200 



Abstract— Analysis of 32 years of stan- 

 dardized survey catches ( 1967-98 ) indi- 

 cated differential distribution patterns 

 for the longfin inshore squid iLoligo 

 pealeii) over the northwest Atlantic 

 U.S. continental shelf, by geographic 

 region, depth, season, and time of day. 

 Catches were greatest in the Mid- 

 Atlantic Bight, where there were sig- 

 nificantly greater catches in deep water 

 during winter and spring, and in 

 shallow water during autumn. Body 

 size generally increased with depth 

 in all seasons. Large catches of juve- 

 niles in shallow waters off southern 

 New England during autumn resulted 

 from inshore spawning observed during 

 late spring and summer; large propor- 

 tions of juveniles in the Mid-Atlantic 

 Bight during spring suggest that sub- 

 stantial winter spawning also occurs. 

 Few mature squid were caught in sur- 

 vey samples in any season; the major- 

 ity of these mature squid were cap- 

 tured south of Cape Hatteras during 

 spring. Spawning occurs inshore from 

 late spring to summer and the data 

 suggest that winter spawning occurs 

 primarily south of Cape Hatteras. 



Geographic and temporal patterns 



in size and maturity of the longfin inshore squid 



iLoligo pealeii) off the northeastern United States 



Emma M.C. Hatfield 



Steven X. Cadrin 



Northeast Fisheries Science Center 



National Manne Fishenes Service, NOAA 



166 Water Street 



Woods Hole, Massachusetts 02543 



Present address (for E.M.C, Hatfield) FRS Marine Laboratory 



Victoria Road 



Aberdeen ABll 9DB 



Scotland, United Kingdom 

 E-mail address (for E M C Hatfield) e hatfield a marlab ac uk 



Manuscript accepted 17 mav 2001 

 Fish. Bull. 200-213 (2002). ' 



The longfin inshore squid, Loligo pea- 

 leii. is distributed in the northwest 

 Atlantic from Canada to the Carib- 

 bean (Cohen, 19761. Within its range of 

 commercial exploitation (from southern 

 Georges Bank to Cape Hatteras) the 

 population is considered to be a unit 

 stock ( NEFC ' ), although heterogeneous 

 subpopulations may exist (Garthwaite 

 etal., 1989). 



North of Cape Hatteras, L. pealeii 

 migrate seasonally. The migration has 

 been described as a movement offshore 

 during late autumn (so that the species 

 can overwinter in warmer waters along 

 the edge of the continental shelf ) and 

 a return movement inshore during the 

 spring and early summer (Summers, 

 1969; Serchuk and Rathjen, 1974; Tib- 

 betts, 1977). Murawski (1993) defined 

 L. pealeii as a member of a migratory, 

 warm-water group of species, centered 

 primarily in mid-Atlantic waters (par- 

 ticularly in the spring), that make in- 

 shore and northward migrations in the 

 spring and offshore and southward mi- 

 grations in late autumn. 



Geographic patterns in Northeast 

 Fisheries Science Center (NEFSC ) sur- 

 vey catches, from the Gulf of Maine 

 to Cape Hatteras, show that L. pealeii 

 are distributed over the entire conti- 

 nental shelf (from inshore to offshore) 

 in the autumn, are concentrated at the 

 edge of the continental shelf and at 

 the southern end of the survey area 

 during winter and spring, and are con- 

 centrated inshore in summer (Sum- 



mers, 1967; 1969; Serchuk and Rathjen, 

 1974; Vovk, 1978; Lange, 1980; Whita- 

 ker, 1980; Lange and Waring, 1992). 



Analyses of sui-vey catches indicate 

 that depth, time of day, and tempera- 

 ture all influence cross-shelf distri- 

 bution patterns (Summers, 1969; Ser- 

 chuk and Rathjen, 1974; Lange and 

 Warmg, 1992; Murawski, 1993; Brod- 

 ziak and Hendrickson, 1999). Diel cor- 

 rection factors have been applied to 

 sui-vey indices in various studies to ad- 

 just nighttime bottom trawl catches to 

 daytime equivalents (daytime catches 

 are higher when squid are concentrat- 

 ed close to the bottom) (Lange and Sis- 

 senwinel983; Lange and Sissenwine-). 

 Research by Lange and Waring (1992) 

 and Brodziak and Hendrickson (1999) 

 demonstrated that the diel differences 

 were size specific and that further con- 

 sideration of these differences in cor- 

 rection factors was warranted. 



Until recently, L. pealeii was thought 

 to have a life span of up to three years, 

 and the stock was assessed accord- 

 ingly (Sissenwine and Tibbetts, 1977; 

 Lange, 1981; Lange and Sissenwine, 



1 NEFC (Northeast Fisheries Center I. 1986. 

 Report of the second NEFC stock assess- 

 ment workshop. NEFC Lab. Ref Doc. 88- 

 02, 114 p. [Available from NEFSC, 166 

 Water Street, Woods Hole. MA 02,543.1 



- Lange, A. M. T, and M. P. Sissenwine. 

 1977. Lo/(go pea/ei stock status. North- 

 east Fisheries Science Center Lab. Ref Doc. 

 77-28, 9 p. [Available from NEFSC, 166 

 Water Street, Woods Hole, MA 002543.] 



