Abstract

We provide the first complete set of survival rate estimates for the Endangered Mediterranean monk sealMonachus monachusfrom birth into adulthood, as well as the first age-specific reproductive rates for the species. From 2002 to 2016, we obtained individual seal live encounter data through non-invasive monitoring techniques that were analyzed to estimate vital rates of Mediterranean monk seals of the Cabo Blanco (Western Sahara/Mauritania) population. From birth to age 2 mo, when pups molt, survival averaged 0.59, ranging from 0.41 to 0.74 among cohorts. From birth to 1 yr and from 1 to 2 yr, median estimated survival rates were 0.46 and 0.75, respectively. Beyond 2 yr, survival estimates differed by sex: 0.94 for males and 0.97 for females. From 2005 to 2016, we estimated a mean gross reproductive rate of 0.71. The youngest parturient females were 3 yr old. Fitted age-specific reproductive rates increased beginning at age 3 yr and exceeded 0.80 from age 6 to 17 yr. Despite low survival during the first 2 mo of life, the aggregate vital rates of the population are favorable for growth; a Leslie matrix containing our survival and fecundity estimates yielded an intrinsic growth rate of 1.058. Increasing abundance and favorable vital rates are a testament to the efficacy of the many measures taken to promote the conservation of this population.

Highlights

  • Survival, fecundity, immigration, and emigration are the parameters that together determine population abundance over time

  • The Endangered Mediterranean monk seal Monachus monachus is the rarest species of pinniped; the most recent published assessment reports that fewer

  • Sex- and age-specific survival rates were calculated by dividing the randomized number of survivors to at least age 2 yr by the number known to have been alive at age 2 mo

Read more

Summary

INTRODUCTION

Fecundity, immigration, and emigration are the parameters that together determine population abundance over time. The monk seal caves are situated just 7 km from Nouadhibou, a rapidly growing commercial center with a population of over 100 000 Both local artisanal and large-scale modern foreign fishing fleets operate in the waters adjacent to Cabo Blanco peninsula (Belhabib et al 2012). The perilous status of the Cabo Blanco monk of reproductive-age females used to estimate birth seal population following the 1997 mass mortality, rates. We analyzed more than a decade coupled with known negative impacts of human dis- of live encounter data to estimate vital rates of Mediturbance on the species throughout its range, terranean monk seals at Cabo Blanco, encompassing prompted the 2006 Action Plan to emphasize hands- a period of population increase and enhanced conoff methods. Tification techniques had already been developed for studying monk seals at Cabo Blanco prior to the mass mortality event (Forcada & Aguilar 2000), and were

Study area and surveillance methods
Individual identification
Survival estimation
Reproductive rate estimation
Intrinsic rate of population growth
RESULTS
Survival from 2 mo to 2 yr
Reproductive rates
Survival
Reproduction
Conservation implications
Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call