FISHERY BULLETIN: VOL. 85, NO. 3 



Table 2. — Changes In mean size at age of witch flounder from 1973-78 to 

 1979-83 for Division 2J; 1970-78 to 1979-83 for Division 3K; and from 1968-78 

 to 1979-83 for Division 3L. Only ages common to both pehods are included in 

 the compansons. 



that Markle (1975) referred only to fish <5 years 

 old, whereas this study has few fish <5 years 

 old. 



Witch flounder preferred depths and tempera- 

 tures at intermediate levels among these samples 

 in Div. 2J, 3K, and 3L. Preferred depth in Div. 3K 

 is more clearly defined than preferred tempera- 

 ture; this is associated with the occurrence of 

 smaller younger fish at intermediate values of 

 the observed ranges. Powles and Kohler (1970) 

 suggested that juveniles in the Gulf of St. 

 Lawrence were in deeper water, separate from 

 the adult, a built-in conservation mechanism for 

 the young. S. J. Walsh (pers. comm.)^ on the other 

 hand, in examining the distribution of juvenile 



versus adult witch flounder in the Gulf of St. 

 Lawrence also found that juveniles (<30 cm) had 

 a well-defined preferred depth range whereas the 

 adults (>30 cm) were distributed over a much 

 wider depth range. For demersal fish it is more 

 common for younger fish to be found in shallower 

 water with most of the larger fish in deeper water 

 (e.g., See Bowering [1984] for Greenland halibut). 

 There is some indication that young American 

 plaice in the Newfoundland-Labrador area may 

 also occupy some intermediate depth over the 



2S. J. Walsh, Juvenile Flatfish Biologist, Department of Fish- 

 eries and Oceans, P.O. Box 5667, St. John's, Newfoundland AlC 

 5X1, Canada, pers. commun. 1986. 



626 



