Evaluating off-bottom sweeps of a U.S. West Coast groundfish bottom trawl: Effects on catch efficiency and seafloor interactions
| Autor: | Mark J.M. Lomeli, W. Waldo Wakefield, Bent Herrmann |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
0106 biological sciences
010604 marine biology & hydrobiology 04 agricultural and veterinary sciences Elevated sweeps Catch comparison Aquatic Science Microstomus pacificus 01 natural sciences Imaging sonar Dover sole Anoplopoma fimbria Seafloor spreading DIDSON imaging sonar Oceanography Benthic zone 040102 fisheries 0401 agriculture forestry and fisheries Environmental science Groundfish West coast Altimeter Sablefish |
| Zdroj: | Fisheries Research May 2019 |
| Popis: | In the U.S. West Coast groundfish bottom trawl fishery, lengthy sweeps (>85 m) that maintain seafloor contact are traditionally used. While these sweeps are effective at herding groundfishes, their bottom tending characteristics increase the potential to cause seafloor disturbances, and injury and unobserved mortality to benthic organisms. In this study, we examined if changing from conventional to modified sweeps (with sections elevated 6.5 cm off bottom) would affect catch efficiency of target groundfishes and seafloor interactions. We used a DIDSON imaging sonar to observe how each sweep configuration interacted with the seafloor. An altimeter was periodically placed on the modified sweep to measure height off bottom. Results detected no significant catch efficiency effect of changing from conventional to modified sweeps. The DIDSON and altimeter data showed the modified sweeps exhibit elevated sections where infaunal and lower-profile epifaunal organisms can pass under without disturbance. Results demonstrate that seafloor interactions can be substantially reduced using elevated sweeps in this fishery without impacting catch efficiency. Further, findings from this research could be potentially applicable to other fisheries nationally and internationally. |
| Databáze: | OpenAIRE |
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