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