Invasive mammal eradications are widely used for managing island ecosystems. However, tracking the outcomes of such large-scale, whole ecosystem projects is challenging and costly, and monitoring all components of an ecosystem is near impossible. Instead, indicators of ecosystem change may provide more practical and integrated measures of ecosystem response to eradications. As high-order marine predators, seabirds subsidise island ecosystems with nutrients isotopically enriched in nitrogen. Invasive mammals have caused a global decline of seabirds on islands, reducing this nutrient subsidisation. Following eradications, nitrogen stable isotope analysis may provide a useful and resource-efficient indicator of ecosystem functional change on eradicated islands. However, isotope ratios are affected by a myriad of factors, with potential sources of variation being introduced by spatial and temporal variation in sampling, and within and between different taxa and ecosystem components. To correctly attribute isotopic change to post-eradication ecosystem function change, these confounding variables need to be understood. To address this need, we analysed stable isotopes of nitrogen in soil, plant, spider, and seabird guano samples collected at different distances from seabird colonies and at different stages of the short-tailed shearwater breeding cycle on six island sites around south-eastern Tasmania, Australia. Across these cool, temperate islands we detected no temporal variability in δ15N throughout the breeding season. However, there was notable spatial variability in δ15N values. The effects of seabird-derived nutrient subsidisation were highly localised with high δ15N values found inside seabird colonies and then rapidly decreasing from the colony boundary. Higher δ15N values also occurred in areas of higher burrow density within a colony. Variability in δ15N values also existed both within and between ecosystem components. Our results highlight the importance of context dependency when using ecological indicators and have important implications for the design, implementation and interpretation of studies employing stable isotopes as indicators for ecosystem change. We provide recommendations for designing future stable isotope studies on seabird islands.

Data to accompany publication on wild diet of southern rock lobster on the east coast of Tasmania. In this study we collected 64 lobsters and analysed the diet of each individual using stomach contents, stable isotope analysis and DNA identification of prey species in faecal samples.

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]

In this study, 34 fledgling Fairy Prions (Pachyptila turtur) recovered during a wreck event in south-eastern Tasmania in 2022 were examined for ingested plastics (number, mass, type, colour, and particle size) and body condition (e.g., wing chord length).

We investigated the effects of seabird presence and seasonality on ground-active spider community structure (activity-density, family-level richness, age class and sex structure) and composition at the family-level across five short-tailed shearwater breeding islands around south-eastern Tasmania, Australia. Using 75 pitfall traps (15 per island), spiders were collected inside, near and outside seabird colonies on each island, at five different stages of the short-tailed shearwater breeding cycle over a year. 3. Pitfall traps were deployed for a total of 2,674 days, capturing 1,592 spiders from 26 families with Linyphiidae and Lycosidae the most common.

The Maugean Skate Zearaja maugeana is a micro-endemic species known from only two isolated estuaries, Bathurst and Macquarie Harbours in southwestern/western Tasmania. This constitutes one of the most limited distributions of any known extant elasmobranch. As a result, the species is listed as ‘Endangered’ under the Threatened Species Protection Act (Tasmania) and the Environmental Protection and Biodiversity Conservation Act (Commonwealth). Even though it was first discovered in Bathurst Harbour, most of what is known about the species comes from the Macquarie Harbour population. Only four individuals have ever been reported in Bathurst Harbour, with the last known sighting occurring in 1992. This study used environmental DNA (eDNA) to determine the presence/absence of the Maugean skate in Bathurst Harbour on the southwest coast of Tasmania. Water samples were collected from the seafloor in Bathurst Harbour in November 2021 and February 2022, and in Macquarie Harbour (control samples) in December 2021. Samples were filtered using a self-preserving eDNA sampling system. Following each survey DNA from the samples was extracted and analysed through qPCR amplification. Mitochondrial primer pairs from two gene regions were used to detect the presence of Maugean skate DNA in the samples. Where possible, positive detections were sequenced, and their identity verified.