Based on the above the following calculations have been made. 



64 nm 2 _ X m ghost nets in traditional grounds 

 0.2 nm 2 710 m ghost nets documented during 

 submersible surveys 



(0.2 nm 2 )(X) = (64 nm 2 ) (710 m net) 



X = 227,200 m ghost net or, 2,497 nets or, 

 250 sets at 10 nets per set; if 12 nets set then 208 

 sets. 



We therefore estimate there are approximately 250 sets of 

 ghost gillnets, or 2,497 nets, lying on the ocean floor of Jeffreys 

 Ledge or within the vicinity of Stellwagen Bank. This estimate is 

 based on the assumption that all ghost gillnets of these two 

 commercial fishing banks are located within the 64 nm 2 defined as 

 traditional commercial gillnet fishing areas. Because of the 

 sightings of only two ghost nets during the quantitative survey and 

 the great variation in lengths of these nets an estimate of the 

 confidence limits about our ghost net abundance estimate of 2,497 

 nets is not warranted. 



We believe that the net abundance estimate of 2,497 is not 

 substantial . We expected during the process of gathering 

 information and data prior to the submersible surveys to document 

 many more ghost gillnets. To attain an estimate of ghost gillnet 

 abundance with reasonably "tight" confidence limits would require a 

 submersible survey of much greater magnitude than was conducted in 

 1985 and 1986 or is likely to be possible in the near future, given 

 current costs of such operations. 



Approximate age of ghost gillnets was estimated at the time of 

 net sighting based on the degree of invertebrate fouling, 

 specifically the sizes of the stalked ascidian, Boltenia ovif era 

 (Figs. 3 and 4). We estimate all of the ghost nets observed from 

 1984 to 1986 were at least 4 years old (time since the last set) 

 and most were probably 7 years and older. None of the nets 

 appeared to be recently lost nets. All nets found were seen to be 

 fixed to the bottom is such a manner that they could only be 

 retrieved with great difficulty. We believe that most of these 

 nets were lost around 1980 when the commercial gillnet fishery was 

 most active and was comprised of fishermen with relatively little 

 experience. Gillnet losses today are much less and not due to 

 inexperience as much as conflict with mobile gear. 



Based on the results of this study, our direct observations of 

 net configuration and net-substrate-animal interactions we present 

 the following recommendations: 



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