FISHERY BULLETIN: VOL. 72, NO. 3 



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LENGTH FREQUENCIES 

 SUMMER, 1970 



I GULF V COLLECTIONS 



I OTTER TRAWL COLLECTIONS 



I I 



I I 



JJL 



 I • 

 111 



44 



4850 53 59 



4 8 12 16 20 24 28 32 36 40 



LARVAL AND POSTLARVAL LENGTH (mmNL) 



Figure 12. — Comparison of length frequencies of silver hake larvae and post-larvae captured in Gulf V plankton samplers near 



surface and otter trawl on bottom during summer cruises, 1970. 



Bay flow west to southwest at average speeds of 

 0.93 km/h over the shelf between Nantucket 

 Shoals and New Jersey (U.S. Navy Hydrographic 

 Office, 1965) to 1.04 km/h over the southeast 

 slope of Georges Bank (Sauskan and Serebryakov, 

 1968). Thus, the maximum distance an egg would 

 drift from spawning to hatching is 76.8 km 

 (1.04 X 73.8 = 76.8) in the area of greatest egg 

 abundance which we observed. This is substan- 

 tiated by the fact that the center of abundance 

 of the prolarvae is only slightly further to the 

 southwest than that of the eggs. Also contributing 

 to the short drift of eggs and prolarvae is the 

 sluggish, meandering nature of currents on the 

 shelf south of New England. During the summer 

 of 1971, while studying vertical distribution of 

 silver hake larvae on the shelf south of Montauk 



Point, we deployed a free-drifting staff buoy and 

 sampled around it for 48 h. The course of the buoy 

 (Figure 13) demonstrates the capriciousness of 

 surface currents in the area, while indicating a net 

 westerly drift. 



I consider the silver hake eggs and larvae 

 which we collected to be 1) representatives of a 

 small brood spawned on the deeper portions of 

 the shelf between Hudson Canyon and Cape Hat- 

 teras; 2) representatives of a brood spawned over 

 Nantucket Shoals and the shelf south of New 

 England; 3) survivors of a brood spawned over 

 Georges Bank or Great South Channel. 



It is during the pelagic period of development 

 that eggs or larvae, unable to control their own 

 movements, are most susceptible to prevailing 

 currents, surface winds, and changing hydro- 



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