Symposium Abstract: Scaling of Natural and Anthropogenic Disturbance on the New York Bight Shelf: Implications for Tilefish Communities of the Shallow Continental Slope
M. C. Sullivan, R. K. Cowen, K. W. Able, and M. P. Fahay
Trawling is a pervasive feature of continental shelf environments worldwide. However, commonalities within individual systems and among habitat types and species are rarely clear cut. Our recent work in the New York Bight apex examined the potential impact of mobile fishing gear within a stormdominated shelf system. Over medium-grain sand sites, scallop dredging was shown to have minimal short-term effects (hours-day) on the abundance of a common, juvenile flatfish (Limanda ferruginea) and its benthic prey (gammarid amphipods, cumaceans). Longer-term impact signatures (months-year), however, were completely obscured by intense physical forcing during the fall (hurricanes) and winter (northeasters) months. Clearly, the intersection between habitat type and prevailing physical regime plays a critical role in defining the susceptibility of marine ecosystems to anthropogenic stress. Thus, an area of immediate concern is the shallow continental slope where natural disturbance is minimal and chronic trawling activity disproportionately high. The tilefish, Lopholatilus chamaeleonticeps, a long-lived, benthic excavator, plays a fundamental role in creating heterogeneity in these low variability habitats and has been compared to other ‘ecosystem engineers’ which alter bottom types favorably for members of lower trophic levels. Tilefish and their commensal associates (i.e. Helicolenus dactylopterus, Anthias spp.) appear particularly vulnerable to significant direct (as bycatch) and indirect (habitat alteration) impacts by mobile bottom fishing gear. Ongoing work is investigating the consequences of chronic trawling, as well as individual trawling events, on tilefish communities in these remote underwater habitats.