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Population Ecology

28 record(s)
 
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  • This record provides an overview of the scope and research output of the NESP Marine Biodiversity Hub project "Monitoring population dynamics of ‘Western’ Right Whales off Southern Australia". For specific data outputs from this project, please see child records associated with this metadata. -------------------- Continuation (since 1993) of annual aerial surveys, to include counts and identification photographs, of Southern Right Whales between Cape Leeuwin (WA) and Ceduna (SA), where wintering animals come close to the coast – adult females to calve, at approximately three-year intervals, other adults and juveniles less regularly. The area is the main wintering ground of a major ‘western’ subpopulation of ‘Australian’ right whales, differing in number and extent of recovery (from 19th century hunting) from an ‘eastern’ subpopulation which so far shows little if any recovery. Counts allow estimation of population trend and current numbers; identification photographs allow estimation of life history parameters. This project serves to implement a very high priority action in the Australian Government’s Conservation Management Plan for Southern Right Whale (2011-21) – Action Area B1: Measuring and monitoring population recovery; continue to obtain and refine population abundance and trends for the south-west population. Planned Outputs • Counts of animals (by class – cows accompanied by calves, other animals, by position (GPS) and time. • Head and (where appropriate) body photographs, by position and time. • Information on Biologically Important Areas for Southern Right Whales in the area surveyed. • ‘Progress’ and ‘Final’ reports, annually • Report annually to the Scientific Committee of the International Whaling Commission. • Public information through press releases and on the Museum website.

  • This record provides an overview of the scope and research output of the NESP Marine Biodiversity Hub project "Grey Nurse Shark CK-MR Population Estimate – East Coast". For specific data outputs from this project, please see child records associated with this metadata. -------------------- A review of the 2002 National Recovery Plan for Grey Nurse Shark (DEWHA 2009) concluded it was not possible to determine if the east coast population had shown any signs of recovery (DoE 2014); recommending a new recovery plan be developed for this species. A primary objective of the new recovery plan (DoE 2014) is to improve knowledge of GNS population status. This will require a robust estimate of population size and trend – something that has not been provided to date. This project will use genetic SNP data to inform close kin-mark recapture analysis to estimate population size and trend, and provide guidance on future monitoring strategies for the east coast population of grey nurse shark. Planned Outputs • Tools to refine and integrate CK-MR and species demographic data for population assessments of a key threatened species at a national scale (combining knowledge developed under this project combined with similar techniques being applied under NESP to euryhaline sharks and white sharks). • A national estimate of (census) population size and trend for the eastern Australian population of grey nurse shark will be developed to fulfil the highest priority actions of the National Recovery Plan. • Identify national strategies to guide future monitoring of grey nurse shark populations. • The project will provide peer-reviewed additions to the scientific literature that will add to the science-support for the development and implementation of policies to support the ecologically sustainable management of Australia’s marine environment.

  • This record describes the sample collection location for grey nurse shark as part of NESP MB Project A9 - Grey Nurse Shark CK-MR Population Estimate – East Coast. The data attached to this record describes the locations and vB parameters of tissue samples collected between December 2002 and April 2017. Sequencing data will be added to ALA as it becomes available. See https://fieldcapture.ala.org.au/project/index/b3376517-e418-4a38-ba45-63faae7ed8be for updates.

  • This record provides an overview of the NESP Marine and Coastal Hub project "Aerial survey of the Southern Right Whale 'western' sub-population off southern Australia". For specific data outputs from this project, please see child records associated with this metadata. -------------------- Southern right whales are listed as Endangered under the EPBC Act and are a species of national conservation significance. Monitoring of their recovery is guided by the Southern Right Whale Conservation Management Plan, which aims to improve the population’s conservation status through regular assessment of population size, calving intervals, and spatial trends. This project continued the long-term aerial survey program of southern right whales along the southern Australian coast, spanning from Perth (WA) to Ceduna (SA). Annual surveys have been conducted since 1993, providing a continuous long-term dataset for the 'western' population and supporting national assessments of connectivity with the smaller ‘eastern’ population. The surveys contribute essential data on population trends, calving rates, and movements of individuals. The August 2022 aerial survey ensured an uninterrupted time series in the long-term population trend data. This is particularly important given the species' non-annual breeding cycle (typically every three years). Annual surveys are essential to maintain an acceptable level of precision in estimating population trends and key life history parameters. A total of 526 whales were recorded, including 247 cow–calf pairs, 31 unaccompanied adults and one yearling. Based on long-term models, this equated to a population estimate of approximately 2,675 individuals, with an average annual growth rate of ~5.3%. While this represents a continued population growth, results suggest a possible slowing in the rate of growth over the past 13 years (from 7.5% in 2009). The 2022 survey also recorded the lowest number of unaccompanied animals in the entire time series, extending a five-year trend of low sightings in this group. Continued monitoring of the population is needed to assess whether these changes represent longer-term shifts in population dynamics and calving intervals, and to inform adaptive management for this long-lived, slow-recovering species. Outputs • Estimate of relative abundance and population trend compared to long-term aerial survey sightings [dataset] • Individual whale photo-identification data - 2021-22 season [imagery - published to ARWPIC] • Final technical report detailing overall numbers of southern right whales observed within the survey region, their gender (and life stage where possible) and spatial distribution of individuals [written]

  • The aim of this study was to assess how individual size-at-hatching and food consumption influences the growth of Octopus pallidus hatchlings reared under simulated seasonal temperature regimes in Tasmania.

  • This record provides an overview of the scope and research output of the NESP Marine Biodiversity Hub project "Estimation of population abundance and mixing of southern right whales in the Australian and New Zealand regions". For specific data outputs from this project, please see child records associated with this metadata. -------------------- A comprehensive understanding of the population abundance and degree of spatial connectivity of southern right whales (Eubalaena australis) in Australian waters is currently lacking. This limits assessments of the species recovery and understanding of the nature and degree of difference between the south-eastern and south-western Australian populations. This project brought together existing photo-identification datasets, including records held in the Australian Right Whale Photo-Identification Catalogue (ARWPIC), to support a national assessment of southern right whale population dynamics and connectivity. It estimated total Australian population abundance, investigated links between whales using breeding areas along the eastern, southern and western coasts of Australia, and assessed future data collection needs for ongoing monitoring. The project supported evaluation of progress against the Conservation Management Plan for southern right whales and contributed to more coordinated conservation planning for the species at regional and national scales.

  • This record provides an overview of the NESP Marine and Coastal Hub Research Plan 2023 project "Delineation and estimation of the Maugean skate population in Macquarie Harbour, Tasmania". No public data outputs are planned for this project. -------------------- The Maugean skate (Zearaja maugeana) is now only found in Macquarie Harbour on Tasmania’s west coast, which has a long history of environmental degradation. The species is listed as Endangered under Commonwealth and Tasmanian legislation, and its restricted distribution, small population size, and exposure to degraded environmental conditions make population monitoring a high conservation priority. Recent research suggests that the Macquarie Harbour population may be declining. However, existing abundance estimation methods are inadequate because the species is cryptic, capture-based methods pose risks to skate health, and conventional optical surveys are limited by the harbour’s shallow, stratified, and highly turbid conditions. This project developed and tested new approaches to estimate and monitor the Maugean skate population using next-generation genetic sequencing and novel imaging technologies. Non-invasive acoustic methods (adaptive resolution imaging sonar (ARIS), synthetic aperture sonar, performed better than optical approaches (LiDAR, conventional video), under Macquarie Harbour conditions. ARIS was identified as the most suitable image-based monitoring tool for future population surveys. The genetic component generated the first reference-quality whole and mitochondrial genomes for the species and sequenced samples from 162 individuals. Genome-wide single nucleotide polymorphism (SNP) analyses showed that the Macquarie Harbour population has very low genetic diversity, which may influence how genetic risks are interpreted in recovery planning. The project produced new monitoring methodologies, genomic reference resources, and population genetic datasets to support future monitoring of Maugean skate abundance, population structure, and genetic health. The findings will inform conservation planning and evaluation of recovery strategies including captive breeding, translocation, and long-term genetic monitoring under changing environmental conditions. Outputs • Tissue sampling results and genome-wide population genetic structure [dataset] • Final project report [written]

  • Landings surveys of bycatch of Solegnathus assessed from interviews with fishers in important fishing ports of NSW and Victoria, ranging from the Brunswick-Byron co-op to Portland in Victoria.

  • In Tasmania, SCUBA surveys of seahorses populations were conducted. Intensive surveys were conducted in 2000 to 2004 in the Derwent River around Hobart (submonthly & then monthly) and twice yearly surveys from 2004/5 on east coast and Derwent River, until 2007. Mark-recapture studies were done to estimate population size, and life history parameters.

  • Assessment of trade in Australian syngnathids was estimated from semi-structured interviews with traditional medicine merchants and aquarium businesses in Perth, Sydney, Adelaide, Brisbane. A database of official records of international trade in syngnathids was also sourced from Department of Environment & Heritage (Federal).