Seasonal abundance, growth, and foraging habits of juvenile smooth dogfish, Mustelus canis, in a New Jersey estuary

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 foraging habits, growth, and seasonal, tidal, and diel patterns of abundance. Young of the year (YOY) were collected from May to October, with apparently newborn 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 TL/day 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 patterns, 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 within the estuary strongly suggests that estuaries are critically important nursery habitats for smooth dogfish within the Mid-Atlantic Bight.