COMMERCE
Subscriber Services
Classified Ads
Subscribe
Advertise
NEWS
This Month
Editorial
Letters
F/V Safety
Past Issues
ABOUT US
Contact Us
Latest Issue
Subscribe
History
MORE CONTENT
CFN Archives
Links
Each month exclusively in the PRINT edition of CFN
Along the Coast
Ask the Lobster Doc
Bearin’s
Classifieds
Coming Events
Editorial
Enforcement Report
FISH SAFE
Fleet Additions
Letters
Lobster Market Report
New Boats
News Catch
Quahog Market Report
|
Commercial Fisheries News
Volume 36 Number 1
September 2008
Video survey finds fewer scallops on Georges
NEW BEDFORD, MA – The scallop biomass on Georges Bank has declined over the past year, especially in portions of the closed areas that are off-limits to the fleet, raising the possibility that the scallops may have died from natural causes.
That’s what researchers found after analyzing results from the 2008 scallop video survey.
Sponsored by industry and overseen by the School for Marine Science and Technology (SMAST) at the University of Massachusetts Dartmouth, the survey documented a 13-million-pound upswing in the Mid-Atlantic resource between 2007 and 2008 due to increases in both the Delmarva and open areas (see CFN August 2008 for details).
But on Georges Bank, the survey results produced a different picture and showed a 78-million-pound decline.
“All of the areas showed reductions in the densities of scallops,” said SMAST’s Mike Marino, video survey program manager.
However, a large percentage of the drop was documented in the non-access portions of the Nantucket Lightship Closed Area and Closed Area II where scallop fishing is prohibited.
Scallop densities in the southern half of Closed Area II, on the other hand, “stayed fairly consistent with last year,” said Marino.
This was welcome news since the southern half of Closed Area II is scheduled to be a scallop rotational access area in 2009.
Biggest drops
The most dramatic biomass reduction occurred in the Nantucket Lightship Closed Area (see Figure 2).
Part of that area has been open for the past two years under the rotational schedule and has been fished by the fleet. As many would expect, this has resulted in a lowering of the area’s stock size.
However, what’s more significant, SMAST researchers said, is that the video survey found the biggest drop to be in the non-access portion of the lightship area.
This single fact – that fishing activity has been prohibited in the parts of Closed Area II and the Nantucket Lightship area where the largest biomass reductions occurred – has largely convinced SMAST researchers that natural mortality is occurring.
They documented a similar phenomenon in 2004 and 2005 in the lightship area.
Last mortality event
Kevin Stokesbury, chair of SMAST’s Department of Fisheries Oceanography, along with Marino, Brad Harris, and Jake Nogueira, published a paper in 2007 in the Marine Ecology Progress Series documenting the 2004 and 2005 event.
They wrote, “The scallops that perished were large and probably old; 80% had shell heights greater than 130 millimeters (5.2 inches).”
They further stated, “Closing the (lightship area) to fishing in 1994 removed fishing mortality, increasing scallop survival rates. Scallops that recruited in 1994 reached 10 years of age in 2004. Individuals of this age may suffer the effects of senescence (old age), including parasitism by shell borers and prokaryotic infection, which likely caused the mass mortality.”
Old scallops
According to Stokesbury, many scallops once again may be dying of natural mortality – old age, predation, and disease.
“Natural mortality might be higher than predicted,” he said.
Scallopers actively fishing in the Nantucket Lightship area also have reported moving off certain beds of scallops due to poor meat quality. The meats – gray, stringy, and tough – are another indication that the scallops are just plain old.
The SMAST team reported these findings to industry at a July 30 video survey steering committee meeting and also presented an initial overview to the New England Fishery Management Council’s scallop plan development team (PDT) at an Aug. 14 meeting.
What’s next?
According to scallop PDT Chair Deirdre Boelke, who serves as the New England council’s scallop plan coordinator, the PDT will hold its next meeting at the end of September and review data from all three of the surveys it uses to gauge the status of the stock.
These include: the SMAST video survey; the federal scallop dredge survey, which this year was conducted aboard the research vessel Sharp (see CFN August 2008 for details); and the dredge survey run by the Virginia Institute of Marine Science, which, like the video survey, uses commercial fishing vessels.
After assimilating all this data, the PDT will report its findings to the full New England council in October.
The New England council develops a framework adjustment setting scallop days-at-sea and access-area allocations every two years. But it built in a provision to annually evaluate certain access areas – even in the off-framework years – to ensure that the biomass in each access area can support the number of assigned trips.
As a result, said Boelke, “Our focus this fall will be on the Mid-Atlantic areas that are scheduled to be part of the rotational program in 2009 – the Elephant Trunk Area and Delmarva.”
Janice M. Plante
Back to story list
|
|
Tell us what you think.
