Scavenging Rates and Community Composition at Different Habitats along a Shallow Water Depth Gradient

Abstract

As fisheries grow and the amount of bycatch being thrown back into the oceans rises, studies on the effects of interferences in natural food chain processes that occur throughout the ocean become increasingly important. This study aims to look at scavenging rates at different depths and make preliminary observations about how quickly carrion will be consumed and affect the food chain. Three identical traps were deployed at three different habitats: intertidal, shallow subtidal, and deep subtidal. The first was pulled up after 6 hours, the second after 12 hours, and the third after 24 hours. All of the species within each trap were counted, identified, recorded, and entered into Primer and Excel to determine the differences between the habitats, the species richness and diversity for each depth, and the percent bait consumption to determine scavenging rates. The results showed that scavenger species varied noticeably at different depths. The shallow subtidal had the highest scavenger diversity and fastest consumption rates. It also seems apparent that scavenging rates in the intertidal are slowest. Therefore, the habitat would probably be most affected by large carrion debris due to slow decomposition, but it would affect upper trophic levels more slowly than in the other habitats. Future studies should be completed at deeper depths, with more replication, and using controls to find more conclusive results.