Pomatomus saltatrix; flounders (Paralichtys dentatus and Pseudo- 

 pleuronectes americanus); striped bass, Morone saxatilis; and had- 

 dock, Melanogrammus aeglefinus (Whiteley 1948: Miner 1950; 

 Wigley 1956). 



REPRODUCTION AND GROWTH: Price (1962), studying the 

 biology of C. septemspinosa in Delaware Bay, made collections in 

 a salinity range of 4.4 to 31.4%„ at temperature extremes of 0.0° to 

 26.0°C. The major breeding season was judged to be March to 

 October, but ovigerous females were found throughout the year in 

 salinities of 17. 7-29.3% and temperatures of 0.0°-25.0°C. He 

 found females to mature in 1 yr, with egg production increasing 

 with increasing size of the female. First egg bearers of the year 

 were found to be large females, with smaller ovigerous females 

 more numerous in July. An average of 300 eggs/female was pro- 

 duced in one annual brood. In Maine waters. Haefner (1972) sug- 

 gested that there may be more than one brood per year. In the 

 laboratory, eggs hatched into planktonic larvae after 6 or 7 d at 

 21°C. Fowler (1912) reported that larvae and young maintained a 

 planktonic existence for a long period of time after hatching. 



Females outnumbered the males especially during the most 

 active spawning season in Prices (1962) study. Growth rate was 

 estimated to be 1.6 mm/mo. with no observed seasonal variation in 

 the rate. Richards and Riley (1967) also reported growth rates of 

 1.6 mm/mo in Long Island Sound. However, Wilcox and Jeffries 

 (1973) found that growth was temperature dependent and varied 

 between 0.4 and 1 . 1 mm/wk off Rhode Island . 



Contrary to the appraisal of other authors. Price (1962) judged 

 that three year classes of females and two year classes of males 

 occur in the shoal waters of Delaware Bay in spring. 



Ovigerous females have been found in North Carolina from 

 December through May and August and late fall (Hay and Shore 

 1918). Individuals taken in winter are larger than those found in 

 spring. Juveniles have been found there from December to July, but 

 from mid-summer to late fall, juveniles and adults disappear from 

 North Carolina estuaries. 



Bigelow and Sears (1939) reported much the same pattern of 

 occurrence in waters of the continental shelf from Cape Cod to 

 Chesapeake Bay, with greatest occurrence in February dwindling to 

 rare occurrence in July, but never abundant anywhere. 



On Georges Bank, where Whiteley (1948) made all collections 

 inside the 100-fathom curve. C. septemspinosa was most common 

 in September and January, rarest in June, and usually occurred near 

 the bottom. He reported maximum numbers in July at Woods Hole, 

 and in August in the Bay of Fundy. Ovigerous females were found 

 in spring and early summer. The species was judged to produce one 

 brood a year and to have a life span of 1 yr. 



In Long Island Sound, C. septemspinosa had mean abundances 

 of 1 2/m : in July 1972 , 1 /m : in April , and 8/m- in September 1 973 in 

 grab samples taken in mud bottom areas. The species had similar 

 abundances in sands (x = 5/m 2 in July 1972 and 16/m : in September 

 1973), and was slightly more common in sandy silts (18/m : in July 

 1972, 22/m : in September 1973) (Reid et al. 1979). In an April 

 through September 1971 survey in the western Sound, using an epi- 

 benthic sled, both larvae and adults were most abundant in July and 

 August (National Marine Fisheries Service 1972). I5 



Fish (1926) found the larvae appearing from February to May 

 and as late as December at Woods Hole, Mass. Needier (1941) 



'^National Marine Fisheries Service. 1972. Davids Island Phase I: A short-term 

 ecological survey of western Long Island Sound. Middle Atlantic Coastal Fisheries 

 Center Informal Rep. 7. 29 p. 



recorded hatching times from late spring to early summer (July) 

 around Prince Edward Island, Canada. She described five larval 

 stages and a postlarval stage. All these stages were obtained in July 

 from plankton tows made about a meter below the surface along the 

 shores of estuaries. Larvae were hatched in the laboratory, but the 

 series of stages was worked out from plankton samples. 



These data indicate an extended breeding season in high lati- 

 tudes. Variations in seasonal abundance in different localities north 

 of Chesapeake Bay are possibly the result, in part, of varied sam- 

 pling methods in different years by different investigators. 



ADDITIONAL INFORMATION: In acute toxicity bioassays 

 with CdC 1 ,-2 '/2H,0 at 20°C and 20%, Eisler ( 197 1 ) found that the 

 concentration, fatal to 50% of the organisms of various marine spe- 

 cies in 96 h. ranged between 0.32 and 55.0 mg/1 Cd : '. Crangon 

 septemspinosa, at 0.32 mg/1, was most sensitive of the species 

 tested. 



In a study of acute toxicities of insecticides on marine decapod 

 crustaceans. Eisler (1969) again found C. septemspinosa to be the 

 most sensitive to 12 insecticides tested. 



In studies of color discrimination among crustaceans, it has been 

 observed that the chromatophores of C. septemspinosa adapt to a 

 background of yellow, orange, and red, chromatophore changes 

 being mediated through the eyes (Barnes 1963). 



Cancer irroratus (Say, 1817) 



DESCRIPTION: The rock crab. The carapace reaches a length 

 of 65 mm (Williams 1965) and a maximum reported width of 160 

 mm(Gosner 1971); it is yellowish in color, closely dotted with dark 

 purplish brown, becoming reddish brown after death. The anterola- 

 teral border is divided into nine teeth with margins granulate, not 

 denticulate as in Cancer borealis. Crabs of the genus Cancer have 

 been in existence since the Eocene epoch; today, there are 19 living 

 species in the world (MacKay 1943). 



DISTRIBUTION: Labrador to South Carolina (Williams 1965); 

 Jeffries ( 1966) listed the southernmost limit as Florida. 



HABITAT: Collected from the intertidal zone to depths of 574 m 

 (Williams 1965). Cancer irroratus prefers sandy or rocky sub- 

 strates, but has also been found on mussel beds (Jeffries 1966; Scar- 

 ratt and Lowe 1972; Winget et al. 1974; Krouse 1976; Reilly and 

 Saila 1978). In general, smaller individuals are found inshore and 

 larger individuals inhabit offshore areas (Scarratt and Lowe 1972: 

 Haefner 1976; Krouse 1976). For example, Haefner (1976). in a 

 study of the Middle Atlantic Bight, found that rock crabs <50 mm 

 in size were most abundant in depths of 15-150 m, and larger crabs 

 (50-100 mm) were generally more common in depths of 150-400 

 m, however, the largest individuals (> 100 mm) were most abun- 

 dant at 20-60 m. 



The preferred temperature range of C. irroratus is reported to be 

 6.8°-14°C, however, they are known to inhabit areas of 3°-20°C 

 (Jeffries 1966). Salinities ranging from 14 to 33% are tolerable 

 (Winget et al. 1974; Haefner and Van Engel 1975). 



In cooler New England waters, larger individuals may emigrate 

 into deeper, warmer offshore waters during winter (Jeffries 1966; 

 Krouse 1976). 



In the New York Bight apex, small C. irroratus were collected in 

 depths ranging from about 1 1 .5 to 29.8 m. They were found in all 

 sediment types, but were most common in low organic medium- 

 fine grain sands (Fig. 67; Table 1). 



45 



