Marancik et al.: Fish assemblages on the southeast United States continental shelf 



115 



c . 



Fall 



:> 



•'M, 



"JOO, 



Water masses 



Salinity Stratification 



# Inner-shelf water <35 



# Inner-shelf-mid-shelf mixed water 35-36 

 O Mid-shelf water >36 



O Mid-shelf-Gulf Stream mixed water 



r~l No data collected 



<10 

 >10 



Figure 3 



Water mass designations for each station for each cruise. Cruises within a season 

 were put together in one map with transects offset from center: (Al spring, (B) 

 summer, (C) fall, and (D) winter. Inner-shelf water was the least saline and found 

 farthest inshore. Mid-shelf-Gulf Stream mixed water was a highly stratified mix 

 of Gulf Stream water and mid-shelf water and was found farthest offshore. 



Canonical correspondence analysis (CCA), which in- 

 corporates environmental variables by aligning species 

 and station data along environmental gradients, was 

 used to explore the relationship between larval assem- 

 blages and the environment. The species-environment 

 correlation is a measure of the strength of the rela- 

 tion between the species data and the environmental 

 data for each CCA dimension (ter Braak and Smilauer, 

 2002). The product of the species-environment correla- 

 tion and the eigenvalue can be used to describe the 

 variance in the data. CA and CCA were performed by 

 using the statistical package CANOCO (Ter Braak, 

 1988). 



Multivariate analyses were used to determine which 

 fish species spawn on the continental shelf off the coast 

 of Georgia, to examine what environmental factors in- 

 fluence larval distribution, and to explore the physical 

 factors affecting the transport of larvae spawned on 

 the shelf. Specifically, six objectives were addressed: 



1) cross-shelf patterns in the larval fish community; 2) 

 larval assemblages associated with cross-shelf patterns 

 in the larval fish community; 3) the relation among 

 cross-shelf patterns in the larval fish community, larval 

 assemblages, and environmental variables; 4) the rela- 

 tion between water mass and larval assemblages; 5) 

 seasonal patterns in the larval fish community and lar- 

 val assemblages; and 6) the relation between seasonal 

 larval assemblages and environmental variables. 



In addition to addressing the six specific objectives, 

 the implications for larval transport were considered. 

 By comparing the distributions of specific taxa to the 

 patterns discerned by addressing the objectives above, 

 some insights were gained into larval transport pro- 

 cesses. The distribution of taxa representative of each 

 larval assemblage was examined for patterns through 

 space and time. Mechanisms driving larval transport 

 were then explored by linking these patterns to water 

 mass and other environmental variables. 



