Scientists, industry join in 'Butterfish Smackdown” to cut bycatch

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Butterfish

PROVIDENCE, RI — The Mid-Atlantic Regional Association Coastal Ocean Observing System (MARACOOS) held a workshop here on Sept. 26 to show the fishing community how ocean data can be helpful to fishermen and how scientists and industry people can work in partnership to solve problems.

A Delaware-based nonprofit, MARACOOS is the part of the Integrated Ocean Observing System (I00S) that covers the region from Cape Cod, MA to Cape Hatteras, NC.

"We are a regional association funded through grant organizations," said MARACOOS Executive Director Gerhard Kuska. "We have 20-to-30 principal investigators from different academic organizations." Among-its missions is supporting science-based decision-making in marine fisheries management and, . to do that, MARACOOS has sought out fishermen partners to work on bycatch reduction and other projects.

During the workshop, Nikitau Georges, a professor of oceanography at the Stevens Institute of Technology in Hoboken. NJ, a MARACOOS member organization, described how ocean condition data can be put into computer models to predict temperature fronts, nutrient movement, and bottom temperatures. This information can help forecast resource availability for the herring and mackerel fisheries.

In creating a first-generation statistical fish habitat model that can forecast and "now-cast" ocean conditions, scientists also hoped to apply this knowledge to predicting where quota-restricted bycatch species are likely to show up. But they needed fishermen's help to ensure that the models were measuring the right criteria and would work in the real world.

To that end, John Manderson, a fisheries biologist with the National Marine Fisheries Service (NMFS), and Greg DiDomenico, executive director of the Garden State Seafood Association, organized a collaborative research project to create a bycatch model for butterfish in the Loligo squid fishery.

The resulting model, which will soon be ready for field-testing, began with scientists and fishermen coming up with separate models that were compared during what was joshingly called a "Butterfish Smackdown."

During two workshops last summer, fishermen and scientists split out into separate groups to work on their butterfish models, then get back together to compare notes. The fisherman’s group concluded that among the most important factors in predicting where butterfish were located were temperature, depth, season, time of day, and moon phase, while the scientists relied mostly on bottom temperature, bathymetry, bottom complexity, and season as predictors.

According to DiDomenico, the fishermen's model outperformed both times the two groups competed. The blended model will be brought back to the fishermen (once more before being tested by "fishing over the model" in real time.

About butterfish and squid co-occurrence, Manderson explained, "Fishermen said they can tell the difference in acoustics. There may be vertical separation, but we don't have data for habitat partitioning yet."

Bycatch avoidance

As an example of how a habitat model works, Manderson presented a simpler case, which involved forecasting where cusk could be found in the Gulf of Maine.

Since cusk is a temperature-sensitive species, the investigators entered two time periods and three climates into the model. The result showed that cusk habitat didn't move north with warmer temperatures. Instead, the cusk habitat broke up into smaller areas at warmer temperatures.

"If you don't understand the habitat fragmentation relationship to temperature, you don't know why regional populations change when they do," said Manderson.

He added that the end goal for butterfish is to create a similar model that allows daily "now-casts" that fishermen can view as they leave the dock and make decisions on where and how to fish to avoid butterfish bycatch.

DiDomenico said the model would quantify in scientific terms the skills fishermen use every day in the wheelhouse. In addition to limited butterfish quota, the primary reason it's so important for fishermen to be able to avoid butterfish bycatch is because that bycatch tends to happen in a big way when it occurs.

He explained that the squid-butterfish co-occurrence - and resulting bycatch events or 'incidental catch" - that has been documented has been characterized by a few large tows.

Since there are not any gear-modification options available at the moment and since the target species, Loligo, and the bycatch species, butterfish, are prey and predator, ecosystem-based management should be considered, DiDomenico said.

Luckily, the Loligo industry is doing OK this year. Back in March, NMFS took action to increase the allowable butterfish catch 311 metric tons for the 2011 fishing year, an action the industry said was vital to heading off a possible early closure of the squid fishery.

"Trimester III (September-December) has began with an ample amount of butterfish cap left," DiDomenico said in mid-October. "Trimester I ended with approximately 7.8 million pounds of Laligo squid caught and only 400,000 pounds of butterfish caught, or approximately 30%-to-40% of the cap."

But Amendment 10 to the Atlantic Mackerel, Squid, and Butterfish Fishery Management Plan, which was developed by the Mid-Atlantis Fishery Management Council and then approved by NIVIFS in 2010, was devised to reduce butterfish bycatch to the lowest level possible. The hope is that the MARACOOS-supported modeling effort will help fishermen meet that goal.

"We don't ever want to be in a situation where we exceed the bycatch limit," said DiDomenico. "We don't want to go back to square-box management or arbitrary closing of areas by dates on the calendar."

Other species

During the September workshop, Greg DeCelles of the University of Massachusetts Dartmouth School for Marine Science and 'Technology (SMAST), a MARACOOS member organization, gave a presentation on the yellowtail flounder avoidance system it administered with the help of scallop fishermen for the scallop access-area fisheries in Nantucket Lightship in 2010 and in Closed Area I and Closed Area II in 2011.

Using a grid system, SMAST scientists used scallopers' reports about where they were seeing yellowtail to map areas where yellowtail were concentrated. The results were sent back to the boats so fishermen could avoid fishing in areas where the quota-limited yellowtail was known to be.

The system helped the fleet reduce bycatch so that excess yellowtail harvest did not occur, allowing scallopers to catch their allocations without a bycatch-forced shutdown of the fishery.

To expand the project, the model for open area will need to be predictive. Determining what factors, such as temperature, influence the movement of yellowtail will allow scientists to better predict where yellowtail likely will show up-and help fishermen avoid them DeCelles said.

More information and the cooperative research projects its members are participating in is available online at sentinel.marine.rutgers.edu.

Joyce Rowley
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