Studies on portunid crabs from the Eastern Pacific. I. Zonation along environmental stress gradients from the Coast of Colombia

✍ Scribed by E. A. Norse; M. Estevez

• Publisher: Springer-Verlag
• Year: 1977
• Tongue: English
• Weight: 834 KB
• Volume: 40
• Category: Article
• ISSN: 0025-3162
• DOI: 10.1007/bf00395729

✦ Synopsis

East Pacific swimming crabs are poorly known ecologically. We trawled samples along 4 estuarine-continental shelf transects to provide information on the population structure and species composition of portunids along environmental stress gradients. Portunids comprised almost 99% of the benthic crabs. Callinectes toxotes dominates the freshest estuarine areas, but is replaced by c. arcuatus in estuary mouth and shallowshelf samples. Deeper shelf samples are dominated by Euphylax robustus and Portunus asper. Great numbers of E. do,i, a pelagic species, were taken on the shelf; their size distribution implies intraspecific competition. Evidence is given that differences in salinity tolerance account for differential landward limits, but competition, predation by fishes, increased fouling and decreased available food exclude eurytopic species from physicochemically equable shelf waters.