FAHAY: OCCURRENCE OF SILVER HAKE EGGS AND LARVAE 



^40*30 



7Mb 

 LONGITUDE WEST 



40°25 



O 



3 



40 20 



L40 15 



Figure 13. — Position of free-drifting staff buoy at 2-h intervals 

 on the continental shelf south of Montauk Point, N.Y. 



ACKNOWLEDGMENTS 



The author thanks especially Lionel A. Walford 

 for reviewing the manuscript and providing valu- 

 able assistance in its preparation; the editorial 

 staff of the Middle Atlantic Coastal Fisheries Cen- 

 ter and Fred Nichy of the Northeast Fisheries 

 Center, Woods Hole Laboratory, National Marine 

 Fisheries Service, NO AA, for providing comments 

 on the manuscript; technicians in the eggs and 

 larvae program at Sandy Hook Laboratory for 

 their diligence in sorting the ichthyoplankton; 

 Pat Burke for hours spent counting and measur- 

 ing; and Cindy deGorgue and Alyce Wells for the 

 preparation of some of the figures. 



graphic conditions. The results of the Dolphin 

 survey indicate several things about sampling 

 fishes during this phase in their development. 

 1) One cannot hope to fully understand the early 

 life history of any one species of fish on explora- 

 tory surveys. Such facts as gross seasonality and 

 geographic limits of spawning might be revealed 

 but a complete evaluation of a species' early life 

 history can only follow a series of frequent 

 cruises where all efforts are focused on one or a 

 very few species. 2) Known or suspected zoo- 

 geographic barriers should be included well 

 within the limits of a survey area, not made to 

 coincide with the edge. 3) Sampling between the 

 surface and levels immediately below the thermo- 

 cline is inadequate when dealing with pelagic 

 young of groundfish. A more complete and 

 accurate picture of developing silver hake could 

 have been drawn if the entire water column, 

 surface to bottom, had been sampled on all 

 stations. 4) The diel activity and vertical distribu- 

 tion of a postlarval fish may be directly related 

 to the behavior of invertebrate food organisms. 

 An analysis of the invertebrate plankton collected 

 with the ichthyoplankton should be considered as 

 an integral part of a survey. 5) Unless discrete- 

 level tows are made with opening-closing nets, an 

 exact temperature-catch relationship cannot be 

 determined, except in vertically isothermal 

 conditions. 



I found no evidence that silver hake depend on 

 or utilize estuaries during their early life history. 

 Their occasional presence in estuarine areas must 

 be considered accidental. 



LITERATURE CITED 



Ahlstrom, E. H. 



1959. Vertical distribution of pelagic fish eggs and larvae 

 off California and Baja California. U.S. Fish Wildl. 

 Serv., Fish. Bull. 60:107-146. 

 Arnold, E. L., Jr. 



1959. The Gulf V plankton sampler. /« Galveston Biolog- 

 ical Laboratory fishery research for the year ending June 

 30, 1959, p. 111-113. U.S. Fish Wildl. Serv., Circ. 62. 



BiGELOW, H. B. 



1927. Physical oceanography of the Gulf of Maine. Bull. 

 U.S. Bur. Fish. 40(2):511-1027. 



BiGELOW, H. B., AND W. C. SCHROEDER. 



1953. Fishes of the Gulf of Maine. U.S. Fish Wildl. 

 Serv., Fish. Bull. 53:1-577. 

 Bridger, J. P. 



1956. On day and night variation in catches offish larvae. 

 J. Cons. 22:42-57. 

 BuMPUs, D. F., AND J. Chase. 



1965. Changes in the hydrography observed along the 

 east coast of the United States. Int. Comm. Northwest 

 Atl. Fish., Spec. Publ. 6:847-853. 

 BuMPUs, D. F., AND L. M. Lauzier. 



1965. Surface circulation on the continental shelf off 



eastern North America between Newfoundland and 



Florida. Ser. Atlas Mar. Environ., Am. Geogr. Soc. 



Folio 7, 4 p., 8 plates. 



Clark, J., W. G. Smith, A. W. Kendall, Jr., and M. P. Fahay. 



1969. Studies of estuarine dependence of Atlantic coastal 

 fishes. Data Report I: Northern Section, Cape Cod to 

 Cape Lookout. R. V. Dolphin cruises 1965-66: Zoo- 

 plankton volumes, midwater trawl collections, tempera- 

 tures and salinities. U.S. Bur. Sport Fish. Wildl., Tech. 

 Pap. 28, 132 p. 

 CoLTON, J. B., Jr. 



1959. A field observation of mortality of marine fish 

 larvae due to warming. Limnol. Oceanogr. 4:219-222. 



1965. The distribution and behaviour of pelagic and 

 early demersal stages of haddock in relation to sampling 

 techniques. Int. Comm. Northwest Atl. Fish., Spec. 

 Publ. 6:317-333. 



829 



