Abstract
Original language | English |
---|---|
Article number | 105311 |
Journal | Fisheries Research |
Volume | 219 |
ISSN | 0165-7836 |
DOIs | |
Publication status | Published - 2019 |
Keywords
- Captivity experiment
- Demersal fishery
- Discard survival analysis
- Landing obligation
- Norway lobster (Nephrops norvegicus)
- Horizontally divided codend
Cite this
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Effects of season, target species and codend design on the survival of undersized plaice (Pleuronectes platessa) discarded in the bottom otter trawl mixed fisheries in Skagerrak. / Savina, Esther; Noack, Thomas; Karlsen, Junita Diana.
In: Fisheries Research, Vol. 219, 105311, 2019.Research output: Contribution to journal › Journal article › Research › peer-review
TY - JOUR
T1 - Effects of season, target species and codend design on the survival of undersized plaice (Pleuronectes platessa) discarded in the bottom otter trawl mixed fisheries in Skagerrak
AU - Savina, Esther
AU - Noack, Thomas
AU - Karlsen, Junita Diana
PY - 2019
Y1 - 2019
N2 - Unaccounted fishing mortality is recognized as an important determinant in the management of bycatch, and discard survival studies have been conducted in commercial and recreational fisheries around the world. A range of environmental, operational and biological factors affect survival of discarded fish and should be considered when presenting survival estimates. The present study compared discard survival of plaice in the bottom otter trawl mixed fisheries in Skagerrak between (a) seasons, (b) target species and (c) codend designs. In the latter, a horizontally divided codend designed to reduce interactions between spiny Norway lobsters (Nephrops norvegicus) and fish during the fishing process was investigated for its capacity to reduce catch damages and improve fish survival. (a) In winter, survival was significantly higher (75%, Confidence Interval (CI): 61–78%) than in summer (44%, CI: 34–61%). (b) When targeting plaice, survival was significantly higher (73%, CI: 63–83%) than when targeting Nephrops (40%, CI: 14–59%) in winter. (c) Using the divided codend, an improvement in discard survival of undersized plaice was possible when targeting Nephrops, but without a significant difference from the 90 mm diamond mesh standard codend (37%, CI: 14–54%) when fish were caught in the 60 mm square mesh lower compartment (61%, CI: 48–73%). In the 120 mm square mesh upper compartment, survival was significantly higher (94% with CI: 81–100%), but few undersized individuals were caught. When targeting plaice, survival rates did not differ between codends.
AB - Unaccounted fishing mortality is recognized as an important determinant in the management of bycatch, and discard survival studies have been conducted in commercial and recreational fisheries around the world. A range of environmental, operational and biological factors affect survival of discarded fish and should be considered when presenting survival estimates. The present study compared discard survival of plaice in the bottom otter trawl mixed fisheries in Skagerrak between (a) seasons, (b) target species and (c) codend designs. In the latter, a horizontally divided codend designed to reduce interactions between spiny Norway lobsters (Nephrops norvegicus) and fish during the fishing process was investigated for its capacity to reduce catch damages and improve fish survival. (a) In winter, survival was significantly higher (75%, Confidence Interval (CI): 61–78%) than in summer (44%, CI: 34–61%). (b) When targeting plaice, survival was significantly higher (73%, CI: 63–83%) than when targeting Nephrops (40%, CI: 14–59%) in winter. (c) Using the divided codend, an improvement in discard survival of undersized plaice was possible when targeting Nephrops, but without a significant difference from the 90 mm diamond mesh standard codend (37%, CI: 14–54%) when fish were caught in the 60 mm square mesh lower compartment (61%, CI: 48–73%). In the 120 mm square mesh upper compartment, survival was significantly higher (94% with CI: 81–100%), but few undersized individuals were caught. When targeting plaice, survival rates did not differ between codends.
KW - Captivity experiment
KW - Demersal fishery
KW - Discard survival analysis
KW - Landing obligation
KW - Norway lobster (Nephrops norvegicus)
KW - Horizontally divided codend
U2 - 10.1016/j.fishres.2019.105311
DO - 10.1016/j.fishres.2019.105311
M3 - Journal article
VL - 219
JO - Fisheries Research
JF - Fisheries Research
SN - 0165-7836
M1 - 105311
ER -