August 28, 2013
Contact: Teri Frady
Commercial Fishing Vessels Complete Flatfish Pilot Survey
Intense interest in the Georges Bank yellowtail flounder stock is one driver behind a just-completed pilot research survey. Two commercial trawlers, F/V Mary K and F/V Yankee Pride, worked about 175 stations over 12 days. The survey was coordinated and funded by NOAA’s Northeast Fisheries Science Center (NEFSC), and designed by a panel that included researchers, fishermen, and gear manufacturers.
Chief scientist Michael Martin of the NEFSC said the operations went well. “We were able to complete a very intensive survey of Georges Bank in a very short time thanks to the dedicated efforts of the captains, crews, and scientists aboard,” said Martin.
Once data are audited for quality, the NEFSC will release an informal report for this cruise as it does for all Center resource surveys. The report is expected by early October.
By conducting this pilot survey, the NEFSC hopes to get a better idea of how an industry-based, dedicated survey for flatfish could augment other data collection in the region, and the resources required to establish and maintain such a survey.
Both the United States and Canada routinely cover Georges Bank during large-scale standardized research surveys for multiple species; however, none of these is specifically focused on flatfish like yellowtail flounder. Species-specific surveys such as this one can often reveal more about that species’ condition and help to better interpret data from the broad-scale survey.
“A directed industry-based flatfish research survey could certainly provide data useful in making baseline population estimates for Georges Bank yellowtail and winter flounder and help us monitor population changes in the future,” said Martin.
Information on the distribution, sizes, and ages of fish collected on the survey could provide some immediate insights into population condition. If the pilot survey evolves into an permanent, regular survey, results can be used to identify trends in Georges Bank flatfish abundance and biomass.
The pilot survey used a modified version of a survey net built by Superior Trawl for an industry-based survey of southern New England yellowtail flounder conducted between 2003 and 2005.
The net is a two-seam, two-bridle flounder net with a 118- foot cookie sweep. Two modifications were made to the 2003-2005 survey net: the twine in the lower wings and first belly was reduced, and a codend liner was installed. Both of these modifications are intended to improve the capture of smaller flounder, ensuring that even very small fish –the youngest in the population—would be represented in survey catches.
The pilot survey targeted areas of Georges Bank that were expected to have high flatfish concentrations. The bank was divided into “high abundance” and “low abundance” areas based on input from fisherman. Stations were randomly selected within those areas, with numbers of stations heavily weighted towards high abundance zones. As on other resource surveys, the scientific party also collected biological samples.Operations were conducted both day and night in depths of about 25 to 60 fathoms. The fishing vessel operators strove for consistency in tow time and speed and in setting and retrieving the net. This helped to minimize the effects of net operation on catch rates, since the goal was to collect a consistent sample rather than to catch as many fish as possible, as would usually happen on a commercial trip.
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