38 



COMMERCIAL FISHERIES REVIEW 



Vol. 28, No. 8 



Area. Catch rates of 1 bushel or more per 

 standard tow were achieved at 5 stations of 

 the 37 fished; only 1 tow yielded no clams. 



CORRELATIONS WITH BOTTOM TYPE 

 AND DEPTH: Consistent with previous sur- 

 vey work the size and distribution of surf 

 clam catches varied according to the type of 

 bottom sediment. Best results were obtained 

 where the predominant sediments were coarse 

 sand, gravel, or a combination of both. 



In all surveyed sections the catch rate of 

 surf clams showed some correlation to water 

 depth. Best catches were made at depths of 

 13 to 15 fathoms. Very few clams were taken 

 at depths over 15 fathoms. All tows made at 

 a depth greater than 24 fathoms yielded no 

 surf clams. 



SIZE OF SURF CLAMS: The predominant 

 size group of surf clams caught and examined 

 were 5 to 7 inches long. All sizes above 1.5 

 inches (reflecting dredge selectivity above 

 1.5 inches) were represented in the catches 

 from both Areas. The average size of clams 

 taken in Area VI was larger from the offshore 

 section of the survey. A record sized clam 

 from Area IV, measuring nearly 8 inches long, 

 is the largest taken by the survey to date. 



OCEAN QUAHOGS: Catches of ocean qua- 

 hogs were very small and widely scattered in 

 both Areas. The largest catch (30 quahogs) 

 was made in the deeper offshore waters of 

 Area VI. 



UNDERWATER TV AND CLAM -SOUNDER 

 WORK: The fishing operation of the dredge 

 and views of the bottom were observed using 

 a closed-circuit underwater TV system. Be- 

 cause of good water transparency, the action 

 of the dredge knife, jet header and other com- 

 ponent parts were seen clearly. Live surf 

 clams in the bottom were not seen but other 

 species of shellfish and fish were visible. 

 Considerable movie film footage was obtained 

 by photographing the shipboard TV monitor. 



Trials were successfully accomplished 

 with a redesigned clam-sounding system. 

 Sounds transmitted by the sounder, while tow- 

 ing on bottom, were tape recorded as the de- 

 vice was viewed through the underwater TV 

 system. Although no identifiable sound of a 

 live clam was recorded other sounds relating 

 to the dredging operation were recorded and 

 identified. 



FISH PRODUCTS IRRADIATOR: Under 

 the fish product irradiation program con- 

 ducted by the Bureau's Technological Labor- 

 atory at Gloucester, Mass., a "portable" (17- 

 ton) shipboard cobalt-60 irradiator was in- 

 stalled aboard the vessel. During trials on 

 this cruise several samples of fresh surf- 

 clam meats were irradiated for comparison 

 with control samples. This was the first ex- 

 periment to determine the value of radiation 

 pasteurization on fishery food products at sea. 

 The process is expected to destroy approxi- 

 mately 99 percent of the bacteria responsible 

 for spoilage in fresh fish pr oducts. " 



Note: See Commercial Fisheries Review. March 1966 p. 28. 



North Atlantic Fisheries Investigations 



RESEARCH VESSEL "ALBATROSS IV" 

 S ETS RECORD FOR DAYS AT SEA: 



The research vessel Albatross IV,~oper- 

 ated by the Interior Department's Bureau of 

 Commercial Fisheries, set a new record dur- 

 ing the period July 1965 to June 1966. In all, 

 14 research cruises were carried out, total- 

 ing 232 days at sea. The bulk of the research 

 was concerned with the distribution and abun- 

 dance of groundfish in the Gulf of Maine and 

 neighboring waters to the north (Scotian Shelf) 

 and south (southern New England). The three 

 cruises in early spring, summer, and fall, 

 lasted 91 days overall. 



Oceanographic surveys in the same area (4 

 cruises totaling 59 days) monitored the dy- 



