An opportunistic comparison of a pulse and a traditional beam trawl fishing gear
Beam trawls are criticized for their negative impact on benthic ecosystems. Pulse trawls may be an environmental more friendly alternative. In addition to the environmental benefits, the pulse trawl is expected to improve the catch efficiency for the main target species (sole Solea solea). Here, we report on an opportunistic comparison between a pulse and traditional tickler chain beam trawl (TCBT). Catch efficiency for sole and plaice was determined in 39 paired hauls, during which both vessels fished parallel, and by comparing average landings during commercial hauls in which the vessels fished in close proximity of each other. Additionally, total catch quantity and composition and benthos composition were compared between both gears. Unfortunately, the TCBT fished with a smaller mesh size than the pulse trawl (67mm versus 80mm). To take account of the differences in mesh-size, plaice and sole catches for the comparative hauls were corrected using selection ogives of recent mesh-size selection experiments. The current study found a 23% higher catch efficiency for market sized sole and a non-significant 3% lower catch efficiency in market sized plaice. The improved size selectivity observed in a similar experiment in 2011, when pulse fishing was just introduced, could not be corroborated. With the exception of Norway lobster and spider crabs, all benthic invertebrate species showed lower catch rates in the pulse-trawl. Due to the difference in cod-end mesh-size, the results of the experiment should be interpreted with caution.
| Main Authors: | , , |
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| Format: | External research report biblioteca |
| Language: | English |
| Published: |
Wageningen Marine Research
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| Subjects: | Life Science, |
| Online Access: | https://research.wur.nl/en/publications/an-opportunistic-comparison-of-a-pulse-and-a-traditional-beam-tra |
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| Summary: | Beam trawls are criticized for their negative impact on benthic ecosystems. Pulse trawls may be an environmental more friendly alternative. In addition to the environmental benefits, the pulse trawl is expected to improve the catch efficiency for the main target species (sole Solea solea). Here, we report on an opportunistic comparison between a pulse and traditional tickler chain beam trawl (TCBT). Catch efficiency for sole and plaice was determined in 39 paired hauls, during which both vessels fished parallel, and by comparing average landings during commercial hauls in which the vessels fished in close proximity of each other. Additionally, total catch quantity and composition and benthos composition were compared between both gears. Unfortunately, the TCBT fished with a smaller mesh size than the pulse trawl (67mm versus 80mm). To take account of the differences in mesh-size, plaice and sole catches for the comparative hauls were corrected using selection ogives of recent mesh-size selection experiments. The current study found a 23% higher catch efficiency for market sized sole and a non-significant 3% lower catch efficiency in market sized plaice. The improved size selectivity observed in a similar experiment in 2011, when pulse fishing was just introduced, could not be corroborated. With the exception of Norway lobster and spider crabs, all benthic invertebrate species showed lower catch rates in the pulse-trawl. Due to the difference in cod-end mesh-size, the results of the experiment should be interpreted with caution. |
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