Distribution and Abundance of Ship-following Seabirds: Assessing the Potential for a Positive Impact of Shrimp Trawling on Seabirds in South Carolina - Year II
The goal of this research is to quantify the extent to which the commercial shrimp fleet may have a positive impact on seabirds in South Carolina through the provisioning of discarded items. The objectives are:
- Determine the distribution and foraging rates of ship-following seabirds with respect to shrimp trawling during late spring and summer
- Determine diet composition of pelicans and terns at two colonies and compare this to the species composition of discards from shrimp trawlers in those regions
- Construct bioenergetic models to quantify the extent to which trawler discards contribute to the energetic requirements of local seabird colonies during the breeding season
Direct negative impacts (e.g. entrapment in fishing gear) of commercial fisheries on seabirds have received substantial attention from research scientists and management agencies. Recently, however, emphasis also has been placed on examining direct positive impacts, such as the provisioning of food to seabirds via fisheries discards. Recent studies from Europe indicate that tens of thousands of seabirds each year may be supported by discards from a single regional shrimp fishery and that discards from commercial fisheries may have contributed to the increase in seabird abundance and distribution in the North Sea and Northeast Atlantic. Here in the southeastern US, however, potentially beneficial seabird-fisheries interactions such as those described above have received little research attention and therefore opportunities to quantify the potential benefit to the seabird community from the commercial fishing industry have not been realized. This is particularly relevant given that the number of nesting brown pelicans and royal terns are declining in South Carolina and that the reasons for this decline, while under investigation by Clemson University and SCDNR, are not clear. If natural levels of food availability constrain seabird reproductive success or nesting effort in the state, then fishery discards may be providing an important food source for these declining species.
This research will provide a substantial increase in our knowledge of seabird ecology in the south Atlantic bight as it relates to commercial fisheries. Surprisingly little research has been conducted in this arena despite documented changes in population sizes and breeding ranges of many seabirds in the region and long-term changes in commercial fishing intensity. Results will be useful to management agencies, industry, and research scientists for informing decisions related to marine ecosystem based management and to management agencies and commercial fisheries for providing insights into the potential use of breeding seabirds as indicators of marine and nearshore ecosystem health. This project also provides an opportunity for evaluating the role of cooperative research (i.e., industry, resource management agencies, and researchers) in ecosystem based management. Successful outreach programs will provide a unique education opportunity for the general public and will increase the public’s appreciation for the unique role of seabirds in the marine and nearshore environment and for the role that commercial fisheries may play in supporting these populations.