462 
Fishery Bulletin 108(4) 
A (NMFS) 
B (NJDEP) C (NYBTS) 
Depth (m) 
Figure 10 
Cumulative distribution functions for available habitat and habitat occupied by Atlantic stur- 
geon ( Acipenser oxyrinchus) in the fall and spring surveys for (A) National Marine Fisheries 
Service bottom trawl surveys (NMFS), (B) New Jersey Department of Environmental Protection 
finfish survey (NJDEP), and (C) New York bottom trawl survey (NYBTS) for depth (m), salinity 
(ppt), and temperature (°C). Solid lines indicate habitat occupied by A. oxyrinchus (gray=fall; 
black=spring) and dashed lines indicate available habitat (dashed gray=fall; dashed black= spring). 
fish, or simply a scarcity of Atlantic sturgeon. Either a 
substantial increase in trawl survey effort or the use 
of different gears, such as gillnets, may be required in 
order to capture Atlantic sturgeon along the shelf. 
Essential fish habitat 
The Magnuson-Stevens Fishery Conservation and Man- 
agement Act requires identification of Essential Fish 
Habitat (EFH), defined as waters or substrate used 
for spawning, breeding, feeding or growth to maturity, 
in order to minimize adverse effects of fishing and to 
promote conservation and enhancement of such habitat 
for particular species. Unfortunately, EFH can only 
be defined for federally managed species and does not 
include species such as Atlantic sturgeon which are 
managed by regional fishery management councils. 
Atlantic sturgeon is a current candidate species for 
listing under the US Endangered Species Act, and if 
listed, the identification of critical habitat necessary to 
recover the species will be required. The identification 
of critical habitat for listed species is mandatory and 
is defined as all areas essential to the conservation 
of the species. Without EFH or critical habitat desig- 
nation, habitat degradation and incidental mortality 
within critical areas will continue to hinder population 
recovery. 
Our analysis of habitat preferences indicated that 
depth was the primary environmental characteristic 
defining the Atlantic sturgeon distribution. Thus, es- 
