Survival and abundance of short‐finned pilot whales in the archipelago of Madeira, NE Atlantic

Abstract

Estimates of population parameters for the short‐finned pilot whale, Globicephala macrorhynchus, are scarce in literature, contributing to an International Union for Conservation of Nature (IUCN) status of Data Deficient. In this study, photo‐identification data collected over 7 yr from Madeira were used to estimate for the first time survivorship, capture probability, and abundance in this species using mark‐recapture methodology. The Cormack‐Jolly‐Seber model estimated that the adult island‐associated (i.e., resident and regular visitor) whales had a constant survival rate of 0.960 (95% CI: 0.853–0.990) and an annual capture probability varying between 0.372 (CI: 0.178–0.619) and 0.843 (CI: 0.619–0.947). A parameterization of the Jolly‐Seber model estimated that 140 island‐associated whales (CI: 131–151) used the area throughout the course of the study. Based on a closed population model, the most precise (lower CV) annual estimate of the total number of pilot whales using the southern and eastern waters of Madeira (~900 km2) in a 3 mo period covering summer/autumn was 334 animals (CI: 260–437). No trend was observed. Despite including biases, the approach used in this study provided plausible estimates of population parameters, which can contribute to the regional conservation strategies.

Complex biogeographical patterns support an ecological connectivity network of a large marine predator in the north‐east Atlantic

“…Additionally, short‐finned pilot whales are considered abundant from tropical to warm‐temperate waters (Olson, ). However, based on the present study and on the available literature, we suggest that the species is not homogenously distributed, nor plays the same ecological role, across its range in the north‐east Atlantic (see Alves et al., ; de Boer, Saulino, Van Waerebeek, & Aarts, ; Hazevoet & Wenzel, ; Picanço, Carvalho, & Brito, ; Servidio, ; Silva et al., ). We suggest that the inshore waters of Madeira and the Canaries play an important role for short‐finned pilot whales in this part of the Atlantic.…”

“…In the Canaries and Madeira, social analyses have showed they live in a well‐differentiated society that encompasses several clans, each containing few matrilineal pods/units (Alves, Quérouil, et al., ; Servidio, ). Additionally, the use of mark–recapture techniques derived high abundance estimates (over 600 individuals) for the south‐west of Tenerife Island (Canary archipelago) and lower numbers (approximately half) for the south of Madeira Island (Alves et al., ; Servidio, ). In Madeira, high survival rates (within the range of other long‐lived mammals) have also been estimated (Alves et al., ).…”

“…Additionally, the use of mark–recapture techniques derived high abundance estimates (over 600 individuals) for the south‐west of Tenerife Island (Canary archipelago) and lower numbers (approximately half) for the south of Madeira Island (Alves et al., ; Servidio, ). In Madeira, high survival rates (within the range of other long‐lived mammals) have also been estimated (Alves et al., ). Moreover, genetic analyses suggested that individuals within the resident, visitor and transient communities inhabiting Madeiran waters may not be genetically isolated but breed across these communities (Alves, Quérouil, et al., ).…”

Analysis of occurrence patterns and biological factors of cetaceans based on long‐term and fine‐scale data from platforms of opportunity: Madeira Island as a case study

“…Alves, Dinis, Cascão, & Freitas, ; Alves, Dinis, et al, ; Alves, Quérouil, et al, ; Dinis, Carvalho, et al, ; Dinis, Alves, et al, ; Quérouil et al, , ), and therefore information on cetacean community structure remains widely unknown. In addition, there is an increasing number of anthropogenic activities in Madeira with potential impacts on cetaceans, in particular the whale‐watching industry (Alves, Dinis, et al, ; Ferreira, ) and marine traffic (Cunha et al, ). Therefore, appropriate distribution studies, to describe cetacean occurrence patterns and evaluate trends, are needed to support conservation measures.…”

Home Sweet Home? Wide-Ranging Movements of Socially Stable Resident Delphinids (Globicephala macrorhynchus)

“…The target species has a wide distribution from tropical to warm temperate waters, and on a global scale its conservation status is described as Data Deficient (Olson 2009). It is considered common throughout its range (Olson 2009), including the studied archipelagos of Madeira and the Azores (Silva et al 2014;Alves et al 2015). In Madeira, short-finned pilot whales are known to demonstrate varying patterns of occurrence, including residents, regular visitors, and transients, which may not be genetically isolated (Alves et al 2013a).…”