( and population simulations suggested th...)Small, smaller, smallest -- The plight of the vaquita

and population simulations suggested that the vaquita has always been rare and that its extreme loss of genomic variability occurred over evolutionary time rather than recently owing to human-caused mortality. Instead of those factors, the “smoking gun?in this instance is accidental mortality in fishing gear, something popularly known as “bycatch?

Large-, medium- and small-mesh gillnets set for fish and shrimp entangle and kill vaquitas far too frequently. The best available quantitative estimate of bycatch refers to only one of the three main fishing ports: 39 vaquitas/yr (95% CI: 14, 93). Current population size could well be around 400 animals. If the vaquita goes extinct, its story will be the chronicle of an announced extinction. For decades scientists from Mexico and abroad, in various international and national fora, have warned the Mexican Government that the vaquita was at risk of being extirpated as a result of the bycatch. The Government has ignored such warnings and chosen to blame the vaquita’s precarious condition on the lack of water in the Colorado River ?a result of damming and diversion in the United States. No data have been offered in support of this idea and, in fact, the Upper Gulf remains a very rich and productive ecosystem.

Is the vaquita destined to become the first marine cetacean to go extinct in modern times because of anthropogenic factors" How can this sad prospect be prevented" The small number of porpoises in the current population cannot be expected to withstand continuing incidental mortality. This needs to be eliminated. However, progress towards even reducing, much less stopping, vaquita bycatch has been painfully slow despite efforts to phase-out fishing with gillnets in the core area of vaquita distribution and to devise schemes involving compensation, incentives and alternative livelihoods for fishermen.

For the first time since 1958, when the vaquita was scientifically described and named as a s
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Source:Blackwell Publishing Ltd.

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