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

Abstract

1. Fin whales ( Balaenoptera physalus) have been documented along the coast of Chile since the early 20th century; however, information on their ecology and movement patterns remains poorly known. 2. In the spring of 2015, six implantable satellite tags were deployed on fin whales around the marine reserves of Isla Chanaral and Islas Choros-Damas ( approximately 29 degrees S) to evaluate their movements and habitat use off the coast of Chile. A switching state-space model was used to estimate the predicted track of the whales as well as behavioural modes classified as ` transiting' and ` area-restricted search' ( ARS). 3. Whales were tracked for periods ranging between 4 and 162 days ( mean = 68 +/- 52 days), covering an average distance of 3225.7 +/- 2871.6 km. Five of the six whales remained at middle latitudes for prolonged periods of time, moving in a north-south pattern near the coast, and spending most of their time in ARS behaviour ( 72.5% of the locations). Only one individual showed a clear southbound migratory behaviour, and remained in transit behaviour for most of the period it was followed. 4. These results suggest that some of the fin whales that are observed in Chile do follow a migration to high latitudes, whereas others remained at middle latitudes, probably using critical habitats as feeding grounds during the summer. This information not only contributes new information on the behaviour and foraging patterns of this species, but is also of particular interest to promote the growing whale-watching activity, and also to better inform conservation and management efforts for this species in Chile.

1. Fin whales ( Balaenoptera physalus) have been documented along the coast of Chile since the early 20th century; however, information on their ecology and movement patterns remains poorly known. 2. In the spring of 2015, six implantable satellite tags were deployed on fin whales around the marine reserves of Isla Chanaral and Islas Choros-Damas ( approximately 29 degrees S) to evaluate their movements and habitat use off the coast of Chile. A switching state-space model was used to estimate the predicted track of the whales as well as behavioural modes classified as ` transiting' and ` area-restricted search' ( ARS). 3. Whales were tracked for periods ranging between 4 and 162 days ( mean = 68 +/- 52 days), covering an average distance of 3225.7 +/- 2871.6 km. Five of the six whales remained at middle latitudes for prolonged periods of time, moving in a north-south pattern near the coast, and spending most of their time in ARS behaviour ( 72.5% of the locations). Only one individual showed a clear southbound migratory behaviour, and remained in transit behaviour for most of the period it was followed. 4. These results suggest that some of the fin whales that are observed in Chile do follow a migration to high latitudes, whereas others remained at middle latitudes, probably using critical habitats as feeding grounds during the summer. This information not only contributes new information on the behaviour and foraging patterns of this species, but is also of particular interest to promote the growing whale-watching activity, and also to better inform conservation and management efforts for this species in Chile.