School of Biodiversity, One Health & Veterinary Medicine

Killen

There is increasing evidence that intense commercial fishing pressure is not only depleting fish stocks but also causing evolutionary changes to fish populations with serious consequences for the viability of marine fish communities. Given that several fisheries have not recovered despite lengthy moratoriums, there is a pressing need to understand the long-term physiological effects of fisheries-induced evolution (FIE) on fish stocks and their capacity to rebound after fishing pressure is lifted.

Although current research on FIE has focused almost exclusively on the effects of size-selective harvest on reproductive potential of wild populations, there are a range of traits besides body size which could also affect the selectivity of fishing gears but which have not been investigated.

For example, overlooked within the context of FIE is the likelihood that, within a given species, variation in physiological traits among individuals – and especially those related to energy balance (e.g. metabolic rate) and swimming performance (e.g. aerobic scope) – could make some fish more catchable or more likely to suffer mortality after discard.

Selection on these traits could produce major shifts in the fundamental structure and function of fish in response to fishing pressure that are yet to be considered but which could directly determine population resource requirements, resiliency, geographic distributions, and responses to environmental change.

This pioneering project will combine innovative approaches in the laboratory with cutting-edge acoustic tracking technology in the field to address this gap in knowledge with three main goals:

1. to examine whether physiological traits make some individuals more catchable by commercial fishing gears, and whether the environment modulates such effects;
2. to investigate the extent to which physiological traits influence recovery and survival after escape from fishing gear or discard; and
3. to determine whether selection on catchability generates changes in physiological traits that reduce population resiliency or erode the ability to cope with environmental change.

The aims of this project are ambitious but this information is vital for truly understanding the mechanisms of FIE and its consequences for stock sustainability and the function of marine ecosystems.

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First published: 6 January 2015