FISHERY BULLETIN: VOL. 73. NO. 4 



GREAT SOUTH BAY 



,000 METERS 



Atlantic Ocean 



Figure 1. -Study area and Sites A, B, and C where cunner were tracked. 



planks, steel sheeting, and piles. Water depth 

 along the basin walls varied between 2.4 and 8.8 m 

 with the bottom composed primarily of sand, 

 gravel, and shell. Site C was an artificial reef, 

 457x46 m, consisting of submerged barges and 

 tires on a sand and gravel bottom in 6 to 7 m of 

 water (Briggs and Zawacki 1974). 



Cunner were observed directly with scuba both 

 day and night at weekly intervals from May 

 through October in 1972 and 1973, and at monthly 

 intervals from November 1972 to April 1973 for a 

 total of 200 h (150 h daytime; 50 h nighttime). 



Cunner and tautog were collected weekly. May 

 through October at Site A for food habit analysis. 

 The fish were either speared by scuba divers or 

 trapped, and specimens were preserved in 10% 

 Formalin. The contents of the entire digestive 

 tract were examined, the food was identified, and 

 its volume measured (Windell 1968). 



RESULTS 



Daily Activity and Movements 



All fish tracked (Table 1) were active during the 

 day and inactive at night. Tagged fish initiated 

 daytime activity 16 to 41 min following the start of 

 morning civil twilight; cessation of activity oc- 

 curred 5 to 55 min before the end of evening civil 

 twilight (Table 2). Direct scuba observations 

 confirmed that the fish were active by day and 

 inactive during the night. During the night, the 

 fish were lying against, in, under, or between 

 bottom or vertical structures. While the fish were 

 quiescent at night, general responsiveness was 

 low as indicated by divers being able to touch or 

 capture fish with a hand-held net. 



Table 1. -Release site, tracking duration, and the maximum distance 

 traveled along the shelter site structure. 



Table 2.-The onset (minutes after morning civil twilight) and the end 

 (minutes before evening civil twilight) of the daily activity of individual 

 cunner as determined by ultrasonic tracking. 



All of the fish tracked (Table 1) were highly 

 localized in their daily movements, remaining 

 within 2 m of the structures affording cover. The 

 ma.ximum distance traveled by any of the fish 

 along structures ranged from 5 to 150 m. 



Due to extreme ambient interference of the 

 transmitter signal encountered during adverse 

 water conditions, cunner no. 8 (Table 1) was 



896 



