approximately 21 inches in front of the footrope. In most 

 instances trawl entry was initiated from the point at which 

 the fish was attempting to maintain station with the gear. 

 During trawl entry, flatfish crossed the footrope at a 

 height of less than 40 inches. 



Two factors determine the limits of this data. First, 

 the maximum herding distance recorded may have been 

 determined by visibility limitations rather than actual 

 herding distance. The maximum recorded herding distance is 

 approximately ten feet from the camera lens. This distance 

 is near the visual limit encountered during our operations. 

 Herding may occur outside this limit but is undetectable by 

 the present methodology. Second, the minimum measured 

 distance fish approached the footrope was determined by the 

 camera angle and position. In many cases fish were observed 

 swimming in positions which appeared to be under the 

 footrope. This, however, is an artifact of camera position 

 and the fish were actually swimming in the region between the 

 footrope and the range of camera visibility. 



Observed active herding times ranged from 2 to 12.2 

 seconds (average 5.2 seconds +3.6 seconds). During active 

 herding, flatfish tended to swim directly away from the gear, 

 with only an occasional fish zigzagging or traversing the 

 footrope. In all cases the fish remained close to the 

 bottom; in several instances the caudal fin was observed 

 striking the substrate. The average distance above bottom 

 maintained during herding was 1.5 inches +0.56 inches. To 

 maintain position with the gear the majority of flatfish 

 observed swam in a burst pattern. The fish would swim 

 rapidly away from the footrope for a short period of time 

 followed by a gliding period during which the fish dropped 

 back towards the footrope. 



Two distinctive behavior patterns were observed when 

 flatfish entered the trawl (Fig. 2). Eighty percent of the 

 fish entered the trawl by turning onto their back and 

 allowing the footrope to pass beneath the fish (sequence A). 

 Individuals exhibiting this behavior pattern tended to be 

 herded closer to the footrope and enter the trawl at a lower 

 level than other fish (Fig. 3). The average herding distance 

 for these fish was 18.3 inches +6.1 inches and they crossed 

 the footrope at an average height of 13.8 inches +7.7 inches. 

 Fish which exhibited this entry pattern ranged from 7 to 23 

 inches in length (average 13.8 inches +4.7 inches). After 

 crossing the footrope, fish righted themselves by executing a 

 180° roll. Fish crossing the footrope at a lower level 

 tended to execute this roll sooner than fish crossing at a 

 higher level. After crossing the footrope, and while still 

 inverted, the fish tended to rise while swimming into the 

 net. 



410 



