Dataset Information

Identifying priority habitat for conservation and management of Australian humpback dolphins within a marine protected area.

ABSTRACT: Increasing human activity along the coast has amplified the extinction risk of inshore delphinids. Informed selection and prioritisation of areas for the conservation of inshore delphinids requires a comprehensive understanding of their distribution and habitat use. In this study, we applied an ensemble species distribution modelling approach, combining results of six modelling algorithms to identify areas of high probability of occurrence of the globally Vulnerable Australian humpback dolphin in northern Ningaloo Marine Park (NMP), north-western Australia. Model outputs were based on sighting data collected during systematic, boat-based surveys between 2013 and 2015, and in relation to various ecogeographic variables. Water depth and distance to coast were identified as the most important variables influencing dolphin presence, with dolphins showing a preference for shallow waters (5-15 m) less than 2 km from the coast. Areas of high probability (>?0.6) of dolphin occurrence were primarily (90%) in multiple use areas where extractive human activities are permitted, and were poorly represented in sanctuary (no-take) zones. This spatial mismatch emphasises the need to reassess for future spatial planning and marine park management plan reviews for NMP. Shallow, coastal waters identified here should be considered priority areas for the conservation of this Vulnerable species.

SUBMITTER: Hunt TN

PROVIDER: S-EPMC7463025 | biostudies-literature | 2020 Sep

REPOSITORIES: biostudies-literature

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Identifying priority habitat for conservation and management of Australian humpback dolphins within a marine protected area.

Hunt Tim N TN Allen Simon J SJ Bejder Lars L Parra Guido J GJ

Scientific reports 20200901 1

Increasing human activity along the coast has amplified the extinction risk of inshore delphinids. Informed selection and prioritisation of areas for the conservation of inshore delphinids requires a comprehensive understanding of their distribution and habitat use. In this study, we applied an ensemble species distribution modelling approach, combining results of six modelling algorithms to identify areas of high probability of occurrence of the globally Vulnerable Australian humpback dolphin i ...[more]

PMID: 32873830

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Project description:Humpback whales (Megaptera novaeangliae) were hunted commercially in Canada's Pacific region until 1966. Depleted to an estimated 1,400 individuals throughout the North Pacific, humpback whales are listed as Threatened under Canada's Species at Risk Act (SARA) and Endangered under the US Endangered Species Act. We conducted an 8-year photo-identification study to monitor humpback whale usage of a coastal fjord system in British Columbia (BC), Canada that was recently proposed as candidate critical habitat for the species under SARA. This participatory research program built collaborations among First Nations, environmental non-governmental organizations and academics. The study site, including the territorial waters of Gitga'at First Nation, is an important summertime feeding destination for migratory humpback whales, but is small relative to the population's range. We estimated abundance and survivorship using mark-recapture methods using photographs of naturally marked individuals. Abundance of humpback whales in the region was large, relative to the site's size, and generally increased throughout the study period. The resulting estimate of adult survivorship (0.979, 95% CI: 0.914, 0.995) is at the high end of previously reported estimates. A high rate of resights provides new evidence for inter-annual site fidelity to these local waters. Habitat characteristics of our study area are considered ecologically significant and unique, and this should be considered as regulatory agencies consider proposals for high-volume crude oil and liquefied natural gas tanker traffic through the area. Monitoring population recovery of a highly mobile, migratory species is daunting for low-cost, community-led science. Focusing on a small, important subset of the animals' range can make this challenge more tractable. Given low statistical power and high variability, our community is considering simpler ecological indicators of population health, such as the number of individuals harmed or killed each year by human activities, including ship strikes and entanglement in fishing gear.

Project description:BackgroundMarine soundscape is the aggregation of sound sources known as geophony, biophony, and anthrophony. The soundscape analysis, in terms of collection and analysis of acoustic signals, has been proposed as a tool to evaluate the specific features of ecological assemblages and to estimate their acoustic variability over space and time. This study aimed to characterise the Capo Caccia-Isola Piana Marine Protected Area (Italy, Western Mediterranean Sea) soundscape over short temporal (few days) and spatial scales (few km) and to quantify the main anthropogenic and biological components, with a focus on fish biophonies.MethodsWithin the MPA, three sites were chosen each in a different protection zone (A for the integral protection, B as the partial protection, and C as the general protection). In each site, two underwater autonomous acoustic recorders were deployed in July 2020 at a depth of about 10 m on rocky bottoms. To characterise the contribution of both biophonies and anthrophonies, sea ambient noise (SAN) levels were measured as sound pressure level (SPL dB re: 1 μ Pa-rms) at eight 1/3 octave bands, centred from 125 Hz to 16 kHz, and biological and anthropogenic sounds were noted. Fish sounds were classified and counted following a catalogue of known fish sounds from the Mediterranean Sea based on the acoustic characteristic of sound types. A contemporary fish visual census had been carried out at the test sites.ResultsSPL were different by site, time (day vs. night), and hour. SPLs bands centred at 125, 250, and 500 Hz were significantly higher in the daytime, due to the high number of boats per minute whose noise dominated the soundscapes. The loudest man-made noise was found in the A zone, followed by the B and the C zone, confirming that MPA current regulations do not provide protection from acoustic pollution. The dominant biological components of the MPA soundscape were the impulsive sounds generated by some invertebrates, snapping shrimps and fish. The vast majority of fish sounds were recorded at the MPA site characterized by the highest sound richness, abundance, and Shannon-Wiener index, coherently with the results of a fish visual census. Moreover, the acoustic monitoring detected a sound associated with a cryptic species (Ophidion spp.) never reported in the study area before, further demonstrating the usefulness of passive acoustic monitoring as a complementary technique to species census. This study provides baseline data to detect future changes of the marine soundscapes and some suggestions to reduce the impact of noise on marine biodiversity.

Dataset Information

Identifying priority habitat for conservation and management of Australian humpback dolphins within a marine protected area.

Publications

Identifying priority habitat for conservation and management of Australian humpback dolphins within a marine protected area.

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