Chapter IV — Marine Mammal-Fisheries Interactions 



Measures for deterring listed species are to be the 

 subject of a separate rulemaking. 



The Marine Mammal Commission commented on 

 the proposed guidelines and regulations by letter of 30 

 August 1995. The Commission noted that, for the 

 most part, the proposed rule accurately reflected the 

 provisions of section 101(a)(4). However, the Com- 

 mission believed that the regulations did little to 

 clarify some of the uncertainties inherent in the 

 statute. For example, the regulations did not explain 

 how imminent the perceived damage to fishing gear or 

 catch or private property must be before deterrence 

 actions could be taken. Similarly, there was no 

 discussion as to how severe the damage to property 

 must be before deterrence measures could be taken. 



The Commission also noted that the proposed rule 

 did not appear to give consideration to well-estab- 

 lished haul-out or rookery sites. Under the proposed 

 rule, it would appear that a property owner could 

 construct a structure at such a site, knowing full well 

 that the area is frequented by marine mammals, and 

 then use deterrence measures to prevent the mammals 

 from returning to the area or to deter the animals 

 from approaching and damaging the structure. The 

 Commission suggested that adequate protection to 

 important marine mammal habitat be provided to 

 prevent conflicts between marine mammals and 

 property owners. Also, the Commission suggested 

 that the rule consider the potential adverse effects that 

 driving marine mammals away from haul-out sites and 

 rookeries could have on populations (e.g., decreased 

 survival or productivity) even if there were no direct 

 mortality or serious injury of a marine mammal. 



The Commission expressed concern about the 

 unrestricted use of noisemakers as deterrence mea- 

 sures. Without any specifications as to the types and 

 intensities of noises that may be used, the Commission 

 was unable to agree that noisemakers, in all cases, 

 would be a safe means of deterring marine mammals . 

 The Commission also expressed concern that certain 

 types of noises might have significant adverse effects 

 on marine mammals by causing them to abandon 

 important habitats. 



The Commission agreed that the use of explosives 

 to deter cetaceans is not warranted. However, the 



Commission questioned the Service's proposal to 

 allow the unrestricted use of certain types of explo- 

 sives for deterring pinnipeds. The Commission noted 

 the possibility that such "light" explosives may cause 

 injury if detonated close to a marine mammal or if 

 they blast sand or other particles into a marine mam- 

 mal's eyes. The Commission therefore suggested that 

 the Service consider prohibiting their use entirely. 

 Alternatively, the Commission suggested that the 

 Service consider setting a distance limit for using seal 

 bombs and prohibiting their use on land. 



As of the end of 1995 a final rule was undergoing 

 review within the National Marine Fisheries Service. 

 Publication of a final rule is expected early in 1996. 

 The Fish and Wildlife Service has yet to publish 

 guidelines or proposed regulations with respect to 

 deterrence of marine mammals under its jurisdiction. 



The Tuna-Dolphin Issue 



For reasons not fully understood, schools of large 

 yellowfin tuna (those greater than 25 kilograms) tend 

 to associate with dolphin schools in the eastern tropi- 

 cal Pacific Ocean. This area covers more than five 

 million square miles stretching from southern Califor- 

 nia to Chile and westward to Hawaii. Late in the 

 1950s U.S. fishermen began to exploit this association 

 by deploying large purse seine nets around observed 

 dolphin schools to catch the tuna swimming below. 

 Despite efforts by the fishermen to release the encir- 

 cled dolphins, some become trapped in the nets and 

 drown. Efforts to reduce the incidental mortality of 

 dolphins in this fishery have been a primary focus of 

 the Marine Mammal Protection Act since it was 

 enacted in 1972. 



Background 



The eastern tropical Pacific tuna fishery was domi- 

 nated by U.S. vessels during the 1960s and early 

 1970s. In the late 1970s and early 1980s the U.S. 

 fleet declined and the number of foreign vessels 

 participating in the fishery grew. Along with these 

 shifts in the fishery came changes in the associated 

 dolphin mortality. As reflected by mortality data 

 presented in Table 9, progress made by the United 



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