Both public and private entities have provided financial support, with funding coming from the Louisiana Department of Wildlife and Fisheries and The Nature Conservancy.

Lapeyre said the engineered reefs may not only provide shoreline stabilization but also create habitat for marine organisms. “The reefs are designed to encourage oyster recruitment and offer a place for fish to spawn or be a refuge from predators,” she said.

Two designs are being used for the construction of the reefs.

One is a concrete-rebar model that is triangular-shaped and is placed in an interlocking fashion. The rebar is designed to degrade in approximately 15 years, leaving behind a reef consisting of recruited organisms.

The second reef is a concrete mixture shaped in a circular form resembling a tire. Researchers hope it, too, will become covered with living organisms.

Lapeyre reported that preliminary data had shown the reefs have provided habitat for a number of fish and crustaceans, including blue crab, bay anchovies and gulf menhaden (pogy). Researchers used a variety of nets to sample the organisms that were using the reefs.

Another facet of the research is examining the role of the reefs in filtering water. The successful recruitment of a viable oyster population is essential for water filtration to occur, Lapeyre said.

“The filtration abilities of the oysters would be a primary contributor to enhancing water quality and clarity, but the reefs’ ability to absorb wave energy would also be a factor,” she said.

Lapeyre noted that not all sites experiencing coastal land loss are suitable for the reefs. She said land that is subsiding would not be an ideal location. Areas that experience high boat traffic and are exposed to wave energy created by localized storms would be better suited.

Another factor in site selection involves choosing locations that are conducive to oyster survival. In order for the reefs to be successful, oysters will play a crucial role. Issues such as water salinity and the firmness of the water bottom should also be considered, Lapeyre said.

“Many of the questions can’t be answered within a short time. Additional monitoring time will be needed to determine whether this is a viable solution to shoreline stabilization,” she said.

The origianl article, by Craig Gautreaux can be see on the LSU Agcenter.com website

“Gulf-caught menhaden is valuable as its own separate fishery,” she said. “There are some fishermen that used to sell it as bait, but it is more valuable to use as Omega-3 oils – fish oils – that it is just not worthwhile to sell as bait.”

Anderson worked on a project manufacturing baits at the University of Delaware. She was trying to find a replacement for horseshoe crabs used as bait in eel and whelk fishing.

She is applying the same techniques to develop a blue crab bait that can replace menhaden.

Anderson tried mixing commercial-grade gelatin with byproducts from oysters, shrimp and crabs – all things blue crabs eat. Tests showed that the crabs were most attracted to the baits with shrimp in them.

Anderson said about a third of a shrimp – such as the shell and the head – is waste, and shrimp processors typically have to pay to have the waste hauled away. Finding a use for the waste can cut down on costs while bringing in money.

“If we can create even just a very small value to this waste product, then some of those processors could make a little more money,” she said.

The researcher is testing different amounts of shrimp and gelatin to make a bait that would first attract the crabs and also hold up in the water as well as be easy to store and handle.

“Preliminary fields work had very similar catches between normal menhaden and our bait,” Anderson said.

She tested the baits in waters with varying salinity levels and found that in waters with high salinity, smaller predators, such as minnows and small crabs, will feed on the bait and break it down faster. This was not a problem in fresher water.

Anderson says it appears the manufactured bait may last longer in the water than menhaden. With longer-lasting bait, fishers wouldn’t have to go out as often to check their traps, which would cut down on fuel costs.

Baits manufactured in Louisiana also decrease shipping costs. While menhaden bait is kept frozen, this manufactured bait may not need to be frozen. Anderson said it would likely be less costly than using menhaden.

“Even if it is just a few cents cheaper per bait, it would definitely add up over the year,” she said.

Anderson has a graduate student working on the project during the next two years, and she hopes to have a product ready for the market at the end of that period.

-- Photo and story by Tobie Blanchard, LSU AgCenter
-- [permalink to AgCenter article]