Vaquita – Last Chance for the Desert Porpoise

September 15, 2010 – Lorenzo Rojas-Bracho National Institute of Ecology, Mexico

The National Institute of Ecology (INE) has played a key role in the conservation action plans for the vaquita.

INE’s Coordinación de Investigación y Conservación de Mamíferos Marinos (CICMM) has been instrumental in the instalation and Works of the International Committee for the Recovery of Vaquita (Comité Internacional para la Recuperación de la Vaquita; CIRVA). CIRVA’s work has been recognized by several international scientific organizations like the Scientific Committee of the International Whaling Commission, the Society for Marine Mammalogy, the American Society of Mammalogists, and The Cousteau Society among others.

These Works include vaquita risk factor analysis, abundance estimates, and population trends using acoustic techniques. These investigations triggered the conservation action plans by the Mexican Government through vaquita’s recovery program: PACE-vaquita under the Ministry of Environment and Natural Resources (SEMARNAT). Currently CICMM is working in the implementation an autonomous acoustic monitoring scheme to assess if the PACE–vaquita actions are achieving success. (Download the PACE-Vaquita report – PDF 2.6 mb).

A precise monitoring of vaquita using autonomous acoustic devices

The abundance of vaquita has declined from approximately 570 in 1997 to approximately 245 in 2008.

Starting in 2008, the Government of Mexico dedicated an unprecedented level of funding and effort to help reverse this decline. It established the Vaquita Refuge as a net-free fishing zone. The level of fishing effort in other areas where vaquitas are found has been reduced by a combination of economic measures (funding fishing permit holders to retire their permits or to switch to other vaquita-safe fishing methods) and enforcement (to eliminate illegal fishing). Whether these measures and future measures are sufficient to reverse the decline in the vaquita population and to allow it to recover is uncertain.

Because scientists recognize the inadequacy of visual methods to monitor vaquita, a joint effort by INE and SWFSC (Vaquita Expedition 2008) was made to see whether new acoustic technologies could be used. During the cruise three different instruments from Japan and the UK were tested.

After the cruise we held a workshop to examine the data from that effort and addressed which of these equipments was sufficiently precise to monitor the abundance of this very small population. The workshop agreed that it was possible to detect a 5% decrease or 4% increase in 5 years with a monitoring scheme that would require an unprecedented level of sampling precision. The precision (measured as the coefficient of variation) of an annual index of vaquita abundance would need to be less than 3% in order to obtain a high probability of achieving the goal. The workshop approved that the only equipment [instrument] that can give the level of precision desired is the C-Pod.

Currently, as part of this research program, we are conducting a series of tests prior to the full operation of the monitoring scheme: the design and testing of mooring techniques and a monitoring a pilot program.

So far we have been successful in the first tests for the installation and retrieval of acoustic sensors on the buoys that delimit the vaquita refuge. We also placed on the ocean floor the first experimental moorings that are specifically designed to install another set of the acoustic sensors.

The challenge is to design anchors and buoys, which are not on the surface, so that the moorings can withstand the strong winds, currents and tides of the Upper Gulf and the fishing by trawlers and vandalism (eg. destruction and theft). The testing of these anchors are with dummies of acoustic detectors. So far the experimental results with these anchors are promising as they have been under water for periods of up to 120 days and have been recovered.

Acknowledgements

The workshop to design the acoustic monitoring scheme was funded by the WWF-Mexico. The mooring tests and the pilot program are being funded by the Ocean Foundation and Equipe Cousteau-Cousteau Society in association with Save Your Logo.

For further information on the monitoring scheme www.ine.gob.mx