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ESR 51:269-283 (2023)  -  DOI:

First demographic parameter estimates for the Mediterranean monk seal population at Madeira, Portugal

Rosa Pires1, Fernando Aparicio2, Jason D. Baker3,*, Sérgio Pereira4, Nélio Caires4, Miguel A. Cedenilla2, Albert L. Harting5, Dilia Menezes4, Pablo Fernández de Larrinoa2

1Serviço de Ambiente e Alterações Climáticas de Santa Maria, Parque Natural de Santa Maria, Rua Teófilo Braga, 10, 12, 14, 9580-535 Vila do Porto, Portugal
2Monk Seal Conservation Program, Fundacion CBD-Habitat. Angel Hernández 13, 28002 Madrid, Spain
3National Oceanic and Atmospheric Administration, Pacific Islands Fisheries Science Center,Protected Species Division, Honolulu, HI 96818, USA
4Instituto das Florestas e Conservaçao da Natureza da Madeira. Madeira Regional Government. R. João de Deus 12e, 9050-027 Funchal, Portugal
5Harting Biological Consulting, Bozeman, MT 59715, USA
*Corresponding author:

ABSTRACT: We provide the first comprehensive demographic assessment of the Endangered Mediterranean monk seal Monachus monachus population residing in the Madeira Archipelago to identify factors that may impede population growth. Encounter data was obtained for this small, elusive population from 2012 to 2021 using a variety of non-invasive methods. From birth to age 2 mo, when pups molt, survival averaged 0.57. From birth to 1 yr and from 1-2 yr, estimated survival rates were 0.47 and 0.85, respectively. Beyond 2 yr, survival estimates differed by sex: 0.98 for females and 0.90 for males. These survival rates are similar to published estimates from the Cabo Blanco (Western Sahara/Mauritania) population. This is remarkable given that Cabo Blanco is situated adjacent to the extremely productive Canary Current system, whereas the marine environment of Madeira is far less productive. Instead of reducing survival, low marine productivity in Madeira appears to manifest in strikingly depressed reproductive rates. We estimated a mean gross reproductive rate of just 0.31; less than half the value (0.71) reported for Cabo Blanco. The youngest parturient females in Madeira were 6 yr old, whereas 3 yr olds give birth at Cabo Blanco. Despite low fecundity, the monk seal population in Madeira has been recovering, aided by a series of conservation measures implemented since 1988. Our results document that abundance increased from 19 seals in 2013 to 27 in 2021. Despite this undeniable success, the monk seals of Madeira remain vulnerable and require continued monitoring and protection in order to persist.

KEY WORDS: Mediterranean monk seal · Madeira · Abundance · Survival · Reproductive rate

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Cite this article as: Pires R, Aparicio F, Baker JD, Pereira S and others (2023) First demographic parameter estimates for the Mediterranean monk seal population at Madeira, Portugal. Endang Species Res 51:269-283.

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