Shocking Study Reveals How Catch-and-Release Fishing Impacts Giant Trevally Behavior—Are We Harming Their Populations?

In a groundbreaking study, researchers have unveiled how catch-and-release fishing practices could be altering the behavior of the giant trevally, a highly sought-after sport fish in the Indian and Pacific Oceans. As fishing regulations tighten to protect vulnerable species, understanding the long-term implications of these fishing methods becomes increasingly critical for conservation efforts.

An international team of biologists led by the University of Massachusetts Amherst and the University of South Florida, in collaboration with conservationists and industry partners in the Seychelles, has provided fresh insights into how overfishing—even catch-and-release—can have unintended consequences. Their findings, published in the Canadian Journal of Fisheries and Aquatic Sciences, suggest that the pressures of sport fishing might indeed be affecting the behavior and sustainability of the giant trevally population.

The research was spurred by concerns from the Island Conservation Society and the Alphonse Fishing Company (now Blue Safari Seychelles Fly Fishing) regarding the sustainability of fishing practices in the Seychelles. Professor Andy Danylchuk, a senior author of the study, emphasized the synergy between their research and the urgent need for science-guided fishing management policies.

The catch-and-release approach is intended to ensure that more fish remain in the water, allowing for sustainable recreational fishing. However, it can lead to various negative outcomes, including increased mortality due to improper handling, altered movements, and—most alarmingly—hook shyness. This phenomenon occurs when fish become increasingly wary of lures after repeated captures, posing a significant risk to anglers who travel far and spend significantly to experience the thrill of catching this elusive species.

Interestingly, during the COVID-19 pandemic, which led to extensive fishing closures, researchers had an unexpected opportunity to conduct a 'natural experiment.' Lucas Griffin, the lead author of the paper and now an assistant professor at the University of South Florida, described how the pandemic allowed them to observe how giant trevally behaved without fishing pressures. The study revealed that while these fish can adapt to some fishing pressure, they do not respond significantly to short-term fishing closures. However, evidence suggests that prolonged fishing pressure may cause the giant trevally to alter their home ranges, potentially impacting future catch rates.

While the study indicates a robust population of giant trevally, the concern remains about how increased angler presence may exacerbate behaviors associated with hook shyness. Thankfully, some results from their research did point to the possibility of new fish entering the fishery, providing hope that population numbers could stabilize.

The researchers concluded that while giant trevally exhibit resilience to the immediate effects of catch-and-release, they are sensitive to overall fishing pressures. As Griffin aptly notes, to maintain healthy fish populations, stakeholders must consider limiting the number of anglers targeting these fish.

In an age of growing environmental awareness, this study highlights an urgent call to action: if we wish to ensure the sustainability of prized game fish like the giant trevally, both anglers and regulatory bodies need to rethink current fishing practices. Could this be the moment we redefine our relationship with the ocean's bounty? Only time will tell!