Estimating protected species bycatch from limited observer coverage: A case study of seal bycatch in static net fisheries
Fisheries bycatch represents a major anthropogenic threat to marine megafauna worldwide. To identify populations at risk, it is essential to estimate the total number of individuals removed from a population as bycatch. However, estimating total bycatch remains challenging due to the often-limited s...
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doaj-f6eefedfd3c6458a81f3f280ed4ebd162020-12-31T04:42:14ZengElsevierGlobal Ecology and Conservation2351-98942020-12-0124e01213Estimating protected species bycatch from limited observer coverage: A case study of seal bycatch in static net fisheriesCian Luck0Mark Jessopp1Oliver Tully2Ronan Cosgrove3Emer Rogan4Michelle Cronin5MaREI Centre for Energy, Climate, and Marine, Environmental Research Institute, University College Cork, Ireland; School of Biological, Earth, and Environmental Sciences, University College Cork, Ireland; Corresponding author. MaREI Centre for Energy, Climate, and Marine, Beaufort Building, Haulbowline Road, Ringaskiddy, County Cork, P43 C573, Ireland.MaREI Centre for Energy, Climate, and Marine, Environmental Research Institute, University College Cork, Ireland; School of Biological, Earth, and Environmental Sciences, University College Cork, IrelandMarine Institute, Oranmore, Galway, IrelandIrish Sea Fisheries Board (BIM), New Docks, Galway, IrelandSchool of Biological, Earth, and Environmental Sciences, University College Cork, IrelandMaREI Centre for Energy, Climate, and Marine, Environmental Research Institute, University College Cork, IrelandFisheries bycatch represents a major anthropogenic threat to marine megafauna worldwide. To identify populations at risk, it is essential to estimate the total number of individuals removed from a population as bycatch. However, estimating total bycatch remains challenging due to the often-limited scope of monitoring programmes. In this study, we aimed to maximise the value of limited bycatch data collected by scientific observers and self-reported by fishers to provide estimates of total seal bycatch for static net fisheries operating in Irish waters. We constructed a model of bycatch rate as a function of known predictors of seal bycatch, and used this to predict bycatch rates throughout the Irish Exclusive Economic Zone. Annual estimates of seal bycatch, from 2011 to 2016, ranged between 202 (90% CI: 2-433) and 349 (90% CI: 6-833) seals per annum. Estimated bycatch exceeded the precautionary threshold of Potential Biological Removal (PBR = 165-218; Fr=0.5) for the national grey seal population but was below less conservative threshold values (PBR = 330-437; Fr=1.0), with confidence intervals spanning both. Further research on the population structure of grey seals in the Northeast Atlantic is needed to set appropriate bycatch thresholds. Nonetheless, this study shows that by utilising predictive models to maximise the value of limited bycatch observer effort, we can produce informative estimates of protected species bycatch and highlight areas of high bycatch risk. We present this as a case study for maritime nations with comparatively limited bycatch data to fill key data gaps in protected species bycatch worldwide.http://www.sciencedirect.com/science/article/pii/S235198942030754XBycatchPotential biological removalSealGillnetStatic net |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Cian Luck Mark Jessopp Oliver Tully Ronan Cosgrove Emer Rogan Michelle Cronin |
spellingShingle |
Cian Luck Mark Jessopp Oliver Tully Ronan Cosgrove Emer Rogan Michelle Cronin Estimating protected species bycatch from limited observer coverage: A case study of seal bycatch in static net fisheries Global Ecology and Conservation Bycatch Potential biological removal Seal Gillnet Static net |
author_facet |
Cian Luck Mark Jessopp Oliver Tully Ronan Cosgrove Emer Rogan Michelle Cronin |
author_sort |
Cian Luck |
title |
Estimating protected species bycatch from limited observer coverage: A case study of seal bycatch in static net fisheries |
title_short |
Estimating protected species bycatch from limited observer coverage: A case study of seal bycatch in static net fisheries |
title_full |
Estimating protected species bycatch from limited observer coverage: A case study of seal bycatch in static net fisheries |
title_fullStr |
Estimating protected species bycatch from limited observer coverage: A case study of seal bycatch in static net fisheries |
title_full_unstemmed |
Estimating protected species bycatch from limited observer coverage: A case study of seal bycatch in static net fisheries |
title_sort |
estimating protected species bycatch from limited observer coverage: a case study of seal bycatch in static net fisheries |
publisher |
Elsevier |
series |
Global Ecology and Conservation |
issn |
2351-9894 |
publishDate |
2020-12-01 |
description |
Fisheries bycatch represents a major anthropogenic threat to marine megafauna worldwide. To identify populations at risk, it is essential to estimate the total number of individuals removed from a population as bycatch. However, estimating total bycatch remains challenging due to the often-limited scope of monitoring programmes. In this study, we aimed to maximise the value of limited bycatch data collected by scientific observers and self-reported by fishers to provide estimates of total seal bycatch for static net fisheries operating in Irish waters. We constructed a model of bycatch rate as a function of known predictors of seal bycatch, and used this to predict bycatch rates throughout the Irish Exclusive Economic Zone. Annual estimates of seal bycatch, from 2011 to 2016, ranged between 202 (90% CI: 2-433) and 349 (90% CI: 6-833) seals per annum. Estimated bycatch exceeded the precautionary threshold of Potential Biological Removal (PBR = 165-218; Fr=0.5) for the national grey seal population but was below less conservative threshold values (PBR = 330-437; Fr=1.0), with confidence intervals spanning both. Further research on the population structure of grey seals in the Northeast Atlantic is needed to set appropriate bycatch thresholds. Nonetheless, this study shows that by utilising predictive models to maximise the value of limited bycatch observer effort, we can produce informative estimates of protected species bycatch and highlight areas of high bycatch risk. We present this as a case study for maritime nations with comparatively limited bycatch data to fill key data gaps in protected species bycatch worldwide. |
topic |
Bycatch Potential biological removal Seal Gillnet Static net |
url |
http://www.sciencedirect.com/science/article/pii/S235198942030754X |
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