Tuesday, January 27, 2015

Blue Cats Stump the Managers

Lack of clear goal, information hampers effort to control blue catfish
Efforts to rein in the region’s escalating blue catfish population through an expanded fishery and other measures could face numerous obstacles, the greatest of which is a lack of basic information about the voracious predators, a new report says.

Nonnative blue and flathead catfish were introduced into Virginia tributaries in the late 1970s but have since exploded in numbers and spread to Maryland.

They are a top predator, and their rapid expansion has raised concerns that they could outcompete native species and also consume large numbers of shad, river herring, blue crabs and other species of concern to fishery managers.
Wayne Fisher, right, with his brother Frankie,
dump most of the blue catfish caught in their nets
on the Rapahannock River because there was no
market for the fish when this photo was taken in May. 
Which is a possible problem they've been raising for quite a while, but for which they have produced little actual evidence. My own point of view is that the River is so eutrophied, that the carrying capacity is much higher than it was during colonial times.
In response, the Bay Program’s Sustainable Fisheries Goal Implementation Team created an Invasive Catfish Task Force, made up of biologists from state and federal agencies, which last spring suggested a variety of actions to control the invasive fish, which is native to the Mississippi basin.

Those recommendations included promoting a large commercial fishery, using electroshocking to harvest fish and targeting high-priority areas such as shad spawning grounds for extra control efforts.
Sound reasonable; I've always maintained that the best way to eliminate them would be to create a commercial market for the fish (some exists already, but not enough), set harsh commercial fishing limits, gear restrictions, and short seasons, and turn a blind eye when the watermen break all the rules and take them all.
Since then, efforts have proceeded to promote the commercial catch of blue catfish — including marketing the fish to consumers — and to experiment with techniques such as using electroshocking to harvest the invasive predator.

Now, a report from the Bay Program Scientific and Technical Advisory Committee commended the task force actions as a good first step, but said it was unclear whether those efforts would succeed in controlling blue catfish, primarily because of a lack of information.
Medium sized Potomac Blue Catfish
In concept, getting rid of them is easy; catch and kill them all. The exact details of how to go about that with a limited budget, and not damaging the remainder of the ecosystem is a little tricky.
The scientific review panel said a clear goal was needed for any fishery. Is it to maintain a sustainable fishery, or reduce blue catfish to the lowest feasible levels? Each of those goals would require different types of management, and if states do not agree on a single goal, problems could be exacerbated, the report cautioned.

“If this becomes a highly profitable fishery, then there is going to be a desire by many groups to maintain it at a certain level,” Bilkovic said. “But if it is maintained at that level, is the ecosystem still compromised? That is unknown.”

The ability of a fishery to control the blue catfish population could also be limited because of opposition to harvesting the largest, trophy-size fish in the population. Those fish are popular with recreational anglers, but also produce the greatest numbers of eggs, the report said. “It seems probable that the largest fish could effectively negate any gains made in the reduction of only smaller fish,” the report said.
Essentially, they're worried that people could come to appreciate the fish so much they will be unwilling to support the managers desire to purge the Potomac River of this illegally planted alien fish. We're already well on the way; my friend Capt. Mike Starrett makes part of a living by taking people out to catch giant Blue Cats.

Maybe President Obama could give them a pardon?

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