FIRST ESTIMATES OF VAQUITA ABUNDANCE

A bstract The abundance of the only population of vaquitas, Gulf of California harbor porpoise ( Phocoena sinus ), is estimated from four surveys conducted in Mexico between 1986 and 1993, using a variety of methods. A line‐transect approach was applied, using some parameters estimated from a relate...

Full description

Bibliographic Details
Published in:Marine Mammal Science
Main Authors: Barlow, Jay, Gerrodette, Tim, Silber, Greg
Format: Article in Journal/Newspaper
Language:English
Published: Wiley 1997
Subjects:
Phocoena phocoena
Online Access:http://dx.doi.org/10.1111/j.1748-7692.1997.tb00611.x
https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1748-7692.1997.tb00611.x
https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1748-7692.1997.tb00611.x
Description
Summary:A bstract The abundance of the only population of vaquitas, Gulf of California harbor porpoise ( Phocoena sinus ), is estimated from four surveys conducted in Mexico between 1986 and 1993, using a variety of methods. A line‐transect approach was applied, using some parameters estimated from a related species, the harbor porpoise ( Phocoena phocoena ). Vaquita abundance is estimated as 503 (CV = 0.63) from 1986–1988 boat surveys, 885 (CV = 0.50) from 1988–1989 aerial surveys, 572 (CV = 1.43) from a 1991 aerial survey, and 224 (CV = 0.39) from a 1993 ship survey. A weighted log‐linear regression indicates a rate of population change (decline) of −17.7% per year (95% CI =−43.2% to +19.3%) between 1986 and 1993. All of these estimates of vaquita abundance indicate that the species is at a critically low level.

Similar Items