Foraging distribution of breeding northern fulmars is predicted by commercial fisheries

Abstract

Habitat-use and distribution models are essential tools of conservation biology. For wide-ranging species, such models may be challenged by the expanse, remoteness and variability of their habitat, these challenges often being compounded by the species’ mobility. In marine environments, direct observations and sampling are usually impractical over broad regions, and instead remotely sensed proxies of prey availability are often used to link species abundance or foraging behaviour to areas that are expected to provide food consistently. One source of food consumed by many marine top predators is fisheries waste, but habitat-use models rarely account for this interaction. We assessed the utility of commercial fishing effort as a covariate in foraging habitat models for northern fulmars Fulmarus glacialis, a species known to exploit fisheries waste, during their summer breeding season. First, we investigated the prevalence of fulmar-vessel interactions using concurrently tracked fulmars and fishing vessels. We infer that over half of our study individuals associate with fishing vessels while foraging, mostly with trawl-type vessels. We then used hidden Markov models to explain the spatio-temporal distribution of putative foraging behaviour as a function of a range of covariates. Persistent commercial fishing effort was a significant predictor of foraging behaviour, and was more important than commonly used environmental covariates retained in the model. This study demonstrates the effect of commercial fisheries on the foraging distribution and behaviour of a marine top predator, and supports the idea that, in some systems, incorporating human activities into distribution studies can improve model fit substantially.

Seabirds from the poles: microplastics pollution sentinels

“…Next to this species, our results evidence the effectiveness of Aptenodytes patagonicus as an indicator of MP accumulation, while Procellariidae efficacy was proven more frequently in the Arctic than in Antarctica. Fulmarus glacialis and Larus hyperboreus, two top predators in the Arctic food web (Bustnes et al, 2005) show similar ecology, breeding in close urban environments and foraging over coasts, bays, harbors, and inshore waters (Darby et al, 2021;Benjaminsen et al, 2022); however, MP abundances retrieved in this review don't support this ecological overlapping, where a similar MP concentration was expected. Indeed, 13 MPs/sample for Fulmarus glacialis and 0.04 MPs/sample for Larus hyperboreus were detected, which is an important difference considering their similar foraging behavior.…”

Fuzzy cognitive mapping as a tool to assess the relative cumulative effects of environmental stressors on an Arctic seabird population to identify conservation action and research priorities

“…Interestingly, Camphuysen and Garthe (1997) have previously shown that the assumed importance of North Sea fisheries on fulmar distribution was overestimated, and that in fact factors which influenced productivity and fish distribution better explained fulmar distribution at sea. However, in a more recent analysis, Darby et al (2021) found that the distribution of fisheries activity was the best predictor of fulmar distribution in the waters around the United Kingdom, better than standardly used metrics like bathymetry and chlorophyll concentration. They attributed the relationship to the tendency for fulmars to scavenge offal from fisheries vessels.…”

Underwater visibility constrains the foraging behaviour of a diving pelagic seabird

“…Chemoreception and olfaction are thought to influence the broad-scale search behaviour of tubenose seabirds (order: Procellariiformes), with indicator compounds (e.g. dimethyl sulfide, pyrazines) likely to attract these birds towards areas of high productivity and prey availability [19,20], or to fishing vessels beyond the range of visual detection [21][22][23]. Great cormorants (Phalacrocorax carbo) have been shown to use acoustic cues underwater for prey capture in highly turbid coastal regions [24] where low-visibility may benefit non-visual methods of prey detection.…”