Among the many species of small “whales” are dolphins and porpoises, more than 40 species of which have been hunted commercially or have been killed inadvertently by other fishing efforts. A classic case is the inadvertent catch of the spinner, spotted, and common dolphins of the eastern Pacific.
Because these carnivorous, fish eating mammals often feed with yellow fin tuna, a major commercial fish, more than 7 million dolphins have been netted and killed inadvertently in the past 40 years. The size varies with the species but can be estimated. Some islands that seem large to us are too small for species we wish to preserve. Another approach is to seek a minimum viable population, a carrying capacity, or an optimal sustainable population or harvest based on data that can be obtained and tested today.
This approach abandons the goal of restoring a species to some hypothetical past abundance. The good news is that many formerly endangered species have been restored to an abundance that suggests they are unlikely to become extinct. Success is achieved when the habitat is restored to conditions required by a species. The conservation and management of wildlife present great challenges but also offer great rewards of long-standing and deep meaning to people.