Small-Scale Organism Distributions And Patterns Of Species-Diversity - Evidence For Positive Interactions In An Estuarine Benthic Community

JE GRAVES
JR MCDOWELL
ML JONES

Abstract

To investigate the genetic basis of stock structure of the weakfish Cynoscion regalis, a total of 370 individuals was collected from four geographic sites along the mid-Atlantic coast of the United States over a period of 4 years. Restriction fragment length polymorphism (RFLP) analysis of weakfish mitochondrial DNA, employing either 6 or 13 restriction endonucleases, demonstrated a low level of intraspecific mtDNA variation, with a mean nucleotide sequence divergence of 0.13% for the pooled samples. The common mtDNA genotype occurred at a frequency of 0.91-0.96 in all samples, and no significant heterogeneity was found among samples in the occurrence of the common mtDNA genotype or rare variants. The lack of spatial partitioning of rare mtDNA genotypes among collection sites suggests considerable gene flow along the mid-Atlantic coast. Together these data are consistent with the hypothesis that weakfish comprise a single gene pool, and indicate that the fishery should be managed as a single, interdependent unit.