Study: Record keeping for trophy fish is bad for threatened species

By on August 26, 2014
Giant sea bass is among the critically endangered species whose records are verified by the IGFA (Credit: Caitlin Childs, via Flickr)

For trophy anglers, bigger is nearly always better. But a new study shows that when anglers land the biggest members of a threatened species, they’re inadvertently harming that species’ chance for survival.

“In recent years, we’ve seen entirely too many news stories about anglers killing IUCN Red List threatened and endangered species along the lines of ‘look at this cool giant fish someone caught’ that don’t mention that the fish is threatened or endangered,” said David Shiffman, a marine biologist at the University of Miami and lead author of the study. “As ethical anglers ourselves as well as marine conservation biologists, this rubbed us the wrong way and we looked into it.”

While the term recreational fishing often conjures scenes of vested figure casting a pheasant tail nymph in the middle of a creek, or of a father and son lazily watching their bobbers from a lakeshore, there are actually more than 10 million saltwater anglers in the U.S., according to the study. Saltwater game fish tend to grow to larger sizes and fight harder than their freshwater counterparts, perhaps contributing to the competitive nature of oceanic angling.

Saltwater trophy anglers seeking out the big ones —  the record-breakers — turn to organizations such as the International Game and Fish Association to verify and record their catches. Catch size is certified by mass at land-based weigh stations, and most fish don’t survive the trip back to shore. Interestingly enough, the study found that “threatened species make up a significantly higher proportion of the largest class size” recognized by the IGFA. The largest fish in any community tend to be egg-bearing females, so when these individuals are killed, their loss can significantly impact populations — especially those of threatened species.

As the authors wrote:

Trophy fishing selectively targets and removes the largest individuals in a population, and as a consequence can have a disproportionately large negative impact on the population dynamics of that species even when relatively few individuals are removed from the population… That people earn prestigious awards for this behavior presents a unique social and biological challenge that warrants further investigation.

To reduce the risk of affecting threatened populations, the researchers suggest that the IGFA and other record-keeping organizations don’t award catches of threatened species. Alternatively, the researchers propose that the IGFA permits measuring threatened fish by length, a simple act which could be performed from a boat and verified using smartphone cameras.

“To us, ‘don’t kill IUCN Red List Threatened species for fun’ should be a part of any ethical angling policy, and many IGFA member anglers that we’ve spoken to agree,” Shiffman said. “We can only hope that the IGFA leadership decides to take the simple step that we propose.”

The IGFA tracks records of the large-tooth sawfish, a critically endangered species. (Credit: Photo by DAVID ILIFF. License: CC-BY-SA 3.0)

The IGFA tracks records of the large-tooth sawfish, a critically endangered species. (Credit: Photo by DAVID ILIFF. License: CC-BY-SA 3.0)

Earlier studies have proposed similar methods to assess fishery stocks, and an Irish recreational fishing organization already touts length-based measurements as more conservationally sound. The state of New York’s Department of Environmental Conservation website even provides a conversion table for judging the weight of various species by their length.

The International Game Fish Association has kept recreational angling records for 1,200 species since 1939. Of those, 85 are listed as vulnerable, endangered or critically endangered by the International Union for Conservation of Nature.

Top image: Giant sea bass is among the critically endangered species whose records are verified by the IGFA (Credit: Caitlin Childs, via Flickr)

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