MARINE MAMMAL COMMISSION — Annual Report for 1991 



(see Chapter VI). Seals also may ingest small items 

 of debris. While evidence of entanglement is clear, 

 no documented cases of monk seals' ingesting debris 

 have been reported. Ingestion of debris has been 

 reported in other seal species. 



From 1974 through 1984, at least 35 cases of 

 entangled monk seals were documented. In most 

 cases, seals were able to free themselves without 

 injury. From 1985 through 1990, 51 entanglement 

 incidents were observed, including four instances in 

 which seals were known to have died. A few other 

 seals that were badly entangled likely would have died 

 had researchers not freed them. Derelict trawl net 

 webbing appears to be the most common and most 

 hazardous form of debris for seals. Routine efforts 

 were begun in 1982 to remove hazardous debris 

 washing ashore. 



Observed entanglement rates have fluctuated. 

 From 1982 to 1985, they declined to a low point of 

 about 0.05 incident per 100 camp days per 100 seals 

 (including pups and adults). Between 1985 and 1988, 

 they increased steadily to a high of about 0.5 incident 

 per 100 camp days per 100 animals. For pups alone, 

 entanglements in 1988 averaged about 1.5 incidents 

 per 100 camp days per 100 pups. 



In 1989, observed entanglement rates declined 

 slightly, in 1990 they declined substantially, and in 

 1991 they increased again to a level approximately 

 half that observed in 1988. Six entanglements were 

 recorded in 1991, none of which are known to have 

 resulted in the animal's death. Entanglement rates 

 vary from island to island and have consistently been 

 greatest at Lisianski Island where, between 1982 and 

 1988, they averaged 4.4 entanglements per 100 camp 

 days per 100 seals. Unfortunately, there is no basis 

 for estimating the number of animals entangled 

 offshore that do not make it back to the beach. 



To mitigate the problem, researchers attempt to 

 free any observed entangled animals and to remove or 

 destroy debris that washes ashore. Since 1985, the 

 Service's Marine Entanglement Research Program has 

 provided funds to help defray program costs needed 

 to accomplish these objectives. Since 1985, the 

 amount of debris observed and removed or destroyed 



from the Northwestern Hawaiian Islands has more 

 than doubled. Efforts to reduce sources of marine 

 debris are discussed in Chapter VI. 



In 1991, derelict "lightsticks" used by longline 

 fishermen also became a source of concern. Light- 

 sticks are sealed plastic tubes, several inches in 

 length, filled with liquid. When bent, an interior tube 

 is snapped, releasing chemicals that react to produce 

 a phosphorescent glow lasting several hours. Light- 

 sticks are attached near baited hooks where their light 

 attracts target species, such as swordfish and albacore, 

 as well as other animals during nighttime fishing. 

 Fish and Wildlife Service personnel stationed on Tern 

 Island in French Frigate Shoals began finding large 

 numbers of lightsticks washing ashore early in 1991 

 during the period when longline fishermen operate 

 closest to the Northwestern Hawaiian Islands. 



There was no evidence of lightsticks being ingested 

 by seals. However, they did find lightsticks in the 

 gullets of some albatrosses. It appeared that light- 

 sticks, used in the tens of thousands by longline 

 fishermen, were being discarded after use. Discard- 

 ing any plastics in U.S. waters is illegal. When the 

 matter was brought to the attention of the Western 

 Pacific Regional Fishery Management Council, it 

 wrote to the National Marine Fisheries Service asking 

 that steps be taken to assess possible effects on 

 Hawaiian monk seals. A copy of the Council's 5 July 

 1991 letter was sent to the Commission and, on 16 

 August 1991, the Commission wrote to the manager 

 of the Service's Marine Entanglement Research 

 Program. 



In its letter, the Conmiission noted the need to 

 investigate possible toxic effects of chemicals in 

 lightsticks on wildlife as well as possible mechanical 

 injury due to ingestion by seals or albatrosses. It also 

 noted that fishermen should be advised that lightsticks 

 were being found on island beaches and posed a 

 hazard to protected species, that intentional discard is 

 illegal, and that fishermen are obligated to take steps 

 to prevent intentional or unintentional losses. 



The program manager replied on 27 September 

 1991, noting that brochures and placards had been 

 provided to the Service's Regional Office in Honolulu 



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