Red Tide Net Invention

A specially designed net intended as a cleanup remedy during Red Tide outbreaks is towed between two boats in a trial run in Tampa Bay, Florida the net sags behind as bags beneath the surface become weighted down with dead fish floating in the path of the net. The large corks spaced periodically along the net's edge mark the bags, which can be emptied and reattached while the net is still in the water. The designer Steve J. Marinovich, observes the operation as the net is fed into the water between the two boats. A six-man crew from the Marine Research Laboratory at Bayboro Harbor, St. Petersburg, dropped a funny-looking net into Tampa Bay Wednesday and Thursday afternoons, a few miles off the Pier. The net came up with 1,000 pounds of dead mullet which they had dumped overboard earlier and the best chance yet of a Red Tide cleanup. For this perennial cleanup problem - tons of stinking dead fish poisoned by the Red Tide organism, Gymnodinium breve, and blown ashore is incredibly expensive. In a single year 1971, the economic loss caused by this marine plague was put at $20-million in seven afflicted counties on Florida's West Coast by Mote Marine Laboratory scientists in Sarasota. You could buy a lot of $7,000 nets for $20-million. The 1974 Legislature provided funding to develop some effective method of handling the great windrows of floating dead fish that appear in the Gulf, usually in late summer and early fall. Alan H. Sellen, project leader who is also administrative assistant at the Bayboro Harbor lab, an arm of Florida's Department of Natural Resources, invited the netting industry (23 Major US firms) to tackle the problem. He specified that nets must be rugged, simple to operate, efficient surface collectors, of adjustable dimensions for use by boats of various sizes. "In addition," manufacturers were told, "the net must have a removable collection bag, so that when it is full it may be detached and closed, to be towed away or transferred to an accompanying collection barge. "The net must he constructed so that it can be raised by a hoist and emptied into a dockside dump truck or offshore barge." Only three replies were received. Of these, says Sellen, Marinovich Trawl Co. Biloxi, Mississippi was the most likely prospect. In the dry run, says Sellen, 500 pounds of dead mullet were dumped onto the water's surface a couple of miles out from the Pier. Then the two vessels, towing the Y-shaped net between them, approached the area. "I think this net is the best thing we've come up with yet," he told The St. Petersburg Times later. "It fished real well and basically, the design seemed good. The mouth of the Y is about 400 feet across when towed. The nylon net bellows down three or four feet from the surface. The mesh is one inch. , "It picked up the fish real well Wednesday afternoon, a nice calm day. Thursday we were in moderate seas, 18 to 24 inches, winds about 20 miles per hour." This time, some of the 600 pounds of fish slipped over the back of the net, although a good portion was picked up. "We'll need more flotation on the net and more experience in net handling," Seller says, "The designer is also modifying the nets, making 'doors' on each side of the net to force it open. This will enable a single vessel to haul it." The net comes in four detachable sections, each 45 feet long. As each one is filled, it is detached and towed away. Since the bags can be reattached while the net stays in the water, a continuous operation is possible. Under terms of the agreement, Sellen says, the collector net's specifications and design are property of the state, not copyrighted by the maker. Hence the lab plans to make these specifications and design available to individual communities, which can then have their own made. He envisions each Gulfside municipality having its own equipment stored for use, much as northern cities have snow removal gear on hand. "But this isn't like snow," the project leader points out, "with snow, just part of it is removed. With dead fish, we've got to get them all. '”We see no reason why this won't work." (Bothwell 1975)