Blue crab, continued 



comm.). The soft shell crab fishery is primarily in 

 Louisiana and Florida (NMFS 1997), and actual land- 

 ings are probably greater than reported (Perry pers. 

 comm.). 



Since the commercial harvest of blue crabs is primarily 

 in state, not federal, territorial waters, the fisheries are 

 managed by the state resource agencies in coopera- 

 tion with the Gulf States Marine Fisheries Commission 

 (GSMFC) (Steele and Perry 1990). State regulations 

 for Gulf of Mexico commercial blue crab fisheries have 

 been summarized by the GSMFC (1993), but these 

 regulations are subject to annual revision. A five inch 

 minimum carapace width generally applies Gulf-wide, 

 and there are additional regulations for fishing season, 

 location, gear type and quantity, mandatory release of 

 gravid females, etc. 



Recreational : The blue crab supports a considerably 

 large recreational fishery. Estimates for recreational 

 landings vary widely, ranging from 4% of the commer- 

 cial landings in Mississippi in 1 971 (Herring and Christ- 

 mas 1974) to 400% of the commercial landings in 

 Louisiana in 1 968 (Lindall and Hall 1 970, Adkins 1 972b). 

 They are taken in the estuaries and nearshore Gulf 

 waters by dip nets, baited lift nets, baited strings, "fold- 

 up" traps, crab pots, and recreational shrimp trawls. No 

 reliable estimates are available for Alabama or the 

 west coast of Florida because reports for recreational 

 landings do not exist (Lindall and Hall 1970, Killam et 

 al. 1 992). Regulations similar to the commercial fish- 

 ery apply to recreational fishing, with marked traps 

 being labeled with name, address, saltwater stamp 

 number, and date set out (TPWD 1987b, GSMFC 

 1 993). In Mississippi crabs can be taken by handline, 

 drop net, dip net, hook and line, and crab pots/traps 

 (MDWC 1 988). The smaller crabs are considered to be 

 excellent bait for game fishes such as red drum. 



Indicator of Environmental Stress This species is well 

 known to be susceptible to low dissolved oxygen (DO) 

 in estuarine waters during the summer (May 1973, 

 Lowery and Tate 1986). The blue crab is sensitive to 

 chemical pollution, and is commonly used in pollution 

 studies due to its widespread distribution in the nation's 

 estuaries, and its commercial, recreational, and eco- 

 logical importance. Cadmium, mercury, and several 

 chlorinated hydrocarbons have been found to be acutely 

 toxic to megalopal blue crabs in low concentrations 

 (Millikin and Williams 1984). Toxicity for several pes- 

 ticides has been determined for juvenile stages as well 

 as adults. Kepone released into the James River, 

 Virginia from 1 950 to 1 975 may have affected juvenile 

 crab abundance and fishery landings (Van Engel 1 982). 

 In a laboratory study, Kepone concentrations of 0.5 

 and 0.75 parts per billion (ppb) were sublethal to blue 

 crab zoeae, whereas 1 .0 ppb caused a survival rate of 



98 



