Effective management allows for sustainable shark fishery
As some of the top predators in the ocean, sharks fill vital roles by regulating food web dynamics and maintaining balance in their ecosystems.
The Gulf of Mexico is home to more than 40 different species of sharks that vary in size (3 feet to 15 feet) and habitat distribution (inshore, coastal waters versus offshore, open waters). Large shark species are highly susceptible to overfishing because they can take decades to reach sexual maturity and often produce only a handful of offspring after a long pregnancy -- two years in dusky sharks. Given these and other traits, such as slow growth and late maturity, populations of large sharks can take a long time to rebound if they have been overfished.
The U.S. originally started harvesting sharks in the 1940s for their fatty, lipid-rich livers as a vitamin A supplement during World War II. Harvesting of sharks increased dramatically in the 1970s with the advent of industrial fishing practices and the release of the movie “Jaws,” which ignited fear and negative public perceptions of sharks. Shark populations in the U.S. declined rapidly thereafter.
In the Gulf of Mexico, the average size of prize-winning sharks landed at three different Gulf state fishing rodeos experienced a 50-70% decline over an 80-year span, which suggests large sharks have been intensively targeted for decades. This decline leaves populations of smaller, less reproductively capable sharks in the Gulf.
In response to the rapidly declining shark populations, the federal government enacted the first Fishery Management Plan for sharks in 1993. This plan implemented recreational and commercial limits on shark fishing in the U.S., and it led to increased research efforts to better understand the biology of these apex predators. As a result of these efforts, additional federal and regional regulations were established to better protect and preserve shark populations in U.S. waters.
After more than two decades of shark management practices, a scientific study published in 2017 compared catch data of seven different shark species in the Southeast from 1975 to 2014. The results indicated all but one of the species showed small, but meaningful increases in abundance starting in the 2000s.
While populations of sharks are nowhere near historical levels, these upward trends are indicative of successful management practices. With continued research on the life histories of sharks, management practices will continue to improve. These studies provide information on which species are quicker to mature and produce more offspring, thereby making them less susceptible to overharvest than species that are slower growing and produce fewer offspring.
To that extent, the state of Mississippi opened a commercial shark fishery this month. Only shark species with healthy populations in the Gulf of Mexico are allowed to be harvested, namely blacktip, Atlantic sharpnose, bonnethead and finetooth sharks.
Landings from this new fishery will be closely monitored by the Mississippi Department of Marine Resources. This oversight will ensure landings never reach an unsustainable level, thereby maintaining healthy shark populations, and consequently healthy Gulf Coast ecosystems, for generations to come.
Editor’s Note: Extension Outdoors is a column authored by several different experts in the Mississippi State University Extension Service.