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

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.