Movement Networks & Habitat Preferences

Title:

Movement networks and habitat preferences of a multi-species elasmobranch assemblage in Bimini, Bahamas.

 

Overview:

Describing the ecological role of a species is contingent upon a holistic understanding of the relationships between animal movement, physical environment, and interactions with con-/heterospecifics. Such interactions define the structure and dynamics of populations and communities. How large predators influence these processes in marine systems, however, remains poorly understood. Here, a combination of passive acoustic telemetry, baited remote underwater video system (BRUVS) and fixed environmental data loggers will be deployed in an island system in Bimini, The Bahamas, to identify physical (water temperature, depth) and biological drivers (competition, prey availability, predation risk) of movement and migration, habitat and space use, habitat specificity and spatial hotspots of lemon Negaprion brevirostris, great hammerhead Sphyrna mokarran, tiger Galeocerdo cuvier, nurse Ginglymostoma cirratum, bull Carcharhinus leucas, blacktip C. limbatus, Caribbean reef C. perezi sharks, and southern stingray Dasyatis americana. A multi-habitat acoustic array will monitor localised movements and residencies, while a data share collaboration of acoustic arrays will monitor long-distance movements. BRUV surveys will be employed to assess relative abundance and distribution of elasmobranch and prey species for each habitat type that are representative of the Bimini array. The creation of mechanistic home range models, through quantification of elasmobranch habitat associations and movement networks, will be vital to delineate key areas for protection and predict home range size and the impacts of anthropogenic perturbations.

Map of recievers around Bimini:

  1. What factors drive observed movements or general movement patterns i.e. physical and biological?
  2. How do movements vary across different temporal scales i.e. tidal, diel, seasonal, inter-annual?
  3. How do movements differ between size cohorts and sexes within and between species?
  4. Which factors and what mechanisms underpin the coexistence of multiple elasmobranch species i.e. spatial and temporal habitat partitioning?

Sharks and rays are keystone species that assist in balancing lower trophic levels in oceanic food webs, making natural communities more resilient to environmental disruptions. However, as elasmobranchs are exposed to increasing anthropogenic stresses, there is a growing urge to identify physical and biological drivers responsible for their movement and to understand how this behaviour may be affected by modifications and fluctuations in their environment. The complementary employment of passive acoustic telemetry, baited-remote-underwater-video-station (BRUVS) and unmanned aerial vehicle (UAV) surveys in this study will provide deeper insights in what habitats individuals use, when they use them and why. The quantifications of movement patterns and habitat preferences between elasmobranch species occupying nearshore waters will aid in defining their ecological roles in nearshore community dynamics. Mechanistic home range models allow prediction of home range size and how these will vary with changes such as climate change. Such models will be vital for the development of effective marine protected areas and successful management of these species and habitats.

Principal Investigator:

Maurits van Zinnicq Bergmann – Bimini Biological Field Station Foundation

 

Collaborators

Dr. Yannis Papastamatiou - Florida International University, USA
 
Dr. Mark Bond - Florida International University, USA
 
Dr. Geert Aarts - IMARES Wageningen University, Netherlands
 
Dr. Samuel Gruber - Bimini Biological Field Station Foundation
 
Dr. Tristan Guttridge - Bimini Biological Field Station Foundation
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