Project number: 2016-118
Project Status:
Completed
Budget expenditure: $96,500.00
Principal Investigator: Rachael Alderman
Organisation: Department of Natural Resources and Environment Tasmania (NRE TAS)
Project start/end date: 26 Oct 2017 - 17 Mar 2019
Contact:
FRDC

Need

Due to the biases and unethical sampling methods conventionally used to collect dietary data, the most recent data for shy albatross is over 20 years old (Hedd et al 2001). A recent international review of albatross diets highlighted the need to 1) incorporate appropriate dietary studies as an integral component of species recovery and management plans, and 2) elevate the importance of dietary studies in long term monitoring plans to link observed demographic parameters to ecological drivers (McInnes et al 2016a). With changing environmental conditions and improvements to mitigation measures used by fisheries, it is important to monitor how TEP species may adapt to these changes. Current, reliable diet information will allow risk assessment tools such as trophic models to be developed and provide a baseline of diet information in which we can test what drives any dietary shifts in TEPs. There is also paucity in information about if and when seabird-fishery engagements occur. This was raised at the AFMA Seabird Workshop in late 2016. Quantification of albatross engagements with vessels would assist with the development of the Seabird Strategy for Commonwealth fisheries to ensure fisheries are managed sustainably.

This project seeks to apply new high-resolution DNA-based diet-analysis (DNA metabarcoding) to characterise the diet of shy albatross, including intra- and inter-annual variability. This trophic information, in combination with existing fine-scale tracking data, will contribute valuable information to assist in fisheries management and ecological risk assessment processes. Specifically, this information will enable us to: i) estimate the range of prey species consumed by shy albatross, (ii) develop trophic models to estimate the relative resource requirements of shy albatross, (iii) evaluate intra-and inter-annual level of engagement of shy albatross with fisheries, (iv) provide baseline data for evaluating efficacy of fisheries management changes, (v) provide a demonstration of the applicability of this technique to other TEP species and regions.

Objectives

1. Develop a South East Australian marine prey DNA database
2. Characterise of the range of prey species consumed by shy albatrosses to high taxonomic resolution (species or genus where possible) and the relative frequency of occurrence of each taxa within the diet.
3. Assess the extent to which the shy albatross engage with fisheries by quantifying the frequency of target, secondary and bycaught species in the diet
4. Assess the spatial and temporal variability of both objectives 2 and 3

Final report

Authors: McInnes J.C Tuck G.N. and Alderman R.
Final Report • 2019-01-01 • 6.07 MB
2016-118-DLD.pdf

Summary

Seabirds are attracted to fishing vessels through the availability of fishery discards, increasing the risk of injury or mortality from interactions with fishing gear. However, it is difficult to estimate what proportion of the population may be at risk. We use DNA metabarcoding of scats to characterise the intra- and inter-annual variability in the diet of Shy Albatross at Albatross Island, and combine this dietary data with foraging range estimates to examine spatial overlaps and species overlaps between albatross and fisheries in the region. Shy Albatross diet consisted predominantly of fish (93% of samples) and cephalopods (38% of samples), with 84 fish and 11 cephalopod species detected. The majority of food was sourced naturally, however, at least 13% of the population overall is sourcing food from fisheries, with up to 29% during some breeding stages. There were spatial overlaps between Shy Albatross and six Commonwealth managed fisheries operating in South-East Australia and two Tasmanian managed fisheries. There was considerable intra-annual variation in the level of engagement with the Commonwealth fishery, but little inter-annual variability. Blue Grenadier, Ling and Warehou sp. were the main Commonwealth managed fishery discard species consumed. This study highlights that fisheries still pose a risk for Shy Albatross in Australian waters. As the majority of albatross food is sourced naturally, it shows that albatross are unlikely to be reliant on discards, therefore a reduction in discard availability would benefit shy albatross populations and improve the sustainability of fisheries in the region. DNA dietary analysis in conjunction with spatial foraging data provides a valuable tool to assess the proportion of a population at risk from fishing operations.

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