Chapter III — Species of Special Concern 



Because assessment results were not yet available, 

 however, the panel did not comment on specific clean- 

 up needs. 



After the review, the Navy provided funds to the 

 National Marine Fisheries Service to help begin the 

 Midway monk seal restoration program. In light of a 

 need for data on at-sea movements of resident and 

 introduced seals to evaluate seal translocation efforts, 

 the funds were used to acquire radio tags to track 

 seals at Midway. The Navy's prompt action in this 

 regard was a welcome and much-needed contribution 

 to the recovery program, and in its 4 August letter, 

 the Commission commended the Navy for its con- 

 structive assistance. To continue recovery work at 

 Midway, the Commission noted that a preliminary 

 cost estimate of $250,000 per year for five years 

 seemed valid, given the costs of transporting seals and 

 personnel, maintaining seal holding pens on Midway, 

 monitoring the population, obtaining and analyzing 

 data, etc. 



The Commission's letters to the Navy and the Fish 

 and Wildlife Service noted the outstanding merit of 

 managing Midway as a national wildlife refuge. 

 Pending further action by Congress, the Commission 

 expressed hope that the two agencies would do all 

 they could to pursue the transfer. The Commission 

 also wrote to members of Hawaii's Congressional 

 delegation on 4 August 1994, noting the importance 

 of Midway's habitat for monk seals and seabirds and 

 urging that these values be considered in any further 

 actions on bills affecting future use of Midway. 



In its 4 August letter to the Coast Guard, the 

 Commission noted the importance of assessing envi- 

 ronmental impacts from the discarded batteries in 

 Midway's lagoon and commended the Coast Guard 

 for ensuring that appropriate clean-up work would be 

 undertaken promptly. 



Mobbing Behavior — Injuries inflicted by sexually 

 aggressive adult male monk seals have resulted in the 

 death of adult female and juvenile seals at several 

 locations but primarily at Laysan and Lisianski 

 Islands. Monitoring studies carried out in the 1980s 

 found that males outnumbered females at both islands, 

 and Service scientists concluded that this was a factor 

 increasing the likelihood of mobbing behavior. 



Therefore in 1994 the Service removed 22 adult male 

 seals from Laysan, leaving its sex ratio slightly biased 

 towards females . One seal died in the process and the 

 remaining animals were released around the main 

 Hawaiian Islands. Having taken this step, Service 

 officials advised the panel that field work in 1995 

 would be limited to monitoring the effects of the 

 removals on mobbing at Laysan. As related matters, 

 they noted that commercial fishermen opposed releas- 

 ing any more seals in the main Hawaiian Islands 

 because of possible impacts on fishing operations, and 

 that studies were being done on captive northern 

 elephant seals to test an improved testosterone-sup- 

 pressing drug to reduce aggressive behavior in male 

 seals. 



The panel noted that local geographic influences on 

 the distribution of adult male seals may be a more 

 important factor than the sex ratio in causing mobbing 

 behavior. Thus, drug treatment could be a useful 

 mitigation approach. The panel therefore recom- 

 mended that the Service test the new drug's effective- 

 ness and delivery protocols on captive monk seals to 

 assess future mobbing-related management options 

 that would not involve capturing and moving animals. 



Predator-Prey Interactions — As noted above, 

 survival of newly weaned pups and juvenile seals at 

 French Frigate Shoals declined sharply after the late 

 1980s due to limited prey availability. Beach counts 

 at French Frigate Shoals had doubled between the late 

 1960s and mid-1980s making it the species' largest 

 colony. It is thought that the colony may have in- 

 creased to a level exceeding its carrying capacity. 

 During the program review, National Marine Fisher- 

 ies Service scientists provided information suggesting 

 that a regional decline in marine productivity occurred 

 in the Northwestern Hawaiian Islands in 1990, possi- 

 bly related to a decadal climate cycle. Simultaneous 

 declines in seabird reproductive success and the size 

 of regional monk seal, reef fishes, and lobster popula- 

 tions were cited in support of the hypothesis. 



Service scientists also presented data from scat 

 studies and satellite-tagging work. Scales and bones 

 of reef fishes were the most common prey remains in 

 the scat samples and a few scats contained lobster and 

 octopus parts. Because of small sample sizes and 

 inherent biases in scat studies, the relative importance 



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