Two scientific efforts brought the need for immediate actions to conserve vaquita as a high priority for the Mexican government. Passive acoustic techniques (Jaramillo-Legorreta, 2008) revealed a negative trend of acoustic detection rates over the past decade, which indicated a decreasing trend in vaquita abundance (Jaramillo-Legorreta and Rojas-Bracho, 2008). The second effort inferred that only about 150 vaquitas remain using information on fishing effort, vaquitas by-catch rate and porpoises’ population growth rates (Jaramillo-Legorreta et al., 2007). Current low vaquita abundance made, finding a new method capable of detecting vaquita trends with greater precision, a necessity.
The mission of Vaquita Expedition 2008 was to evaluate the performance of different passive acoustic detectors to develop methods to monitor trends in abundance of the vaquita in the Upper Gulf of California. The ultimate goal of the expedition was to obtain data on the distribution, movements, and density of the vaquita to allow scientists to design a monitoring scheme and inform management decisions. Monitoring is critical to assess the effectiveness of the Mexican Government’s vaquita recovery plan. (SC/61/SM23)