Moult in the Mediterranean monk seal from Cap Blanc, western Sahara

We document and compare the annual molt of the Pacific harbor seal (Phoca vitulina richardii) on two islands off the west coast of the Baja California Peninsula that are the northern and southern extremes of its distribution in Mexico. During 2014, observations were made from March to July on Todos Santos Island (northern extreme) and from January to June on San Roque Island (southern extreme). On Todos Santos, the premolt lasted 15 wk (March–June) and the molt 12 wk (April–July). On San Roque, the premolt lasted 22 wk (January–June) and the molt 17 wk (February–June). The proportion of seals undergoing molt peaked on 26 May on Todos Santos and on 7 June on San Roque. Shedding of old hair most commonly initiated on the torso and progressed to the head and flippers (reverse molting pattern). The period when the highest number of harbor seals haul out in Mexico is in late April on the more southerly islands and in early May on the more northerly islands, when a large proportion of seals are in premolt.

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“…, Badosa et al . ). As large amounts of heat and energy are lost during the molting process (Feltz and Fay , Boily , Paterson et al .…”

mentioning

confidence: 97%

Molting phenology of the Pacific harbor seal (Phoca vitulina richardii) on two islands off the Baja California Peninsula, Mexico

Tapia-Harris

Heckel

Schramm

et al. 2017

Marine Mammal Science

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“…Published values for molt duration in wild phocid seals are 19–33 d for harbor seals (Thompson and Rothery ), approximately 14 d for Mediterranean monk seals ( Monachus monachus ) (Badosa et al . ), 7–14 d for female southern elephant seals ( Mirounga leonina ) (Boyd et al . , Fedak et al .…”

Section: Discussionmentioning

confidence: 99%

Onset and duration of gray seal (Halichoerus grypus) molt in the Wadden Sea, and the role of environmental conditions

Schop

Aarts

Kirkwood

et al. 2017

Marine Mammal Science

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Surveys of gray seals (Halichoerus grypus) during the molt period, when they are abundant on land, can be used to monitor changes in population size, but accurate interpretation of results requires an understanding of the molt process and how it may vary between years. This study investigates variability in onset (start date) and duration of visible molt by gray seals in the Wadden Sea, and the influence of environmental conditions on the onset. Molt was monitored in nine captive seals and observed molt phases were applied to wild seals over seven annual molt periods between 2004 and 2010, monitored using aerial photography. The onset of visible molt varied significantly between years, for example it differed 28 d between 2008 and 2009. Model selection by AIC retained one environmental variable that correlated with molt onset; however, its effect was inconsistent within the molt season and did not explain some of the apparent observed annual variation. Hence, the main causes of interannual variability in the onset of molt remain unclear and warrant further study. Researchers should account for annual variability in the onset of molt when interpreting survey results based on molt counts.

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“…Consequently, females that tend to birth earlier each year appear to be common in this colony. A further phenomenon that would also contribute to this stratification of relatedness is that there seems to be a 6 mo shift between the observed month of birth of a female and the month when it would subsequently deliver its offsprings (Badosa et al 2006). In conclusion, at present the colony would organize according to a relatively relaxed polygynic structure, with some internal stratification in relatedness.…”

Section: Discussionmentioning

confidence: 99%

The mating system of the Mediterranean monk seal in the Western Sahara

Pastor

Cappozzo

Grau

et al. 2011

Marine Mammal Science

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The mating system of the Mediterranean monk seal was studied combining the use of diverse technologies. Sexual dimorphism in size was limited. Sexual activity was only observed to occur in the water. The different segments of the population segregated spatially: females, pups, and juveniles aggregated inside two main caves, whose entrances were controlled by a small number (2–3) of territorial males that defended aquatic territories situated at the very mouth of the caves. Other territorial males defended aquatic territories located further away (5–30 km). The tenure of aquatic territories was nonseasonal and spanned several years. Relatedness among pups belonging to the same cohort was low or null, indicating a low level of polygyny, which is not surprising for an aquatically mating phocid with a protracted reproductive season. However, in addition, genetic relatedness showed a remarkable temporal periodicity. These results in combination point to the existence of a complex social structure in this species.

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Moult in the Mediterranean monk seal from Cap Blanc, western Sahara

Cited by 7 publications

References 2 publications

Molting phenology of the Pacific harbor seal (Phoca vitulina richardii) on two islands off the Baja California Peninsula, Mexico

Molting phenology of the Pacific harbor seal (Phoca vitulina richardii) on two islands off the Baja California Peninsula, Mexico

Onset and duration of gray seal (Halichoerus grypus) molt in the Wadden Sea, and the role of environmental conditions

The mating system of the Mediterranean monk seal in the Western Sahara

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