Chapter III — Species of Special Concern 
1976). In the mid-1980s, the Commission provided 
support for beach surveys along the shores of the 
northern Gulf of California to locate the remains of 
dead animals and to train Mexican students in identi- 
fying, collecting, and preparing vaquita specimens for 
museums. In 1987, the Commission supported a 
study of environmental contaminants present in 
blubber samples of vaquitas incidentally caught and 
killed in fishing gear. The results of the latter study 
Suggest that, to date, pollutants have not been a 
significant threat to the vaquita. 
Impacts of the Totoaba Fishery 
The totoaba fishery began in the mid-1920s and 
grew to its peak in the 1940s. Between the 1940s and 
the early 1970s, the totoaba catch declined dramatical- 
ly. The Mexican Government responded by closing 
the fishery in 1975 to allow the species to recover. 
Despite the closure, illegal totoaba fishing continues, 
and the incidental mortality of vaquitas in totoaba 
gillnets remains substantial. Compounding the prob- 
lem was the decision by the Mexican Government in 
1985 to authorize experimental gillnet fishing in order 
to assess the status of the totoaba stock. 
Although incidental take of vaquitas is known to 
have occurred prior to 1985, no detailed information 
is available. However, between February 1985 and 
June 1991, the deaths of 121 vaquitas in fishing 
activities were documented. Of these, 78 died during 
illegal or experimental gillnet operations for totoaba, 
32 died in shark and ray gillnets, and 11 died in 
gillnets set for sierra (a mackerel-like fish) and in 
shrimp trawls. In the first two months of 1992, five 
vaquitas were known to have died in fishing opera- 
tions. Given the facts that the monitoring effort is not 
comprehensive and that fishermen do not report all 
incidental takes of vaquitas, the actual mortality is 
probably much higher than reported. Whatever the 
mortality rate may be, it is likely that the depleted 
population cannot sustain the current rate of removal. 
Based on a series of interviews with fishermen in 
1988, researchers at the Center for the Study of 
Deserts and Oceans in Puerto Penasco, Mexico, and 
the Autonomous National University of Mexico esti- 
mated that an average of 32 vaquitas per year die in 
gillnets. The report concluded, among other things, 
69 
that the vast majority of reported takes occurred in 
water depths of 25 to 160 feet, that most deaths 
occurred in nets with large mesh sizes, and that 
mortality rates resulting from gillnet entanglement 
were highest in the spring, the period when calving is 
believed to occur. The report recommended (1) clos- 
ing certain areas to gillnet fishing; (2) prohibiting all 
sale of totoaba; and (3) developing (a) economic 
alternatives for gillnet fishermen, (b) public education 
programs focusing on conservation of marine resourc- 
es in the northern Gulf of California, and (c) a vaquita 
management plan. 
International Efforts To Protect Vaquitas 
Also in 1988 the Cetacean Specialist Group of 
IUCN-The World Conservation Union’s Species 
Survival Commission published an action plan for 
conserving the biological diversity of cetaceans 
throughout the world. The plan called for a three- 
year project to promote conservation of the vaquita, 
categorizing it as an undertaking of highest priority. 
The project, which has not yet been fully implement- 
ed, would include (1) population monitoring projects, 
(2) a program to monitor incidental take by fisheries, 
(3) a salvage-necropsy program to examine vaquita 
carcasses, (4) a public awareness program, and (5) a 
species recovery plan. 
In October 1990 a Workshop on the Mortality of 
Cetaceans in Passive Fishing Nets and Traps was 
convened at the request of the International Whaling 
Commission with partial support from the Marine 
Mammal Commission. The workshop participants 
concluded that the vaquita’s future is seriously threat- 
ened by illegal totoaba fishing and other gillnet 
fisheries and that inadequate enforcement and lack of 
economic alternatives for gillnet fishermen were com- 
pounding the problems. Highest priority was placed 
on the goal of immediately reducing vaquita mortality 
incidental to fisheries. Copies of the workshop report 
and recommendations were forwarded to the Secretary 
General of the United Nations, as well as to Commis- 
sioners and members of the Scientific Committee of 
the International Whaling Commission. 
At its May 1991 meeting in Reykjavik, Iceland, the 
International Whaling Commission’s Scientific Com- 
mittee endorsed several recommendations of its 
