CARLINE: PRODUCTION BY WILD BROOK TROUT 



19 



15 



29 l 



27 



25 



23 



2H 



50 100 150 



MEAN BIOMASS (kg/ ha) 



200 



250 



FIGURE 4. — Relationships between mean biomass of all ages 

 of trout and mean lengths of ages 1,2, and 3 trout on 15 Septem- 

 ber. (*P<0.05; **P<0.01.) 



TABLE 9. — Annual fishery statistics for brook trout populations 

 in study ponds. 



because the pond was privately owned and public- 

 access was restricted. The largest trout (up to 

 430 mm) were harvested from Maxwell Springs 

 which supported the greatest number of age 4 

 and older trout. In spring 1969 there were about 

 530 age 4 and older trout/ha in Maxwell Springs 

 and only 16/ha and 69/ha in Clubhouse and Hog- 

 lot springs, respectively. 



Age 2 trout made up the major portion of the 

 harvest in Clubhouse and Hoglot springs (Figure 

 5). In both populations, proportions of age 2 and 

 older trout in the harvest were higher than their 

 proportions in the spring populations, suggesting 

 some size selection by anglers. 



The fishery at Maxwell Springs differed signifi- 

 cantly from the public ponds in 1969 when age 5 

 and older trout dominated the catch (Figure 5). 

 Large numbers of age 5 trout were present in 

 spring 1969 and 58% were harvested that season. 

 The owner of Maxwell Springs reported that 

 harvest and fishing pressure in years prior to the 

 study were well below those of 1969 and 1970; 



K 



* 



CLUBHOUSE SPRINGS 



A A HARVEST 



HOGLOT SPRINGS 



A 



.:. 



2 3. 



MAXWELL SPRINGS 1969 



independent variables of fishing pressure and 

 trout biomass in spring (r = 0.88; P<0.05). 

 Fishing pressure was lowest at Maxwell Springs 



FIGURE 5.— Age-frequency distributions of harvests and popula- 

 tions of legal-sized trout in spring. Data points for Clubhouse 

 and Hoglot springs are means of data from 1968 to 1970, and 

 1972. 



759 



