females; crabs 200-mm. wide averaged 398 g. 

 for males and 272 g. for females. The heaviest 

 crab was a 225-mm. male from the Oklawaha 

 River that weighed 550 g. The weight advantage 

 of males over females at a given size grew 

 with increased width (fig. 9). The difference in 

 weight was undoubtedly due to the generally- 

 longer lateral spines of females relative to the 

 size of their bodies. 



Weights given for females are exclusive of 

 sponge. Comparisons of weights of sponge 

 females and nonsponge females of the same 

 widths revealed the sponge had an average 

 weight of 37 g. (range 24-98 g.). 



Minimum Market Size 



Catches of crabs usually are not culled 

 before they are taken to processing plants. 

 Fishermen, especially trawlers, who handle 

 their captured crabs individually may discard 

 very small individuals, but the majority of pot 

 fishermen dump the contents of each pot 

 directly into receiving containers. Crabs 

 smaller than 120 mm. did not comprise a 

 large segment in the samples from unculled 

 catches. Approximately 5 percent of the trawl 

 catches and less than 5 percent of the pot 

 catches contained crabs less than 120 mm. 

 When catches do contain large numbers of 

 small crabs, crab plants either refuse them 

 or pay a lower rate. When small individuals 

 are numerous, crabbers will cull their catches 

 to ensure acceptance by the plant. Compari- 

 sons of widths of crabs brought to processing 

 plants and of unculled catches at time of 

 capture also indicated no appreciable amount 

 of culling. Catches sampled at plants contained 

 6.9 percent of crabs less than 127mm. and 3.3 

 percent of crabs less than 120 mm. Unculled 

 catches consisted of 8.9 percent of crabs less 

 than 127 mm. and 5.0 percent of crabs less 

 than 120 mm. 



Crabs sold by the fishermen directly to the 

 public usually have been culled. Catches sold 

 to retail markets generally are not culled; 



1^ 



no 



I ' I ' I ' I ' I ' I ' I ' I 



120 130 140 150 160 170 180 190 

 CARAPACE WIDTH CMM.) 



Figure 9.--Width-weight relation of crabs from the com- 

 mercial fishery, St. Johns River, 1961-62. (Crabs are 

 grouped to the nearest 5 mm., females are not in sponge.) 



smaller crabs commonly are separated from 

 the larger individuals and sold at a reduced 

 price. 



FACTORS AFFECTING SIZE OF CATCH 



The factors primarily responsible for deter- 

 mining the size of the 1961 and 1962 catches 

 were market conditions, crab migrations, and 

 abundance. Variations in monthly catches 

 among areas and between years could be 

 accounted for by one or more of these factors. 



The role of the market in regulating the 

 size of the catch is basedupondemand, availa- 

 bility of outlets, and price. The demand of 

 processing plants for crabs largely determines 

 the extent of utilization of the resource. 

 Processing plants handled the majority of the 

 1961-62 catches and bought crabs from over 

 half of the fishermen. The percentage of the 

 catch handled by retail markets or retailed by 

 the fishermen decreased more than half in 

 1962 (even though the catch was more than 

 twice that of 1961) because sales through these 

 outlets were limited by a fairly stable local 

 consumer demand. 



Utilization of crabs from other areas in- 

 fluences the demand for crabs from the St. 

 Johns River. Processing plants along the river 

 obtain crabs from the Nassau, Ft. George, 

 Matanzas, North, and Indian Rivers, from the 

 ocean, and from dealers on the west coast of 

 Florida. The greater demand for St. Johns 

 River crabs in 1962 than in 196 1 resulted partly 

 from a decrease in landings in other areas. 

 The total catch of crabs in Florida was approxi- 

 mately 6,400,000 pounds less in 1962 than in 

 1961 (U.S. Fish and Wildlife Service, 1962). 

 Improved local demand brings increased land- 

 ings by encouraging increases in the number 

 of fishermen, the number of gear units, and 

 the time spent fishing. The large increase in 

 the catch by trawls in 1962 resulted almost 

 entirely from changes in market demand. 

 Market operators readily purchased trawl- 

 caught crabs in 1962 whereas in 1961 they 

 preferred to buy pot-caught crabs (usually in 

 better condition and fewer in sponge). 



The addition of new market outlets for St. 

 Johns River crabs during 1962 also increased 

 landings. Crab fishing is generally localized 

 where major market outlets are available, 

 and new activity starts when new outlets arise. 

 Fishing was more active in Areas 2 and 3 

 because truck operators transported crabs 

 from these areas. A new crab plant built in 

 Area 2 during the fall of 1962 had a further 

 marked effect on the fishery. Fewer fisher- 

 men operated in September pending the opening 

 of the new plant, which eliminated the need to 

 haul their catches some distance to market. 

 When the plant began full operation in October, 

 the number of fishermenmore than doubled and 



