Sightings of an Adult Male Killer Whale Match Humpback Whale Breeding Seasons in Both Hemispheres in the Eastern Tropical Pacific

Ecological aspects of killer whales from the Mexican Central Pacific coast: Revealing a new ecotype in the Eastern Tropical Pacific

“…Dorsal fin roundness was similar to the description of the resident type by Dahlheim et al (2008), rounded but with a small trailing tip. In addition, some KW observed in MCP waters had barnacles attached to their dorsal fin, probably Xenobalanus spp., as has been previously reported (Kane, Olson, Gerrodette, & Fiedler, 2008; Olson & Gerrodette, 2008; Pacheco et al, 2019).…”

“…Dorsal fin roundness was similar to the description of the resident type by Dahlheim et al (2008), rounded but with a small trailing tip. In addition, some KW observed in MCP waters had barnacles attached to their dorsal fin, probably Xenobalanus spp., as has been previously reported (Kane, Olson, Gerrodette, & Fiedler, 2008;Pacheco et al, 2019). For behavioral activity, 68% of sightings corresponded to KW traveling, while 18% of sightings corresponded to confirmed predatory events on fish (Pacific crevalle jack, Caranx caninus, and dolphinfish, Coryphaena hippurus) and on olive ridley sea turtles; while 14% of sightings were suspected predation events because KW were pushingdragging one olive ridley sea turtle (sighting #19; Table 2, Figure 2) and chasing humpback whales (sighting #5 and #18; Table 2).…”

“…Second, photographic matches between KW individuals from the ENP and the ETP have been limited to a few individuals, and no “transient” KW populations have been documented further south than California; therefore, it has been suggested that there is a southern distribution boundary for KW from the ENP (Black, Schulma‐Janiger, Ternullo, & Guerrero‐Ruiz, 1997). Additionally, evidence of KW sighted in Mexican waters and then re‐sighted in Peruvian waters (Guerrero‐Ruiz, García‐Godos, & Urbán, 2005; Pacheco et al, 2019) suggests a potential wide tropical range of distribution for KW from the ETP. Third, genetic analyses of a small sample of KW from the ETP have suggested a proximity to the “offshore” ecotype (Morin et al, 2010).…”

Observations of parturition in humpback whales (Megaptera novaeangliae) and occurrence of escorting and competitive behavior around birthing females

“…Meanwhile in an ocean basin‐wide study into killer whale rake marks on humpback whale flukes in the North Pacific, Steiger et al (2008) concluded that Mexico (the location of Birthing Event 5), not Hawaii, had the highest level of regional killer whale predation. Additionally, an accumulation of eyewitness accounts of attacks suggests that in Mexico young humpback whales (Figure 8) may be a relatively common prey item of killer whales (Ford & Reeves, 2008; Jefferson et al, 1991; Pacheco et al, 2019; Salazar Bernal, 2005; Vargas‐Bravo et al, 2020). Therefore, we believe birthing female humpback whales may sometimes tolerate a lone escort's presence, especially in areas of high densities of breeding males or predators, as the risk of harassment by one male may be offset by the advantages of additional protection for vulnerable neonates.…”

“…However, today growing evidence from around the world (e.g. Australia, Brazil, Cameroon, the Caribbean, Colombia, Ecuador, Hawaii, Mexico, Peru, and Tonga) suggests that calves in some wintering areas may face a significant threat of predation (Figure 8), (Bornatowski et al, 2012;Fl orez-González et al, 1994;Mazzuca et al, 1998;Pacheco et al 2019;Patterson & Van Dyck, 1991;Pitman et al, 2015;Pitman et al, 2017;Testino et al, 2019;Vargas-Bravo et al, 2020).…”