Loligo eggs hatch in 11 to 27 days. The newly-hatched planktonic young 

 closely resemble the adults, and do not undergo metamorphosis. Summers (1971) 

 has made laboratory observations that demonstrate significant female mortality 

 after mating. 



In spite of their relatively small size, longfin squid are aggressive and 

 have voracious appetites. They feed primarily on euphausiid shrimp and small 

 fishes (especially young butterfish and silver hake). During the spawning 

 season, smaller squid are preyed upon by the adults. Both young and adult 

 Loligo are in turn preyed upon by at least 48 different species of fish, 

 including bluefish, fourspot flounder, spiny dogfish and silver hake, as well 

 as marine mammals (Lange 1982). 



Serchuk and Ratnjen (1974) attempted to estimate population size but 

 discrete analysis is hindered due to seasonal migrations of this squid. 



Bottom Trawl Survey Results 



The cumulative spring and autumn distributions over the time series are 

 shown in Figures 22.1 and 22.2. In spring, the longfin squid we-e primarily 

 concentrated near and deeper than the 100 m contour; in autumn, the squid were 

 found over the entire shelf. The striking difference in distribution between 

 spring and autumn reflects a real increase in Loligo biomass found inshore 

 during the autumn (Serchuk and Rathjen 1974). A likely explanation for this 

 is the availability of both spring and summer spawned longfin squid to the 

 autumn surveys. 



Seasonal graphs of mean weight and number per tow are shown in Figures 

 22.3-22.6. The dramatic increase in fall catches is also reflected in these 

 plots; this is especially true with greater increases in relative numbers 



475 



