522 



AbStraCt.-Smooth dogfish, Mustelus 

 canis, were collected with weirs, seines, 

 gill nets, trawls, and by hook and line 

 from 1988 to 1990 in the Little Egg 

 Harbor-Great Bay estuary of southern 

 New Jersey to determine their forag- 

 ing habits, growth, and seasonal, tidal, 

 and diel patterns of abundance. Young 

 of the year (YOY) were collected from 

 May to October, with apparently new- 

 born individuals dominating catches 

 from May to July. Subadult and adult 

 individuals were rare. Young of the year 

 reached 550-700 mm total length (TL) 

 by October, growing an estimated 1.9 

 mm TlVday and 6.0 g/day. Tidal and diel 

 patterns suggest that smooth dogfish 

 use shallow shoal and marsh creek 

 habitats primarily during night hours. 

 High catches during flood tides also 

 suggest increased activity at that time. 

 A comparison of abundance patterns 

 among gears suggests that marsh 

 creeks may be particularly important 

 to newborn individuals during June- 

 July. From an analysis of sex ratio pat- 

 terns, young of the year do not appear 

 to aggregate by sex or exhibit different 

 emigration patterns between sexes. 

 Smooth dogfish YOY feed primarily on 

 small shrimps, Crangon septemspinosa 

 and Palaemonetes vulgaris, polychaete 

 worms, and the crabs Callinectes 

 sapidus, Libinia sp., and Ovalipes 

 ocellatus. The abundance of YOY with- 

 in the estuary strongly suggests that 

 estuaries are critically important nurs- 

 ery habitats for smooth dogfish within 

 the Mid-Atlantic Bight. 



Seasonal abundance, growth, and 

 foraging habits of juvenile smooth 

 dogfish, Mustelus canis, in a New 

 Jersey estuary* 



Rodney A. Rountree 



Marine Field Station. Institute of Marine and Coastal Sciences 



Rutgers University 



800 Great Bay Boulevard, Tuckerton. New Jersey 08087 



Present address. Woods Hole Laboratory, Northeast Fisheries Science Center 



National Marine Fisheries Service, NO/V\ 



Woods Hole. Massachusetts 02543 



Kenneth W. Able 



Marine Field Station, Institute of Marine and Coastal Sciences 



Rutgers University 



800 Great Bay Boulevard, Tuckerton. New Jersey 08087 



Manuscript accepted 18 April 1996. 

 Fishery Bulletin 94:522-534 (1996 1. 



The smooth dogfish, Mustelus canis, 

 is one of the most abundant inshore 

 sharks in the western Atlantic 

 (Smith, 1907; Bigelow and Schroeder, 

 1948, 1953; Hoese, 1962; Com- 

 pagno, 1984). Despite its abun- 

 dance, little ecological information, 

 other than anecdotal accounts of 

 growth, and seasonal and life his- 

 tory patterns, is available (Castro, 

 1983; Compagno, 1984). The most 

 comprehensive accounts of smooth 

 dogfish are found in two summaries 

 by Bigelow and Schroeder (1948, 

 1953); however, little data on dis- 

 tribution, length frequency, or re- 

 production are presented in these 

 general descriptive accounts. Food 

 habits have been examined by Field 

 (1907) and Breder (1921). Several 

 studies have examined physical as- 

 pects of reproduction (Fowler, 1918; 

 TeWinkel, 1950, 1963, 1964; Gra- 

 ham, 1967; Gilbert and Heath, 

 1972; Hisaw and Abramowitz 1 ), 

 other physiology and behavior 

 (Parker, 1909, 1913; Ifft and Zinn, 

 1948; Clark, 1963; Gilbert, 1963) 

 and growth (Moss, 1972; Francis, 

 1981). Although a small fishery for 

 smooth dogfish has grown in recent 

 years, with landings in excess of 



780,000 lb and valued at over 

 $100,000 during 1992, 2 the great- 

 est value in smooth dogfish has 

 probably been its extensive use as 

 a subject for research in medical 

 physiology, morphology, and mo- 

 lecular biology (e.g. Greig, 1977; 

 Kalmijn, 1977; Hodgson and Ma- 

 thewson, 1978; Casterlin and Rey- 

 nolds, 1979, a and b; Bartlett, 1982; 

 Barry etal., 1988). 



In this study we examine aspects 

 of smooth dogfish habitat during 

 that part of the first year of life 

 when estuaries are used as nurser- 

 ies. More specifically, we collect data 

 with a variety of gears within an 

 estuary of southern New Jersey to 

 determine seasonal abundance and 

 habitat use patterns, growth, and 

 food habits of smooth dogfish. 



♦Contribution 96-12 from the Institute of 

 Marine and Coastal Sciences, Rutgers 

 University, New Brunswick, New Jersey 

 08903. 



1 Hisaw, F. L.. and A. A. Abramowitz. 

 1937 The physiology of reproduction in 

 the dogfish, Mustelus cams. Annual 

 Rep., Woods Hole Oceanogr. Inst. 1937: 

 21-22. 



2 Fishery Analysis Div., Fisheries Informa- 

 tion Section, National Marine Fisheries 

 Service, Gloucester, MA. 



