Fish aggregating devices (FADs) as conservation tools: understanding community dynamics at pelagic moored FADs

Schneider, Eric Vaughn Captain (2023) Fish aggregating devices (FADs) as conservation tools: understanding community dynamics at pelagic moored FADs. PhD thesis, University of Glasgow.

Abstract

The pelagic ocean covers the majority of the planet and is the largest ecosystem by volume. It is estimated to harbor considerable biodiversity, and a few select species support some of the largest fisheries in existence. The expanse of the open ocean provides important resources and services to humans, and also poses challenges to understanding the biology and ecology of its resident species. Focusing effort, both fishing and research, on hotspots or other aggregation sites increases the feasibility of interacting with these often patchily-distributed animals. Fish aggregating devices (FADs) have become a widespread fishing tool in many of the world’s oceans. Leveraging the natural behavior of many fish species to aggregate around floating or submerged structures, FADs are used to increase the capture efficiency in a range of marine fisheries and the scale of their use has raised concerns around potential effects these artificial structures have on the ecosystems in which they are used. Research efforts have focused on understanding these impacts by taking advantage of the fisheries-related opportunities and data made available by these fishing tools and the fleets that use them. However, this may potentially bias studies towards fishing hotspots and larger, commercially important species. Here, we discuss how subsurface FADs, purpose-built and discretely deployed, can act as useful research platforms to address important pelagic ecology questions and conservation topics. We describe the colonization of new FADs and the aggregation fluctuations through long-term video and visual surveys, provide evidence for invertebrate micronekton aggregation as a potential mechanism behind fish attraction to FADs, and detail a new acoustic telemetry array design that can provide previously unavailable position metrics of tagged fish in the open ocean, a notably challenging habitat to study. These new data and scientific tools will allow for the continued and enhanced study of the pelagic ecosystem and the diversity of species that inhabit it.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Subjects: G Geography. Anthropology. Recreation > GC Oceanography; G Geography. Anthropology. Recreation > GE Environmental Sciences; S Agriculture > SH Aquaculture. Fisheries. Angling
• Colleges/Schools: College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine
• Supervisor's Name: Bailey, Dr. David and Killen, Professor Shaun
• Date of Award: 2023
• Depositing User: Theses Team
• Unique ID: glathesis:2023-83926
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 09 Nov 2023 16:22
• Last Modified: 09 Nov 2023 16:25
• Thesis DOI: 10.5525/gla.thesis.83926
• URI: https://theses.gla.ac.uk/id/eprint/83926