Along the East Coast of the United States there is arguably no large pelagic fish more widely targeted by recreational rod-and-reel anglers than the yellowfin tuna (Thunnus albacares). Year after year, recreational fishermen fishing in the Atlantic Ocean and Gulf of Mexico land more than twice the number of yellowfin tuna than all other tuna species combined—that’s bluefin (Thunnus thynnus), bigeye (Thunnus obesus), albacore (Thunnus alalunga), and skipjack (Katsuwonus pelamis). Unfortunately, the demand and popularity of yellowfin in the Atlantic does not come without consequences.
A 2016 stock assessment performed by the International Commission for the Conservation of Atlantic Tunas (ICCAT) lists the Atlantic yellowfin stock as overfished. However, the good news is that the stock biomass is only slightly below target levels. To complicate matters, the stock assessment models used by ICCAT scientists have yielded inconsistent results, which cloud our understanding of the true status of the stock. In the face of scientific uncertainty and the stock’s overfished status, there is a clear need to better understand the biology and ecology of this valuable species and find ways to rebuild its depleted population.
In the U.S. Atlantic, yellowfin are managed domestically by NOAA Fisheries Highly Migratory Species (HMS) Branch, a group that is responsible for monitoring commercial and recreational harvest of all HMS, including tunas, sharks, and billfishes. Under current federal regulations, recreational anglers may retain three yellowfin tuna measuring more than 27 inches curved fork length per person per trip. All yellowfin less than 27 inches or those caught in excess of the bag limit, must be released.
Believe it or not, data from NOAA Fisheries’ Large Pelagics Survey suggest that up to 40 percent of all the recreationally-caught yellowfin are released in a given year, with an estimated 4,600 yellowfin having been returned to the sea over the past five years. This is far and away more releases than have occurred for all other tuna species combined.
For many popular recreational fish species, like largemouth bass and striped bass, scientific studies have shown that catch and release on rod and reel is an effective method for mitigating fishing mortality—as long as released fish are captured and handled appropriately. However, no previous studies have thoroughly examined the effects of rod-and-reel capture on the post-release survival of yellowfin tuna, even though it is one of the most frequently released large pelagic species. This data gap precludes a thorough understanding of how many of the yellowfin that are released annually may suffer mortality due to the capture and handling process.
Using funding provided to Dr. Walt Golet at the University of Maine by the NOAA Saltonstall-Kennedy Program, scientists from the Anderson Cabot Center for Ocean Life Fisheries Science and Emerging Technologies (FSET) Program have been working collaboratively with Dr. Golet and colleagues from the University of Massachusetts Dartmouth and Massachusetts Division of Marine Fisheries to estimate the survival rate of yellowfin following release in the U.S. Atlantic recreational troll fishery using pop-up satellite tags. Data from these tags will provide information on the fate of each fish following release, and allow us to both estimate post-release survival rates and generate best-practice capture and handling recommendations that will maximize the survival rate of yellowfin following release in the fishery.
Since summer 2016, our research group has deployed tags on 52 yellowfin tuna off the coast of North Carolina and southern New England in partnership with recreational fishermen Captain Rom Whitaker and Captain Don Riley, and aboard collaborator Dr. Diego Bernal’s research vessel.
Preliminary data obtained from these tags suggest that yellowfin tuna are resilient and exhibit a high rate of survival—possibly as high as 90 to 95 percent when fought for up to 20 minutes and handled properly. Over the next two months, we hope to use data from the final eight satellite tags, which were deployed on July 2 and July 3, to finalize our survival estimate and best-practice capture and handling recommendations. In the meantime, we recommend that recreational anglers follow these preliminary guidelines to remain in compliance with federal laws and maximize the chance that all released yellowfin survive to fight another day.
Scientific and Industry Collaborators: Dr. Jeff Kneebone, (Anderson Cabot Center for Ocean Life); Dr. Walt Golet (Gulf of Maine Research Institute); Dr. Diego Bernal (University of Massachusetts Dartmouth); Dr. Greg Skomal (MA Division of Marine Fisheries).