of the 1984-1985 survey, the total number of Hector's dolphins 

 in the Banks Peninsula area was estimated at 740 animals. 



The species' preference for nearshore habitat also makes 

 it vulnerable to pollutants such as heavy metals and pesticide 

 residues. Although the biological effects of the pollutants 

 are poorly known, the level of contaminants found in dolphin 

 tissues examined to date gives cause for concern. 



Long-term studies of the species indicate that females 

 become sexually mature at seven to nine years of age and 

 produce, at most, one calf every two years. Considering the 

 species' inherently low reproductive rate, it seems possible 

 that the impact from gill net entanglement, in addition to 

 natural mortality, will cause this small population to decline 

 in size. 



The New Zealand Department of Conservation is aware of 

 the urgent nature of the problem and, in 1988, prepared a 

 discussion paper that addressed possible ways to increase 

 protection of Hector's dolphins. Based on analyses in the 

 document, the Department initiated steps at the end of 1988 

 to designate waters around the Banks Peninsula as a Marine 

 Mammal Sanctuary under provisions of the New Zealand Marine 

 Mammal Protection Act of 1978. Among the specific measures 

 to be taken to address the incidental take of Hector's dolphins 

 in gill nets were the following: a ban on gill netting in the 

 Sanctuary from November through February; a ban on use of 

 gill nets longer than 30 meters during the period March through 

 October; and a requirement that fishermen using gill nets 

 deploy no more than one net per boat, remain with the nets 

 while they are deployed, and refrain from leaving nets to 

 soak overnight. At the end of 1988, it was the Commission's 

 understanding that these provisions would become effective 

 early in 1989. 



During 1989, the Marine Mammal Commission will continue 

 to cooperate, as requested, in efforts to help determine 

 steps that might be taken to ensure the protection of the 

 Hector's dolphin population. 



Gulf of California Harbor Porpoise (Phocoena sinus) 



The Gulf of California harbor porpoise is one of the 

 smallest and perhaps the rarest of all cetaceans. Until 

 recently, there have been few confirmed sightings of live 

 animals and most of what is known of the species has been 

 obtained from examination of carcasses washed up on beaches 

 or taken incidentally in gill net fisheries in the upper Gulf 

 of California, Mexico. Confirmed sighting and stranding data 



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