length of average St. Lucie Canal 

 flow exists for mullet, a five-week 

 lag behind average discharges result 

 in mullet catch rate increases down 

 the South Fork. 



Table 3 lists the additional 

 influences of C-23 and C-23A dis- 

 charges on the specific species and 

 in the zones already selected as be- 

 ing significantly affected by the St. 

 Lucie Canal discharges. Although 

 this is not a complete look at the 

 effects of the agricultural canals, 

 it aids in the interpretation of St. 

 Lucie Canal discharge effects. For 

 instance, in interpreting the move- 

 ment of sheephead, the influences of 

 discharges from the St. Lucie Canal 

 or C-23 alone do not indicate an 

 exodus from the inner estuary to 

 cause the increase in the catch rate 

 in the inlet section. However, 

 analysis of discharges from C-23A in- 

 dicate that the first response is a 

 decrease in catch rate in the North 

 Fork followed by an increase in the 

 inlet section. The analysis of C-23A 

 flow has apparently captured subtle- 

 ties in the change in rates that the 

 other analyses have not. 



PAST AND PRESENT SPORT 

 FISHING PRESSURE 



The total number of boaters in 

 the North Fork and fishermen in the 

 South Fork, bridge and inlet 

 sections, was estimated to be 

 70,500 angler days spent in the 

 late 1950' s (Table 4). Estimated 

 angler days for this 1978-79 study 

 (including for comparison only the 

 boaters from the North Fork) was 

 66,303. Based on a 25-year 

 projection included in the Fish and 

 Wildlife Service 1959 report, the 



current angler utilization is less 

 than the actual 1956-57 survey and 

 only 42 percent of the projected 

 amount . 



Over the years, species prefer- 

 ences in the North Fork have changed 

 and diversified. However, the per- 

 centage of fishermen who are after 

 certain species has remained about 

 the same and snook still leads as the 

 most preferred species. In terms of 

 species that make up the harvest, 

 snook has dropped from over 26 per- 

 cent of the harvest to just over 2 

 percent in this survey. Croaker 

 has also dropped significantly from 

 14.1 percent to only 3 percent of the 

 harvest, whereas gray snapper has 

 remained about the same. Three 

 species that have greatly increased 

 as a percentage of the harvest are 

 bream or sunfishes which have moved 

 from 1.3 percent to 19.3 percent, 

 mullet which has increased from 0.5 

 percent to 18.9 percent, and the com- 

 bined catch of weakfish and spotted 

 seatrout which has increased from 

 0.5 percent of the harvest to 8.2 

 percent in this study. 



North Fork catch-per-unit of 

 effort was calculated for the months 

 July through April. The puffer, mul- 

 let, and bream catches have signifi- 

 cantly increased the catch rates for 

 the summer months. In the 1956-57 

 survey, the most successful month was 

 December. February, with a substan- 

 tial contribution by bream, was the 

 most successful month of this 1978- 

 79 survey. 



CONCLUSIONS 



The catch rates of nine impor- 

 tant fish species were found to be 

 significantly influenced by the mod- 

 erate freshwater discharges from the 

 St. Lucie Canal, Stuart, Florida, 



277 



