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



267 



80'0'W 



-3rO'N - 



30°0'N 



Fall 



Inner- She It 

 Assemblage (sla 1 1 



- Lanmus fascialus 

 Syngnathus scovelli 



Mid-Shelt 

 Assmblaqe (sla 2-5) 



Ophidion selenops 

 Diplectrum formosum ' 

 Dactyloscopus moorei 

 Synodus foetens 

 Monocarithus hispidus 

 Anchoa hepsetus 

 Bothus robinsi 

 Symphurus urospilus 

 Pnonotus carolmus 

 Serraniculus pumilio 

 Anosoma balearicum 

 Stenotomus sp. 

 Scorpaena plumien 



Outer-Shelf 



Assemblage (sla 6-7) 



Diplectrum formosum ' 

 Symphurus minor 

 Otophidium omostigmum 

 Haemulon aurolineatum 

 Syacium papillosum 



3ro'N 



- 30'0'N 



80 O'W 



31 O'W 



80 O'W 



sro'N- 



30^0'N 



Inner- Shelf 

 Assemblage (sla 1-2) 



Winter 



Mid-Shelf 

 Assemblage (sla 2-5) 



Ophidton selenops 

 Pnonotus carolmus 

 Dactyloscopus moorei 

 Urophyas regia 

 Synodus foetens 

 Otophidium omostigmum 

 , Symphurus urospilus 

 ' Diplectrum fotmosum 

 Serraniculus pumilio 

  Stenotomus sp 

 Scorpaena plumien 

 Anosoma baleancum 

 Decapterus punctatus 



Outer-She It 

 Assemblage (sta 4-7) 



Bothus robinsi 

 t^ugil cephalus 

 Symphurus minor 

 Centropristis ocyurus 

 Monocanthus hispidus 

 Serranus phoebe 



•3rO'N 



■30 O'N 



81 O'W 80 0'\A/ 



Figure 4 



Cross-shelf juvenile fish assemblages identified from correspondence analysis for spring (A), fall (B). and winter 

 (C). Summer was not plotted because there was only one summer assemblage. Hatched circles enclose stations that 

 grouped together each season. Ta.xa from the 10% cross-shelf data set, in order of abundance, for each assemblage 

 are shown in the tables. Asterisks indicate species that were found in multiple assemblages. 



and was mainly influenced by depth; the shallower 

 inner- and mid-shelf stations were separate from the 

 outer-shelf stations. The second dimension was related 

 to bottom salinity (Fig. 5C) and correlated with the 

 separation of the inner-shelf station from the higher 

 saline mid- and outer-shelf stations (Fig. 2). A Monte 

 Carlo permutation test of the relationships between the 

 assemblages and environmental data for the fall indi- 

 cated that depth and bottom salinity were significantly 

 related to the juvenile assemblages and cross-shelf sta- 

 tion groups (Table 6). 



The inclusion of environmental variables in the analy- 

 sis of winter juvenile assemblage showed a weak rela- 

 tionship with the cross-shelf groups and juvenile assem- 

 blages, as indicated by the CCA correlation (Table 5). 



The addition of the environmental data also changed 

 the ordination of the stations (Fig. 5D); yet there was 

 still a cross-shelf gradient. Along the first dimension, 

 depth, bottom temperature, and stratification were re- 

 lated to the juvenile assemblages and cross-shelf groups 

 (Fig. 5D). The shallow inner- and mid-shelf groups 

 were lower in bottom temperature and stratification, 

 whereas bottom density was lowest on the inner- and 

 outer-shelves and highest on the mid-shelf (Fig. 2). A 

 Monte Carlo permutation test for the winter relation- 

 ships indicated that depth and bottom density were 

 significantly correlated with the fish assemblages and 

 station groups (Table 6), although the bottom density 

 did not appear to have any relation to the patterns 

 described (Fig. 5D). 



