MARINE MAMMAL COMMISSION - Annual Report for 1998 



fishing only with pingers) on the existing system of 

 gillnet fishing closures to protect groundfish and right 

 whales (see Figure 3). The time period for one man- 

 agement zone was shortened, it was extended for 

 another, and it was shifted for a third. For the mid- 

 Atlantic area, the Service adopted its proposed mea- 

 sures with one change. It eliminated application of 

 the rules to gillnets with small mesh (less than 5-inch 

 mesh) used to catch bluefish, weakfish, croaker, 

 baitfish, and other species. The exemption was based 

 on a very low estimate of bycatch levels in the small- 

 mesh gillnet fishery. 



Regarding the Commission's recommendations, 

 the Service noted that if bycatch levels are not re- 

 duced below the potential biological removal level, 

 further bycatch reduction measures, including those 

 recommended by the Commission and others, would 

 be reconsidered. 



Marine Mammal Commission 

 Harbor Porpoise Review 



To help determine if all necessary and possible 

 steps were being taken to assess and monitor the 

 status of the Gulf of Maine harbor porpoises and to 

 reduce porpoise bycatch levels, the Commission held 

 a review of the harbor porpoise research and manage- 

 ment program during its 10-12 November 1998 

 annual meeting in Portland, Maine. At the meeting 

 the Service reviewed its ongoing and planned activities 

 to implement the above-noted take reduction plan. 



With regard to research activities, representatives 

 of the Service noted that another harbor porpoise 

 population survey is planned for the summer of 1999. 

 The results are expected to provide a basis for assess- 

 ing recent population trends. They also noted that the 

 Service and the Canadian Department of Fisheries and 

 Oceans plan to jointly sponsor a study in 1999 to 

 assess the effectiveness of "reflective" net designs to 

 reduce harbor porpoise bycatch. Reflective nets are 

 made of materials that harbor porpoises might detect 

 and thereby avoid more readily. 



With regard to research on pingers, it was noted 

 that an initial study had been supported during 1998 

 to determine if harbor porpoises habituate to pinger 



sounds over time, thereby lessening the devices' 

 effectiveness as a deterrent. Preliminary results 

 suggest some evidence of habituation, but there were 

 no strong indications in this regard. Further studies 

 of habituation and studies of the effects of pinger 

 sound on other marine species are being planned. 

 The Commission also was advised that a 1997 study 

 on the effectiveness of pingers in reducing bycatch 

 also tested the ability of different sound characteristics 

 {e.g., frequencies) to deter harbor porpoises. Al- 

 though the results indicate that different frequencies 

 and frequency sweeps are effective, no plans for re- 

 search to further define effective sound characteristics 

 were identified. 



Representatives of the Service also reviewed steps 

 being taken to resolve a number of management 

 issues. They noted that bycatch estimates would be 

 developed and made available in a more timely 

 manner. In the past, availability of these estimates 

 has lagged one or two years behind the end of a 

 fishing season. In the future, the Service stated that 

 bycatch estimates would be developed quarterly and 

 be made available three to four months after a fishing 

 season. It also noted that some gillnetters have 

 thwarted Service efforts to place observers aboard 

 their vessels to monitor bycatch, even though they are 

 required to take observers when asked. It was noted 

 that efforts to enforce this requirement would be 

 strengthened in the future. For fishing boats too small 

 to carry an observer, observations would be made 

 from a separate boat. 



Representatives of the Service also noted that 

 steps were being taken to ensure that gillnetters meet 

 the requirements for using pingers. They noted that 

 a series of regional workshops for gillnetters on the 

 deployment and maintenance of pingers had already 

 been initiated. Gillnetters fishing with pingers will be 

 required to have a certificate attesting to their partici- 

 pation in one of these workshops. The Commission 

 also was advised that the Service was exploring means 

 of defraying the cost of purchasing pingers, estimated 

 at perhaps $3,000 to $6,000 per vessel depending on 

 the number of nets carried. It also was noted that 

 work was being done to develop and provide enforce- 

 ment officials with hydrophones for checking whether 

 deployed gillnets are equipped with functioning 

 pingers in times and areas where they are required. 



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