[MARMAM] New paper: Imminent Risk of Extirpation for Two Bottlenose Dolphin Communities in the Gulf of Guayaquil, Ecuador

Fernando Félix Grijalva fefelix90 at hotmail.com
Fri Sep 4 10:08:08 PDT 2020


My co-author and I are pleased to inform you about this recently published article in Frontiers on Marine Science.

Abstract
A long-term study of a common bottlenose dolphin (Tursiops truncatus) population
inhabiting the Gulf of Guayaquil, Ecuador (2330 S, 79200W), has been carried out
for almost 30 years. Similarly, as in other parts of the world, this population is structured
socially and spatially in well-defined subunits or communities. Two of these communities,
referred to as Posorja and El Morro, have been studied with major intensity in the
last 10 years in the western inner estuary, among others to calculate population
parameters that allow assessing their viability in time. Calculated parameters include
annual abundance, age and sex composition, annual crude birth rate, calf survival, calf
production interval, and average annual mortality/emigration.With these parameters and
others derived from other better-studied populations, the trend of both subunits was
modeled using the software Vortex. Results show that even under an optimistic scenery
both communities will be extinct in the short (Posorja) and mid-term (El Morro), if current
stressors continue. Most population parameters calculated in both communities show
similar values as in populations elsewhere, but a very low calf survival in Posorja and
high mortality/emigration ratios in adults, and probably in juveniles in both communities,
contribute to this trend. Population deterioration seems to be the result of different
human-induced threats such as fisheries, maritime traffic and others still not well
assessed, as well as stochastic demographic events. We recommend taking actions
in the short term to halt population decline addressing the major causes of mortality
affecting these dolphin communities.

The article is free available from the editorial site DOI: 10.3389/fmars.2020.537010.

Regards
Fernando Félix

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