Fisheries surveys are generally divided into two different categories: fisheries dependent surveys, which are based upon data gathered by commercial and recreational fishermen, and fisheries independent surveys, which are undertaken by scientists for research or monitoring purposes.
IOCS scientists and staff have years of experience in fisheries science and have employed a variety of fisheries independent survey techniques to research and assess fish populations around the globe. These have included using a longline survey and acoustic surveys to monitor sharks in Belize, satellite tagging to track Caspian sea sturgeon and Atlantic sturgeon, acoustic tagging to monitor summer flounder in Shinnecock Bay, and estimating groundfish populations in Alaska and along the U.S. west coast.
Fisheries monitoring in Shinnecock Bay, NY
We have been surveying the fish and invertebrate communities in Shinnecock Bay for over ten years. The surveys provide us with standardized and consistent information on the range of biodiversity in the bay, and the size, abundance, and local distribution of the various species we catch.
Our longest running survey method, now in its eleventh year, involves trawling with a small net towed behind our research vessel for several minutes at different sampling stations around the bay. Our staff and volunteers quickly identify, measure, and release organisms back into the water, documenting catch in various bay locations, habitats, and seasons.
We have also used Baited Remote Underwater Videos (BRUVs). These are submersible HD video cameras anchored to the bottom in front of a bait bag that attracts nearby marine life. After resting on the bottom for at least an hour, the cameras are retrieved and the videos are downloaded and processed. Trained students and volunteers review the footage in the lab and identify species recorded on video.
We began using Environmental DNA, or eDNA, as an additional survey technique in 2019. eDNA allows us to obtain a “biodiversity snapshot” of a particular area by collecting and processing a water sample. We have taken eDNA samples alongside in parallel with trawl tow, so that the two methods can be directly compared.
Individually and collectively, these monitoring surveys can identify common or “resident” species, but also reveal how the composition of marine life in the bay might change over seasons or years. By cross-referencing the biodiversity data with temperature and water quality, we can also infer how life in the bay may be impacted by environmental factors. Importantly, we expect that this long term fisheries monitoring work in Shinnecock Bay will help document how our ShiRP restoration efforts over the last decade have had transformative benefits to the wider bay ecosystem.