A survey of the bottcaa using a special underwater camera 

 appeared to be the most praotical method of determining quantitatively 

 the numbers of the larger animals living on the surface of the bottom. 

 To obtain a sample of the small burrowing animals in the upper two 

 to four inches of the bottom an orange peel dredge 9-1/4 inches in 

 diameter was used* 



A four-square^nile area in the Hudson Canyon region, eleven miles 

 south (170® True) of Ambrose Lightship (fig. 1), was the area in which 

 the acid solvit! on disposal was to take plaoe* For the survey, stations 

 were laid out within this square at .4-41116 intervals* As a control 

 area which would help to distinguish changes in bottom life owing to 

 seasonal variation from those caused by acid disposal, a similar 

 Square was laid out in a region known as the Mud Hole, just south of 

 the lightship* 



A oorarage of these tiro areas was planned just before the start 

 of the aoid disposal operation in April 1948 and at intervals there- 

 after. The Balanus of the Woods Hole Oceanographle Institution made 

 the first or-uise from March 26 to April 2, On this cruise various 

 difficulties we're encountered, chiefly those concerned with the 

 operation of tne camera and the adverse weather conditions. Con- 

 sequently, the desired number of bottom photographs could not be 

 obtained in the time allotted, but enough were taken to give a good 

 Indication of the character of the bottom. Out of 52 lowerings, 

 22 black and white (fig. 2) and four color photographs were obtained 

 in the Disposal Areaj also four black and white and 3 color photographs 

 were taken in the Mud Hole. At each station, also, samples were taken 

 with the orange peel dredge. 



Station procedure 



At the start of each day's operations, the initial station was 

 located as accurately as possible and a buoy set out as a reference 

 point. Subsequent stations were made by dead reckonings, soundings, 

 and frequent checking by Loran. Camera and bottom sampling lowerings 

 were made, with the vessel dead in the water, or nearly so, to eliminate 

 wire angle and prevent breakage of gear. At each station pertinent data 

 were inscribed in the special vinderwater camera log. Bottom sample 

 material was carefully washed over a fine-meshed screen and organisms 

 found were preserved for later identification. As each roll of film was 

 finished it was developed immediately, thus serving as a check on operation 

 of gear and technique. 



To supplement the initial attempt, a second cruise was made in May 

 1948, on the U. S. Fish and Wildlife Service's research vessel Albatross III * 

 In examinirg the photographs and bottom samples from the earlier cruise it 

 was fotmd that a preponderance of the marine life Inhabited muddy bottom. 



