. Contribution a la connaissance des variations

saisonnieres dans Ie Golfe de Guinee. Observa­tions de surface Ie long des Jignes de navigation.Cah. Oceanogr. Bull. Inf. Com. Cent. Oceanogr.Etud. Cotes 13: 715-727.

BLACKBURN, M.1965. Oceanography and the ecology of tunas.

Oceanogr. Mar. Biol. Annu. Rev. 3 :299-322.DE JAGER, B. V. D., C. S. DE V. NEPGEN, AND

R. J. VAN WYK.

1963. A preliminary report on South African westcoast tuna. S. Afr. Div. Sea Fish., Invest. Rep.47, 40 p.

DRAGOVICH, A.1969. Review of studies of tuna food in the At-

DRAGOVICH and POTTHOFF: FOOD OF SKIPJACK AND YF.LLOWFIN TUNAS

lantic Ocean. U.S. Fish Wildl. Serv., Spec. Sci.Rep. Fish. 593, 21 p.

1970. The food of skipjack and yellowfin tunasin the Atlantic Ocean. Fish. Bull., U.S. 68 :445­460.

JONES, A. C.

1969. Tropical Atlantic tuna investigations, 1968.Gulf Caribb. Fish. Inst., Proc. 21st Annu. Sess.,p. 76-85.

KING, J. E., AND I. I. IKEHARA.

1956. Comparative study of food of bigeye andyellowfin tuna in the central Pacific. U.S. FishWildl. Serv., Fish. Bull. 57 :61-85.

MARCHAL, E.1959. Analyse de quelques contenus stomacaux de

Neothunnu8 albacora (Lowe). Bull. Inst. Fr.Afr. Noire, Ser. A 21 :112::J-1136.

NAKAMURA, E. L.1965. Food and feeding habits of skipjack tuna

(Kat8uwonus pelamis) from the Marquesas andTuamotu Islands. Trans. Am. Fish. Soc. 94:236-242.

NEPGEN, C. S. DE V.1970. Exploratory fishing for tuna off the South

African West Coast. S. Afr. Div. Sea Fish.,Invest. Rep. 87, 26 p.

PENRITH, M. J.

196::J. The systematics and biology of the SouthAfrican tunas. MS Thesis, Univ. Cape Town,Cape Town, Union S. Afr., 216 p.

POSTEL, E.1954. Contribution it I'etude des Thonides de I-At­

lantique tropical. J. Cons. 19:356-362.

1955a. Recherches sur l'ecologie du Thon a nag­eoires jaunes, Neothunnu8 albacora (Lowe), dansI'Atlantique tropico-oriental. Bull. Inst. Fr. Afr.Noire, Ser. A 17: 279-318.

1955b. La Bonite a ventre raye (Katsuwonus pe­lamis) dans la region du Cap Vert. Bull. Inst.Fr. Afr. Noire, Ser. A 17: 1202-1213.

POTTHOFF, T., AND W. J. RICHARDS.

1970. Juvenile bluefin tuna, TJmnnus thynnus(Linnaeus), and other scombrids taken by ternsin the Dry Tortugas, Florida. Bull. Mar. Sci.20: 889-41::J.

REINTJES, J. W .. AND J. E. KING.

1958. F'ood of yellowfin tuna in the central Pa­cific. U.S. Fish Wildl. Serv., Fish. Bull. 54 :91­110.

SUAREZ CAABRO, J. A., AND P. P. DVARTE BELLO.

1961. Biologia pesquera del bonito (Katsuwonuspebl111 is) y la albacora (Thwlnus at/anticus) enCuba. 1. Inst. Cubano Invest. Tecnol., Ser.Estud. Trab. Invest. 1;', 151 p.

STEEL, R. G. D., AND J. H. TORRIE.

1960. Principles and procedures of statistics withspecial reference to the biological sciences. Mc­Graw-Hill, N.Y., 481 p.

SUND, P. N., AND W. J. RICHARDS.

1967. Preliminary report on the feeding habits oftunas in the Gulf of Guinea. U.S. Fish Wildl.Serv., Spec. Sci. Rep. Fish. 551, 6 p.

WILLIAMS, F.1966. Food of longline-caught yellowfin tuna from

East African waters. East Afr. Agric. For. J.31: 375-382.

1101

FISHERY Bl:LLETIN, VOL. 70, NO.4

ApPENDIX TABLE l.-List of forage organisms found in stomachs from 356 skipjacktunas, collected off the west coast of Africa during UN6801. Number of organisms,frequency of occurrence, and percentage of total volume are given for each taxon. Sizeranges and mean sizes are given only for certain forage fishes. Fishes are listed indecreasing order of frequency of occurrence by families; crustaceans, mollusks, andmiscellaneous groups are listed by broad categories.

Frequencyof

occurrenceTaxonNumber

oforganisms ---------

Number %

Volume

ml %

Size (mm)

Range Mean

1102

fishes:Uniden1lfioble

CarangidaeYomtr utapinnisDtcaptauI spp.Unidentified Carangidae

ScombridaeEuthynnul al/tt/tra/usAuxir spp.

KafJuwonuJ pdami!ThunnuJ !opp.Unid"ntified Seambridae

GempylidaeGnnpy/uJ urpnuNtalo/us tripaPromtthichthYJ prOm!tAt1"Nniarcluu naJutUJ

Unidentified Gempylidae

Mull/da"PuuduptntuJ pfilytnJisUnidentified Mullidae

PriaconthidaeP,iQCQl1tn.UJ spp.Priacanthul artna!us

lutionidoeUnidentified Lutjanidae

SerranidaeUnidentified Serranidoe

Acant'huridaeAeanthurUl monroviat'Unidentified Acanthuridoe

DoctylopteridaeDacty/optrrul vo/itanJ

Gonostomatidoel'inciguuria nimbariaUnidentified Gonostomotidoe

EngraulidoeAnchovidla gui1lunIif

SynodontidoeSaurida brasuitnsisUnidentified Synodontidoe

BothidaeUnidentified Bolnidae

BolistidaeUnidentified Balistidoe

TetroadantidaeUnidentified Tetraodontidae

Parol"pididaeUnidentified Parolepididoe

Angui lIeideiUnidentified Anguillaldei

HclocentrldoeUnidentified Haloeentridae

Scorpoen'ldaeUnidentified Searpaenidoe

BlennidaeOphiohltuiuJ wlbbi

AulopidaeAu/opuJ spp.

1.\112

1746

85

12053

224

48138I

B9

27845

8424

J%

2165

62

5,23726

3,()98

108106

43

22

22

64

20

12

13

10

5

885

54

667.<1

223

28II7I

54

8018

5014

64

62

II40

49

386

25

817

23

19

18

13

13

12

12

9

4

64.3

24.71.4

15.2

18.5B,10.60.60.8

7.93. I2.00.3

15.2

22.55.1

14.03.9

18.0

17.4

3.111.2

13.8

10.71.7

7.0

2.24.8

6.5

5.3

5. I

3.7

3.7

3.4

3.4

2.5

LI

179.5

25.31.5

14.8

28.19.50.31.40.5

34.310.23.00.1

26.4

196.822.1

23.615.8

55.3

69.8

10.113.8

16.5

1233.91.9

247.0

11.011.9

5.0

5.1

3.5

5.9

3.2

1.7

3.3

1.4

6.5

0.9<0.1

0.5

1.00.3

<0.1<0.1<0.1

1.20.40.1

<0.10.9

7.10.8

0.90.6

2.0

2.5

0.40.5

0.6

44.60.1

8.9

0.40.4

0.2

0.2

0.1

0.2

0,1

0.1

0,1

0.1

<0.1

7'<>7

8-3320-43

6-46

10-6812-3720-3234-47

18-21620-6524-65

16-83

32-494<l-46

9-3122-33

10036

11-28

13-306-29

11-34

27-4832-41

'21-34

14.(3223·39

16-30

4-20

10-18

34-71

10-36

4-20

29-42

26-45

19

IS2520

29292641

705145

57

4.244

2\30

16

2418

19

3537

27

2531

23

,15

13

46

24

13

34

33

DRAGOVICH and POTTHOFF: FOOD OF SKIPJACK AND YELLOWFIN TCNAS

ApPENDIX TARLE l.-Continued.

FrequencyNumber of

Taxon of occurrence Volume Size (mm)organisms

Number % ml % Range Mean

BromidesPttrycombuJ broma 0.6 1.4 <1).1 28.(36 32Taractichtlt:ys longipinnis 0.3 0.3 <0.1Unidentified Bramidae 0.3 0.2 <0.1

Chio'smodontidoe

DYJalotus S1pp. 4 1.1 2.0 <0.1 18.(39 32Ophichthidoe

Unidentified Ophichthidae 0.6 0,2 <0.1Sternoptychidoe

Strrnoptyx diaphana 0.6 1.4 <0.1 20.26 23Myctophiclae

Unidentified Myctophidae 10 0.0 0.3 <0.1 7-9 8Chaunacidae

Chaunax pictuJ 0.6 0.2 <1).1 8-9 9Brotulidae

Unidentified Brotulidae 0.6 0.7 <0.1 28-44 36Exocoetidae

Unidentified Exocoetidae 0.6 2.7 <0.1Trochipteridae

TrachipttruJ tracnypttruJ 0.6 0.5 <0.1 47·51 49Triglidoe

Chdidoniththys gabontnsis 0.6 06 <0.,1 20-22 21Sphyraeniclae

Sphyratna spp. 0.6 0.5 <0.1 28..:31 29

UranoscopidaeUranoJCopus spp. 0.6 0.5 <0.<1 17 17

TrichiuridaeUnidentified Trichiuridae 4 2 0.6 0.8 <0.1 42-83 68

1stiophoridaeUnidentified Istiophoridae 2 0.6 0.2 <0.1 13·17 15

MonoconthidoeUnidentified Monaconflhidae 0.6 3.6 0.1 15-5,1 33

OstraciontidaeUnidentified Ostraciontidoe 06 0.3 <0.1 8-10 9

CongridoeUnidentified Congridoe 0.3 0.2 <0.1

AntennoriidaeUnidentified Antennarjjdae 0.3 0.3 <0.1

AulostomidoeAu/o!tornu! ma.cu/atus 03 0.2 <0.1

StromatedoideiUnidentified Stromatedoidei 0.3 0.1 <0.1

AriommidaeAriomma spp. 0.3 1.3 <0.. 1

ChaetodontidaeUnidentified Chaetodontidae 0.3 0_2 <0.1

Crustaceans:Unidentified Crustacea ~2 14.6 17.0 0.6Stomatopodo

Unidentified Stomatopoda 346 115 32.3 49.8 1.8Decapoda

Brachyura (megalopae) 268 26 73 13.3 0.5BraohyurQ (zoeo) 7 1 0.3 0.2 <0.1Raninidae (megalopoe) 473 55 15.4 44.0 1.6Grapsidae (megolopae) 2 2 0.6 0.3 <0.1

AnomouraPorcellanidae (mega/opae) 9 2 06 0.3 «LIDardanu! putinatu! (Glaucothoe) 20 11 3.1 1.9 <0.1PttrochiruJ sp. (Glaucothoe) 4 4 1.1 0.5 <0.1Unidentified Paguridea (Gloucothoe) 11 11 3.1 0.4 <0.1

Macrura·NatantiaStrgntrs sp. 0.3 0.3 <0.1Luciftr sp. 0.3 0.3 <0.1

1103

1104

FISHERY BULLETIN: VOL. 70, NO.4

ApPENDIX TABLE I.-Continued.

FrequencyNumber of

Taxon of OCcurrence Volume Size (mm)organisms ----_ .•.._--

Number % ml % Range Mean

CarideaBrachycarpus biuguinculattH :>3 23 6.5 2.8 <0.1

(Rttrocaris spinosa·--larvol stage)Erdrnocaris sp. (larvae of 0.3 0.1 <0.1

Lysmala sp.-Hyppolytidae)Enoplometopus antilt1uiJ 1 0.3 0.5 <0.1lfeltrocQnpus (Mila 6 1.7 1.0 <0.1Prorli'tn stage (11 tferocorpuI

~nJiltr) 3 0.8 0.4 <0.1Anifoca,is sp. (larval Caridean

genus) I I 0.3 0.2 <0.1Hippo'lytidae (larvae) , I 0.3 0.1 <0.1Unidef'\tified Caridea 14 \3 3.7 1.7 <0.1

Macrura-Reptantia (all Phylrlosoma stages)Unidel"ltified MocTuro·Reptantia 0.6 0.3 <0,1Panuti,u! riHoni 0.3 0.2 <0.1

Amphipoda (Hyperidea)Phrosillfl umifunata 56 42 11.8 9.0 0.3BrachYJCelluJ spp. 49 35 9.8 4.4 0.2Phronima srdt'ntaria 52 41 115 7.9 0.3OXYCl'phaluJ clausii 10 10 2.8 U <0.1Plalyudln! ovoidtr 6 6 1.7 0.8 <0,1Anchylomera hlofJtvil/~i 3 2 0.6 0.2 <0,1Vibilia cultriPts 1 1 0.3 0.1 <0.1Strutsia ~ht1l1tngtri I I 0.3 0.1 <0.1PlalyuelluJ armalu! var. iuum;J 1 I 0.3 0.1 <0.1Unidentified Hyperidea 9 4 1.1 1.8 <0.1

CopepodaUnidentified Copepoda 6 08 0.3 <0.1

Isopoda

Cymathoidae 0.3 0.1 <0,1Euphausiacea

Euphausia hanu1li 1.4 0.5 <0.1

Mollusks.Cephalopoda (adulls and juveniles)

Unidentified Cephalopoda \8 \5 4.2 9.6 0.3Oclopoda 27 13 3.7 10.0 0.4Argonauta argo 4 1 0.3 9.0 0.3

TeuthoideaUn'ldentH'red Ommostreph'ldoe 189 28 7.9 129. , 4.7Unidentified Teuthoidea 99 84 23.6 41.8 1.5

GastropodaPteropoda

Cavolinia IOnKiroJt,iJ 923 17 4.8 20.4 0.7Diaeria triJpinosQ 1 1 0.3 0.1 <0.1

HeteropodaOxygyruf ktraudrt,..i 0.3 l)"] <0,1IItlanta ptroni 0.6 0.'2 <0.1

MiscellaneoLls:Salpidae 85 49 13.8 63.0 2.3Polychaete I I 0.3 0.2 <0.1Syphonophora 1 1 0.3 0.1 <0.1Unidentifiable 23 6.5 5.0 0.2

DRAGOVICH and POTIIlOl'F: FOOD OF SKIPJACK AND YELLOWFIN TUNAS

ApPENDIX TABLE 2.-List of forage organisms found in stomachs from 83 yellowfin tunascollected off the west coast of Africa during cruise UN6801. Number of organisms,frequency of occurrence, and percentage of total volume are given for each taxon. Sizerange and mean sizes are given only for certain forage fishes. Fishes are listed in de-creasing order of frequency of occurrence by families; crustaceans, mollusks, and mis-cellaneous groups are listed by broad categories.

FrequencyNumber 01

Taxon 01 oCcurrence Volume Size (mm)organisms

mlNumber % % Range Mean

Fishes:Unidentifiable 748 69 83.1 730.0 lOA 11-43 27Carangidae

Yomtr Jeto.pinnis 101 36 43.4 23.3 0.9 8-32 16Dtrapterus spp. I 1 1.2 0.8 <0.1NaucrattS durtof 1 I 1.~ 55.0 2.2Unidentified Carangidae 107 31 37.3 14.3 0.6 9-40 19

MullidaePuudop,'nellJ prayensis 386 24 28.9 227.4 9.3 '23-51 42Unidentified Mulolidae ~15 20 24.1 136.2 5.5 39-51 44

PriacantlhidaePriacanthuJ spp. 66 3 , 37.3 173 0.7 13-34 20P,io,conthus arenat'llJ 15 1·0 12.0 9.1 0.4 18-32 27Priaconthus ',uenoluJ I I 1.2 0.7 <0.1 29

AcanthuridaeAcanlhurur monroviat 51() 8 9.6 11.3 0.5 15-27 23Unidentified Acanthuridae 44 /26 311:3 7.7 0.3 11-30 20

ScombridaeEuthynnus alltleratus 58 21 25.3 18.0 0.7 11-70 33Auxis spp. 7 5 6.0 1.4 <0.1 12·50 22Thunnus spp. 3 3 36 0.8 <0.1 29-40 36KatsuwonuJ pIlamis I I 1.'2 0.2 <0.1 38

GonostomatidaeVincigurrria 11.imbaria 1.163 23 27.7 518.8 21.1 3'2-50 40Unidentified Gonostomatidae 78 7 8.4 24.5 1.0 17-44 29

BothidaeUnidentified Bolhidae 86 29 34.9 11.2 0.5 15..50 24

DactylopteridaeDactylop/lrus volitanJ 45 25 30.1 5.9 0.2 10./25 17

BalistidaeUnidentified Bali'stidae 84 '23 27.7 16.0 0.7 10-19 14

GempylidaeGimpylus Serpt1U 9 6 7.2 2.8 <0.1 44·118 65NtalotuI triptJ 2 2 2.4 1.1 <0.1 :9·71 45N t$iarchus nasutus 1 1 1.2 0.2 <0.1PromtthichthYI promttAtuJ I 1 1.2 O.i2 <0.1Unidentified Gempy\idae 14 12 14.5 3.5 <0.1

SerranidaeUnidentified Serranidae 43 18 21.7 7.1 0.3 16·26 21

LutjanidaeUnidentified lutjanidoe 29 17 2'0.5 5.1 0.2 14-38 2'2

TetraodontidaeUnidentified Tetraodontidae 18 16 19.3 3.8 0.2 9-36 16

BlenniidaeOphioh!tnnlus wlbbi 27 14 169 7.8 0.3 15·40 32

Paralepidida9Unidentified Paralepididae 130 13 15.7 37.2 1.5 36·100 66

HolocentridaeAfyr~priJtis jacobu! 2 2 '2.4 0.6 <0.11 2'2-'26 24Unidentified Holocentridae 20 11 13.3 5.8 0.2 11-3'2 23

ScorpaenidaeUnidentified Scorpaenidae 13 13 i15.7 3.2 <0.1 11-29 18

AnguilloideiUnidentified Anguill/oidel 25 II 13.3 2.7 <0.'1

SternoptychidaeSternoptyx diaphana 7 5 6.0 7.0 0.3 25-32 29Unidentified Slemoptyehiclae 4 3 3.6 1.9 <0.1 :20-'27 24Unidentified Stromateoidei 8 6 7.2 1.8 <0. 1 18-'34 26

AU/QpidaeAulopus spp. 11 5 6.0 5.7 0.2 26-49 38

1105

FISHERY BULLETIN: VOL. 70, NO. 4

ApPENDIX TABLE 2.-Continued.

FrequencyNumber of

Taxon of occurrence Volume Size (mm)organisms

Number ml % Range Mean%

TrochipteridaeTrochipttruJ tracnyptuul 5 6.0 4.0 0.2 45-70 53

SyngnathidaeHippocampus spp. 1 1.2 0.1 <0.1 16-22 II'llippocompuJ punc/uta!u! 2 2.4 1.2 <0.1 50-52 51Unidentified Syngnathidae 2 2.4 0.3 <0.1

OphichthidaeUnidentified Ophid1thidae 19 4 4.8 2.1 <0.1 8OJ I08 96

BramidaePttrycombul brama 1 1.2 0.4 <0.1Unidentified Bramidae 2 2.4 0.4 <0.1 14-11' 17

NettastomidaeUnidentified Nettostomidae 7 2.4 1.0 <0.1

CongridaeUnidentified Congridae 7 2 2.4 2.1 <0.1 80-178 121'

SynodontidaeSaurida brasilitftsis 7 1.2 1.2 <0.1 31-32 32Unidentified Synoclontidae I 1.2 0.1 <0.1

MyctophidaeUnidentified Myctophidae 2.4 0.3 <0.1 14J23 II'

AntennariidaeUnidentifiecl Antennariidoe 2 2.4 1.1' <0.1 16-21 18

Monacanthidae

Unidentified Monacanthidae 2.4 1.2 <0.1 17-38 28Ophidiidae

Ophidion barbatum 23 2.4 1.4 <0.1 32-37 35FistlJlariidae

Fistu{a,ia spp. 2 2.4 0.3 <0.1 70-86 78Triglidae

Unidentified Triglidae 2 2.4 0.5 <0.1 21J2(2 22Diretmidae

Di,dmuJ artinltUI 1.2 3J 0.1Nemichthyidae

Unidentified Nemichthyidae 1.2 0.1 <0.1Brotuljdae

Unidentified Brotulidoe 1.2 0.8 <0.1Trachichthyidae

Gtphyrobtryx darwin; 1.2 1.0 <0.1GrammicO'lepiclidae

X tno[tpidichthYJ spp. 1.2 0.3 <0.1Caproidae

Antigonia capros 1.2 3.1 0 ..1Trachipteroidei

Unidentified Trochipteroidei 1.2 0.1 <0.1Coryphaenidae

Corypn.atna hiPPuruJ 1.2 0.1 <0.1Chaetodontidae

Unidentified Chaetodontidae 1.2 0.1 <0.1$phyraenidae

Sphyratna spp. 1.2 0.2 <0.1Chiosmodontidae

DyJalotul spp. 1.2 1.0 <0.1Istiophoridae

Unidentified Istiophoridae 1.2 0.2 <0.1Tetrogonuridae

TtlraKOnUrtlJ ("vit,i 4 1.2 154.0 6.3 165·183 174

Crustaceans:Unidentified Crustacea 12 14.5 11.2 0.5Stomatopoda

Unidentified Stomatopada (larvae) 1.081 63 75.9 J61.1' 6.6Decapodo

8rachyura (megaiopae) 287 19 '12.9 31.3 1.3Unidentified Raninidae (megalopae) 235 23 27.7 25.1 1.0Unidentified Grapsidae (megaJopae) 8 2 2.4 1.0 <0.1

1106

DRAGOVICH and POTTHOFF; FOOD OF SKIPJACK AND YELLOWFIN TUNAS

ApPENDIX TABLE 2.-Continued.

FrequencyNumber of

Taxon of occurrence Volume Size (mm)organisms

Number % ml % Range Mean

Pogurideo (011 GloucothoeJDardanuJ spp. 3 3 3.6 0.3 <0.1DardanuJ patinaIus 89 11 13.3 9.5 0.4PrlrochiruJ Sp. 1 1 1.2 0.1 <0.1Unidentified Paguridea 10 4 4.8 1.0 <0.1

Macrura-NatantiaCoridea

Unidentified Pondolidae (larvae) 14 6 7.2 3.9 0.2Pociphatu s~miJpiftosa 10 1 1.2 4.0 012H It"ocor1lu1 l1ui/a 1 I 1.2 0.2 <0.1Proclttn stage (Ht/trocarpu!

lfUi/tr) 6 3 3.6 0.9 <0.1Anil0(oris sp. (larval genvs) 5 2 2.4 0.5 <0.1Ert'tmocoris sp. (larval genus) 2 2 2.4 0.3 <0.1Oplopho,uJ ,p. (lorval genII') 1 I 1.2 0.1 <0.1EnoplomtlopuJ anti/tnSil 6 5 6.0 2.0 <0.1Unidentified Corideo 16 9 10.a 4.6 0.2

Mocruro-Reptontio (011 Phyllloooma ,tage,)Scyllar"! arc/us 5 2 2.4 1.2 <0.1Unidentified Mocrura-Reptantia 6 3 3.6 0.6 <0.1

Amphipoda (Hyperiidea)PhroJina umilunata 73 29 34.9 14.6 0.6BracAysulluJ sp. 58 14 16.9 4.8 0.2Phronima udt1ttaria 17 8 9.6 2.0 <0.1OxyctphaluJ rlausii 9 6 7.2 0.9 <0.1PJatYJC(lIuJ ovoidts 1 1 1.2 0.1 <0.1StruUia chalhngtri 1 I 1.2 0.1 <0.1

EuphausiaceaEuphausia h01lJ/lIi U 6 7.2 1.3 <0.1

Mollu,"'"Cephalopoda (adult. and iuvenile,)

Unidentified Cephalopoda 48 1'2 14.5 30.7 1.2Octopoda

Argo1lauta sp. 1 1 1.2 1.5 0.1Tfl'moctopus via/actus 9 1 1.2 4.5 0.2Octopus sp. 5 2 2.4 2.8 <0.1Unidentified Oct-opoda 25 12 14.5 31.6 1.3

TeuthoideaUnidentified Ommastrephidae 437 :J6 43.4 314.2 12.8Unidentified Chiroteuthidae 1 I 1.2 1.0 <0.1Ornithottuthis anti/arum 5 1 1.2 1.5 <0.1Liocranchia rti,.hardti 11 1 1.2 5.0 OJ2Liocranchia sp. 1 1 1.2 0.2 <0.1Cranchia uabro 3 12 2.4 3..2 0.1Onycnottuthis banksi 1 1 1.(2 0.4 <0.1MostiKottuthis sp. 1 1 1.2 0.5 <0.101ly/.:io 'po 4 '2 2.4 5.5 0.2Unidentified Cronchiidae 5 3 3.6 2.8 0.1Unidentified Enoploteuthidoe 4 3 3.6 1.7 <n.'lUnidentified Teuthoidea 204 45 54.2 124.6 5.1

GastropodaUnidentified Atlantidae 2.4 0.2 <0.1

MiscellaneOl/'5:Solpidae 27 17 20.5 8.8 0.4

1107

FISHERY BCLLETI~: VOL. 70, 1\0. 4

ApPENDIX TABLE 3.-List of forage organisms fond in stomachs from 202 skipjack tunas,collected off the west coast of Africa during cruise UN6802. Number of organisms,frequency of occurrence, and percentage of total volume are given for each taxon. Sizeranges and mean sizes are given only for certain forage fishes. Fishes are listed indecreasing order of frequency of occurrence by families; crustaceans, mollusks, andmiscellaneous groups are listed by broad categories.

TaxonNumber

oforganisms

Frequencyof

occurrence

Number %

Volume

mJ 0/0

Size (mm)

Range Mean

1108

Fishes:UnidentifiableParolepididae

Unidentifiable Paralepididae

CarongidaeVomer St'tapinnisTrackinotus ovatUJUnidentified Carangidae

GempylidaeGempyluJ serptnsUnidentified Gempylidae

TrichiuriclaeUnidentified Trichiuridae

ScombriclaeAuxis spp.

Sarda sardaScombu japonicuJ

SerranidaeUnidentified Serranidae

ScorpaenidoeUnidentified Scorpaenidae

LutjanidaeUnidentified Lutjanidae

Berycoidei

Unidentified BerycoideiPercoidei

Unidentified PercoideiAngui lIoidei

Unidentified leptocephalusBothidae

Unidentified BothidaeAcan~huridoe

Unidentified AconthuridoeTroch ipteridae

TrachipttruJ trachypttruJ

Trig!;daeUnidentified Triglidae

ChoetodontidoeChadodon spp.

ClupeoideiUnidentified Clupeoidei

SyngnothidaeUnidentified Syngnathidae

SynodontidaeUnidentified $ynodontldae

Alepi~auridoe

Altpi:aurul /erox

HolocentridaeUnidentified Holocentridae

OphidiidaeUnidentified Ophidiidae

PriacanfhidoePriacanthul spp.

StromateoideiUnidentified Stromateoidei

TetraodonfidaeUnidentified Tetraodontidae

UralloscopiclaeUranoJeopui spp.

698

1,026

444

15

125

49

3341

151

13

9

8

257

6

4

70

14

155

59

334

13

I17

18

104I

12

10

6

76.7

29.2

16.32.06.4

058.4

8.9

5.02.005

5.9

5.0

3.5

4.0

30

2.5

2.5

2.0

2.0

2.5

1.5

I.S

1.0

1.0

0.5

0.5

1.0

0.5

05

05

0.5

109.3

21>0.5

24.00.66.0

0.311.9

13.6

8.62.31.3

15.0

26

1.4

1.4

65.1

0.7

1.1

0.8

2.6

1.2

2.3

4.7

0.7

2.0

3.6

D.5

1.4

0.2

2.5

0.1

O.B

11.1

28.4

2.40.10.6

0.11.2

1.4

0.90.20.1

1.5

0.3

0.1

0.1

8.6

0.1

0.1

0.1

0.3

0.1

0.2

0.5

Q.l

0.2

0.4

0.1

0.1

<0.1

0.2

<0.1

0.1

52-112

9-3617-2311-56

62-94

66-110

15-6325-43

14-25

15-125

15-24

19-32

20-30

13-17

17-23

12-35

100-113

23-53

68

271922

94

3 i34

19

18

19

15

27

25

15

20

23

106

31>

DRAGOVICH and POTTHOFF; FOOD OF SKIPJACK AND YELLOWFIN TUNAS

ApPENDIX TABLE 3.-Continued.

FrequencyNumber of

Taxon of occurrence Volume Size (mm)organisms

Number ml% % Range Mean

Crustaceans:Amphipoda (Hyperiidea)

Phrosi1la Jtmilunata 561 139 68.8 83.8 6.2Brachysct'/!us spp. 281 94 46.5 18.9 1.4Phronima s,d/'nlaria 39 26 12.9 4.3 0.3.4 nchylomaa bloJJevillti 27 3 1.5 1.2 <0.1FlatYJeellouJ ovoides 9 6 3.0 0.7 <0.1Vibilia armata 6 6 3.0 0.6 <0.1Platyscdlus urratuluJ 2 2 1.0 0.4 <0.1PlatyJcellllJ armatUJ intrmis 1 1 0.5 0.2 <0.1(}xc)'CI'pha!us cla/oi 1 1 0.5 0.1 <0.1

DecapodaRaninido9 (megalopae) 112 58 28.7 9.0 0.7Brachyuro (megalopae) 16 13 6.4 1.9 0.1

Siomotopoda Ilarvol forms) 43 31 15.3 5.4 0.4Euphausiacea

Euphausia nanuni 3,556 19 9.4 118.0 8.8AnomuraPagurideo lall Gloucolhoe)

Dardanus putinatus 9 7 3.5 0.9 <0.1Mocrura·Replantia (all Phyllosomae larvae)

Scyllarus arctUJ 5 5 2.5 0.9 <0.1Scyllarus sp. 2 2 1.0 0.2 <0.1Scylla,idts sp. 1 1 0.5 0.1 <0.1

Macrura~Natantia

Serge,stidae 0.5 0.2 <0.1Lucifer sp. 0.5 0.1 <0.1Caridea 0.5 0.1 <0.1Polaemonidae 0.5 0.1 <0.1

CopepodaArietelluJ armatUJ 0.5 0.1 <0.1Candacia varirans 0.5 0.1 <0.1

Unidentifiable Crustacea 0.9 <0.1

Mo~1 usks,Cephalopoda ladults and iuveniles)

Unidentified Cephalopoda 14 13 6.4 3.2 0.2Oetopoda

Argonauta sp. 1.0 6.7 0.5Other Octopoda 0.5 0.1 <0.1

TeuthoideaOrnithofeurhis antillarum 78 33 16.3 126.4 10.1Ommastrephidae 37 31 15.3 9.4 0.7Unidentified Teuthoidea 4 3 1.5 0.3 <0.1

GastropodaPteropoda

Cavolinia longirostris 39 12 5.9 1.8 <0.1Heteropoda

Atlantidae 4 4 2.0 0.3 <0.1Atlanta sp. 2 2 1.0 0.:2 <0.1Atlanta ptroni 1 I 0.5 0.1 <0.1Oxygyrus ktraudrtni 1 1 0.5 0.1 <0.1

Miscellaneous:Salpidae 8 7 3.5 1.1 <0.1

1109

FISHERY BULLETIN, VOL. 70, NO. 3

ApPENDIX TABLE 4.-List of forage organisms found in stomachs from 43 yellowfin tunas,

collected off the west coast of Africa during cruise UN6802. Number of organisms,frequency of occurrence, and percentage of total volume are given for each taxon. Sizeranges and mean sizes are given only for certain forage fishes. Fishes listed in decreasingorder of frequency of occurrence; crustaceans, mollusks, and miscellaneous groups arelisted by broad categories.

FrequencyNumber of

Taxon of occurrence Volume Size (mm)organisms

mlNumber % % Range Mean

Fishes,Unidentifiable 238 38 88.4 61.1 17.1Scombridae

Auxis spp. 53 11 25.6 7.4 2.1 15-34 22Sarda Jarda 4 '2 4.7 0.5 0.1 15-<21 188combtr ;aponicus 1 1 2.3 0.1 <0.1Unidentified Scombridoe 15 6 14.0 0.8 0.2

Carangidaeromir sttapi,,1Jis 14 10 23.3 4.5 1.2Unidentified Carangidae 3 3 7fJ 5.3 1.5 21-98 48

ParalepjdjdoeUnidentified ParalepJdidae 10 5 11.6 2.1 0.6

GempylidoeGlimYP[ul Urpt1U 3 7.0 0.4 0.1Unidentified Gempylidae 2 2.3 0:1 <0.1

Tricl1luridaeUnidentified Trichlurldae 4 3 7.0 2.1 0.6

ChaetodontldaeChattodon spp. 2 4.7 2.5 0.7 20-35 27

ExocoetidaeCypuluruJ spp. 2.3 27.5 7.7Unidentified Exocoetidae 2.3 7.0 1.9

PercoideiUnidentified PercoldeJ 16 2 4.7 5.0 1.4 rzo..28 24

TrochipteridaeTrac}"ipttrUJ trachYPUrul 4.7 9.2 2.6

AlepisQuridae~tltpiJauruJ /trox 2.3 20.0 5.6

BothidaeUnidentified Bothldae 2.3 0.1 <0.1Of=lhidlidae

Unidentified Ophidiidae 2.3 2.0 0.6Syngnathidae

Unidentified Syngnothidae 2.3 0.3 0.1

CrustaceaN:Stomatopoda (larval forms) 81 24 55.8 7.4 1.!.1Amphipodo (Hyperiidea)

PArosina umilunota 62 19 44.2 9.4 2.6BrachYJuluJ spp. 8 6 13.9 0.7 1.9Phronima udtntaria 8 4 9.3 1.3 3.6Vibilia armata 1 1 2.3 0.1 0.1

DecapodaBrachyura (megalopae) 13 4 9.3 1.7 0.5Raninidae (megalopoe) 5 4 9.3 0.4 0.1

AnomuraMacrura·Reptantia (all

phyllosema& larvae)ScylltJridat sp. 2 2 4.6 0.2 0.1ScylltJruJ sp. 2 2 4.6 0.2 <0.1

Paguridea (all Glaucothoe)DtJrdanul 'PutintJtul 4 4.6 0.4 1.1Unidentifiable Crustacea 0.4 1.1

Mollusk"Cephalopoda (adults and iuvenHes)

Unidentified Cephalopoda 7 6 13.9 3.5 1.0OctopodaArKontJuta argo 6 5 11.6 165.5 46.3

TeuthoideaOmmostreophidae 10 2 4.6 4.6 1.3Ornithrttuthil antillaru". 2 2 4.6 1.3 0.4Tttrtnychottuthis dusumitri I I 2.3 d,\l 0.4Unidentified Teut'hoidea 4 4 9.2 0.4 1.1

Misce~laneous:

Solpidae 4 6.9 0.3 0.1

1110