TY - BOOK

T1 - The impact of mobile demersal fishing on blue carbon in seabed sediments

T2 - Fisheries Industry Science Partnerships scheme (FISP) report

AU - Whitton, Timothy

AU - Austin, Martin

AU - Newbould, Alice

AU - Kennedy, Hilary

AU - Allender, Susan

AU - Cavan, Emma

AU - Parker, Ruth

AU - North, Chloe

AU - Hatchman, Juliette

AU - Hiddink, Jan Geert

PY - 2024/7/1

Y1 - 2024/7/1

N2 - Seabed sediments are one of the largest stores of organic carbon, and as such are an important stock of natural capital as this process aids in carbon sequestration. Recent scientific papers have raised concern over the potential impacts of mobile bottom gears on sediment carbon, suggesting that bottom trawling leads to a remineralisation of this organic carbon, and therefore reducing net uptake of CO2 from the atmosphere. Empirical data on the effect of bottom fishing on seabed organic carbon and its potential to be mineralised are mixed in outcome, and so more empirical data in needed from a range of fishing gears and habitat types to fully inform any potential management decision. In April 2023 experimental fishing was conducted by a beam trawler and scallop dredger off the southwestern coast of England to measure how, and if, organic carbon in the sediment is affected if resuspended and subsequently remineralized. We found no clear evidence of reduction in organic carbon due to trawling and dredging in the low carbon (mean 0.13 % Corg), coarse sediments (sandy gravels) of the study area. Potential signals of sediment resuspension were observed, but no consistent or significant signals of clear organic carbon resuspension and remineralisation from the carbon and nutrient analysis on water samples were found. We suggest that the underlying sedimentary environment results in low organic carbon content with naturally high remineralisation rates, which made the experimental fishing conducted limited in its potential direct effect on sedimentary carbon and remineralisation, and the ability of detecting any potential fishing effect difficult to detect.

AB - Seabed sediments are one of the largest stores of organic carbon, and as such are an important stock of natural capital as this process aids in carbon sequestration. Recent scientific papers have raised concern over the potential impacts of mobile bottom gears on sediment carbon, suggesting that bottom trawling leads to a remineralisation of this organic carbon, and therefore reducing net uptake of CO2 from the atmosphere. Empirical data on the effect of bottom fishing on seabed organic carbon and its potential to be mineralised are mixed in outcome, and so more empirical data in needed from a range of fishing gears and habitat types to fully inform any potential management decision. In April 2023 experimental fishing was conducted by a beam trawler and scallop dredger off the southwestern coast of England to measure how, and if, organic carbon in the sediment is affected if resuspended and subsequently remineralized. We found no clear evidence of reduction in organic carbon due to trawling and dredging in the low carbon (mean 0.13 % Corg), coarse sediments (sandy gravels) of the study area. Potential signals of sediment resuspension were observed, but no consistent or significant signals of clear organic carbon resuspension and remineralisation from the carbon and nutrient analysis on water samples were found. We suggest that the underlying sedimentary environment results in low organic carbon content with naturally high remineralisation rates, which made the experimental fishing conducted limited in its potential direct effect on sedimentary carbon and remineralisation, and the ability of detecting any potential fishing effect difficult to detect.

M3 - Other report

BT - The impact of mobile demersal fishing on blue carbon in seabed sediments

PB - Bangor University

ER -