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Across borders: external factors and prior behavior influence North Pacific albatross associations with fishing vessels

Citation

Orben, Rachael et al. (2021), Across borders: external factors and prior behavior influence North Pacific albatross associations with fishing vessels, Dryad, Dataset, https://doi.org/10.5061/dryad.gmsbcc2md

Abstract

1. Understanding encounters between marine predators and fisheries across national borders and outside national jurisdictions offers new perspectives on unwanted interactions to inform ocean management and predator conservation. Although seabird-fisheries overlap has been documented at many scales, remote identification of vessel encounters has lagged because vessel movement data often is lacking.

2. Here, we reveal albatross-fisheries associations throughout the North Pacific Ocean. We identified commercial fishing operations using Global Fishing Watch data and algorithms to detect fishing vessels. We compiled GPS tracks of adult black-footed (Phoebastria nigripes) and Laysan (P. immutabilis) albatrosses, and juvenile short-tailed albatrosses (P. albatrus). We quantified albatross-vessel encounters based on the assumed distance that birds perceive a vessel (≤30km), and associations when birds approached vessels (≤3km). For each event we quantified bird behavior, environmental conditions, and vessel characteristics and then applied Boosted Regression Tree models to identify drivers and the duration of these associations.

3. In regions of greater fishing effort short-tailed and Laysan albatross associated with fishing vessels more frequently. However, fishing method (e.g. longline, trawl) and flag nation did not influence association prevalence nor the duration short-tailed albatross attended fishing vessels. Laysan albatross were more likely to approach longer vessels. Black-footed albatross were the most likely to approach vessels (61.9%), but limited vessel encounters (n=21) prevented evaluation of meaningful explanatory models for this species of high bycatch concern.

4. Temporal variables (time of day and month) and bird behavioral state helped explain when short-tailed albatross were in close proximity to a vessel, but environmental conditions were more important for explaining interaction duration. Laysan albatross were more likely to associate with vessels while searching and during the last 60% (by time) of their trips.

5. Our results provide specific species-fisheries insight regarding contributing factors of high-risk associations that could lead to bycatch of albatross within national waters and on the high-seas.

6. Policy implications. Given the global availability of Global Fishing Watch data, our methods can be applied to other marine predators to identify spatio-temporal patterns, vessel specific attributes, and predator behaviors associated with fishing vessel associations thus enabling predictive modeling and targeted mitigation measures.

Methods

The dataset contains the processed detection (<30km) and associations (<3km) between AIS vessel data and GPS bird tracking data. The data collection and processing methods are outlined in the associated manuscript. 

Usage Notes

Missing values are coded as NA.