CALICO SCALLOP DISTRIBUTION, ABUNDANCE, AND YIELD 

 OFF EASTERN FLORIDA, 1967-68' 



Richard B. Roe," Robert Cummins, Jr.,' and Harvey R. Bullis, Jr.* 



ABSTRACT 



During 18 months, from August 1967 to December 1968, the National Marine Fisheries Service Explor- 

 atory Fishing and Gear Research Base in Pascagoula, Miss., conducted a comprehensive survey of the 

 calico scallop (Argopecten gibbiis) grounds off eastern Florida. The survey disclosed various aspects 

 of the life history, distribution, abundance, and yield and annual variation in geographical and depth 

 distribution. Predictions for a fall fishery are possible since distribution and abundance are established 

 at spat set and can be delineated by midsummer. A fall fishery is recommended as catch rates and 

 yield were highest between September and December and decreased rapidly during late winter and 

 spring. 



There are two or more species of Argopecten 

 called "calico" scallops (Waller, 1969); how- 

 ever, the more common is A. gibbus (L.). This 

 is the species involved in our study, occurring 

 from Delaware Bay to the Caribbean Sea and 

 throughout the Gulf of Mexico (Johnson, 1934; 

 Bullis and Ingle, 1959; Carpenter, 1967; Waller, 

 1969). Calico scallops derive their name from 

 the blotched coloration of their shells which 

 vary from red to light brown on a white back- 

 ground, giving a "calico" effect to the shell. 



Three commercial grounds have been delin- 

 eated by the Exploratory Fishing and Gear Re- 

 search Base at Pascagoula, Miss., and its Field 

 Station in Brunswick, Ga. These are located 

 off North Carolina (Cummins, Rivers, and 

 Struhsaker, 1962) , off eastern Florida near Cape 

 Kennedy (Bullis and Cummins, 1961; Cummins, 

 et al., 1969;' Drummond, 1969), and in the 



' Exploratory Fishing and Gear Research Base, Pas- 

 cagoula, Miss., Contribution No. 232. 



" National Marine Fisheries Service Exploratory 

 Fishing and Gear Research Base, Pascagoula, Miss. 

 39567. 



' National Marine Fisheries Service Exploratory 

 Fishing and Gear Research Station, Brunswick, Ga. 

 31520. 



' National Marine Fisheries Service, Washington, 

 D.C. 20240. 



' Cummins, R., Jr., R. Maurer, L. May, and J. Rivers. 

 1969. Summary log of scallop locations with predicted 

 catch rates of Cape Kennedy grounds — fall 1969. Is- 

 sued by Bureau of Commercial Fisheries Exploratory 

 Fishing and Gear Research Field Station, Brunswick, 

 Ga., for limited distribution. 



Manuscript received January 1971. 



FISHERY BULLETIN; VOL. 69. NO. 2. 1971. 



northeastern Gulf of Mexico (Bullis and Ingle, 

 1959; Carpenter, 1967). Explorations had 

 shown a large resource exists, particularly off 

 Florida, but monthly and yearly changes in dis- 

 tribution and abundance had seriously hampered 

 delineation of the resource. 



In August 1967 an 18-month survey was ini- 

 tiated on the Cape Kennedy grounds to assess 

 the scallop stock and determine the causes of 

 variation in distribution, abundance, and yield. 

 These grounds were selected because of size, 

 location, and a developing industry. 



The survey provided information on the dy- 

 namics of the scallop population present at that 

 time, but there is a need for additional studies 

 on life history, age, and growth. 



METHODS 



Cruises were conducted monthly between Au- 

 gust and December 1967, and bimonthly between 

 February and December 1968. Four standard 

 transects, each extending from 10 to 40 fm, were 

 made on each cruise. These were: transect A at 

 lat 28°03' N, transect B at lat 28°27' N, transect 

 C at lat 29°03' N, and transect D at lat 29°25' N 

 (Figure 1). Tows were also made between 

 transects. An 8-ft scallop dredge, fitted with 

 2-inch bag rings and 21/2-inch mesh nylon liners, 

 was used in the survey. All tows were 30 min. 



399 



