FISHERY BULLETIN: VOL. 72, NO. 3 



Black, and eastern Mediterranean Sea (Figure 

 26). 



The extreme southern record by Ringuelet 

 (1963) is substantiated by the figure in his paper. 

 Records north of Cape Cod occur only during 

 favorable warm periods (Scattergood, 1960). 



Holthuis and Gottlieb (1955, 1958). Holthuis 

 (1961, 1969), and Christiansen (1969) summa- 

 rized the introduction of C. sapidus into Europe, 

 and Bulgurkov ( 1968) extended the known range, 

 recording an adult female taken in the western 

 part of Varna Bay in October 1967. From these 

 accounts it is clear that introduction in the Med- 

 iterranean and adjacent waters is an active one 

 involving a breeding population, whereas the 

 others seem to be temporary occurrences, but 

 all are judged to have come from transport of small 

 specimens in the ballast tanks of ships (op. cit., 

 and Wolff, 1954a, 1954b). Banoub (1963) pub- 

 lished one of the most complete accounts, noting 

 that presence in Egypt does not seem to have been 

 recorded before 1940. When C. sapidus was first 

 noticed in Lake Manzilah, Egypt, it was confused 

 with Portunus pelagicus (Linnaeus), itself an 

 immigrant to the area from the Indian Ocean 

 via the Suez Canal, and this confusion has per- 

 sisted in literature on both species. Banoub 

 thought that C. sapidus may have migrated from 

 Greece around the eastern Mediterranean to 

 flourish in the brackish lakes of Egypt, repro- 

 ducing the life pattern it exhibits in the Western 

 Hemisphere. 



Habitat. — The blue crab is a coastal creature 

 occurring on a variety of bottoms in fresh, es- 

 tuarine, and shallow ocean from the water's edge 

 to approximately 90 m (Franks et al., 1972). but 

 mainly in the shallows to depths of 35 m. Biolog\' 

 of the species is better known than that of any 

 other in the genus. Hatching in mouths of es- 

 tuaries and shallow ocean, development of lai'vae 

 progresses in the ocean (development studied both 

 in nature and the laboratory), followed by migra- 

 tion of megalopae and young crabs back into 

 estuaries to mature into adults (summarized in 

 Williams, 1965, 1971; Tagatz, 1968; Taissoun. 

 1969: and literature compilation, Tagatz and Hall, 

 1971). It is probable that all species in the genus 

 carry out their life histories on this model. 



Tolerant of extremes, the species has been found 

 from fresh water to hypersaline lagoons such as 

 Laguna Madre de Tamaulipas, Mexico, where 

 collections have been made in salinities ranging 



from 44 to 48/<''r and unproductive portions of the 

 lagoon range up to 117^,^ (Hildebrand, 1957), in 

 temperatures ranging from 3° to 35°C, and in 

 tertiary sewage treatment ponds in which mean 

 daily O2 tension dropped as low as 0.08 mg/liter in 

 summer (Smith. 1971). In Lebanon it has been 

 collected in winter in 39'<r salinity water at 

 17.5^C where there is no good place for estuarine 

 development because streams are small, seasonal, 

 and exceedingly foul in dry weather (George and 

 Athanassiou, 1965). In Marion Co., Fla., large 

 males have been taken from salt springs in the St. 

 Johns River over 180 miles from the sea. 



Often considered a scavenger, which it certainly 

 is, the normal diet includes a variety of materials 

 including fishes, benthic invertebrates, and plant 

 material (Darnell, 1959; Tagatz, 1968). Odum and 

 Heald (1972) confirmed this assessment, finding 

 mainly an abundance of small mussels in stomach 

 contents of individuals in a marsh in SW Florida. 



Spawning. — Most spawning occurs in spring 

 and early summer, warm months helping to as- 

 sure survival of larvae. Females with egg masses 

 have been found in North Carolina from mid- 

 March to late November. Northward the season is 

 somewhat shorter and to the south (United States) 

 it is longer (Williams, 1965). Early spring spawn- 

 ers may cast a second batch of eggs in late 

 summer contributing to a lengthened spawning 

 season or a secondary late summer peak. The 

 number of eggs per spaw-ning has been estimated 

 at 700,000 to more than 2 million (Williams, 

 1965). Ovigerous females in museum collections 

 are rare, but suggest that at least some eggs are 

 spawned almost the year round in tropical waters. 

 Taissoun ( 1969 ) showed this to be true in the Golfo 

 de Venezuela where ovigerous females are most 

 abundant between April and September, reaching 

 a sample maximum of 15Vc in July and August. 

 Also, in the northern part of Bahia del Tablazo, 

 Venezuela, ovigerous females occur during all of 

 the year except between August and November, 

 reaching a sample maximum of 95*;^ in May. 

 Absence of ovigerous females there in late sum- 

 mer and fall occurs because heavy rainfall and 

 increasing river flow freshen the area, driving 

 females downstream to areas of higher salinity; 

 consequent increases of ovigerous females occur in 

 the Golfo de Venezuela during August and Sep- 

 tember. 



Economic importance. — Though all species of 

 Callinectes are consumed as human food, there is 



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