Migratory destinations of endangered humpback whales, Megaptera novaeangliae (Cetartiodactyla: Balaenopteridae), from El Salvador

Abstract

Introduction: The study of many aspects of cetacean ecology is made possible by identifying individuals through space and time. Humpback whales (Megaptera novaeangliae) can be easily identified by photographing their ventral tail flukes’ unique shape and pigmentation patterns. The small and endangered distinct population segment (DPS) of Central America humpback whales visit El Salvador seasonally each winter; however, dedicated research has been extremely limited there. Before 2018, only 11 individual whales had been photo-identified, and the migratory destinations of Salvadoran humpback whales were unknown. In recent years, photo-identification efforts have increased, and today there are 92 individually identified humpback whales from El Salvador.
 Objective: To identify the main high-latitude feeding areas of Salvadoran humpback whales.
 Methods: Using the online matching platform Happywhale, Salvadoran whales were matched via automated image recognition to a global humpback whale fluke photo-identification catalog of 66 043 individuals.
 Results: In total, 80 (87.0 %) of the whales photographed in El Salvador were matched to individuals seen in North Pacific feeding areas. Sighting histories of Salvadoran whales resighted in feeding areas ranged from two to 29 years (average = 12.1, SD = 5.8). While we note that survey effort was likely very different between regions, the main feeding area of Salvadoran humpback whales on Happywhale was Central California (n = 70, 76.1 %). Of these whales, 21 (22.8 %) had also been sighted in Southern California, while just three (3.3 %) individual whales were registered only in Southern California. Additionally, two whales (2.2 %) were sighted in Southern British Columbia, Canada, and one whale was matched to a humpback whale from Southeast Alaska. This whale (of unknown sex) has a sighting history of 27 years but no prior documentation in a breeding area and is the first published sighting of a Southeast Alaskan humpback whale in the breeding area of the endangered Central America DPS.
 Conclusions: Our study shows that while Salvadoran humpback whales were matched to various feeding areas in the Eastern North Pacific, their primary migratory destinations are in Southern and Central California.