ACAP Small Grant 2023-06

Multi-sensor assessment of fine-scale fisheries overlap and bycatch risk of Southern Buller’s Albatross across life history stages

Project Leader: Jonathan Rutter, University of Oxford Department of Biology, United Kingdom

Co-investigators: Igor Debski, New Zealand Department of Conservation Johannes Fischer, New Zealand Department of Conservation Tim Guilford, University of Oxford Katrina Davis, University of Oxford

Amount Awarded: AUD 30,000

Detection of seabird-fishery overlap at sea is a powerful tool for quantifying bycatch risk of seabirds. Additionally, the increasing availability of vessel location data from Vessel Monitoring Systems (VMS) and Automatic Identification Systems (AIS) has enabled more nuanced analyses of finer-scale overlap between individual seabirds with individual fishing vessels (e.g., Corbeau et al., 2021, Orben et al., 2021). However, these analyses remain subject to two important sources of bias. First, many vessels, especially small-scale or illegal, unreported, or unregulated (IUU) vessels, do not regularly broadcast their locations (GFW, 2023a) and are hence unaccounted for in most overlap analyses. Second, non-breeding life history stages are often overlooked because they are more difficult to track than breeding populations (Carneiro et al., 2020).

Southern Buller’s Albatross (Thalassarche bulleri bulleri) are in urgent need of improved risk assessments that incorporate more comprehensive fine-scale overlap analyses. They have shown concerning declines in adult breeder survival in recent years (<0.9 since 2020; Thompson and Sagar, 2022) and are now considered the seabird species most at-risk of bycatch in New Zealand (Edwards et al., in press).

This project will integrate data from multiple sensors. We propose analysing fine-scale overlap with fishing vessels across all life history stages and the entire foraging range of this species. In addition, we intend to incorporate and test emerging methodologies that are currently in development through the project leader’s PhD work at the University of Oxford.

Objectives:

1. Determine how bycatch risk of Southern Buller’s Albatross varies across areas, time periods, vessels, and life history stages.

2. Test and refine new analytical methodologies to quantify seabird-vessel interactions.

3. Trial the use of bird-borne miniature hydrophones as a vessel detection device.

Existing tracking plans (Objective 1-2): A high-intensity monitoring and tracking project for Southern Buller’s Albatross is already planned for 2024-2026 (time-depth recorders, archival GPS, and geolocator/immersion loggers on chick-rearing individuals; 20 Platform Terminal Transmitters and 20 geolocators per year on birds leaving the colony).

Proposed tracking plans (Objective 1-2): 10 or more solar-powered satellite-transmitting GPS tags, with which we intend to collect high-resolution positional data (~40 min daytime intervals) from non-breeding individuals for several months.

Fisheries data (Objective 1-2): Locations of most large commercial vessels are available in the form of Automatic Identification System (AIS) data from Global Fishing Watch (GFW, AC14 Inf 01 Agenda Item 15.4 8 2023a). For New Zealand fisheries, we will supplement any missing locations with GPS data provided by Fisheries New Zealand. We also aim to obtain VMS data through future collaboration with distant water fleets.

Analysis of fisheries overlap (Objective 1-2): When working with low resolution data (i.e., >15 mins), we will incorporate time geographic methods to quantify vessel attendance duration with explicit measures of uncertainty. We aim to improve upon existing time geographic methods by incorporating data from geolocator/immersion loggers and time-depth recorders.

Pilot study: Acoustic detection of vessels (Objective 3): 15 miniature hydrophone devices to test the potential of acoustic detection of seabird attendance at fishing vessels. They will be co-deployed with archival GPS loggers, with which we can confirm vessel attendance using the methods above.

The project’s principal purpose is to contribute to the long-term persistence and recovery of the Southern Buller’s Albatross. Two key outputs will be essential to achieving this goal: First, we will identify fleets and vessels that pose the highest potential risk to albatross populations. This output will inform strategic targeting of outreach to high-risk fisheries, both near-shore and in the high seas, to promote uptake of and compliance with ACAP best practice mitigation policies. Second, we will identify areas and time periods during which different life history stages are at highest risk of bycatch. This output will provide evidence for area- and time-based management policies that seek to reduce seabird-fishery interactions.

The project’s secondary purpose is to improve ecological risk assessment for other frequently bycaught species, especially seabirds. Three key outputs will contribute towards this goal: First, we will refine existing time geographic methodology to facilitate quantification of uncertainty across multiple risk assessments. Second, we aim to produce improved models to diagnose vessel attendance using biologging data from multiple sensors, even in the absence of fishing vessel data. This output will help improve estimations of bycatch risk from “hidden” fisheries, including those that are small-scale or IUU. Third, we will determine whether vessel attendance can be detected acoustically using leg-mounted hydrophones. This output could pave the way to further acoustic tagging programmes that also seek to understand “hidden” fisheries.