Casting a wide net: Ecological insights to strengthen marine spatial planning for coastal shark conservation

Cook, Neil D. 2023. Casting a wide net: Ecological insights to strengthen marine spatial planning for coastal shark conservation. PhD Thesis, Cardiff University. Item availability restricted.

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Abstract

Industrialised fishing of the oceans has driven extensive declines in predatory fish biomass. Many shark species are now threatened with extinction, with implications for ecosystem functioning and socioeconomic equity. Spatial protection and fisheries management require ecological evidence to enable recovery but knowledge gaps remain, including population status and critical habitats. I use baited remote underwater video (BRUVS) and laser ablation inductively coupled mass spectrometry (LA-ICP-MS) to address knowledge gaps in Tobago and the UK. Trinidad and Tobago is a regional shark trade hub, but a UNESCO Man and the Biosphere Reserve, marine protected area plans, an updated Fisheries Management Bill and Sustainable Shark and Ray Management Plan for Tobago present conservation opportunities. The departure of the UK from the European Union presents opportunities to overhaul marine resource management, including the Welsh Marine Evidence Strategy (2019-2025). Regional goals can align with the international Decade of Ocean Science for Sustainable Development. BRUVS yielded surprisingly high species richness in Northeast Tobago, unexpected given shark fishing in Trinidad or Tobago. Habitat relief, depth and season drive shark abundance; specific habitat areas may be important for wider Caribbean shark populations and should feature in Biosphere and MPA management. BRUVS yielded novel spatiotemporal habitat insights for the nursehound, Scyliorhinus stellaris, in the Cardigan Bay Special Area of Conservation (SAC), UK, including important nearshore reef areas and potential temporal niche partitioning with smallspotted catsharks, Scyliorhinus canicula. Further work should assess shark nursery status, and advocate for stronger shark protection within SAC networks. LA-ICP-MS elemental analysis of S. canicula vertebrae yielded population structure and heavy metal contamination insights. Shared young-of-year and sub-adult habitat use precedes adult dispersal, sexual segregation, and potentially multiple birthing grounds that could be important for population recruitment. Heavy metal hotspots and bioaccumulation have implications for regional fisheries and may be a physiological stressor.

Item Type:	Thesis (PhD)
Date Type:	Completion
Status:	Unpublished
Schools:	Biosciences
Subjects:	Q Science > Q Science (General)
Date of First Compliant Deposit:	10 May 2024
Last Modified:	10 May 2024 12:43
URI:	https://orca.cardiff.ac.uk/id/eprint/168830

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