A new study by NOAA Fisheries has identified shifting distributions of Atlantic Highly Migratory Species catch, including tunas, billfish, and sharks, off the northeastern United States. The findings are part of efforts to better understand the effects of climate change on marine species and the fishing communities that rely on them.
“Shifts in the timing and location of Highly Migratory Species catch have important implications for recreational anglers, including seasonal fishing tournaments, and coastal communities that rely on these fisheries,” said lead author Dr. Dan Crear, Marine Spatial Ecologist, NOAA Fisheries HMS Management Division. “Fishermen may have to travel farther and/or fish earlier in the year to find certain target species. The species found at a favorite fishing spot may be changing over time, with species typically found further south becoming more common in northern waters earlier.”
“It was striking to see the extent of shifts in the catch for some of these species over the last 20 years,” said author Dr. Tobey Curtis, Fishery Management Specialist, NOAA Fisheries HMS Management Division. “Fishermen are observing these changes in fish distributions, and adapting to these shifts.”
The study used recreational fishery data collected as part of NOAA’s Large Pelagics Survey to explore the locations and timing of HMS recreational catches from 2002 through 2019. Recent studies are finding that HMS and other species in the region are generally shifting northward along the coast and arriving earlier in the year as ocean temperatures warm. These behavioral shifts are now reflected in HMS recreational catches, according to this current study. For example, catches of large and small bluefin tuna were found to be shifting northward at a rate of 4–10 kilometers (2.5–6.2 miles) per year.
The spatial shifts appeared to be related to the increasing water temperatures across the study region, which spanned from Maine through Virginia. Recreational catches of blue sharks and thresher sharks are shifting northward at rates of 30–40 km (19–25 miles) for each 1°C increase in water temperature.
The survey collects data from June through October each year when most offshore recreational fishing occurs. The study found that catches for most HMS have been occurring earlier in the season over time. For example, early bluefin tuna catches off Massachusetts in 2019 were estimated to have occurred 80 days earlier than in 2002. Similarly, early blue shark catches were estimated 66 days earlier off Connecticut, and early blue marlin catches were estimated 27 days earlier off New York.
“Understanding these shifts allows managers to be more responsive and flexible, and also helps communities prepare for changes, whether it be a switch to fishing for a new species or shifts in the fishing season,” added Dr. Crear.
“NOAA Fisheries is committed to helping fishing communities plan and respond to how climate affects the species we manage,” said Randy Blankinship, chief of the Atlantic HMS Management Division. “This study demonstrates the utility of publicly accessible fisheries survey data and how communicating with fishermen can help us sustain these valuable HMS fisheries in the face of a changing ocean.”
Results from this study may be used to improve the Large Pelagics Survey and will be considered in ongoing agency climate initiatives such as the Climate, Ecosystem, and Fisheries Initiative and the implementation of the NOAA Fisheries Climate Science Strategy.
This study can be viewed in the NOAA Central Library.