Dear colleagues,
the article below is currently available online in the Articles in Press
section of Biological Conservation:
http://www.sciencedirect.com/science/journal/00063207 or
doi:10.1016/j.biocon.2005.10.031 . Alternatively, a pdf
reprint is available from me.
Parra, G., J., Corkeron Peter, J., Marsh, H., in press. Population
sizes, site fidelity and residence patterns of Australian snubfin and
Indo-Pacific humpback dolphins: Implications for conservation. Biological
Conservation.
Abstract
Very little is known about the ecology of snubfin Orcaella
heinsohni and Indo-Pacific humpback dolphins Sousa chinensis
in Australian waters. We used photo-identification data collected between
1999 and 2002 in Cleveland Bay, northeast Queensland, to estimate
abundance, site fidelity and residence patterns of these species in order
to make recommendations for their effective conservation and management.
Our abundance estimates indicate that less than a hundred individuals of
each species inhabit this coastal area. Even with relatively unbiased and
precise abundance estimates population trends will be extremely difficult
to detect in less than three years unless changes in population size are
very high (>20% p.a.). Though both species are not permanent residents
in Cleveland Bay, they both used the area regularly from year to year
following a model of emigration and reimmigration. Individuals of both
species spend periods of days to a month or more in coastal waters of
Cleveland Bay before leaving, and periods of over a month outside the
study area before entering the bay again. Because of their small
population sizes and movement patterns, snubfin and humpback dolphins are
particularly vulnerable to local extinction. Our results illustrate that:
(1) detection of population trends should not be a necessary criterion
for enacting conservation measures of both species in this region, and
(2) efforts to maintain viable populations of both species in Cleveland
Bay must include management strategies that integrate anthropogenic
activities in surrounding areas.
Best regards,
Guido
____________________________________
Guido J. Parra, Ph.D
School of Tropical Environment Studies and Geography
James Cook University
Townsville
Queensland 4811
Office TG-239
Phone: 61 7 47815560
Fax: 61 7 47814020
Mobile: 0437630843
e-mail:guido.parravergara@jcu.edu.au