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• Acoustic monitoring

Results

• 2025REPORT

  Vaquita Research Campaign 2025: Report of the September Vaquita Survey

  Cárdenas-Hinojosa and co-authors · CONANP · Vaquita survey 2025

  In September 2025, scientists aboard two Sea Shepherd ships searched the northern Gulf of California for vaquitas, using underwater microphones at 66 sites to decide where to look. They most likely saw between 7 and 10 different animals, including at least one or two calves. This counts the vaquitas seen in the area they searched. It is not an estimate of how many are left in total.

  Population & surveys Acoustic monitoring

• 2024REPORT

  Reporte del crucero de observación de la vaquita 2024

  Cárdenas-Hinojosa and co-authors · CONANP (Comisión Nacional de Áreas Naturales Protegidas) · CONANP 2024

  This Spanish-language report covers the May 2024 vaquita survey, which searched the Zero Tolerance Area and a new Extension Area next to it from two ships. The team made 9 sightings and recorded 70 acoustic encounters. Expert elicitation gave a 75% probability that 6 to 8 different vaquitas were seen, and most likely no calf, though one animal of about a year old was seen.

  Population & surveys Acoustic monitoring Habitat & ecosystem In Spanish

• 2019RESEARCH

  Decline towards extinction of Mexico's vaquita porpoise (Phocoena sinus)

  Jaramillo-Legorreta and co-authors · Royal Society Open Science 6(7): 190598 · Peer reviewed · Jaramillo-Legorreta et al. 2019

  This paper gives the last estimate of the whole vaquita population, for 2018, about 9 animals (95% credible interval 6 to 19). It combines eight years of acoustic monitoring (2011 to 2018) with the 2015 survey estimate and with minimum counts of animals seen in 2017 and 2018. The authors also revise the 2015 estimate upward, from a posterior mean of about 60 to 100.

  Population & surveys Acoustic monitoring Gillnets & bycatch

• 2017RESEARCH

  Last call: Passive acoustic monitoring shows continued rapid decline of critically endangered vaquita

  Thomas and co-authors · The Journal of the Acoustical Society of America 142(5):EL512-EL517 (JASA Express Letters) · Peer reviewed · Thomas et al. 2017

  A grid of underwater click recorders has been run in the vaquita refuge for about three months each year since 2011, and this paper reports the 2016 results. Acoustic detections fell by 49% between 2015 and 2016 (95% credible interval, 82% decline to 8% increase), and by more than 90% overall between 2011 and 2016. Assuming detections track population size, about 30 vaquitas (95% credible interval 8 to 96) remained in November 2016.

  Population & surveys Acoustic monitoring

• 2016RESEARCH

  Extinction is Imminent for Mexico's Endemic Porpoise Unless Fishery Bycatch is Eliminated

  Taylor and co-authors · Conservation Letters 10(5):588-595 · Peer reviewed · Taylor et al. 2016

  The authors combined a ship-based visual line-transect survey with an array of underwater click detectors (C-PODs), run at the same time in autumn 2015, to estimate how many vaquitas were left across the species' whole range. They estimated 59 vaquitas (median of the posterior distribution, 95% Bayesian credible interval 22 to 145), a decrease of 92% since 1997 (95% credible interval 80 to 97%). They also projected the population forward under two scenarios, one with the gillnet ban kept and enforced and one with a return to the 2011-2015 rate of decline.

  Population & surveys Acoustic monitoring Gillnets & bycatch

• 2011RESEARCH

  A combined visual and acoustic estimate of 2008 abundance, and change in abundance since 1997, for the vaquita, Phocoena sinus

  Gerrodette and co-authors · Marine Mammal Science 27(2):E79-E100 · Peer reviewed · Gerrodette et al. 2011

  A line-transect survey in October and November 2008 combined visual searching from a large research vessel with an acoustic array towed by a sailboat in the shallowest areas. It estimated 245 vaquitas (95% CI 68 to 884), which is 57% lower than the 1997 estimate of 567. The authors found an 89% probability that the total population declined between the two surveys.

  Population & surveys Acoustic monitoring