Modelling Dolphin Distribution to Inform Future Spatial Conservation Decisions in a Marine Protected Area

Abstract

As marine predators experience increasing anthropogenic pressures, there is an urgent need to understand their distribution and their drivers to inform spatial conservation planning. We used an ensemble modelling approach to investigate the spatio-temporal distribution of southern Australian bottlenose dolphins (Tursiops cf. australis) in relation to a variety of ecogeographical and anthropogenic variables in Coffin Bay, Thorny Passage Marine Park, South Australia. Further, we evaluated the overlap between current spatial management measures and important dolphin habitat. Dolphins showed no distinct seasonal shifts in distribution patterns. Models of the entire study area indicate that zones of high probability of dolphin occurrence were located mainly within the inner area of Coffin Bay. In the inner area, zones with high probability of dolphin occurrence were associated with shallow waters (2–4 m and 7–10 m) and located within 1,000 m from land and 2,500 m from oyster farms. The multi-modal response curve of depth in the models likely shows how the different dolphin communities in Coffin Bay occupy different embayments characterized by distinct depth patterns. The majority of areas of high (>0.6) probability of dolphin occurrence are outside sanctuary zones where multiple human activities are allowed. The inner area of Coffin Bay is an important area of year-round habitat suitability for dolphins. Our results can inform future spatial conservation decisions and improve protection of important dolphin habitat.

Using Cost-Effective Surveys From Platforms of Opportunity to Assess Cetacean Occurrence Patterns for Marine Park Management in the Heart of the Coral Triangle

“…Important human disturbances include direct (bycatch) and indirect (prey depletion) impacts from fisheries (Reeves et al, 2013), as well as physical and acoustic disturbance mainly by marine traffic (Pennino et al, 2017;Erbe et al, 2019), seismic activities from oil and gas exploration and naval sonars (Rosenbaum and Collins, 2006;Henderson et al, 2014), and various sources of pollution (Tanabe, 2002;Allen et al, 2011;Venn-Watson et al, 2015). Increasing anthropogenic stressors include coastal-offshore development and energy production, resource extraction, tourism, and climate change (MacLeod, 2009;Passadore et al, 2018b). To assess the potential impact from these human threats, baseline information on cetacean occurrence at a local level is urgently needed.…”

Cetacean habitat modelling to inform conservation management, marine spatial planning, and as a basis for anthropogenic threat mitigation in Indonesia

“…This is in agreement with what Ilangakoon and Sathasivam (2012) suggested that blue whales can be present in relatively small, localized highly productive feeding areas associated with strong upwelling year-round in Sri Lanka, and only make localized movements within this area. O. brevirostris prefers shallow, sheltered estuaries, such as in the NEBS, since such areas are commonly highly productive systems that can attract fish and top predators (Passadore et al, 2018). It has been shown before that distinct isobaths (-200m and -1000m) are important factors in determining the distribution of many cetaceans known to forage on pelagic schooling fish or deep-water prey (Goetz et al, 2015;Scales et al, 2014).…”

“…Cetaceans are particularly susceptible to human threats because of their life-history traits i.e. late maturity and low reproductive rate (Passadore et al, 2018). The variety of anthropogenic pressures includes interactions with fisheries (entanglement, bycatch, prey depletion) (Read, 2008;Reeves et al, 2013), physical and acoustic disturbance mainly by marine traffic (ship strikes, underwater noise) (Erbe et al, 2019;Pennino et al, 2017), seismic activities from oil and gas exploration and naval sonars (Henderson et al, 2014;Rosenbaum and Collins, 2006), and pollution (oil spills, plastic debris, heavy metals, and other chemicals) (Allen et al, 2011;Monk et al, 2014;Tanabe, 2002;Venn-Watson et al, 2015).…”

“…The variety of anthropogenic pressures includes interactions with fisheries (entanglement, bycatch, prey depletion) (Read, 2008;Reeves et al, 2013), physical and acoustic disturbance mainly by marine traffic (ship strikes, underwater noise) (Erbe et al, 2019;Pennino et al, 2017), seismic activities from oil and gas exploration and naval sonars (Henderson et al, 2014;Rosenbaum and Collins, 2006), and pollution (oil spills, plastic debris, heavy metals, and other chemicals) (Allen et al, 2011;Monk et al, 2014;Tanabe, 2002;Venn-Watson et al, 2015). New threats have also been recognized, including coastal-offshore development and energy production, resource extraction, tourism, and climate change (MacLeod, 2009;Passadore et al, 2018). A prominent stressor to cetaceans is marine traffic which is to some extent linked to shipping (Coomber et al, 2016).…”

Using cost-effective surveys from platforms of opportunity to assess cetacean occurrence patterns for marine park management in the heart of the Coral Triangle

“…Important human disturbances include direct (bycatch) and indirect (prey depletion) impacts from fisheries (Reeves et al, 2013), as well as physical and acoustic disturbance mainly by marine traffic (Erbe et al, 2019;Pennino et al, 2017), seismic activities from oil and gas exploration and naval sonars (Henderson et al, 2014;Rosenbaum and Collins, 2006), and various sources of pollution (Allen et al, 2011;Tanabe, 2002;Venn-Watson et al, 2015). Increasing anthropogenic stressors include coastaloffshore development and energy production, resource extraction, tourism, and climate change (MacLeod, 2009;Passadore et al, 2018b). To assess the potential impact from these human threats, baseline information on cetacean occurrence at a local level is urgently needed.…”