Global distribution of fin whalesBalaenoptera physalusin the post‐whaling era (1980–2012)

Abstract

The global distribution of fin whales Balaenoptera physalus is not fully understood. Existing maps can be divided into two conflicting categories: one showing a continuous global distribution and another showing an equatorial hiatus (gap in the global distribution) between approximately 20°N and 20°S. Questions also remain about the seasonal distribution of fin whales. To explore the suggested equatorial hiatus and seasonal distribution patterns, we synthesised information on fin whale distribution in the post‐whaling era (1980–2012) from published literature, publicly available reports and studies conducted by various organisations. We created four seasonally stratified maps showing line‐transect density estimates, line‐transect survey effort, acoustic detections, and sightings. An equatorial hiatus in the global distribution of fin whales during the post‐whaling era is supported by numerous line‐transect surveys and by the rarity of equatorial acoustic detections and sightings, and corroborated by whaling era reports, morphological analyses, and genetic analyses. Our synthesis of post‐whaling era data is consistent with results from other studies indicating that fin whales are more abundant at higher latitudes during warmer months and more abundant at lower latitudes (although these latitudes are still greater than 20°) during colder months. However, our synthesis and results from other studies also indicate that some fin whales in both hemispheres remain in higher latitudes (50°–60° north or south) during colder months and in lower latitudes (to approximately 20°–30° north or south) during warmer months, indicating that seasonal fin whale movements differ from the seasonal migrations of blue whales Balaenoptera musculus and humpback whales Megaptera novaeangliae. Our maps of global fin whale distribution provide a comprehensive picture of current knowledge and highlight important geographical and temporal data gaps. Surveys should be conducted within the identified data gaps in order to increase fine‐scale spatial and temporal knowledge of distribution patterns, improve fin whale taxonomy, and identify areas of elevated fin whale densities that may require management of threats, such as ship strikes.

From whaling to whale watching: Identifying fin whale critical foraging habitats off the Chilean coast

“…Our results support the current view that at least some fin whale populations may not follow the typical seasonal migratory pattern of other baleen whales (e.g. humpback whales), with clearly defined low‐latitude breeding grounds and high‐latitude feeding habitats, and that seasonal movements and habitat use are probably more complex (Edwards et al, ; Geijer et al, ; Mizroch et al, ). The presence of fin whales during summer in Chile, as well as information that many of the catches off of Chile occurred in the same season as those in Antarctica (International Whaling Commission catch records), suggest that there may be at least two different feeding sites for this fin whale population.…”

“…For instance, fin whales have been observed during the winter in high latitudes, such as the North Pacific Ocean (Mizroch, Rice, Zwiefelhofer, Waite, & Perryman, ), or even all year round in high latitudes in both the Northern Hemisphere (i.e. North Atlantic Ocean off Norway and near the Faroe Islands; Jonsgard, ) and the Southern Hemisphere (near South Georgia; Edwards, Hall, Moore, Sheredy, & Redfern, ; Mackintosh, ). On the other hand, the presence of fin whales in the summer months at lower latitudes has also been reported, in both the Northern Hemisphere (Notarbartolo Di Sciara et al, ; Oleson, Širović, Bayless, & Hildebrand, ) and the Southern Hemisphere (Pérez et al, ; Sepúlveda et al, ).…”

Should I stay or should I go? Modelling year‐round habitat suitability and drivers of residency for fin whales in the California Current

“…inter-and intra-specific competition, predation risk and spatial memory; and extrinsic 46 factors such as heterogeneity and variability in habitat quality (Schick et ranging, long-lived, large-brained and social marine vertebrate is known to occur 82 throughout the temperate zones of the global ocean (Edwards et al 2015). However, our 83 understanding of fin whale spatial ecology at (sub-)ocean-basin scales, including 84 population structure, migration patterns, preferred habitats, inter-and intra-population 85 variability and plasticity in habitat selection decisions, is severely lacking, which 86 complicates conservation (Geijer et al 2016).…”

Modelling the spatial abundance of a migratory predator: A call for transboundary marine protected areas

“…Fin whales are widely distributed in the North Atlantic (NA), spending the summer in high‐latitude feeding grounds and breeding in middle and low latitudes during winter (Edwards et al, ). Their migratory patterns remain unclear and not all individuals migrate seasonally: some individuals remain in higher latitudes during colder months and in lower latitudes during warmer months (Edwards et al, ).…”

“…Fin whales are widely distributed in the North Atlantic (NA), spending the summer in high‐latitude feeding grounds and breeding in middle and low latitudes during winter (Edwards et al, ). Their migratory patterns remain unclear and not all individuals migrate seasonally: some individuals remain in higher latitudes during colder months and in lower latitudes during warmer months (Edwards et al, ). Lack of detailed knowledge about their migratory patterns partly stems from most research taking place in non‐breeding high latitudes areas, while temperate latitudes have been less studied (Mizroch, Rice, Zwiefelhofer, Waite, & Perryman, ).…”