Vaquita marina, a small species of porpoise endemic to the Northern Gulf of California in Mexico, is the world's most endangered cetacean species. With the purpose of preserving vaquita, the Mexican government launched PACE-Vaquita in 2008. This voluntary program offers an innovative schedule of compensations: as in a payment-for-conservation program, PACE-Vaquita compensates for temporary reductions in fishing effort; as in a program to accelerate technology adoption, PACE-Vaquita compensates for switching to vaquita-safe fishing methods; and as in a buyback program, PACE-Vaquita compensates fishermen for a permanent exit from fisheries. This paper seeks the factors explaining fishermen's participation in PACE-Vaquita during its first year of operation. Analysis is carried out through a multinomial logit specification on a data set collected one week after the enrollment deadline. This paper shows that fishermen with skills in alternative economic activities more likely quit fishing, and fishermen with relatively less productive vessels more likely switched to vaquita-safe fishing methods. Discussion of public policy implications is provided. ► Enrollment in PACE-Vaquita is modelled with a multinomial logit specification. ► Likelihood of buy-out increases with skills in non-fishing activities. ► Likelihood of switch-out decreases with profits. ► Under current rules, buy-out is not an option to prevent vaquita's extinction. ► Increase in compensation for buy-out may increase participation in buy-out.