Atlantic Calico Scallop
Argopecten gibbus
Description 2
Valves of Argopecten gibbus are deep and generally equal, with 17 - 23 (usually 20) deep, radiating ribs (Allen and Costello 1972). The left (upper) valve is somewhat more convex than the right (lower) (Broom 1976). Base color of the shell is creamy white to yellowish, splotched with patches of bright red, maroon, or lavender, with the left valve typically more brightly colored that the right. Wings lateral to the hinge of the shell are equal in length. Calico scallops may reach 2 inches in shell height, and over 3 inches in shell length.
Distribution 3
The range of the calico scallop extends from Maryland through Florida, the Gulf of Mexico, and south to Brazil, including Bermuda and much of the Caribbean. While it is sometimes observed in or around inlet areas, it is primarily found in nearshore and offshore waters where it supports a commercial fishery (Arnold 1995; Moyer and Blake, 1986; Blake and Moyer 1991).
Look alikes 4
Valve color and shell morphometry are used to distinguish calico scallops from related species. Argopecten gibbus is distinguished by its yellowish to white base color splotched with patches of bright red, maroon, or lavender. It is also slightly convex in the left (upper) valve (Broom 1976). The bay scallop, Argopecten irradians, is generally a uniform gray to gray-brown color with distinct convexity of the right (lower) valve. The rough scallop, Aequipecten muscosus, may also be mistaken for the calico scallop. However, the rough scallop has unequal wings and sharp scales on lower surface of the ribs, with shell color ranging into shades of yellow and brown.
Reproduction 5
Argopecten gibbus reach sexual maturity at approximately 4 months of age, or when they reach a size of 19 mm shell height (Miller et al. 1979; Arnold 1995), though Roe et al. (1971) found that sexual maturity correlates more to size rather than age. Spawning and recruitment in calico scallops occur throughout the year (Allen, 1979), with healthy individuals spawning as much as 3 - 4 times (Roe et al. 1971; Arnold 1995). Maximum reproductive effort occurs from late fall through spring, with fall spawning being somewhat less intense than spring spawning (Moyer and Blake, 1986). Despite its decreased intensity, some evidence suggests that fall spawns may be crucial to maintaining standing stocks of calico scallops in the following year (Moyer and Blake, 1986). Calico scallops are sequential hermaphrodites, first releasing sperm in to the water column followed by eggs, likely in response to changes in water temperature due to upwelling effects (Arnold 1995).
Link to Access Genomic Data 6
http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=78525&lvl=0
Sources and Credits
- (c) Femorale, some rights reserved (CC BY-NC), http://www.femorale.com/shellphotos/detail.asp?species=Argopecten%20gibbus%20(L.,%201758)
- (c) Smithsonian Marine Station at Fort Pierce, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/11525603
- Adapted by matbio from a work by (c) Smithsonian Marine Station at Fort Pierce, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/11525604
- Adapted by matbio from a work by (c) Smithsonian Marine Station at Fort Pierce, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/11525606
- (c) Smithsonian Marine Station at Fort Pierce, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/11525608
- (c) Emily Rose Sharkey, all rights reserved
