Maturation of the Calico Scallop, Argopecten Gibbus, Determined by Ovarian Color Changes George C

Northeast Gulf Science Volume 3 Article 5 Number 2 Number 2 12-1979 Maturation of the Calico Scallop, Argopecten gibbus, Determined by Ovarian Color Changes George C. Miller National Marine Fisheries Service Donald M. Allen National Marine Fisheries Service T.J. Costello National Marine Fisheries Service J. Harold Hudson U.S. Geological Survey DOI: 10.18785/negs.0302.05 Follow this and additional works at: https://aquila.usm.edu/goms Recommended Citation Miller, G. C., D. M. Allen, T. Costello and J. Hudson. 1979. Maturation of the Calico Scallop, Argopecten gibbus, Determined by Ovarian Color Changes. Northeast Gulf Science 3 (2). Retrieved from https://aquila.usm.edu/goms/vol3/iss2/5 This Article is brought to you for free and open access by The Aquila Digital Community. It has been accepted for inclusion in Gulf of Mexico Science by an authorized editor of The Aquila Digital Community. For more information, please contact [email protected]. Miller et al.: Maturation of the Calico Scallop, Argopecten gibbus, Determined b Northeast Gulf Sciences Vol. 3, No.2, p. 96-103 December 1979 MATURATION OF THE CALICO SCALLOP, Argopecten gibbus, DETERMINED BY OVARIAN COLOR CHANGES 1 George C. Miller, Donald M. Allen, and T.J. Costello Southeast Fisheries Center National Marine Fisheries Service, NOAA 75 Virginia Beach Drive Miami, FL 33149 and J. Harold Hudson U.S. Geological Survey Fisher Island. Station Miami Beach, FL 33139 ABSTRACT:: Ovarian color was described for the calico scallop, Argopecten gibbus, by sizes and seasons from May 1970 to October 1971 on the Cape Canaveral grounds, Florida. Seven stages of ovarian development were recognized primarily by color and sequence of development and graded from immature to ripe to spent. Scallops as small as 20 mm shell height can be ripe. There were distinct changes in developmental stage by season. Most scallops were ripe·from January to May; in August, large scallops were spent or developing and small scallops were immature. Based on seasonal occurrence of ripe and partially spawned scallops, spawning extended primarily from about November to July and was intense from January to May. There was no spawning in August. Variations occurred in the spawning pattern between years. The calico scallop, Argopecten gibbus, (1) rate of development; a benthic marine mollusk found in the (2) developmental stages by season; western North Atlantic Ocean, is most and abundant at depths from 28 to 65 m (3) spawning. (15 to 36 fm). Commercial beds of the Other factors that might influence calico scallop are fished off North ovarian color were also determined. Carolina and off the east and west coasts Color changes in scallop ovaries with of Florida (Allen and Costello, 1972). maturation and spawning have been The biology of the calico scallop was reported previously. In the sea scallop, studied by the Bureau of Commercial Placopecten magellanicus, the sexes Fisheries, Tropical Atlantic Biological are separate; the ovaries are brilliant Laboratory (now National Marine Fish coral red when ripe, pale pink when eries Service, Miami Laboratory) from partially spent, and clear when spent 1969 to 1971. One objective of the study (Posgay and Norman, 1958). Posgay et al. was to describe color changes in ovarian (1962) listed the following stages of tissue of the calico scallop and to relate development by ovarian color for the sea those changes to matnri ty of the ovaries. scallop: Ovarian color was then used to recognize and delimit the following aspects of Stage 1: Immature, sexes indistin gonads trans- maturation: quishable, lucent. 1 Contribution Number 80-llM, Southeast Stage II: Immature, developing, light Fisheries Center, National Marine Fisheries Service, NOAA, Miami, FL 33149, pink. 96 Published by The Aquila Digital Community, 1979 1 Gulf of Mexico Science, Vol. 3 [1979], No. 2, Art. 5 Maturation of the calico scallop 97 Stage III: Immature, orange-pink to noticeable. Coloration and incidence orange-red. increased into fall and winter and by Stage N: Mature, ripe, coral-red. February ovaries were predominantly Stage V: Mature, partially spent, color reddish-orange or ripe. The majority still bright. of ovaries taken in April were bright Stage VI: Mature, spent, sexes diffi reddish-orange. June ovaries were cult to distinguish, dull gray largely uncolored." orange. From the progression of color changes, Color was also used to describe ovarian Roe et al. ( 1971) concluded that the development in the hermaphroditic bay maturation period "begins in August scallop, Argopecten irradians, a species and ends in March or April." closely related to the calico scallop. Ripe calico scallops, which had orange Belding ( 1910) reported that with devel red ovaries, were induced to spawn in the opment the ovaries change "from an in laboratory and produced viable eggs, discernible pink to a deep orange color." larvae, and juveniles (Costello et al. According to Gutsell ( 1931 ), the ovaries (1973). are pink or red when ripe. Costello et al. (1957) reported that the ovaries were METHODS bright orange-pink when ripe and pale after spawning. Castagna and Duggan A study site for calico scallops on the (1971) found that ripe ovaries were Cape Canaveral grounds, Florida, desig reddish-orange, although black epi nated Buoy 2, was established at latitude thelium sometimes obscured the initial 28°49.l'N and longitude 80°29.0W in color change of the ovaries. Sastry ( 1963) a depth of 22m (12 fm) (Figure 1). A distinguished the following stages of scallop bed located immediately west of development by ovarian color: Buoy 2 was sampled seasonally by two Stage I: Immature, sexes indistin 5-min tows of a 3m (10 ft) otter trawl guishable, transparent. (trynet) equipped with a double-tickler Stage II: Immature, sexes indistin- chain between the trawl doors. Buoy 2 guishable, translucent. was the primary source of scallops for Stage III: Immature, pale orange. the ovarian color study, and 11 samples Stage IV: Mature, ripe, bright orange. were obtained there from May 1970 to Stage V: Mature, partially spent, pale October 1971 (Figure 2). Each sample orange. contained at least 10 scallops selected Stage VI: Mature, spent, sexes indis over the size range of those caught, tinguishable, light brown. except that for July 1970, which con In the hermaphroditic calico scallop, tained 9 scallops. In May, June, and Roe et aL (1971) observed that ovarian August 1971, each sample included 10 color changes occurred with maturation. additional scallops less than 41 mm shell Undeveloped ovaries were whitish, rest height is a straight line measurement ing ovaries whitish-yellow, maturing of the greatest distance between the ovaries yellow-orange, and ripe ovaries umbo and the ventral margin) to estab bright reddish-orange. They noted that: lish minimum size at maturity. The live 'Yellow-orange coloration was seen scallops were opened 1 to 2 hours after in very few scallops during the August capture and the color of the ovaries was cruise, but by September the rate and observed. In March 1971, an additional incidence of color change was highly 10 scallops were kept alive in running https://aquila.usm.edu/goms/vol3/iss2/5 2 DOI: 10.18785/negs.0302.05 Miller et al.: Maturation of the Calico Scallop, Argopecten gibbus, Determined b 98 G. C. Miller et al. RESULTS N Relation of Ovarian Color to Develop BUOY 2 2a~ so' .... ,A mental Stages: ········· ... // \\\ By reference to work of earlier \'; \ investigators and from our laboratory ·~t9-1t. and field observations, we were able to relate ovarian color to maturation stages. ······· As points of departure we observed the CAPE color and texture of ovaries of: CANAVERAL j /..... ·~ ( 1) young, immature scallops raised from the egg in the laboratory: (2) ripe scallops before they spawned in the so" so' so· Jo' so" 20' W laboratory and produced healthy, viable eggs; (3) those same scallops (2) after they partially Figure 1. Location of calico scallop sampling site spawned in the laboratory. at Buoy 2 off Cape Canaveral, F1orida. (4) young, immature scallops in the field; (5) small, mature scallops which had recently spawned and were in a spent condition: seawater for about 16 hours after which (6) ripe scallops in the field; and the ovaries were compared to those (7) those same scallops (6) after they partially examined soon after capture. Additional, spawned in holding tanks in the field. random observations of ovarian color were made on small and large scallops The ovarian colors distinguished in collected at several sites on the Cape our samples were taken over an 18- Canaveral scallop grounds. To follow month period, May 1970 to October 1971, development through t1me of live and are shown by shell height by season individual scallops, the ovarian colors in Figure 2. The colors were initially were observed through the gaping valves separated into four groups: ( 1) drab, with of the live scallops. ovaries lacking orange or red pigmenta We recognized that for comparing tion; (2) brownish-orange, Pantone 156- ovarian colors, a standard would be 158; (3) reddish-orange, Pantone 163- required. The standard we used was the 165; and (4) dark orange-red, Pantone Pantone Color® Specifier, 2 which 170-172. designates color by number, not by name. An additional color may indicate in The color names we apply to the Pan tone fection of scallops by nematodes or numbers do not follow a previously trematodes. Dissection of a scallop gonad established system. When the ovaries colored irridescent orange revealed that were parasitized, or of a drab color, i.e., gonadal tissue was destroyed and that lacking orange or red pigments, wd did the ovary and testis were occupied by not assign a Pantone number. more than 50 reddish, immature nema todes (unidentified). Bisexual differenti ation by color was obliterated.

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