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Effects of Bottom Fishing on Georges Bank

出版	University of Rhode Island, Graduate School of Oceanography, 2005
URL	http://books.google.com.hk/books?id=VKm_jwEACAAJ&hl=&source=gbs_api

註釋In order to gain a better understanding of how bottom fishing impacts benthic organisms, a team of researchers from the University of Rhode Island's Graduate School of Oceanography (GSO) and the U.S. Geological Survey (USGS) set out in 1994 to survey the benthic megafaunal community of Georges Bank. This project's study area was confined to the gravel habitat that straddles the boundary between the U.S. and Canadian exclusive economic zones (EEZs). This area was selected because previous research has indicated that it serves as an important nursery for juvenile cod (Gadus morhua) and haddock (Melanogrammus aeglefinus). Within this region, trawl marks appearing in side scan sonar images were counted in order to identify sites with different levels of bottom fishing disturbance. Based on this information, six study sites were pinpointed and classified as either "disturbed" or "undisturbed." At these sites, benthic dredge samples have been collected on a nearly annual basis. In addition, photographs and videos of the sea floor have been recorded using the SEABOSS system, remotely operated vehicles (ROVs), and manned submersibles. Data from this project have revealed significant differences between disturbed and undisturbed sites in terms of abundance, biomass, species diversity, and benthic community structure. In December 1994, three large sections of Georges Bank, comprising an area of 17,000 km2, were closed to all types of fishing gear capable of retaining groundfish. Since one of our most disturbed study sites was located within a closed area, this event provided a unique opportunity to investigate the changes that occur as a benthic ecosystem recovers from chronic fishing impacts.