vehicle Mini Rover II to re-examine a ghost gillnet found during 

 the June, 1986 quantitative survey. 



RESULTS AND DISCUSSION 



Twenty- four submersible transects were completed in the 

 quantitative survey of ghost gillnets during June, 1985 and June, 

 1986, fourteen on Jeffreys Ledge and ten on Stellwagen Bank. The 

 Jeffreys Ledge transects ranged in depth from 30 to 127 m and 

 averaged 0.5 nm linear distance over the ocean floor. With the 

 mean visibility at 6.4 m we surveyed approximately 0.1 nm^ or 92 

 acres. Bottom habitats encountered on Jeffreys within the survey 

 sites can be categorized into five distinct types: 



1. Slope of ledge - clay, silt substrate with Cerianthus 

 (anemone like anthozoan) as the dominant megabenthic 

 fauna. 



2. Slope and ledge top - scattered rocks and boulders on a 

 silt-clay substrate. 



3. Ledge top - cobble, gravel substrate with a scattering of 

 boulders, up to 1 m in diameter. 



4. Ledge top - boulder fields with occasional large boulder 

 mounds . 



5. Ledge top - granite bedrock substrate. 



During the Johnson Sea-Link transects on Jeffreys Ledge, we 

 found two 20 mm trawl wires, one 5-8 m piece of braided nylon 

 netting, two derelict longlines, a series of overturned boulders 

 and rocks, and one 10 m piece of gillnet. The gillnet was attached 

 to the bottom by the leadline and floating up diagonally toward the 

 surface. It had a vertical profile of 2 m or more (similar to an 

 actively-fished commercial gillnet). No catch or evidence of catch 

 was observed in or at the base of the net. 



The Delta dives on Stellwagen Bank ranged in depth from 30 to 

 107 m and averaged a distance of 0.6 nm. The mean visibility was 

 about 6.4 m and the total bottom surveyed was approximately 94 

 acres or 0.1 nm^. Bottom type was similar to Jeffreys Ledge except 

 for a larger component of sand on the bank and a lack of granite 

 bedrock. 



The 700 m long ghost net, discovered during the June, 1986 

 survey on Stellwagen Bank, lay on the bottom that was primarily a 

 boulder field at a depth of 77 m; one end of the net did reach onto 

 a smooth silt-clay substrate. This ghost net had a vertical 

 profile averaging 0.5 m with a maximum profile of one meter. Most 

 of the net, including the webbing, was covered with a heavy 



434 



