256 



Abstract — Patterns were investigated 

 in juvenile fish use of unconsolidated 

 sediments on the southeast United 

 States continental shelf off Georgia. 

 Juvenile fish and environmental data 

 were sampled at ten stations along a 

 110-km cross-shelf transect, including 

 four stations surrounding Gray's Reef 

 National Marine Sanctuary (Gray's 

 Reef NMFS). Cross-shelf stations 

 were sampled approximately quar- 

 terly from spring 2000 to winter 2002. 

 Additional stations were sampled on 

 three transects inshore of Gray's Reef 

 NMS and four transects offshore of 

 the Sanctuary during three cruises 

 to investigate along-shelf patterns in 

 the juvenile fish assemblages. Sam- 

 ples were collected in beam trawls, 

 and 121 juvenile taxa, of which 33 

 were reef-associated species, were 

 identified. Correspondence analy- 

 sis on untransformed juvenile fish 

 abundance indicated a cross-shelf 

 gradient in assemblages, and the 

 station groupings and assemblages 

 varied seasonally. During the spring, 

 fall, and winter, three cross-shelf 

 regions were identified: inner-shelf, 

 mid-shelf, and outer-shelf regions. In 

 the summer, the shelf consisted of a 

 single juvenile fi.sh assemblage. Water 

 depth was the primary environmental 

 variable correlated with cross-shelf 

 assemblages. However, salinity, den- 

 sity, and water column stratification 

 also correlated with the distribution 

 of assemblages during the spring, fall, 

 and winter, and along with tempera- 

 ture likely influenced the distribu- 

 tion of juvenile fish. No along-shelf 

 spatial patterns were found in the 

 juvenile fish assemblages, but the 

 along-shelf dimension sampled was 

 small (-60 km). Our results revealed 

 that a number of commercially and 

 recreationally important species used 

 unconsolidated sediments on the shelf 

 off Georgia as juvenile habitat. We 

 conclude that management efforts 

 would be improved through a greater 

 recognition of the importance of these 

 habitats to fish production and the 

 interconnectedness of multiple habi- 

 tats in the southeast U.S. continental 

 shelf ecosystem. 



Manuscript submitted 26 October 2004 

 to the Scientific Editor's Office. 



Manuscript approved for publication 

 25 August 2005 by the Scientific Editor. 



Fish. Bull. 104:256-277(20061. 



Juvenile fish assemblages collected on 



unconsolidated sediments of 



the southeast United States continental shelf 



Harvey J. Walsh 

 Katrin E. Marancik 

 Jonathan A. Hare 



NOAA, NOS. NCCOS 



Center for Coastal Fisheries and Habitat Research 



101 Pivers Island Road 



Beaufort, North Carolina 28516 



Present address (for H J, Walsh): Biology Department MS #50 



Woods Hole Oceanographic Institution 

 Woods Hole, Massachusetts 02543 



E-mail address (tor H J Walsh) hwalshM'whoi edu 



Fisheries management has been rap- 

 idly evolving for the southeast United 

 States with the development of a 

 formal stock assessment process (i.e., 

 SEDARM, and the identification of 

 essential fish habitat (EFH; SAFMC, 

 1998). Single-species management 

 plans have been used as the basis 

 for fisheries management along the 

 southeast United States for decades, 

 and EFH is just beginning to be incor- 

 porated into management plans (e.g., 

 Sar-gassum and Oculina bank habitat 

 of particular concern: FR, 2000). Glob- 

 ally, as fish stocks continue to decline 

 (Botsford et al., 1997) and harvest 

 shifts to new species (Pauly et al., 

 1998), interest in ecosystem manage- 

 ment and implementation of MPAs 

 in many areas, including the south- 

 east U.S. continental shelf, is growing 

 (SAFMC, 2001). Understanding how 

 juvenile fish use habitat is important 

 for both single-species fishery man- 

 agement and ecosystem approaches 

 to fishery management. A description 

 of habitat needs at each life history 

 stage for species that represent the 

 "significant food web" are also a recog- 

 nized part of fishery ecosystem plans 

 (N0AA2; CFEPTAP, 2004). 



Adult population variability, in 

 most species, is caused by variability 

 in the survival of the early-life stages; 

 egg, larval, and juvenile (Sissenwine, 

 1984; Rothschild, 1986). Survival of 

 these early stages is influenced by 

 both habitat quantity and quality 

 (Gibson, 1994; Peterson, 2003). One 



approach to improving marine fish- 

 eries management is to incorporate 

 habitat effects on early-life stage sur- 

 vival into stock assessments (Beck 

 et al., 2001; Peterson, 2003). Deter- 

 mining how juvenile fish use habitat 

 also benefits marine protected area 

 (MPA) design and implementation. 

 MPAs have been proposed to comple- 

 ment traditional fishery management 

 practices by imposing site-specific 

 rules to protect enclosed resources 

 (Parrish, 1999; Dayton et al., 2000; 

 Beck and Odaya, 2001). In some in- 

 stances, MPAs provide benefits to 

 outside areas through spillover effects 

 (Roberts et al, 2001). MPAs may also 

 provide a source of recruits to other 

 nonprotected areas through plank- 

 tonic transport (Cowen et al., 2000; 

 Shanks et al., 2003). To be effective 

 in protecting fishery resources, an 

 MPA or a network of MPAs needs to 

 encompass the habitats used by spe- 



' SEDAR (Southeast Data Assessment 

 and Review). 2002. Southeast Data 

 Assessment and Review (SEDAR). South 

 Atlantic Fishery Management Council, 

 Charleston, SC. Website: http://www. 

 sefsc.noaa.gov/sedar.jsp [Accessed on 19 

 October 2004.1 



-NOAA (National Oceanic and Atmo- 

 spheric Administration). 1999. Eco- 

 system-based fishery management. A 

 report to Congress by the Ecosystems 

 Principles Advisory Panel. lAvailable 

 from National Technical Information Ser- 

 vice, U.S. Department of Commerce, 5285 

 Port Royal Road, Springfield, VA.] 



