Feeding studies of short-finned (Illex illecebrosus) andlong-finned (Loligo pealei) squids were conducted during the May to November period of 1976 on the Nova Scotian shelf, on Georges Bank and in adjacent waters. The analysis of 2 604 sp. Of Illex and 578 sp. of Loligo, showed that the food composition of both species was predominated by fish and squids. Cannibalism was more typical of short-finned squids and the fish were a prevalent food items in the long-finned squids' diet. In all areas and at all depths, coefficients of stomach fullness for larger short-finned squids were 1.5-2 times higher than for

smaller specimens, although the feeding intensity of both groups was low. The feeding intensity of immature long-finned squids was higher than that of mature specimens

Vinogradov, V. I.

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NOT TO BE CITED WITHOUT PRIORREVRENCE TO THE AUTHOR (S)Northwest Atlantic Fisheries OrganizationSerial No. N914		 NAFO SCR Doc. 84/IX/117 SCIENTIFIC COUNCIL MEETING - SEPTEMBER 1984 On Feeding of Two Squid Species in the Northwest Atlantic byV. I. VinogradovAtlantic Research Institute of Marine Fisheries and Oceanography (AtlantNIRO)5 Dmitry Donskoy Street, Kaliningrad, 236000,\USSRAbstract Feeding studies of short-finned (Illex illecebrosus) andlong-finned (Loligo pealei) squids were conducted during theMay to November period of 1976 on the Nova Scotian shelf, onGeorges Bank and in adjacent waters. The analysis of 2 604 sp.of Illex and 578 sp. • of Loligo, showed that the food compositionof both species was predominated by fish and squids. Canniba-lism was more typical of short-finned squids and the fish werea prevalent food items in the long-finned squids' diet. In allareas and at all depths, coefficients of stomach fullness forlarger short-finned squids were 1.5-2 times higher than forCYsmaller specimens, although the feeding intensity of bothgroups was low. The feeding intensity of immature long-finnedCDsquids was higher than that of mature specimens.w(/)Introduction w	Short-finned (Illex illecebrosus) and long-finned (Loligo,a.cr)pealei) squids have long been the target of the fisheries forcoastal states and member-countries of NAFO. In recent yearsthe increased interest to squids' ecology has been reflectedin the papers of many researchers including Zuev, Nesis, 1971;Summers, 1971; Mesnil, 1976; Tibbets, 1977; Ennis, Collins,1978; Amaratunga, 1980; Dupouy at al., 1982. The subject dis-cussed in the paper by Vinog radov, Noskov, 1979, has beenfurther developed based on the data from feeding studies onsquids carried out on the Nova Scotian shelf, on Georges Bankand in adjacent waters in the May to November period of 1976.- 2 -terials and MethodsSampling of stomachs for feeding studies of squids wasmade on board the research vessels "Belogorsk", "Kvant" and"Stvor" in May through November 1976, during the trawl surveysof Scotian shelf, Georges Bank and adjacent waters.Sampling locations are shown in the figure .Methods described in our paper (Vinogradov and Noskov,1979) and in "Methodic manual... 1974" were used to preservestomachs, to sort them out by size groups,to determine compo-sition of stomachs' contents, to identify food items to species,and to calculate coefficients of stomach fullness.ResultsFood composition and feeding intensity of squids2 604 specimens of Illex and 578 specimens of holim wereexamined for food composition and feeding intensity of varioussize groups (Table 1). The analysis showed that the both specieshad prevalence for three groups of food organisms: squids, fishesand crustaceans (Table 1). The diet of Illex included for themost part squids (68% by weight); other groups were lessimportant (euphausiids - 14%, fishes - 11%). Fishes (40%) andsquids (35%) were common as food for Longo, the proportion ofshrimps being 17% by weight. Diets of short-finned and long-finned squids are the topic of the papers by Proerman (1983)and Vovk (1983). These authors reported that Illex and hone.mainly consumed fishes, squids and crustaceans. Their foodcomposition varied depending on the area, season and mantlelength (Vinogradov, Noskov, 1979). In the given paper an.attempt is made to represent the feeding of short-finned andlong-finned squids during the May to November period of 1976 byarea, length group and depth.Short-finned scull. On Emerald Bank, in June the foodcomposition of immature (10-18 cm) and mature squids was mainlyrepresented by euphausiids and other crustaceans (Table 2),however, the diet of mature specimens often included squids(27% by weight). Occurrence of large numbers of euphausiids,particularly in smaller squid stomachs (27% by weight), canextensive aggregation of this crustacean in thefeeding intensity of squids on Brownsdecreased, especially that of wall, immature squids,the fish (60%). The feeding intensity ofsquids was considerably higher; their food.l s repreequally by mysids (46%) and squids (44%).In ,:y, the feeding intensity of both small and largeshort-finned squids on Georges Bank was low, with the fishbeing a predominant food.In September, the feeding intensity of small and largesquids increased on Georges Bank. Diets of small and largesquids included primarily the fish (93%) and squids (84%)respectively.In October, on Georges Bank young squids fed on euphau-siids (80%), and large specimens consumed squids (83%). Compared with September, the feeding intensity of small squidsdecreased, and that of large squids ®` increased (50%00)(Table 2). In November, cannibali was again common to largesquids, however, the feeding intensity decreased 2.5 timescompared with October (Table 2).In September and October, in the Long Island area, bothsmall and large squid specimens took squids as food. Althoughthe coefficient of stomach fullness of young squids wasapproximately similar in September and October, and did notexceed 31%00 , the feeding intensity of large squids conside-rably increased in October (151%00) compared with September(14%00)It should be noted that in all areas the feeding intensityof small squids was somewhat lower (3000) on the average thanthat of large specimens, although large squids had slightlymore empty stomachs (54%) than small squids (50%).Similar results were obtained in the experiments ofO'Dor et al. (1980), and by Ennis and Collins (1978). These- 4 -authors recorded a large number of empty stomachs beginningin September, and identified very small squids as a main sourceof food which influenced the future abundance of squids.Long-finned squids. The feeding of long-finned squids wasstudied in September and October of 1976. The results showedthat young squids (8-15 cm) fed on crustaceans (primarily eu-phauatids and shrimps), fishes and squids, and in some areas(Nuntacket area, October) only on fishes and squids which gavea higher coefficient of stomach fullness (to 120% 00 ). Thefeeding intensity of squids from other areas did not exceed36%00 (Table 3).Large mature specimens of short-finned squid mainly con-sumed the fish and squids with shrimps being a favoured foodon Georges Bank in October. In September, in Nuntacket areawhere the diet was made of fish, the feeding intensity was low(3900)1The feeding intensity of small squids was 1.5 times higher(36%0 ®) than that of large specimens with a larger number ofempty stomachs (Table 3).Changes in food and feeding intensitywith depthDuring the study of changes in food and feeding intensitywith depth certain peculiarities were observed in some areas.On Nova Scotia, in 100 to 240 m depths the food of short-finnedsquids of varying sizes mainly consisted of crustaceans (witheuphausiids prevailing), although the diet of larger specimensincluded approximately 30% of squids (Table 4). The feedingintensity did not exceed 3000.On Georges Bank, in 43 to 350 m depths the bulk of thefood of short-finned squids of different sizes was made ofsquids (Table 4). The feeding intensity of both large and smallsquids increased with depth, and in 101 to 150 m depths it didnot exceed 36%0 for small and 44%0 0 for large specimens(Table 4).In the Long Island area, in 30 to 124 m depths long-finnedsquids fed :inly on squids kd fish although at all depthsthe diet of large squids included a considerable proportion ofbottom crustaceans (30). The feeding intensity of small spe-cimens a higher and ounted to 36-37% 00 (Table 4). Suches in food compo ition and feeding intensity with depthon Georges Bank and in adjacent waters, as well as on ScotianShelf were observed with respect to silver hake, red hake andother fish speciesmA change of productive zones, formed as a result of inter-action between the Gulfstream waters with cold Labrador watersat 100-150 m depths, can be related to aggregation of meso-and macroplankton (Sheldon et.al ., 1977), and its transport toGeorges Bank (Bigelow, 1926), where it concentrates in upperlayers (S shev, Sushin, 1975) varying in total biomass valuesby year (Noskov, Romanchenko, 1979)•Summary.The diet of immature short-finned squids (10-18 cm)included for the most part euphausiids, fishes and squids inproportions depending on month and areaCannibalism was typical of large short-finned squids(19-25 cm) everywhere, except for Scotian shelf. The feedingintensity (to 150%00 ) and cannibalism were the highest immaturesquids in southern areas.In the food of immature long-finned squids (8-15 cm) in allareas the fish predominated, although euphausiids and squidswere a common food item. The highest recorded feeding intensity(120%00 was in October, in the Nuntacket area, with the fishand squids as major food organisms.Large long-finned squids (1630 cm) southwards of GeorgesBank consumed fishes, but in September and October the bulk oftheir diets was represented by squids and shrimps respectively.In 100 to 240 m depths of Scotian shelf short-finned squidsshowed prevalence for euphausiids, and in 43 to 350 m depths ofGeorges Bank and in adjacent waters ® for squids.In all areas and in all depths coefficients of stomach full-ness were 1.5 ®2 times higher for large squids compared with thosefor smaller specimens.Food of long-finned squids differed with depth insiy.ifi-cantly and consisted of squids, the fish and bottom crustaceans,the feeding intensity being higher in immature specimens.References Amaratunga T., 1980. Preliminary estimates of predation by theshort-finned squid Illex  ijlecebrosus on Scotianshelf. NAFO SCR Doc. 80/31. Ser. No.63, pp. 1-13.Bigelow H.B., 1926. Plankton of the offshore waters of the Gulfof Maine. Bull. of the U.S. Bureau of Fisheries.Washington. vol. 40, part 2(968), pp. 1-509.Dupouy H. Amaratunga T. and Coelho L., 1982. Preliminary dataon predation of fishes on squid (Illex illeeebrosus)on the Scotian shelf (NAFO Div. 4VWX). NAFO SCR Doc.82/VI/43. Ser.No. 532, pp. 1-8.Ennis G.P. and Collins P.W., 1978. Food and feeding of theshort-finned squid (Illex illecebrosus) during itsseasonal occurrence inshore at Newfoundland and abrief review of the trophic relationships of thespecies. ICNAF Res.Doc. 78/11/7, Ser.No. 5159,pp. 1-9.Froerman Yu.M., 1983. Feeding spectrum and food relationshipsof short-finned squid (Illex illecebrosus LeSueur,1821). NAFO SCR Doc. 83/IX/82, Ser.No. N748,pp.1.22.Mesnil B. 1976. Growth and life cycle of squid, Loligo pealei and Illex illecebrosus. ICNAF Res.Doe. 76/VI/65.Ser.No. 3852, pp. 1-20.Methodic manual for studies of food and feeding relationshipsbetween the fish in natural environment. 1974. Izd."Nauka". M., 251 p.- 7Noskov A.S. Romanchenko A.N., 1979. Composition, distributionand abundance of Georges Bank zooplankton in summer1965 to 1977. In: "Problems of fisheries oceanologyof the World Ocean" (Theses of rep. at the VthAll-Union Conf.), Kaliningrad, pp. 50-52.0 Dor	Burward R.D., Vessey E. and Amaratunga T., 1980.Feeding and growth in captive squid, Illex illece-brosus, and the influence of food availability ongrowth in the natural population. ICNAF Res.Doc.80/IX/16 Ser. No.5342, pp. 1-15.Samyshev E.Z., Sushin V.A., 1975. Regularities of zooplanktongrowth in Georges Bank area. Trudy AtlantNIRO,vyp. 58, pp. 89-96.Summers W.C. 1971. Age and growth of Loligo pealei, a populationstudy of the common Atlantic coast s quid. Biol.Bull.,147, pp© 189-201.Sheldon R.W., Suteliffe W.11. Jr, Paranjape M.H., 1977. Structure,pelagic food chain and relationship between planktonand fish production. ® J. Fish. Res. Board .Can.No. 34, pp. 2344-2353.Tibbets A.N. , 1977. Squid fisheries loll so pealei and Illex ille-cebrosus, off the northwestern coast of the UnitedStates of America, 1963-74. ICNAF Sel.Pap. No.2,pp. 85-109.Vinogradov V.I. and Noskov A.S., 1979. Feeding of short-finnedsquid, Illex illecebrosus, and long-finnedsquid, Loligo pealei, of Nova Scotia and Newland, 1974-75. ICNAF Sel.Papers No.5,pp. 31-36.Vinogradov V.I., 1982. Food and feeding relationships betweensilver hake Merluccius bilintaris (Mitchill) andred hake Urophycis chuss (Walbaum) on GeorgesBank and in adjacent waters. Synopsis of thesisto pursue a Doctor's degree. M., pp. 1-23.Table 1 Food composition (% by weight) of short-finnedand long-finned squids in the Northwest Atlantic(Subareas 4, 5, 6) in May-November 1976Food organisms Short-finnedsquidsLong-finnedsquidsEvadne spp.Calanus finmarchicusMysidsCirolana app.Anonyx spp.GammaridsEuphausiidsShrimpsCrabsDecapodaNon,identified crustaceansTotal crustaceansSquidsRound herringMyctophidaeNon-identified fishesTotal fish and squidsClione limacinaDiacria trispinosaChaetognathaSagittaEchinodermataNo of examined stomachsMID1452168110792 6046172253513975578Table 2 Food composition (% by weight ) of short-finned squids by length, season and areaof Northwest Atlantic in May-November 1976Emerald : Browns : Georges Bank	:Long Island area: ForFood organisms	: Bank,	: Bank,: July : Sept : May : Sept :Oct :Nov : Sept : Oct	areasImmature squids 10-18 cm (mantle length)Euphausiids	64 -	80 -	27 - 57Decapoda 2	MD	emr.	-	OM	...	_ 2Non-identified crustaceans 30 10 - - _ - - 25Total crustaceans 96 10 - - 80 27 - 84Squids	4	30 -7 20 62 100 15ctophidae - - -	- 4	- -Ron-identified fish	+ 60 100 - 9) - 7 - 1Total fish and squids 4 90 100 100 20	- 73 100 .16Examined stomachs 520	32 40	38 40 - 86 40 796empty, % 49 78 90 58 50 - .24	52 50Coeff. of stomach fullness,%00	37 9 2 10 6 27 31 33MaLure squids 19-25 cm . (mantle length)Cirolana spp.GammaridssidsEuphausiidsDecapoda	5Non-identified crustaceans	18.Total crustaceans 71Squids 27MyctophidaeNon-identified fish	2Total fish and squids 29Diacria trispinosaClione limacinaClione limacinaSagittaNoe of examined stomachs	520empty, %	51Coeff. of stomach fullness,%,„ 2846	1	- -	- i10 - 1 - - 71 - 1- -_ 356	3	+ -	- +	1244-	84 83 80 72 87 75	3 2 - 1100 8 15 20 28 • 13 1144	100 95	100 100	100 100	87- 1 - - - 11 - - -- 1 _ --	- _	_ +	+60	40 672 247 60 89 120 180822 87 60 62 33 35 57 5423 10 20 50 20 14 151 37Sept •OctNuntacket area•-ForLong Island area;all:areasOct :•Georges Bank• SeptOctSeptFood organisms- 10 -Table 3 :rood cowpusition (% by weight) of long-finned squids by length and area ofthe Northwest Atlantic in September and October 1976Immature squids, 8-15 cm (mantle length)Evadne spp®Calanus finmarchicusMysidsAnonyx spp.GammaridsEuphausiidsShrimps	 -Crabs -Non-identified crustaceans	20Total crustaceans	20Squids	 67Non-identified fish 10Total fish and squids	77ChaetognathaSagittaEchinodermata	3No of examined stomachs	158empty, % 41Coeff. of stomach fullness,% 00	18Shrimps	 -Non-identified crustaceansTotal crustaceans	-Squids	 100Non-identified fish -Round herringTotal fish and squids	100Noo of examined stomachs 9empty, %	 44Coeff. of stomach fullness,% 0 0	27-	-	149	-	1	25	10.39	- - 31 3+346	49	33	25	167 1 45	19 55 4247 50 55 47 20 4154	51 100 66 75	83-	0 1- -	-- - - -	146	60 5160	 80 45567 50 72 6	56 486 36 120	31 28	36Mature squids 16-30 cm (mantle length)	6o	- - - 4022	-	-	-	160 22 - - 4120	- - 28 2220 78	-	64	35- -	- 8 240	78 - - 100 5960 4	- -	50	12333 25 - 46 3928	39 -	16 22-tr (-2 4-40p.CH4-1	002tO.f1 •vi 0 corici	Di	ka) to (1)+)4-404-4	rda) a)toas0 •rl •1*--4rj1 4-440-P	rd0 gali40edrlEflCO40F.4	yes kay	04-4 PIr-I11-41 034-1	-P-P 4-)as4) eci 00 el r: rP-4

On Feeding of Two Squid Species in the Northwest Atlantic

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