Ampelisca agasaUi (Judd) 18% 



Geographic Distribution. This species has been 

 refwrted from both the Atlantic and Pacific coasts of 

 North America (Barnard 1971; Mills 1971). Bousfieid 

 (1973) reported that this 8[)ecies is distributed from 

 Nova Scotia to the Caribbean along the eastern coast of 

 North America. In our collections from the Middle 

 Atlantic Bight region, A. agassizi occurred in 161 sam- 

 ples from 125 stations between Massachusetts and 

 North Carolina (Fig. 4). This was the most abundant 

 species in our study area with a mean density of 910/m^, 

 ranging between 2/m^ and lb,000/m'. Ampelisca agassizi 

 showed a clear trend of decreasing abundance from 

 north to south with mean densities decreasing from 

 l,2(X)/m' in southern New England to 290/m^ in the New 

 York Bight and 75/m^ in the Chesapeake Bight. 



Bathymetric Distribution. Mills (1971) gave a depth 

 range for A. agassizi as 5-450 m. We collected A. agas- 

 sizi between 22 and 450 m. The highest densities (1,500- 

 3,000/m2) occurred between 70 and 99 m, and 70''; of the 

 samples were collected between 40 and 99 m (Table 3). 

 South of Cape May, N.J., A. agassizi was found only in 

 the deeper (73-400 m) and colder waters of the outer 

 continental shelf and upper continental slope. This pat- 

 tern of "southern submergence" is usually interpreted 

 as an avoidance response by the species to the higher 

 temperatures found in southern inshore waters (Ekman 

 1953). 



Sediment Relationship. Bousfieid (1973) reported that 

 A. agassizi is most often collected from stable coarse 



Table 3. — Bathymetric distribution of Ampeluca 

 agastUi in samples from Middle Atlantic Bight. 



Table 4. — Sediment associations of Ampelisca agas- 

 aiii in samples from Middle Atlantic Bight. 



sands. We collected this species on sediments ranging 

 from sand-gravel to silt-clay (Table 4), but the highest 

 mean densities (1,300/m^) and the largest number of 

 samples were found on sand l>ottoms. 



Ampelisca declivitatia Mills 1967 



Mills (1967b, 1971) reported that A. declivitatis has 

 been recorded from western Greenland south to the 

 Middle Atlantic States between ICX) and 1,100 m with 

 maximum abundance around 400 m. Our collections 

 from the Middle Atlantic Bight consisted of a few speci- 

 mens from each of seven stations in upper bathyal 

 waters (440-580 m) between Long Island and Cape Hat- 

 teras (Fig. 4). Bottom types at these seven stations in- 

 cluded sand (3/7), sand-silt (3^), and silt (1/7). The 

 abundance of A. declivitatis was uniformly low at all 

 stations with a mean density of 4/m^ ranging between 

 2/m'i and ll/m^. 



Ampelisca macrocephala Liljeborg 1852 



Geographic Distribution. This cosmopwlitan sptecies 

 has been collected from Norway to Alaska in the North 

 Atlantic and Arctic Oceans, and from Washington to 

 California in the North Pacific Ocean (Barnard 1971; 

 Mills 1967b). Bousfieid (1973) reported that this species 

 has been recorded from Greenland south to Rhode 

 Island along the North American coast. We collected A. 

 macrocephala in 31 samples at 23 stations between Cape 

 Cod and central New Jersey (Fig. 4). The three stations 

 south of Long Island and the single station east of New 

 Jersey extend the known geographic range of this species 

 along the east coast of North America. This species was 

 moderately abundant in our study area with a mean 

 density ot 8U/m-, ranging from 2/m-' to 400/m-. The high- 

 est densities of this arctic boreal species were found at 

 the more northerly stations, which is to be expected 

 since species normally decrease in abundance as they 

 approach the limits of their geographic range. 



Bathymetric Distribution. The bathymetric range of 

 A. macrocephala is from 10 to 280 m (Mills 1971). We 

 collected this species between 34 and 73 m. The bulk of 

 the samples (24/31) occurred between 30 and 59 m, but 

 the highest densities occurred at the stations >60 m 

 (Table 5). 



Table 5. — Bathymetric distribution of i4inpeli<ca ma- 

 crocephala in samples fV-om Middle Atlantic Bight. 



Sediment Relationship. Bousfieid (1973) reported that 

 A. macrocephala is usually found on stable sandy bot- 



