Walsh et al Juvenile fish assemblages on the southeast United States continental shelf 



269 



Along-shelf and cross-shelf patterns 

 in the offshore juvenile fish data set 



The offshore juvenile fish data set 

 included primarily (76'7f) coastal, 

 open-shelf, and slope species (Table 

 4, Appendix) and patterns in the 

 data set varied with season. During 

 the fall, there were both cross-shelf 

 (Fig. 7A) and along-shelf patterns 

 (Fig. 7B). Along the first dimen- 

 sion, there was a cross-shelf gra- 

 dient (Fig. 7A) from the shallow 

 stations (30-45 m depth; Fig. IC) 

 to the 50-m station group. The juve- 

 nile assemblage at the 50-m sta- 

 tion group had high abundances of 

 reef-associated species (Table 4). 

 The stations on the northern most 

 transect (Fig. IC) also separated 

 from the others along the second 

 dimension, and had higher abun- 

 dances of reef-associated species. 

 The cross-shelf pattern was present 

 in the winter, with greater abun- 

 dances of reef-associated species 

 at the 50-m station group (Fig. 7C), 

 but there was no along-shelf pat- 

 tern (Fig. 7D). 



Discussion 



Cross-shelf 



Along-shelf 



CA 1 



CA 1 



One hundred and twenty-one taxa 

 of juvenile fish were collected on 

 unconsolidated sediments on the 

 continental shelf off Georgia. The 

 actual number of species was 

 higher, but taxonomic problems 

 limited species identification (e.g., 

 identification of Etropus spp., Pri- 

 onotus spp., Sphoeroides spp., and 



Microgobius spp.). With concurrent ichthyoplankton 

 sampling of the cross-shelf stations (Fig. 1), we collected 

 161 taxa (Marancik et al., 2005); the larval community 

 had more pelagic species, including several scombrids 

 (e.g., Auxis rochei, Scomberomorus cavcilla, and S. macu- 

 latus) and 17 myctophids. The large juvenile and adult 

 fish communities of the shallow coastal zone (<10 m) 

 and continental shelf (9-180 m) comprised about 150 

 species, including both pelagic and demersal species 

 (Wenner et al.^ ^ '^ ' ; Wenner and Sedberry, 1989). A 

 maximum of 164 species were reported from rocky-reefs 

 in the region (Chester et al., 1984; Parker et al. 1994; 



Figure 6 



Correspondence analysis ordinations (portraying the first and second dimen- 

 sion scores! of the inshore juvenile fish community data showing cross-shelf 

 and along-shelf station groups in spring (A and B) and winter (C and D). 

 Solid lines enclose the boundary of each station group with three or more 

 stations. Station groups comprising one or two stations are not enclosed by a 

 solid line. Each station group is labeled and portrayed with a different symbol. 

 The dashed lines intersect at the origin of the plot. Analyses were conducted 

 by using juvenile fish abundance data only. 



Baron et al., 2004). Fewer species inhabit estuaries 

 than shelf habitats of the southeast (<90), particularly 



■« Wenner, C. A., C. A. Barans, B. W. Stender, and F. H. 

 Berry. 1979a. Results of MARMAP otter trawl investi- 

 gations in the South Atlantic Bight. II, spring 1974, 78 p. 

 lAvailable from Marine Resources Division, South Carolina 

 Department of Natural Resources, 217 Ft. Johnson Rd.. P.O. 

 Box 12559, Charleston, SC 29412.] 



•' Wenner, C. A., C. A. Barans, B. W. Stender, and F. H. 

 Berry. 1979b. Results of MARMAP otter trawl investi- 

 gations in the South Atlantic Bight. Ill, summer 1974. 62 p. 

 [Available from Marine Resources Division, South Carolina 

 Department of Natural Resources, 217 Ft. Johnson Rd., P.O. 

 Box 12559, Charleston, SC 29412.1 



I* Wenner, C. A., C. A. Barans, B. W. Stender, and F. H. 

 Berry. 1979c. Results of MARMAP otter trawl investi- 

 gations in the South Atlantic Bight. IV, winter-early spring 

 1975, 59 p. [Available from Marine Resources Division, South 

 Carolina Department of Natural Resources, 217 Ft. Johnson 

 Rd., P.O. Box 12559, Charleston, SC 29412.1 



'Wenner, C. A., C. A. Barans, B. W. Stender, and F. H. 

 Berry. 1980. Results of MARMAP otter trawl investiga- 

 tions in the South Atlantic Bight. V, summer 1975, 57 p. 

 [Available from Marine Resources Division, South Carolina 

 Department of Natural Resources, 217 Ft. Johnson Rd., P.O. 

 Box 12559, Charleston, SC 29412.] 



