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Can Alligator Gar Aid in the Fight Against Asian Carp?

Can Alligator Gar Aid in the Fight Against Asian Carp?

The alligator gar, the second largest freshwater fish in North America after the white sturgeon of the Pacific northwest, was once the apex aquatic predator throughout the Mississippi basin of the central U.S.

In a last ditch effort to save the country against an invading horde, a race of nightmarish dinosaurs that were almost exterminated by our forefathers are now our last hope.

Or not, depending on who you talk to.

The alligator gar, the second largest freshwater fish in North America after the white sturgeon of the Pacific Northwest, was once the apex aquatic predator throughout the Mississippi basin of the central US. Documented as growing to over ten feet long and 350lbs, they are almost unchanged since the Cretaceous period, having never lost the ability to breathe both water and air, which allows them to survive in anoxic conditions that other species would perish in. Their scales were once used as arrow points by native americans, and their skin is so tough that pioneer farmers used it to cover wooden plows to guard against abrasion. But it is the mouth–or more correctly, "bill"–of the gar that is their most striking feature. Up to several feet long in large specimens and filled with dozens of teeth evolved to grab and hold prey, the business end of the alligator gar is what creates the most fearsome eating machine around. Oh, did I mention they will take flies? More on this later.

Recent press has referenced the potential use of gar as a control agent to help in the fight against silver carp, also know as Asian carp, an invasive species of fish that have now taken hold in the tributaries of the Upper Mississippi. Asian carp populations have now multiplied to the point that they are being measured by biologists not by individual fish counts, but by metric tons per mile. Presumed to have been introduced from live imported asian market/grocery store food stock, they are primarily filter feeders, taking nourishment directly from suspended microorganisms and algal life as freshwater plankton. Plankton are also a crucial food resource for the larval stage of sportfish who do not derive additional nutrients from algae, so without it their maturation cycle is inturrupted and collapses.

Silver carp have now moved upriver from where they were first documented in this country, and are now threatening to enter the Great Lakes. This has potentially devastating implications for both sport and commercial fisheries in there, which have experienced an impressive rebound in the last several decades, owing to strong legislative efforts to reduce pollution and support fish and wildlife initiatives. Silver carp are now seen as a direct economic threat to these interests. As it stands, the only physical barrier between the carp and access to Great Lakes waterways is an underwater electric fence strung across the head of the Chicago Sanitary and Shipping Canal about 25 miles downstream from Lake Michigan. Lawmakers from the state senate of Illinois have now introduced a bill that would support funding for hatchery breeding and direct stocking of gar into waterways in an effort to introduce a predator that is potentially large enough to eat adult Silvers, which can grow to four feet long and weigh up to 100lbs.

Can Alligator Gar Aid in the Fight Against Asian Carp?
They've been waiting millions of years for this opportunity. Armored giants twice the size of a man, with rows of teeth as long as a piano keyboard are about to be unleashed into our waterways.

However, as with many things where science and politics intersect, there appears to be a disconnect. Academic and fisheries experts on alligator gar see the fish as being ineffective at controlling anything other than juvenile carp in a specific size range of 9" to 12", a bracket that is quickly passed though with the rapid growth that most Asian carp exhibit. When adult gar were examined from environments where multiple prey species were present, stomach samples taken showed the gar preferred gizzard shad almost exclusively, a fish that reaches maturity with a length in the size range noted above. The maximum gape of an adult gar's mouth and the diameter of it's gullet are apparently at issue, with both limiting the size of prey it can consume.

Biologists involved with the proposed stocking program say that while they are pleased with the potential support, the intent of their efforts was never to initiate control measures for the Asian carp problem, but only to restore a uniquely American species of fish that had been largely eradicated in the majority of it's home range. But even if stocking programs were able to reintroduce gar to historical populations, it wouldn't make a dent in the numbers of Asian carp that are now being documented through the Midwest.

So what does this mean for the silver carp problem? Good question, but it doesn't sound like alligator gar are going to the the silver bullet. Massive netting efforts are currently in place, with harvested carp being used for commercial fertilizer.

In the meantime, Biologists involved with the reintroduction program are making reference to gar as a potential trophy sport species, offering anglers a chance to catch a fish orders of magnitude larger than anything else they could normally have a shot at. While they are prolific eaters, the problem, especially with larger specimens, is that their mouths are so bony that penetrating them with a hook is almost impossible.

Back to an original premise of this post. gar will readily take flies–big ones–and the unique advantage for fly fishermen is that they can be effectively constructed with hookless designs. Using foot long sections of soft nylon rope, gar fly fishermen unbraid the fibers and lash them to cotter pins with heavy sections of hackle, fur or flash at the collar. The gar take the fly, and are allowed to attempt to eat the offering after letting them turn after the strike. Their multitudes of teeth get caught in the rope fibers and the fight is on.

The future of fisheries management in this country is getting interesting. On the one hand, invasive specie are an ongoing problem that needs innovative solutions. On the other, it sounds like there might be an emerging market for 12 wt big game rods in Illinois.


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