Rountree and Able Abundance, growth, and foraging habits of Mustelus cants 



523 



Materials and methods 



Study area 



The study was conducted in polyhaline 

 (22-337«) sections of the Little Egg 

 Harbor-Great Bay estuary in southern 

 New Jersey during 1988-90 (Fig. 1). 

 Primary sampling was conducted 

 within tidal marsh creek and adjacent 

 bay shoal habitats with several gear 

 types (Table 1 ). The four primary study 

 creeks (Schooner, New, Foxboro, and 

 Story Island creeks) were approxi- 

 mately 1.0 km long blind cul-de-sacs 

 that received fresh water only through 

 local runoff (Fig. 1). Story Island Creek 

 was intertidal except for a shallow 

 (<0.5 m) subtidal cove formed at the 

 mouth at low tide. The other three 

 creeks were subtidal with maximum 

 depths of 0.5-2.0 m at low tide. All 

 creeks had a mud substrate and were 

 located 1.3-2.9 km from Little Egg In- 

 let (for a more complete description of 

 the study creeks see Rountree [1992]). 

 The marsh creeks are typically sepa- 

 rated from the adjacent bay by a shal- 

 low sill formed at the creek mouth. Be- 

 yond the sill, Story Island and Foxboro 

 creeks emptied onto extensive bay 

 shoals ( <2 m at high tide ) bordering the 

 relatively deep (4-9 m at high tide) 

 Marshelder Channel ( Fig. 1 ). In contrast, 

 New and Schooner creeks each emptied 

 directly into deep channels (Fig. 1). 



Sampling techniques 



The creeks were sampled with weirs, 



seines, and gill nets (Table 1). Shallow 



bay shoal habitats adjacent to Foxboro 



and Story Island creeks were sampled 



with gill nets and hook and line (Fig. 



1 ). Additional data were derived from extensive trawl 



collections made in many habitats throughout the 



estuary, including other marsh creeks and Marshelder 



Channel in the vicinity of Foxboro Creek (Szedlmayer 



et al., 1992; Szedlmayer and Able, in press). 



Weir and seine sampling For each sampling event, 

 a temporary weir was erected at high tide approxi- 

 mately 30 m above the creek sill. The creek was 

 blocked off entirely by two wing nets ( 15.2 m x 3.0 

 m; 6.4-mm mesh) that ran at an angle from each 



Figure 1 



(Al Little Egg Harbor-Great Bay estuary indicating the location of four 

 marsh creek (l=Schooner, 2=New, 3=Foxboro, and 4=Story Island) sam- 

 pling sites for smooth dogfish, Mustelus canis. (B) Detail of the primary 

 sampling area including Foxboro, Story Island, and New creeks. Gill-net 

 sites include the mouth of Foxboro (net 1) and Story Island (nets 5 and 6) 

 creeks, and the shallow bay shoals adjacent to Foxboro Creek (nets 2^4). 



creek bank to a weir ( 1.2 m wide x 3.0 m long x 3.0 m 

 high; 6.4-mm mesh) located in the center of the creek 

 channel. Deployment of the weir and wings began 

 about 30 min before slack high tide and was com- 

 pleted within 1 h. Fish moving out of the creek with 

 the ebb tide were led along the wings into the weir, 

 where they were trapped by two sets of internal doors. 

 Live fish were removed from the weir at low tide 

 through a codend after raising the weir above the 

 water line. The weir was removed from the creek 

 after each sampling event. 



