reliable information on the species, numbers, ages, and sex 

 of marine mammals being taken, both deliberately and inci- 

 dentally, in set net, drift net, troll, and other fisheries. 

 With respect to the numbers of animals, participants con- 

 cluded that mark/resighting studies should be done to 

 determine whether depredation of fish by California sea lions 

 and harbor seals in the party boat, gill net, and salmon 

 troll fisheries is being caused by a small number of 

 "nuisance" animals that have learned that food is easily 

 found around fishing operations or by a general cross- 

 section of populations occurring in the fishing areas. 



Participants pointed out that it might be possible to 

 use non-lethal, aversive stimuli to frighten and keep seals 

 and sea lions away from fishing gear and fishing areas. They 

 noted that completed studies indicate that loud noises and 

 other stimuli can keep seals and sea lions away from fishing 

 gear and fishing areas for some periods but, unless the 

 stimuli cause substantial pain, the animals eventually cease 

 to respond. In some cases, animals may learn to associate 

 the theoretically aversive stimuli with food and be attracted 

 by them. Noting that it might be possible to avoid or delay 

 such habituation, participants recommended that further 

 studies be carried out to determine whether acoustic 

 cues paired with shooting, loud sounds, or other aversive 

 stimuli could suppress habituation and effectively condition 

 California sea lions and harbor seals to avoid fish caught by 

 salmon trollers or party boat fishermen. 



With regard to aversive conditioning, participants also 

 recommended that the California Department of Fish and Game 

 carry out planned feasibility trials to determine whether 

 lithium chloride-injected fish can be used under field 

 conditions to induce and maintain taste aversion in Cali- 

 fornia sea lions. Recognizing that the effects of lithium 

 chloride on sea lions and other marine mammals are not fully 

 understood, the participants recommended that additional 

 captive animal studies be carried out to better determine the 

 physical and physiological as well as psychological responses 

 to lithium chloride. 



Finally, workshop participants noted that additional 

 studies are needed to better assess the effects of certain 

 interactions and that long-term monitoring of both the 

 involved fisheries and marine mammal populations is necessary 

 to determine the effectiveness of measures taken to avoid or 

 reduce adverse interactions. 



The workshop report, published in June 1986, has been 

 widely distributed and used by State and Federal agencies, 

 fishermen, and environmental groups to help determine and 

 initiate priority actions. In 1987, the Commission plans to 



64 



