Sea Scallop Research: Environmental Assessment

"The scallop video survey constitutes the largest Before-After-Control-Impact examination of the environmental impacts of bottom-tending mobile fishing gear ever conducted."

One aspect of our scallop research program is examining the effects of scallop harvesting on the marine benthic habitat. The use of mobile fishing gear in United States coastal waters is hotly debated with opinions ranging from the gear having little effect, to the gear devastating the marine benthic community. We have conducted a series of experiments examining the environmental impact of scallop harvesting on Georges Bank. We address the issues by:Boulders, cobble, gravel and sand with several species of sponge and one scallop.

  • mapping the sea floor,
  • conducting a Before-After-Control-Impact (BACI) study of the scallop resource,
  • conducting a comparison study with more than 125 stations within and outside the HAPC,
  • publishing our observations.

Mapping the sea floor. Scallops have evolved to live on a dynamic sand-gravel substrate, which does not support sessile and encrusting invertebrates very well. By defining the gravel areas into their subgroups and showing where the substrates and sessile invertebrates do and don’t exist some of the conflict over the effects of fishing on habitat may be removed.

We have successfully collected the information for one of the largest Before-After-Control-Impact (BACI) studies ever conducted on a scallop resource. We surveyed the historic scallop fishing grounds of Georges Bank that have been closed to mobile gear since 1994. Our survey design was a BACI with a 1-year set of baseline observations, 2 experimental areas (NLSA and North of 43660 in CAI) that were exposed to intense fishing pressure, two control areas (the northern portion of CAII, and South of 43660 in CAI) with no fishing, and one control with constant fishing (South Channel).

We have a comparison study with >125 stations within and outside the HAPC which had been closed for 8 years at the time of the study. This is one of our best data sets with both the large (2.8 m2) and small (0.6 m2) images.

Actual data on these topics are so lacking that all of our observations can be published. Even things such as what fish we observed and what substrate the fish were associated with will be of use.

We are presently organizing, analyzing and preparing several manuscripts on these data. Preliminary data have been presented to the New England Fisheries Management Council, Habitat Oversight Committee (12 Sept 02), and Habitat Technician Team (25 Nov 02). We have also presented the preliminary results from our BACI experiment at the Benthic meeting in Florida:
Stokesbury, K.D.E. and B. Harris. A Before-After-Control-Impact Study of the Sea Scallop Fishing Grounds of Georges Bank. Symposium on the Effects of Fishing activities on benthic habitats. USGS, NOAA, AFS, ESA. Tampa Florida, 12-14 November 2002.

Photograph: Boulders, cobble, gravel and sand with several species of sponge and one scallop.

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