MEPS 350:267-276 (2007)  -  DOI: https://doi.org/10.3354/meps07194

Food subsidies from fisheries to continental shelf benthic scavengers

Michel J. Kaiser*, Jan Geert Hiddink

School of Ocean Sciences, College of Natural Sciences, Bangor University, Menai Bridge, Anglesey LL59 5AB, UK

ABSTRACT: Fisheries generate carrion as a result of material discarded at sea from fishing boats, and as a result of the direct mortality of organisms on the seabed that is caused by the bottom trawling gears. It is unclear whether the increases in the population sizes in scavenging seabirds that have been partially attributed to discarding practices might be mirrored in populations of benthic scavengers. We used a previously published and field-validated, size-based model to calculate the effects of bottom fishing on benthic invertebrate production and production of invertebrate carrion at the seabed in the North Sea. This estimate was combined with previously published estimates of discarded fish carrion that reaches the seabed. Fishing decreases benthic biomass; this means that benthic production is also reduced. In this process, fishing increases production in the short term (2 to 3 d) by generating carrion. However, the production of carrion only compensates for 22% of the reduction in production. Calculations of ash free dry weight of carrion produced per unit area were similar to other previous estimates for the North Sea, which indicated that fisheries-generated carrion was sufficient to sustain benthic carnivores for only approximately 3 d yr–1.


KEY WORDS: Benthic scavengers · Energy subsidies · Model · Fishing disturbance


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Cite this article as: Kaiser MJ, Hiddink JG (2007) Food subsidies from fisheries to continental shelf benthic scavengers. Mar Ecol Prog Ser 350:267-276. https://doi.org/10.3354/meps07194

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