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October 22, 2019

Angry damsels: do species interactions after overfishing enhance or inhibit coral reef recovery?

Angry damsels: do species interactions after overfishing enhance or inhibit coral reef recovery?

Coral reef species are undergoing widespread mortality under increasingly frequent mass coral bleaching events, which will continue until global efforts reduce CO2 emissions. In the meantime, it is critical to enhance reef resilience and recovery processes. Overharvesting of herbivorous fishes threatens these processes and can encourage shifts towards algal-dominated reefs. Overfishing also alters the abundance of other fishes within the community, disrupting complex species interactions. Whether these more subtle impacts enhance or inhibit the function of herbivores is unclear. Resolving how species interactions can mediate responses to disturbance in hyper-diverse communities is necessary to provide realistic predictions on the effects of global change.

Damselfishes live amongst the branches of coral colonies and aggressively defend their hosts against intruders. In areas of high fishing intensity, damselfish are largely ignored whereas their predators are targeted. This situation can lead to a surge in damselfish abundance, increasing the proportion of reef that is aggressively defended. The extent to which this “Wild West” scenario prevents herbivores from grazing, and consequently its impact on resilience and recovery of reefs, is unknown yet potentially significant.

This project aims to reveal the impact of heightened aggression between fish species on coral reef resilience and recovery. You will work with project Partner Operation Wallacea at their Honduras field sites to take advantage of pioneering stereo-video methods to generate 3D-heatmaps of fish behaviour across a gradient of fishing pressure, and to conduct field experiments on damselfish aggression. With these data, you will develop an ecosystem-based model to assess the impact of cross-species interference on future reef resilience and recovery. Model outputs will inform management strategies to maintain optimum relative fish abundances for recovery.

With supervisory and project support at Lancaster University, Bangor University and Operation Wallacea, the project offers unique opportunities for research and training in coral reef science.

Applicants should hold a minimum of a UK Honours Degree at 2:1 level or equivalent in subjects such as Ecology, Marine Biology or Natural Sciences. Applicants with Masters degrees, relevant research experience, or publications will be highly competitive. Exposure to statistical analyses and ecological modelling desirable.

Applicants should hold a minimum SCUBA diving qualification of PADI Rescue Diver, with PADI Divemaster or equivalent preferred.

For further details please contact Dr Sally A. Keith (sally.keith@lancaster.ac.uk).