The Spawning, Growth, and General Beha Vior of the Blue Head Wrasse, Thalassoma Bifasciatum (Pisces: Labridae)1

Home , Ajax Reef, Chaenopsidae, Milt, Sparisoma, Thalassoma bifasciatum

THE SPAWNING, GROWTH, AND GENERAL BEHA VIOR OF THE BLUE HEAD WRASSE, THALASSOMA BIFASCIATUM (PISCES: LABRIDAE)1

HENRY A. FEDDERN Institute of Marine Science, University of Miami

ABSTRACT Aspects of the life history of the tropical marine fish Thalassoma bifasciatum were investigated on a reef in the Florida Keys during a two-year period. Emphasis was placed on analyses of both spawning and growth. Two types of spawning patterns, aggregate and paired, were observed; in both, the eggs and milt were expelled in midwater. Size-frequency analyses of ovum-size indicate peaks of spawning activities on Florida reefs at intervals of 1Y2 to 2 months throughout the year, with individuals spawning many times during the year. Average maximum standard lengths of 55 to 65 mm are attained in about a year, with exceptional individuals reaching 90 mm or more. Size- frequencies of standard lengths indicate that peaks of abundance of particular sizes are related to sex, although no difference in growth rate between adult males and females could be demonstrated. Other aspects discussed are coloration, morphometry, foods and feeding, general behavior, and mimics. A synonymy is included.

INTRODUCTiON AND ACKNOWLEDGMENTS The bluehead, Thalassoma bifasciatum, is a small fish of the family Labridae reaching a length of about 15 cm (Longley & Hildebrand, 1941: 197). This wrasse is characterized by several different color patterns, the most conspicuous one giving the species its common name. Individuals occur inshore and on the reefs, to depths of about one hundred feet. They are most abundant on a rock or coral substrate. This species is a prominent member of the West Indian fauna, especially in coral areas. The limits of its geographic range as defined by collected specimens are Bermuda (Goode, 1877: 291), Cape Verde Islands (Osorio, 1909: 71), the Grenadines, British West Indies (Beebe & Hollister, 1935: 219), Cura~ao (Metzelaar, 1919: 107), Courtown Keys, Colombia (Fowler, 1953: 65), Sheen Cay, Honduras (Fowler, 1942b: 12), Cozumel, Yucatan (Bean, 1890: 198), Panama City, Florida (Caldwell, 1959: 72), and Riviera Beach, Florida (seen by author). At present, little is known about this species, apart from studies on the color patterns of specimens and the relationship between parasite- picking activities and total food intake. lContribution No. 656 from The Institute of Marine Science, University of Miami. This paper was adapted from a thesis submitted in partial fulfillment for the Master of Science degree. 1965] Feddern: The Bluehead Wrasse 897 The present study attempts to show relationships between the frequency of spawning and the development of ova of females. An attempt is also made to determine the growth rate of specimens of all sizes. I thank Dr. C. Richard Robins for his patience and help during the preparation of this thesis, and for his permission to use the specimens in the research collection at the Institute of Marine Science. I am also indebted to Dr. Donald P. de Sylva for his assistance during the research and the preparation of the manuscript. Dr. Albert C. Jones gave valuable advice on statistical problems that arose when obtaining and evaluating data. Mrs. Elizabeth McKenney and Mrs. EIlen McCormick were extremely helpful in obtaining obscure references. Dr. Francis J. Bernard freely offered his time and effort to prepare histological mounts of gonads. Captain Walter E. Starck provided free dockage for the boat used in collecting the specimens. The members of my Committee of Graduate Study, Drs. C. Richard Robins, Donald P. de Sylva, Gilbert L. Voss, Charles E. Lane, Gene A. Rusnak, and Andrew Sobczyk, read and edited the manuscript. Thanks are also extended to Drs. Walter A. Starck II, Thomas W. McKenney, and Walter R. Courtenay, Jr., for their interest and comments during the course of this study.

METHODS OF COLLECTION AND MEASUREMENT Most specimens of Thalassoma bifasciatum were collected by the author in a small area from one-quarter to one-half mile southwest of Alligator Reef Light in the Florida Keys, approximately Lat. 24°50'N, Long. 80035'W. The bottom in this area is composed of a rocky ledge extending roughly northeast to southwest and facing northwest. A sandy area extends from the base of the ledge to a coral rubble area. The top of the ledge, at a depth of 15 feet, is covered primarily with algae, alcyonarians, some colonies of Millepora complanata. and occasional small coral heads. The rubble area, at a depth of 20 feet, is primarily overgrown with algae. The most productive gear for the capture of specimens was a drop net. This was constructed of a 4-foot bronze hoop supporting the wide base of a cone-shaped bag of one-quarter-inch mesh cotton netting. A nylon bridle was tied to the hoop. In use, the entire net was laid on the sea bottom with the bridle leading straight up to the boat. A crushed sea urchin, Lytechinus variegatus or Diadema antillarum, whichever was available, was placed on the center of the net. When the wrasses rushed in to feed, the net was hauled rapidly up to the boat. Specimens were preserved immediately in 10 per cent freshwater formalin. Specimens smaller than about 30 mm standard length were not attracted to crushed urchins, so these were collected with hand net and anesthetic. The hand net was constructed of gray fiberglass screening, and its 898 Bulletin of Marine Science [15(4) dimensions were about one foot long by six inches wide by one foot deep. The anesthetic was a mixture of quinaldine and acetone. No unbiased samples could be obtained by this method because specimens of a group had to be cornered before the anesthetic could be used; (anesthesia required about a ten-second exposure), and the escape of cornered specimens was related to their size-the larger the fish, the more likely was its escape. This was largely because a larger fish could swim faster than a smaller one, and a larger fish required a longer time for anesthesia. The third method of collection was the use of a vaso-constrictor called pronox-fish (5 per cent emulsifiable rotenone and other cube extracts with synergists). This chemical constricts the blood vessels of the gills, reducing the flow of blood to the point that the fish dies of asphyxiation. Thalassoma bifasciatum unfortunately proved remarkably resistant to the chemical, and few specimens could be obtained by its use. During the period from 30 April 1961 to 5 October 1962, eighteen collections were made using the drop net. With most of these collections were included a small group of juveniles caught by hand net and anesthetic. For the other colJections, no attempt was made to capture juveniles, although they were present. Table 3 indicates the date, total number of specimens, number of males, number of females, and number of juveniles for each of these collections. All measurements (in millimeters) were taken with dial calipers to the nearest 0.1 mm, except when specifically noted otherwise. All measurements of body length are standard length (S.L.). Measurements used to determine degrees of allometry are given in Table 1. These measurements, except that of preanal length, were taken according to the following definitions given by Hubbs & Lagler (1958: 25-26) : 1. Dorsal and anal fin-ray counts are designated by the formula: number of spines (in Roman numerals), number of soft rays (in Arabic numerals). The last two soft rays have a common base and are counted as one. 2. All pectoral and all segmented caudal-fin rays arc counted (in Arabic numerals). 3. Lateral-line scales are counted from the first scale posterior to the operculum to the scale ending at the posterior edge of the hypural plate. If this edge bisects a scale, the scale is counted. 4. The scales above the lateral line are counted from the scale touching the side of the first dorsal spine posteroventrally to the scale just above the lateral line. S. The scales below the lateral line are counted from the scale touching the side of the first anal spine anterodorsally to the scale just below the lateral line. 1965] Feddern: The Bluehead Wrasse 899 6. The caudal-peduncle scale count represents the number of scale rows around the smallest circumference of the caudal peduncle. 7. Standard length is measured from the tip of the snout to the posterior edge of the hypural plate. 8. Pre dorsal length extends from the tip of the snout to the structural base of the first dorsal spine. 9. Preanal length extends from the tip of the snout to the structural base of the first anal spine. 10. Body depth is measured just anterior to the dorsal fin. 11. Head length extends from the tip of the snout to the posteriormost point on the opercular membrane. 12. Snout length extends from the tip of the snout to the anterior margin of the orbit. 13. Orbit length is th~ greatest horizontal distance between the free orbital rims. Specimens examined during this study are listed by catalog number, locality, and date collected. The abbreviation "UMML" re~ers to the collection of the University of Miami Marine Laboratory. The number of specimens examined and their range in standard length is given in parentheses following the catalog number.

Thalassoma bifasciatum (Bloch) Labrus capite ob/uso Gronow, 1781 (Antilles; not seen). Labrus bifascia/us Bloch, 1791: 131, pI. 283 (incorrectly referred to the East Indies).-Bloch & Schneider, 1801: 243 (compiled; after Bloch). Labrus bifascia/us var. /orqua/us Bloch and Schneider, 1801: 243 (Antilles; after Gronow). Julis de/ersor Valenciennes, in Cuvier & Valenciennes, 1839: 408-409 (San Domingo; Martinique).-Storer, 1846: 141 (compiled).-Giinther, 1862: 186 (compiled) .-Jordan, 1886a: 540 (reidentification of the type). Chloric/hys bifascia/Us, Swainson, 1839: 232 (name only).-Swain, 1882: 275 (based on Swainson).-Longley, 1914: 208 (coloration in relation to synonymy). Labrus orna/us Gray, 1854: 83 (type locality Antilles, after Gronow). Julis gillianus Poey, 1860: 214 (type locality Cuba).-Poey, 1868: 332-333 (Cuba). Julis bifascia/a, Gunther, 1862: 186 (Jamaica).-Metzelaar, 1919: 107 (St. Martins; St. Eustatius; Cura<;ao; Lake Bonaire). Julis nitida Gunther, 1862: 190 (type locality Jamaica).-Osorio, 1909: 71 (Santo AnHio Island, Cape Verde Islands).-Metzelaar, 1919: 106-107 (Cura<;ao; Bonaire; St. Eustatius). Julis bifasda/us, Poey, 1875: 107 (Jamaica).-Goode, 1877: 291 (Bermuda). Julis nitidissima Goode, 1877: 291, 293-295 (color notes; type locality Ber- muda). Thalassoma nitidum, Jordan, 1886b: 590 (compiled).-Jordan and Hughes, 1887: 67-70 (key; synonymy) .-Bean, 1890: 198 (Cozumel, Yucatan). -Jordan, ] 89]: 652-653, 691 (key; compiled) .-Jordan and Thompson, 1905: 246 (Tortugas, Florida; coloration).-Reighard, 1909: 299 (used 900 Bulletin of Marine Science [15(4) as bait).-Nichols, 1915: 144 (Puerto Rico) .-Nichols, 1921: 23 (Turk Island, Bahamas).-Fowler, 1928: 454 (Key West, Florida).-Nichols, 1930: 316 (type locality).-Jordan, Evermann & Clark, 1930: 429 (compiled). Thalassoma bifasciatum, Jordan, 1886b: 590 (compiled) .-Jordan & Hughes, 1887: 67-70 (key; synonymy).-Jordan, 1891: 652, 654, 691 (key; synonymy).-Jordan & Thompson, 1905: 246 (Tortugas, Florida).-Reigh- ard, 1909: 297,299 (used as bait).-Nichols, 1915: 144 (Puerto Rico).- Nichols, 1921: 23 (Turk Island, Bahamas).-Fowler, 1928: 454 (Key West, F1orida).-Nichols, 1930: 317, fig. 193 (type locality).-Parr, 1930: 87 (Bahamas) .-Jordan, Evermann & Clark, 1930: 429 (compiled). -Tee-Van, 1932: 43-47 (color changes).-Beebe & Tee-Van, 1933a: 151-152 (Bermuda; synonymy).-Beebe & Tee-Van, 1933b: 201, 305, fig. (Bermuda; color description; key).-Manter, 1934: 170 (trematode parasites) .-Beebe & Hollister, 1935: 219 (the Grenadines, British West Indies).-Fowler, 1937: 313 (Port-au-Prince, Haiti).-Longley & Hilde- brand, 1940: 273-275 (mimicking activity of Hemiemblemaria simulus). -Longley & Hildebrand, 1941: 196-198, pI. 26, fig. 1 (color phases, behavior), 185 (feeding).-Fowler, 1942: 12 (Sheen Cay, Honduras).- Fowler, 1944: 113-114,449,471 (synonymy).-Fowler, 1947: 7 (Ba- hamas).-Sperry, 1948: 357 (oplic nerve regeneration).-Breder, 1948a: 288, 290, 304 (behavior; habitats) .-Breder & Rasquin, 1950: 11 (light reactions).-Fowler, 1950: 89 (color description; St. Andrews Island).- Fowler, 1952: 102 (Haiti) .-Fowler, 1953: 65 (Courtown Keys, Colom- bia).-Goodrich & Biesinger, 1953: 465, 471-478, 480-482, fig. 1, pI. 2 (chromatophores and color pattern formation).-Randall, 1955: 237 (sexual dimorphism).-Stoll, 1955: 125-132, tab. 1, pIs. 1-3 (relationship of hormones to pigmentation).-Eibl-Eibesfeldt, 1955: 203,209-210, figs. 8-9 (parasite-picking activity) .-Ladiges, 1956: 67, figs. 56 and 93 (parasite-picking activity) .-Briggs, 1958: 284 (distribution) .-Rasquin, 1958: 24 (head morphology), 38, tab. 2, 49 (reactions from injected hormones). -Randall, 1958: 333 (parasite-picking activity) .-Duarte-Bello, 1959: 101-102 (compiled).-Breder, 1959: 422, tab. 1 (light reactions).-Ran- dall & Randall, 1960: 444, 449-451, fig. 1 (mimicry by Hemiemhlemaria sirnulus).-Bailey, et al., 1960: 34 (compiled). -Herald, 1961: 203, pIs. 68, 69, and 98 (color changes; parasite-picking activity.)-Randall, 1962: 43 (parasite-picking activity) .-Randall & Randall, 1963: 50, 54-56 (spawning behavior). Chlorichthys bifasciatus, Jordan & Evermann, 1896: 414 (compiled).- Jordan & Rutter, 1897: 119 (Kingston, Jamaica).-Jordan & Evermann, 1898: 1609-1610 (compiled) .-Bean, 1905: 315 (Clarence Harbor, Bahamas).-Bean, 1906: 68 (Bermuda).-Linton, 1910: 18, 19, 32, 62, 93 (helminth parasites) .-Rosen, 1911: 24,60 (Andros Island, Bahamas). -Fowler, 1919: 144,150 (St. Croix, Virgin Islands; Nassau, Bahamas). -Fowler, 1923: 31 (Miami, Florida). Chlorichthys nitidus, Jordan & Evermann, 1896: 414 (compiled).-Jordan & Evermann, 1898: 1608 (compiled) .-Bean, 1905: 315 (Eleuthera Island; Nassau; Clarence Harbor, Bahamas) .-Bean, 1906: 68-69 (Ber- muda).-Blosser, 1909: 298 (St. Croix, Virgin Islands).-Rosen, 1911: 60 (Nassau and Andros Island, Bahamas). Chlorichthys nitidissimus, Jordan & Evermann, 1896: 414 (compiJed).- Jordan & Evermann, 1898: 1608 (compiled).-Barbour, 1905: 126 (Bermuda) . 1965] Feddern: The Bluehead Wrasse 901 lridio cyanocephalus Barbour, 1905: 125 (not of Bloch; very dark specimen of Thalassoma bifasciatum, according to Beebe & Tee-Van, 1933a). Chloricthys nitidus, Longley, 1914: 208 (coloration in relation to synonymy). Chloricthys nitidissimus, Longley, 1914: 208 (coloration in relation to synonymy). Thalassoma nitidissima, Longley, 1915: 208 (color changes). Thalassoma bifasciatus, Longley, 1915: 208 (color changes).-Breder, 1927: 60-63, figs. 24-26, tab. 10 (color and body variations).-Beebe & Tee-Van, 1928: 205, fig. (Port-au-Prince Bay, Haiti).-Breder, 1948a: 203, 206- 207, fig. (key; color changes).-Breder, 1948b: 292-293,295 (misprints, should be Thalassoma bifasciatum). Thalassoma nitidus, Longley, 1915: 208 (color changes). Bermudichthys subfurcatus Nichols, 1920: 62 (color phase of Thalassoma bifasciatum; type locality Bermuda). Thalassoma nitida, Beebe & Tee-Van, 1928: 205-206, fig. (Port-au-Prince Bay, Haiti).-Fowler, 1936: 1314 (from GUnther).-Blanc & Bauchot, 1960: 93-94 (key; from Osorio). Thalassoma bifasciata, Fowler, 1928: 462 (Port-au-Prince, Haiti). Thalassoma bivittatus Breder, 1948a: 294, tab. 1 (misprint, should be Thalassoma bifasciatus). Thallasoma bifasciatum, Caldwell, 1959: 72 (Panama City, Florida). Longley (1914: 208) stated that individuals alternated color patterns characteristic of nitidum and nitidissimum, and that all intermediate colors between nitidum and hifasciatum could be seen. Beebe & Tee-Van (1928: 205) found that six specimens of nitidum were females and sixteen specimens of hifasciatum were males, but did not synonymize the names. Longley & Hildebrand (1941: 197) found that males of nitidum existed, and said: "Clearly this is a single sexually dimorphic species, in which the male attains sexual maturity while still displaying that juvenile coloration which the female retains throughout life." Stoll (1955: 125-132) injected methyl testosterone into specimens of nitidum of both sexes and obtained bifasciatum in all cases. Tee-Van (1932: 43-47) studied the coloration and constructed a diagram showing the relationships between patterns. Beebe & Tee-Van (l933a: 152) stated that a specimen identified by Barbour (1905: ] 25) as lridio cyanocephalus is actually a very dark specimen of Thalassoma bifasciatum. They also examined Nichols' (] 920: 62) type of Bermudichthys subfurcatus and found that it was a damaged specimen of Thalassoma hifasciatum.

MATERIAL EXAMINED FLORIDA: UMML 7251 (l9, 26.5-77.1) Dade County, Ajax Reef, 4 April 1959.-UMML 9188 (36, 10.4-58.9) Monroe County, Y2 mile SSW of Alligator Reef Light in 15-20 feet at ledge, 30 April 1961, CRR-F-296.- UMML 9687 (88, 11.7-86.0) Monroe County, V2 mile SW of Alligator Reef Light in 8 feet, 19 November 1961.-UMML 9691 (9, 40.9-59.2) Monroe County, 112 mile SSW of Alligator Reef Light, 11 November 1961.-UMML 9791 (66, 11.7-78.0) Monroe County, % mile SW of Alligator Reef Light in 902 Bulletin of Marine Science [15(4) 8-15 feet, 17 December 1961.-UMML 10179 (17, 12.7-76.9) Monroe County ]/2 mile SW of Alligator Reef Light in 15 feet, 4 November ]961.- UMML 10224 (22, 39.7-76.6) Monroe County, ],4 mile WSW of Alligator Reef Light in 10 feet, 28 January 1962.-UMML 11248 (186, 12.0-76.4) Monroe County, ca. V4 mile SW of Alligator Reef Light in 15 feet,S May 1962.-UMML 11255 (25, 12.8-79.2) Monroe County, ca. 1/2 mile SW of Alligator Reef Light in 8-15 feet, 13 February 1962.-UMML 11259 (8, 52.8-71.3) Monroe County, ca. % mile SW of Alligator Reef Light in 10 feet, 10 March 1962.-UMML 11263 (45, 11.5-72.4) Monroe County, ca. V2 mile SW of Alligator Reef Light in 10-15 feet, 20 March 1962.-UMML 11268 (26, 11.2-66.0) Monroe County, ca. ],4 mile SW of Alligator Reef Light in 15 feet, 31 March 1962.-UMML 11273 (295, 10.7-78.9) Monroe County, ],4 -]/2 mile SW of Alligator Reef Light in 15 feet at ledge, 20 June 1962.- UMML 11279 (243,35.0-70.3) Monroe County, ca. ]/2 mile SW of Alligator Reef Light in 20 feet at ledge, 1 July 1962.-UMML 11291 (420, 10.1-87.5) Monroe County, %-V2 mile SW of Alligator Reef Light in 15 feet at ledge, 5 August 1962.-UMML 11298 (513, 26.4-77.3) Monroe County, ],4-V2 mile SW of Alligator Reef Light in 15-20 feet at ledge, 27 August 1962.-UMML 11304 (484, 29.4-79.6) Monroe County, ]/<1 -¥2 mile SW of Alligator Reef Light in 15 feet at ledge, 16 September 1962.-UMML 11307 (292,29.7-79.6) Monroe County, %-Vz mile SW of Alligator Reef Light in 15 feet at ledge, 25 September 1962.-UMML 11312 (78, 31.6-70.5) Monroe County, ],4 mile SW of Alligator Reef Light in 15 feet, 5 October 1962.-UMML 11317 (51, 26.1-85.5) Monroe County, V4 mile SW of Alligator Reef Light in 15 feet at ledge, 1 February 1963.

COLORATION Color patterns of juveniles and adults of Thalassoma bifasciatum fall into three general phases. The first is a yellow phase in which the upper half of the head and body is bright yellow and the lower half is white, with two large orange-brown spots posterior to the eye. The dorsal fin has an anterior black spot within a gray stripe extending along the middle of the fin. Two variations of this phase are the addition either of a lateral greenish-black stripe extending from the posterior edge of the operculum to the caudal fin, or a single series of large greenish-black squares in the same area, separated by whitish vertical stripes. The white phase is similar to the two variations of the yelJow phase except that no yellow color is present. There may be a black stripe along the nape and the dorsal edge of the body. A white-phase individual never lacks the dark markings. Individuals in the bluehead phase have blue heads and green bodies. These two colors are separated just posterior to the base of the pectoral fin by two broad vertical black bands, these separated in turn by a broad bluish-white band. A black area is present on the distal portion of each pectoral fin. All individuals on the reef other than those in the bluehead phase are in the yellow phase. Most often, these yellow-phase individuals are plain, with only faint suggestions of the greenish-black body markings. However, 1965] Feddern: The Bluehead Wrasse 903 individuals can acquire the stripe or the squares in seconds. This usually happens when they are captured with the drop net. Almost all preserved specimens possess the stripe or the squares; very few are plain. This may indicate that the stripe and the squares are fright patterns, displayed during an emergency. Occasionally, undisturbed individuals showing the stripe or the squares are seen. In these cases, almost all other individuals nearby exhibit the same pattern. Those inshore, except for individuals in the bluehead phase, almost always display the white phase, with either a stripe or the squares. Bluehead-phase fish are the same color in all habitats. No apparent differences exist between individuals in different areas, and no individuals were found that could change to yellow or white-phase coloration, except possibly those in the process of acquiring bluehead-phase coloration. Nichols (1930: 317) may have referred to these when he noted that the bluehead pattern may change in a few minutes to one resembling the yellow phase, because when several of these between-phase fish were kept overnight, the bluehead coloration faded almost completely. Tee-Van (1932: 47) stated that individuals do not adapt their color to their surroundings. However, Longley (1915: 208) noted that color changes are commonly induced by changes in the environment and domi- nated by the color character of the environment which actuates it. The author's own observations suggest that individuals make little attempt to adjust to minute changes in the environment, such as local variations in the substrate. The preponderance of white-phase fish inshore may be an adjustment to the environment, where the water is usually quite turbid compared to that at the reefs. Individuals can change from the yellow to the white phase and vice versa, but this is a slow process. There is no difference in coloration between sexes in the yellow and white phases. Bluehead-phase individuals are males.

COUNTS AND MORPHOMETRY Fin-ray counts of Thalassoma bifascia(um are as follows, with the modal values in parentheses: Dorsal VIII, 12 to VIII, 13 (VIII, 13); anal III, 10 to III, 11 (III, 11); caudal (segmented) 14 to 16 (16); and pectoral 13 to 15 (14). Scale counts are: lateral-line 26; scales above lateral line 3; scales below lateral line 9; caudal-peduncle scales 15 to 16 (16). Gill-raker counts varied from 17 to 19, with most counts 17 or 18. Morphological changes during the growth of juveniles and adults of both sexes and including yellow-phase and bluehead-phase specimens are shown in Table 1 and Figures 1-6. Among the ratios plotted against standard 904 Bulletin of Marine Science [15(4) TABLE 1

BODYMEASUREMENTS(MM.) OF JUVENILEANDADULT Thalassoma bifasciatum (BLOCH)

Specimen Predorsal Preanal Body Head Snout Orbit Number S.L. Length Length Depth Length Length Length

UMML 7251 1 77.1 25.0 45.2 20.1 23.8 6.5 4.9 2 72.4 24.7 41.3 18.6 22.8 6.8 4.3 3 69.2 22.5 40.4 17.6 21.4 5.5 5.0 4 62.2 19.3 33.9 14.9 19.2 5.0 4.0 5 62.7 18.8 34.9 14.7 18.8 4.9 4.0 6 52.5 16.4 29.3 13.4 15.5 3.9 3.2 7 54.5 17.7 30.9 14.4 16.8 4.4 3.7 8 55.4 17.0 31.5 12.7 16.7 4.3 3.4 9 54.4 17.4 29.9 ] 3.2 16.2 4.1 3.8 10 47.8 15.2 27.6 10.9 15.2 3.6 3.3 11 53.2 16.1 31.0 13.2 16.2 4.0 3.8 12 47.4 15.7 27.7 11.6 14.2 3.4 3.1 13 38.7 12.3 22.2 9.6 ] 1.9 2.7 2.8 14 46.6 ]5.3 26.4 12. ] ]5.0 3.4 3.2 15 47.6 15.2 26.4 11.5 14.4 3.3 3.2 16 41.1 13.2 22.4 9.7 12.3 2.8 3.] 17 36.7 ] 1.8 21.0 9.6 11.5 2.6 2.6 18 32.8 10.8 17.4 8.1 ]0.7 2.3 2.4 19 26.5 9.2 14.4 5.8 8.7 1.9 2.2 UMML 9791 1 71.8 22.6 40.4 17.4 22.0 6.2 4.6 2 78.0 24.7 43.0 19.6 23.5 6.6 4.5 3 72.4 23.0 41.3 17.5 22.3 6.4 4.6 4 70.2 22.4 40.4 18.0 21.7 6.6 4.6 5 69.6 23.1 39.4 16.0 22.0 6.3 4.7 6 73.5 23.8 40.7 17.9 22.8 6.2 4.2 7 52.7 17.1 29.] 12.5 16.1 4.3 3.4 8 59.3 18.9 33.7 13.5 18.5 5.0 3.6 9 62.0 19.3 33.6 14.8 18.8 4.8 3.5 10 52.0 16.2 29.4 11.4 16.6 4.1 3.0 11 51.2 16.2 29.2 12,1 15.9 4.2 2.8 12 49.4 15.5 27.7 11.5 15.6 4.1 3.0 13 59.4 18.6 33.8 14.5 18.9 5.2 3.2 ]4 49.5 16.0 28.2 11.4 15.5 4.0 3.2 15 49.4 15.7 27.3 12.0 14.5 4.0 2.6 16 55.3 17.4 31.2 12.9 17.0 4.6 3.5 17 51.0 16.8 29.0 12.6 15.2 4.0 2.6 18 54.5 17.1 30.4 13.0 15.9 4.3 3.0 19 49.7 16.2 27.9 ] 1.5 15.4 4.3 2.9 20 61.0 20.0 34.6 14.6 20.0 5.2 4.1 21 40.8 13.3 22.9 9.4 13.0 3.6 2.8 22 58.0 19.7 32.8 14.4 ]8.6 4.8 3.4 23 45.4 15.5 25.2 11.3 14.4 3.7 2.7 1965] Feddern: The Bluehead Wrasse 905 TABLE 1 (continued) BODYMEASUREMENTS(MM.) OF JUVENILEANDADULT Thalassoma bifasciatum (BLOCH)

Specimen Predorsal Preanal Body Head Snout Orbit Number S.L. Length Length Depth Length Length Length

UMML9791 24 51.7 17.3 29.4 12.4 17.0 4.4 3.6 25 58.6 19.2 33.6 14.1 18.6 4.6 3.8 26 64.9 21.9 37.3 16.3 20.2 5.9 4.2 27 58.6 19.5 33.4 13.7 17.9 4.9 4.0 28 51.9 17.7 29.8 11.9 15.7 4.2 3.4 29 70.6 30 12.6 4.7 7.2 3.1 4.7 1.2 1.5 31 14.1 5.5 8.4 3.6 5.1 1.2 1.6 32 13.5 5.3 7.9 3.4 5.1 1.1 1.5 33 12.2 4.8 7.0 3.1 4.6 1.1 1.4 34 11.7 4.4 6.4 2.9 4.2 1.0 1.4 35 12.5 4.7 7.0 3.1 4.7 1.1 1.4 36 38.8 12.7 22.0 10.0 12.6 3.0 2.6 37 45.1 15.5 26.2 11.6 14.4 3.6 3.3 38 51.5 17.0 30.8 12.3 16.2 4.1 3.4 39 58.8 21.0 35.0 14.9 19.1 5.6 3.9 40 53.5 17.8 30.6 12.8 17.2 4.6 3.4 41 47.7 16.0 27.4 11.3 14.7 4.1 2.9 42 64.6 43 47.8 16.0 27.0 11.2 14.5 4.1 3.0 44 44.1 14.5 24.0 10.0 13.9 3.8 2.9 45 44.2 14.2 25.4 10.5 13.8 3.5 2.8 46 57.2 47 48.9 48 44.7 49 66.3 50 42.6 51 48.2 52 43.6 14.2 25.1 11.0 13.4 3.7 3.0 53 43.3 54 43.1 55 44.7 56 44.0 57 46.9 58 40.0 13.2 22.3 10.0 12.6 3.2 2.8 59 36.9 12.7 20.7 8.4 11.6 3.0 2.6 60 46.1 61 45.1 62 41.1 14.0 23.2 9.6 13.0 3.5 2.9 63 40.0 13.4 23.3 9.7 12.9 3.2 2.6 64 35.4 12.8 20.5 8.8 11.4 2.7 3.0 65 40.1 66 38.0 906 Bulletin of Marine Science [15(4)

...i .450 iii x.400 I- '"Z 'j .350 .0 ' • .. " .. ...J ',. " ~ .300 '"o Q ~ .250 Q. 10 15 20 25 50 55 60 65 70 75 80 STANDARD LENGTH IN MM FIGURE 1. Thalassoma bifasciatum (Bloch). The relationship of the ratio of predorsal length/standard length to standard length, expressed in thousandths of standard length. length, only the predorsallength and the head length show any proportional changes during growth. Both of these are decreases of the ratio, The ratio of snout length plotted against head length shows an increase with growth while that of the orbit length shows a decrease. No sexual dimorphism is exhibited in morphometric features in Thalas- soma bifasciatum.

SPAWNING Thalassoma bifasciatum, in common with many scarids and other labrids, exhibits two spawning patterns: an aggregate spawning, involving many specimens of yellow-phase fish; and pair-spawning, involving a bluehead-phase male and a yellow-phase female. Randall & Randall (1963: 55) described spawning in this species as follows: The fish usually concentrate their activity over prominent rocks or heads of coral. As many as 80 or more were seen milling at one time over a single coral head. Within this aggregation smaller groups of about 5 to 10 or more fish began to swim more rapidly in one direction and then

...i ,650 ui .... :1:.600 I- '"Z ,', ~ ,550

...J ~.. ,500 w a: Q. 450 ~ ~ ~ ~ ~ ~ ~ w ~ ro ~ 00 STANDARD LENGTH IN M'" FIGURE 2, Thalassoma bifasciatum (Bloch). The relationship of the ratio of preanal length/ standard length to standard length, expressed in thousandths of standard length. 1965] Feddern: The Bluehead Wrasse 907

.350~1-~-~-~-~-~-~-~-~------J ...i - 8.200 m .150 10 30 35 40 45 50 55 60 65 70 75 80 STANDARD LENGTH IN 101M

FIGURE 3. Thalassoma bifasciatum (Bloch). The relationship of the ratio of body depth/ standard length to standard length, expressed in thousandths of standard length.

another. As with parrotfish, there is a sudden upward or diagonally upward movement which resulted in the fish being a maximum of about 2 feet above the rest of the group. A small cloud of white could often be seen, indicating release of sperm. Rarely were the large blueheads present in the milling aggregations of the yellow "nitidum" and then they mostly chased individual yellow fish. On only two occasions was spawning by blueheads and yellow phase females observed. After a very short chase the female fish darted upward with the male bluehead and they spawned. Randall (personal communication) believed that those scarids and labrids that possess distinctively colored male patterns have similar two- phase spawning patterns. In the early afternoon of 9 April 1963 at Alligator Reef, four or five temporary spawning groups, each of about 10-15 specimens, were observed to form from a small ag3:regation concentrated over a mound of Millepora complanata at a depth of eight feet about 100 yards east of Alligator Reef Light. Three separate spawnings occurred in a few minutes. Even after

.. 400 ...J ••••• ~ .300 ...J

~ .250 w :I: .200 ~ w ~ w ~ 70 75 80 IN 101M FIGURE 4. Thalassoma bifasciatum (Bloch). The relationship of the ratio of head length/ standard length to standard length, expressed in thousandths of standard length. 908 Bulletin of Marine Science [15(4)

.400

...J .350 :I:

.300 :I: ~r- z w .250 ...J

r- ~ .200 z en .150 o 5 10 15 20 25 HEAD LENGTH IN MM FIGURE 5. Thalassoma bifasciatum (Bloch). The relationship of the ratio of snout length/head length to head length, expressed in thousandths of head length.

specimens in a group had just spawned, the group did not break up. Possibly ova are not all shed at once by an individual female. After a few minutes of this group activity, the groups broke up and specimens resumed normal aggregate behavior, with no suggestion of spawning activity. Aggregate spawning was observed by Dr. C. Richard Robins in water less than 10 feet deep at Ajax Reef off the northern end of the chain of the

.400

.350

.300

:r t; .250 z o w ...J . , . :. , ," .: ," .200 r- oo a:: o .150

.100 o 15 30 HEAD LENGTH IN MM FIGURE 6. Thalassoma bifasciatum (Bloch). The relationship of the ratio of orbit length/head length to head length, expressed in thousandths of head length. 1965] Feddern: The Bluehead Wrasse 909 Florida Keys. Aggregate spawning was also observed by the author near the outer end of the south jetty at Riviera Beach, Palm Beach County, Florida, above the rocks in about 10 feet, also during the afternoon. Two factors make it difficult to observe the spawning of these fish: actual spawning takes place very rapidly; relatively few individuals are in breeding condition at anyone time because of the lengthy spawning season. Dates on which Randall (personal communication) saw spawning in the Virgin Islands are given in Table 2. These do not include observations of spawning made one or two days after an initial sighting. Most sightings were very close to either full moon or new moon. However, since spawning takes place during the day, it is doubtful that moonlight has any effect. During the three-year period, spawning in the Virgin Islands took place in all months of the year except September. Testes in yellow-phase fish are always large, elongated, flattened, smooth, and white, and are located latero-ventrally between the viscera and the coelomic wall. Non-ripe ovaries are always small, short, thick, granular, and yellowish, and are located just dorsal to the intestine. With increase in degree of ripeness, the posterior portion of the ovary enlarges to fill almost the entire coelomic cavity. Large males in the bluehead color phase have testes ranging in size from very small, smooth, whitish organs located beside the posterior portion of

- - - Opaque Ova 50 -- Transparent Ova

~40 --, o \ \ u. o \ \ 630 \ z \ \ \ \ 20 \ \ \ \ 10 "- .... " "\ o ~---~_ I .068 .136 .204 .272 .340 .408 .476 .544 .612 .680 .748 .816 OVUM DIAMETER IN MM FIGURE 7. Thalassoma bifasciatum (Bloch). Diameter frequencies of ova of a 38.0 mm female (specimen no. 65) caught on 17 December 1961. 910 Bulletin of Marine Science [15(4)

--1 - - - Opaque Ova 50 \ -- Transparent O~Q \ \ ;j!40 \ o \ \ ~ \ 1\

630 " I \ z " I \ '\ I \ \ I \ \ I \ 20 \! \ \ \ 10 \ \ \ \...._-"'l-.. ... o .068 .340 .408 .476 .816 OVUM DIAMETER IN MM FIGURE 8. Thalassoma bifasciatum (Bloch). Diameter frequencies of ova of a 52.0 mm female (specimen no. 10) caught on 17 December 1961.

-- - Opaque Ova -- Transparent Ova

.816

FIGURE 9. Thalassoma bifasciatum (Bloch). Diameter frequencies of ova of a 48.2 mm female (specimen no. 51) caught on 17 December 1961. 1965] Feddern: The Bluehead Wrasse 911 TABLE 2

Thalassoma bijasciatum (BLOCH). DATES ON WHICH SPAWNING WAS OBSERVED IN THE FIELD. Number of Days Date of Spawning Closest Moon Phase Date of Closest Between Spawning (new or full) Moon Phase and Moon Phase Virgin Islands (Randall) 18 October 1958 new 12 October 1958 1 28 November 1958 full 26 November 1958 1 25 December 1958 full 26 December 1958 0 23 January 1959 full 24 January 1959 0 4 February 1959 new 7 February 1959 2 9 February 1959 new 7 February 1959 1 20 March 1959 full 24 March 1959 3 8 May 1959 new 7 May 1959 0 20 May 1959 full 22 May 1959 1 20 July 1959 full 20 July 1959 0 4 December 1959 new 30 November 1959 3 8 August 1960 full 7 August 1960 0 23 August 1960 new 22 August 1960 0 17 November 1960 new 18 November 1960 1 5 January 1961 full 1 January 1961 3 23 January 1961 new 16 January 1961 6 10 March 1961 new 16 March 1961 5 29 April 1961 full 30 April 1961 0 23 June 1961 full 28 June 1961 4 Florida 17 February 1962 full 19 February 1962 1 9 April 1963 full 9 April 1963 0 the intestine to large typically yellow-phase organs located against the coelomic wall. Many large yellow-phase specimens, as well as a few bluehead-phase specimens, apparently have very degenerate gonads, for in spite of extensive macroscopic search, no gonads were found. These specimens are most likely sterile. In the unripe ovary, ova in all stages of maturation are distributed evenly throughout the ovary. In the ripe ovary, however, there is a sharp gradient from primary ovarian cells at the anterior end of the ovary to mixed sizes of unripe ova in the anterior third to exclusively ripe ova in the distended portion of the ovary. The ovaries of seven selected females in different stages of ripeness were removed and all ova in a portion from the middle of each ovary were measured. In fully ripe ovaries, all ovarian material was removed and thoroughly mixed to get a random portion for measurements of ova. Figures 7-13 show these measurements in graphic form. 912 Bulletin of Marine Science [15(4)

60 A 1\ I \ -- - Opaque Ova 50 I \ -- Transparent Ova I \ I \ I \ ~40 o \ ... \ o \ 030z \ A \ /\ \ I \ V \ 20 \ \ \ \0 \ \ \ I V o .068 .544 810 MM FIGURE 10. Thalassoma bifasciatum (Bloch). Diameter frequencies of ova of a 70.8 mm female (specimen no. 8) caught on 19 November 1961.

A 1\ 60 I \ I \ I \ - - - Opaque Ova 50 I \ I \ -- Transparent Ova I \

<[ \ 1'; 40 \ ... o "- "'" " "- '\ \ \ 20 \ \ \ \ 10 \ \ \ o .068 .816

FIGURE 11. Thalassoma bifasciatum (Bloch). Diameter frequencies of ova of a 69.1 mm female (specimen no. 11) caught on 19 November 1961. 1965] Feddern: The Bluehead Wrasse 913

~ --- Opaque Ova '\ 50 1\ -- Transparent Ova I \ I \ I \ ~40 I \ I \ lL o I \ I "- I "- I "\ I \ I \ 20 I \

" '\ " '\ 10 \ \ \ o I .068 .340 .408 .476 .544 .816 OVUM OIAMETER IN MM FIGURE 12. Thalassoma bifasciatum (Bloch). Diameter frequencies of ova of a 66.5 mm female (specimen no. 15) caught on 19 November 1961.

70 ~ 1\ 60 I \ I \ I \ "'" /_ v~ \ --- Opaque Ova 50 I \ -- Transparent Ova I \ I '--, I \ ~40 I \ I \ lL o \ \ ci 30 z \ \, \ 20 \ \ \ I \ 10 \ \ \ \ \ o '-- .068 .340 .408 .476 .544 .748 .816 OVUM OIAMETER IN MM FIGURE 13. Thalassoma bifasciatum (Bloch). Diameter frequencies of ova of a 41.5 mm female (specimen no. 35) caught on 20 March 1962. 914 Bulletin of Marine Science [15(4) Judging from the figures, there appears to be a permanent reservoir of immature opaque ova about 0.13 mm in diameter in all ovaries. In addition, there is a secondary peak of ripening ova. When these ripening ova attain a diameter of about 0.27 to 0.37 mm, they become transparent. Ova continue to enlarge until they are ripe, at about 0.54 mm diameter. Most are then expelled. However, a few remnant ova 0.75 and 0.78 mm in diameter have been found, indicating that resorption of unexpelled ova probably does not occur. Ripe ova always contain a yellow oil globule, although in many cases other structures of unknown identity are present. Data on diameter of ova for studies of spawning were collected in the following manner: five of the larger opaque ova in each ovary were measured. If the ovary also contained transparent ova, the first five encountered were also measured. The measurements of opaque and of transparent ova were averaged separately for each specimen. Graphs were constructed in which all specimens were first represented by averages of opaque ova, and if they also contained transparent ova, they were also represented by averages of transparent ova (Figs. 14-20). Dots on these graphs represent averages of opaque ova for ovaries containing no transparent ova. To check the validity of measuring only five ova from each ovary, 20 ova of each type (opaque or transparent) were measured for one collection of fishes, and the averages of these graphed. Essential similarity was noted when comparing this graph to one constructed by using the average of the first five values of each set of twenty measurements. The collection for 27 August 1962 comprised individuals from the entire area along the ledge southwest of Alligator Reef Light. This was done by

~ 5 MAY 1962 P-., /., ,:,h ,":\ / . \ ~ l::1 o 10 r.~::\\ , \ L1.. ,: ::: J o ,.....\ o c::::\ z 0 I::::: :! .204 .272 .340 .408 .476 .544 .612 .680 .748 .816 AVERAGE OVUM DIAMETER IN MM FIGURE 14. Thalassoma bifasciatum (Bloch). Average ova-diameter frequencies from females collected on 5 May 1962. Dashed lines indicate averages of five of the larger opaque ova of each ovary. Solid lines indicate averages of the first five transparent ova encountered in each ovary. Dots represent average opaque ova values in ovaries lacking transparent ova. 1965] Feddern: The Bluehead Wrasse 915

20 JUNE 1962

~20

o .204 .272 .544 .816 AVERAGE OVUM DIAMETER IN MM FIGURE15. Thalassoma bijasciatum (Bloch). Average ova-diameter frequencies from females collected on 20 June 1962. See Figure 14 for explanation. making sets of the drop net in many different spots. Of the 289 females in this collection, 243 specimens (84 per cent) contained transparent ova, as seen through the microscope. State of ovarian ripeness was noted for each female in the collection by visual observation. The ova were measured under the microscope with an ocular micrometer. The results then were plotted as follows: the frequency distribution of transparent ova diameters was indicated by the solid line; the average diameters of ova from ripe ovaries were indicated

JULY 1962

I .408 .476 .544 .816 AVERAGE OVUM DIAMETER IN MM FIGURE16. Thalassoma bifasciatum (Bloch). Average ova-diameter frequencies from females collected on 1 July 1962. See Figure 14 for explanation. 916 Bulletin of Marine Science [15( 4)

40 ~, 5 AUGUST 1962 I I I I I I 1 I i I o I, 20 I in "- J III o , II, o I : \ z 10 :I 1, I I

,,1" .. . I o I!:::: :. ~, .204 .212 .816

FIGURE17. Thalassoma bifasciatum (Bloch). Average ova-diameter frequencies from females collected on 5 August 1962. See Figure 14 for explanation.

by open circles; the average diameters of ova from nearly-ripe ovaries were indicated by points (Fig. 21). This graph indicates that each spawning period lasts for a week or more, because some specimens had no transparent ova (had probably just spawned), others were ripe, others were almost ripe, and others were of doubtful ripeness. . The arithmetic means of the curves in Figures 14-20 were plotted against time, and curves drawn by eye through these points (Fig. 22) to indicate possible rates of ova diameter increases. The average diameters of the ova from 58 ripe specimens of 27 August 1962 were again averaged to obtain the mean diameter of ripe ova. This was added to Figure 22 as a horizontal dashed line. The trend lines indicate that four spawning periods occurred in seven months. Apparently, however, each female has spawned only three times during this period, since the average diameter of ova of about half of the females of 1 July 1962 and 5 August 1962 formed one peak and the other half formed another peak. In other collections, almost all diameters of opaque ova formed a unimodal curve. A few aberrant individuals were present in each collection. These specimens must spawn at other times. The variation in ripeness and the indication that, after spawning, a second group of ova begins to develop, suggests that ova ripen continuously throughout the year, with frequency of spawning dependent on the rate 1965] Feddern: The Bluehead Wrasse 917 of ripening. The disadvantageous effect of few specimens being ready to spawn at one time is offset by the aggregate-spawning by individuals, and also by the alternate pair-spawning. The diameters of ova of each specimen are independent of the size of the individual, being the same in both small and large females. Figure 23 shows the relationship between average diameter of ova and size of 152 specimens collected on 27 August 1962. These specimens ranged from 28 mm to 67 mm, yet there was no gradient of diameter of ova from small specimens to large. To obtain a measure of fecundity in this species, all ripe ova in each of five specimens were counted under a microscope with the results shown in Figure 24. Numbers of ripe ova in each female ranged from 800 in a 38.5 mm specimen to 3000 in a 53.9 mm specimen. For all large and small collections, the preponderance of females over males (Table 3) indicates that sex reversal from female to male is a

80 I • "II II 70 I' I'" I 27 AUGUST 1962 I I I 60 I I I

~, I I o"- I 30 I I o I z I I I I 20 I I I I I 10 I I I 1 t' I I : - 1 I.: :. l o It. 1.1 •• ::..\ .204 .272 .340 .408 .816 AVERAGE OVUM DIAMETER IN MM FIGURE 18. Thalassoma bifasciatum (Bloch). Average ova-diameter frequencies from females collected on 27 August 1962. See Figure 14 for explanation. 918 Bulletin of Marine Science [15(4)

~\ 50 ~:, IS SEPT. 1962 ,~:~..~ I::~ ""1 I'w",:::, ::::11"'\ ,:::l1"'\ ,::: ~ ::::~ ••.. o r/ ! d20 ~:::: z 1 ,t:::•..•• :J L:J

10 1\\ \ \n\ 1······1 1'::::::'•••••• \ o I:::::·~_ . .204 .272 .544 .816 AVERAGE OVUM DIAMETER IN MM FIGURE19. Thalassoma bifasciatum (Bloch), Average ova-diameter frequencies from females collected on 16 September 1962. See Figure 14 for explanation.

40 25 SEPT. 1962 ~ '.1 ,.\'.' I" ,',,'\ (I '" ::!"\ ::1

I'"" J'" . LL j o ,.,Ji:: t:: :\ zo ,...., I::::;I····' I ••••••

o tFr~j1~i!~1\ .204 .272 .340 .544 .816 AVERAGE OVUM DIAMETER IN MM FIGURE20. Thalassoma bifasciatum (Bloch). Average ova-diameter frequencies from females collected on 25 September 1962, See Figure 14 for explanation, 1965] Feddern: The Bluehead Wrasse 919 definite possibility, although this is a relatively unimportant aspect in the life history of this species due to the extreme scarcity of bluehead-phase fish in relation to the abundance of yellow-phase fish. Bluehead-phase individuals are estimated to form less than 4 per cent of the population. Lannberg & Gustafson (1936) noted that Labrus ossifagus, a European wrasse, has two color phases. Individuals smaller than 255-310 mm possess a red phase, and are mostly females, whereas most individuals larger than 255 mm have a blue phase, and are mostly males. Many intersexual specimens in the process of changing their color phase were recorded. Males become ripe while still in the red phase, and later change to the blue phase. Thus both males and at least some females become blue, the females changing to males in the process. Bacci & Razzauti (1958) concluded that Coris julis, another European labrid, is only a color phase of the older individuals of C. giofredi, and that the sexual change from female to male runs roughly parallel to the change from the giofredi to the julis pattern, respectively. However, only a few individuals showed signs of a preceding female phase by means of small and degenerating oocytes. Apparently there is a rapid development of spermatocytes.

TABLE 3 ThaJassoma bifasciatulIl (BLOCH). COMPOSITIONBY SEX OF SEPARATE COLLECTIONS. - ---- Date of Collection Total Specimens Number of Number of Number of Males Females Juveniles* ------~~-- -- 30 April 1961 36 3 13 20 4 November 1961 17 3 6 8 11 November 1961 9 0 9 0 19 November 1961 8 18 3 34 17 December 196] 66 25 33 6 28 January 1962 22 8 14 0 ]3 February 1962 25 8 12 5 10 March 1962 8 3 5 0 20 March 1962 45 12 25 7 31 March 1962 26 5 10 11 5 May 1962 186 75 84 27 20 June 1962 292 104 167 21 1 July 1962 242 106 136 0 5 August 1962 419 174 226 19 27 August 1962 513 223 289 1 16 September ]962 483 237 246 0 25 September 1962 292 128 162 2 5 October 1962 78 31 47 0 *Juvenileswere captured by a method differentfrom that used for males and females; thus numbers of juveniles are not proportionate. For certain collections.no effort was made to capture juveniles. 920 Bulletin of Marine Science [15(4) Stoll (1955) found that females of Thalassoma bifasdaturn, injected with methyl testosterone, developed testicular tissue in the ovary, with concomitant absorption of ovarian tissue. These ovotestes also contained large amounts of connective tissue absent in normal gonads. With the development of ovotestes, the individuals developed bluehead-phase coloration. Natural sex reversal has not yet been recorded in Thalassoma bifasciatum, although Stoll (1955) collected a true hermaphrodite with one lobe of testicular tissue and one of ovarian tissue. The main aspects in the spawning of Thalassoma bifasciatum therefore seem to be a twofold spawning pattern of individuals larger than about 30 mm performed during the day and involving either a group of yellow-phase fish of both sexes or a pair consisting of a bluehead-phase male and a yellow-phase female. A single ovary may contain more than one group of ripening ova at a time, with ripening, and thus spawning, occurring at intervals throughout the year.

27 AUGUST 1962

VI l.U Cl« 1520 ~ ;; 0 15 IJ.. o o z 10

5 ·0000000. ·000.000- ·00000000·· 00000000000' .476 .510 .646 AVERAGE OVUM DIAMETER IN MM FIGURE 21. Thalassorna hi/asciaturn (Bloch). Size-frequencies of ova from females collected 25 September 1962. The solid line represents transparent ova, the open circles represent ova from ripe ovaries, and the points represent ova from nearly-ripe ovaries. 1965] Feddern: The Bluehead Wrasse 921

TEMPERATURE ·C ",0

iii 0: III CD .~ c:::0 E o~;.::::.2ro ~ .•..•• ctt·- 0: 'Clc:::"O:>:;E III CD "'O~"O'" IO::E ~~~~ro -Ill ro~'"C~:{i :> OJ ~ ._ 5-l 0 z ~..9...... u::1 c:::o.-S •.• i<) ,~ c:::0 ~ o~S.so 0: N o,~ III E CD '(ii ~ t; 8 0 . III PS.•.•·5 "':C en --..oel)o:l'E i<) t:§>.'" •.• °E •... en -=Q)t~ .~ E'c § !f!6 S ::> ~QJ~C'jQJ ~..c:::~.e-'- x .., -.. .-::: J-4 r-rJJ ~ ~ on c:::X , ~~~~,....;..a ,';::"0 8 N 'C No:l 0 N:>~",~[i; III 0 o.~.••.•••...• eJ)0 •• ~ ,5 ~ o..c::: o..~~i3'- '5o:l ~.~ ~]~ Q) ~ ~...'~° !Xl iii

x -::E

GROWTH Since spawning takes place periodically throughout the year, and each spawning period is an extended one, all sizes of juvenile and adult fish can be expected to occur on the reef at all times. This is the case, although definite size-frequency peaks occur. The smallest juvenile found on the reef was 10.1 mm. Maturity occurs at about 30 mm. Based upon size-frequency graphs (Figs. 25-31), most fish attain a length of 60-70 mm; a few grow much larger. The only collecting method that yielded sufficient specimens for analysis was the use of the drop net. Unfortunately, this method was effective on large specimens only, since those smaller than 30-35 mm were not attracted to the bait. The small individuals were noted by observation and by collection with a hand net, but were not included in analysis. In the size-frequency graphs (Figs. 25-31) based on the drop net

.646

.612

.578 ...... ~... :2; .544 :2; . q"() ~ .510

:5 .476 ~ ~ .442 « o .408 :2; ~ .374 o ..,l.Il.340 « ffi .306 ~ .272

.238

.204

.170 25 55 70 STANDARD IN MM FIGURE 23. Thalassoma bifasciatum (Bloch). Average ova diameters of opaque and transparent ova according to size of fish. Each specimen is represented by a point for the average of five of the larger opaque ova and a point for the average of five transparent ova (if present). Circled points represent two points of the same value. 1965] Feddern: The Bluehead Wrasse 923

4,000

3,000 •

2,000 • ~ o

lL.. o • o z

•

500

30 35 40 45 50 55 60 65 STANDARD LENGTH IN MM FIGURE 24. Thalassoma bifasciatum (Bloch). Number of ova per female as it varies with size of fish. 924 Bulletin of Marine Science [15(4)

25 5 MAY 1962

(/) ~ 20 ---- Females :IE --- Male o -- Combined ~ 15 (/)

~ 10 o Z 5

25 30 35 40 45 50 55 60 65 70 75 80 85 90 STANDARD LENGTH IN MM FIGURE 25. Thalassoma bifasciatum (Bloch). Size frequencies of specimens collected on 5 May 1962. Midpoints of 2.5-mm class intervals were used.

35 (' 20 JUNE 1962 30 ''\j' ----- Females --- Males

25 -- Combined 1\ " \

I \ I " , " \/ ,V \ \

LL o ,,/ '; \\'~ J ,'" • ....L. ci 10 : / \ \ z / / \ \ j, / \ \ . 5 0<"'-/ // \~~·0. '/::::'7 -;. -./ \'---._-\'~ L..', .....•--- / . , .~-'-.;::. 25 30 35 40 45 50 55 60 65 70 75 80 85 90 STANDARD LENGTH IN MM FIGURE 26. Thalassoma bifasciatum (Bloch). Size frequencies of specimens collected on 20 June 1962. Midpoints of 2.5-mm class intervals were used. 1965] Feddern: The Bluehead Wrasse 925

30 /~\/ I JULY 1962 (/) 2S ----- Females z w ~", . --- Males :!: \ 20 I \ --Combined U I ,",'~\ • w I \ 11. I \ (/) " \ 15 " './", \. IL ~ o , . ,", .---.~.~\ .\ .----- I .".. '\\ 10 ! g / I / '- . /\ ;' i...... / "' \\.~ / \ I I '...... \ S ) I AI \ \ . / ,'. \ .....•...••\" .-. ~f--'---: '-:---.::-.....---' ..... "' ...... • -- _.~,. .';-... 25 30 35 65 70 90 IN MM FIGURE 27. Thalassoma bifasciatum (Bloch). Size frequencies of specimens collected on I July ]962. Midpoints of 2.5-mm class intervals were used.

40 5 AUGUST 1962 35 \/~·~/\ ----- Females (/) . /"'... --" ---Males ~ 30 I , I I -' - Combined ~ • I I I '. , \ u I I , \ ~ 25 , I (/) / I /\ //J\ \ ~ 20 ./ ~i ,/\ V·'\,. ci 11 1 ,'\ /' \ z 15 1 i \: \ /\)~ ./\ / I \ / • . \ I ,\ / I ~' \ I .' '\ 10 l/f /I \ \'I '-.,>-;;, \ ./ ! '.--"~\\i\" ".' // '\-/' ,?~ .,....., ;::.. .- . .--...... •- .-. " 25 30 35 40 45 50 5S 60 65 70 75 80 85 90 STANDARD LENGTH IN MM FIGURE 28. Thalassoma bifasciatum (Bloch). Size frequencies of specimens collected on 5 August 1962. Midpoints of 2.5-mm class intervals were used. 926 Bulletin of Marine Science [15(4) collections, most modes of females alternated with modes of males within the same collection. This distribution of modes indicates that at some time during the life history the growth rates of males and females differ. Differential growth does not occur in the adults, however, according to Figure 32, In this graph, the major modes of Figures 25-31 are plotted and connected. Assuming that the modes represent true increases of previously sampled modes, female growth ranged from 1 mm per 8.5 days to 1 mm per 15 days. Male growth varied from 1 mm per 9 days to 1 mm per 18 days. The growth rates shown by individuals kept in aquaria seemed to vary

55 27 AUGUST 1962

50 ---- - Female --- Mole 45 -- Combined

~40 w ::E I,;\ ~ ~35 / \ I' .\ f \ I \ a. I \ , \ CJ) : \ I \ 30 I • I \ • L-. " it\ .,' ~ ./\ o . : / \\ : \ 25 o :/.-1/"\~: : \\ z 20 1/ \7-' \\'~ I' \ \ . 15 ' /f \ ./\ :\...... \ IA 1\ 'I" I \ ,\,\\.1\/ \ ''. \ 10 / ",. \ , \ 1 \ \ / \.\ / IF I, ,/ \ \/ . " I .., \ 5 / "' ... . " j~,;I, ...... •" .'" ", o ",,.,' "', •...... 25 55 60 65 70 75 80 85 90 STANDARD LENGTH IN MM FIGURE 29. Thalassoma bifasciatum (Bloch). Size frequencies of specimens collected on 27 August 1962. Midpoints of 2.5-mm class intervals were used. 1965] Feddern: The Bluehead Wrasse 927 directly with the quantities of food supplied to the fish. In one aquarium, the fish were not fed, and almost no growth occurred (Table 4). In the other aquaria, sufficient quantities of food were supplied so that abdomens of the fish were normally distended. From these and other individuals, the general growth rate was estimated (Fig. 33). According to the graph, a specimen of 10 mm would attain a length of 60 mm in about eight months. The maximum size of any female collected is 79.5 mm; the largest yellow-phase male collected is about the same. The largest bluehead-phase male collected is 87.5 mm. Longley & Hildebrand (1941: 197) noted size ranges of 64 to 117 mm for 50 yellow-phase females, 84 to 114 mm for 19 yellow-phase males, and 114 to 146 mm for eight bluehead-phase males. They did not indicate which length measurement was used, but it is probably total length. Breder (1948a: 207) noted a maximum length of about six inches (150 mm) for the species.

FOOD AND FEEDING Randall & Randall (1960: 449), in their analysis of the stomach con-

45 40 /j/\/\ 16 SEPT. 1962 ---- - Females 35 --- Males

-- Combined

~ 20 ci z 15 I! \\ I'\,'\ //\><\\ \ '-'! / \1 \ I "'-. \ I /. '! '. \ \. 10 i:'/) /-- \\ \~~\ ' 5 il',/ " ~ /" I/ . ".'-'-•. -''/'-. " o ,,'-' ~ " " 25 30 35 40 45 50 55 60 65 70 75 80 85 90 STANDARD LENGTH IN MM FIGURE 30. Thalassoma bifasciatum (Bloch). Size frequencies of specimens collected on 16 September 1962. Midpoints of 2.5-mm class intervals were used. 928 Bulletin of Marine Science [15(4)

TABLE 4 Thalassoma bijasciatum (BLOCH). GROWTH OF JUVENILESAND ADULTS Initial Lengths Subsequent Lengths Type of Holding System (mm) (mm) 15-gallon open-system 11 Sept ]961 18 Sept 1961 4 Oct 1961 14 Oct 1961 aquarium 14.3 ]5.1 16.5 17.3 14.7 15.3 19.7 23.0 ]5-gallon open-system 15 Oct 1961 28 Oct 1961 7 Nov 1961 25 Nov 196] aquarium 13.4 16.6 20.1 20.2 13.2 15.1 13.4 16.0 13.3 16.0 13.2 24.4 24.8 24.6 27.0 30.0 31.0 11.4 11.4 11.6 11.6 12.2 ]2.5 20.4 20.6 20.4 20.6 22.0 24.1 26.2 20-gallon open-system 13.8 14.4 14.8 16.1 aquarium 13.9 15.0 16.2 20.7 13.9 16.0 21.3 23.1 19.4 27.8 28.7 19.3 22.4 23.6 25.1 19.4 22.7 25.5 28.6 19.2 21.7 23.6 23.3 27.3 29.9 27.4 31.2 33.3 33.5 Fiberglass-screen cage 1 Feb 1963 7 Feb 1963 in Bear Cut, Miami, 16.0 16.0 Florida 16.0 16.5 16.0 17.0 12.0 12.5 21.0 21.5 21.0 20.5 22.0 25.0 26.0 31.0 31.0 62.0 63.5 65.0 67.0 tents of 32 specimens of Thalassoma bifasciatum ranging in size from 29 to 63 mm, found occasional crustacean ectoparasites of fishes, primarily small isopods. Most other stomach material consisted of free-living pelagic crustaceans, especially copepods. However, Beebe & Tee-Van (1928: 205) reported that stomach contents of the specimens they examined consisted of polychaetes. Longley & Hildebrand (1941: 198) found no external parasites in stomach contents. 1965J Feddern: The Bluehead Wrasse 929

30 25 SEPT. 1962

----- Females

80 /' - - - - females 75 -- Moles .---' :E 70 ~ ~ 65

:r ---- I- 60 (!) .--.=..--=-=.::":":'--=-- __ 0--'_- Z W ....J 55 --- c ,-,,/' ~ - - 0------. ------. -- - ./ ~50 z j! (I) 45 ---~--'--" ------.---- -',";,,,- .-- .------.------.- 40

35 I ~ AUGUST SEPTEMBER FIGURE 32, Thalassoma bifasciatum (Bloch), Increase in modal size with time for the principal modes of females and males of Figures 25-31. 930 Bulletin of Marine Science [15(4) Juveniles (individuals with immature gonads) most often form schools and roam close to the bottom picking at rocks, algae, and gorgonians, apparently searching for small benthic organisms. Adults are most often in loose aggregations, picking at particulate plankton. Yellow-phase individuals of both sexes and of all sizes occasionally pick parasites of other fish, although, as Randall & Randall (1960: 449) pointed out, this forms a minor part of the food. The author has seen an individual of Acanthurus coeruleus (Acanthuri- dae) being cleaned of parasites by several Thalassoma bifasciatum about 30 mm long. Longley & Hildebrand (1941: 198) noted that young individuals were frequently seen picking at other fishes, such as surgeon- fishes (Acanthuridae), chubs (Kyphosidae), demoiselles (Pomaccntridae) and the bar jack, Caranx ruber (Carangidae). Eibl-Eibesfeldt (1955: 209) noted Thalassoma bifasciatum cleaning parasites from Chromis marginatus and C. cyanea (Pomacentridae), Clepticus parrai (Labridae), Cdranx ruber, and Ocyurus chrysurus (Lutjanidae). Herald (1961: pI. 98) showed an Acanthurus bahianus being cleaned of parasites by Thalassoma bifasciatum.

120

110

100

~ 90

?; 80 i= 70 z~ lj 60

0 ~ 50 0z ~40 (/l 30

10 -

0 no r.vs FIGURE 33. Thalassoma bifasciatum (Bloch). Growth rate determined from specimens in aquaria, and one marked specimen. Successive standard lengths of specimens were plotted so that the combination formed a probable growth curve for juveniles and adults. 1965] Feddern: The Bluehead Wrasse 931 Bluehead-phase individuals have never been seen by the author or reported in the literature to clean parasites from fish. According to Randall (1958) all four species of the Indo-Pacific labrid genus Labroides are obligate parasite-pickers, individuals of Labroides dimidiatus even cleaning parasites from individuals of L. bieolor. Although adults of Thalassoma bifasciatum most often feed on particulate plankton, they will eat other food when it is offered. Longley & Hilde- brand (1941: 185) noted that the young eat eggs from the nest of Abudefduf saxatilis (Pomacentridae). When a large amount of food, such as a crushed sea urchin, is suddenly offered, the fish go into a feeding frenzy. This behavior pattern is initiated by one of more specimens of Thalassoma bifaseiatum or Haliehoeres slowly approaching the food and then picking at it frantically. This immediately attracts other individuals until a large number of Thalassoma and Haliehoeres are concentrated around the food. These fish may lose interest in a few minutes and start to drift away, but are again attracted when other individuals initiate the frenzy feeding. Thalassoma bifaseiatum may enjoy a partial freedom from predation because of its occasional activity in cleaning fish of ectoparasites. However, this immunity is not complete, as shown by the fact that a specimen of Hypoplectrus (Serranidae) disgorged a 10-mm specimen of Thalassoma bifasciatum and a similar-sized specimen of Haliehoeres. Dr. Donald P. de Sylva (personal communication) found four yellow-phase specimens of Thalassoma bifasciatum and one specimen of Haliehoeres sp. in the stomach of a specimen of Dasyatis eentroura (Dasyatidae) caught at West End, Bahamas, in May 1962.

MIMICRY By Hemiemblemaria simulus A clinid, Hemiemblemaria simulus, takes advantage of this partial immunity from predation by mimicking the color patterns and behavior of yellow-phase individuals of T. bifasciatum. (Stephens [1961J separates a number of blennioid genera including Hemiemblemaria into the Chaenop- sidae.) According to present literature this clinid only occurs in Florida and the Bahamas. The close resemblance of this fish to T. bifasciatum and its relative scarcity may account for the lack of distributional records. Juveniles of H. simulus are very unlike juveniles of T. bifasciatum. The very elongate body, apart from a white abdomen and a horizontal black line extending through the red eye and terminating in a black spot at the base of the caudal fin, is almost completely transparent, with only a trace of yellow dorsa-laterally. Individuals larger than about 35 to 40 mm reproduce all yellow-phase color patterns of T. bifasciatum, but apparently cannot reproduce bluehead-phase coioration. No individuals of H. simulus 932 Bulletin of Marine Science (15(4) have been found inshore, and none has been seen to possess the white color phase of T. bifasciatum. This is the only species of the family Clinidae in the Caribbean that swims with its pectoral fins. This is most likely an adaptive feature enhancing the fish's mimicry of T. bifasciatum. H. simu/us can only be recognized as it swims by its elongate body, larger mouth, and red eye (T. bifasciatum has a golden eye). Longley & Hildebrand (1940: 273) noted that H. simulus is solitary, each individual remaining in its particular area. It lives almost exclusively around large coral heads, where it is usually seen with its head protruding from the burrow made by a boring mollusk. The burrow of each large individual is almost exactly the diameter of the fish's body. Thus, a specimen probably changes burrows many times during its growth, as in the manner of hermit crabs. However, it often emerges and swims freely with Halichoeres bivittatus and T. bifasciatum. The author has noticed that young individuals of H. simu/us not yet possessing good mimicking coloration swim close to coral rock but do not retreat toward a burrow when chased. Longley & Hildebrand (1940: 275) also observed a nest of H. simulus with the eggs adhering to the inside of a mollusk burrow 28 mm in diameter. Each egg was 1.25 mm in diameter and contained one large oil globule and many smaller ones. The eggs were laid close together. Most of them were almost ready to hatch, while the rest were in an early stage of development in which the head and tail of the embryo were not yet free of the yolk mass. The nest was guarded by the male. Randall & Randall (1960) noted that four out of eleven specimens of H. simu/us contained free-living copepods, three others contained mysid shrimps (one also with the head of a 12-mm labrid fish), one specimen contained a 17-mm fish, possibly a microdesmid, while another specimen contained a pomacentrid. The remaining two specimens had empty stomachs. The mimicking ability of H. simu/us may serve two purposes (Randall & Randall, 1960: 451). Mimicry may help H. simulus escape predation since T. bifasciatum is relatively predation-free. Mimicry may also help H. simulus approach fish prey more closely since T. bifasciatum does not eat fish.

GENERAL BEHAVIOR

Tha/assoma bifasciatum is active only during the day, as are Halichoeres bivittatus, H. maculipinna, H. garnoti, and H. poeyi. During numerous night-time dives at Alligator Reef, Walter A. Starck II, William P. Davis, Robert Schroeder, and the author failed to find any of these species active. Late evening dives established that Thalassoma bifasciatum burrows or otherwise hides in the bottom at about one-half hour before sunset. About 1965] Feddern: The Bluehead Wrasse 933 one-half hour after sunrise, individuals were observed to appear suddenly above the bottom. All individuals seem to hide at about the same time and emerge at about the same time. Longley & Hildebrand (1941: 197) stated that Thalassoma bifasciatum buries itself in the sand, but this is probably not always true in nature. The collecting area southwest of Alligator Reef Light is extremely eroded solid limestone along the top of the ledge, where Thalassoma bifasciatum is most abundant. One observation made in the morning established the fact that the individuals inhabiting the top of this ledge hide in rock crevices and burrows at night. At this time, individuals emerged from rock crevices, rather than migrating from the nearest sandy area. Individuals in the rubble area northwest of the ledge probably do bury in the sand where it is available. Schooling behavior is seen only in individuals smaller than about 30 mm (visual estimate). Schools, usually composed of individuals of various lengths below this size, move about the reef just above the bottom. Specimens larger than 30 mm in the yellow phase form loose aggregations that remain almost stationary above a particular area. Individuals move around within an aggregation but generally do not stray from it. Seldom is more than one fish moving in the same direction as an adjacent one, and seldom are individuals close to one another. Movement is rather slow, and the fish are uniformly distributed throughout the aggregation. During spawning, this aggregation still exists for the most part, but the distribution of individuals is irregular due to the formation of a variable number of temporary schools of closely-grouped yellow-phase fish. The fish in each group move as a unit, swimming rapidly. Bluehead-phase individuals roam more widely than yellow-phase individuals, and seem to be more solitary. Individuals ordinarily use only the pectoral fins for swimming, keeping the rest of the body straight. As a result, the normal swimming motion is irregular. Escape reaction is more vigorous and involves use of the pectoral and caudal fins. However, the distance covered in escape is slight and small individuals can be headed off and cornered. Some then try to hide, but most try immediately to escape again.

SUMMARY 1. Thalassoma bifasciatum ranges from Bermuda and Florida to Cura<;ao, and from Cozumel Island, Yucatan, to the Cape Verde Islands. 2. The specific names nitidum and nitidissimum refer to different color patterns of Thalassoma bifasciatum. 3. The only allometry shown by juvenile and adult specimens is a relative decrease in predorsallength and head length as related to standard 934 Bulletin of Marine Science [15(4) length, and in orbit length as related to head length. The only increase is that of snout length as related to head length. 4. Three basic color phases occur in T. bifasciatum: a yellow phase on the offshore reefs; a white phase inshore; and a bluehead phase in all areas. 5. Both sexes exhibit the first two phases, but bluehead-phase fish are exclusively male. 6. Two types of spawning patterns exist: an aggregate spawning by a group of yellow-phase specimens; and pair-spawning by a bluehead-phase male and a yellow-phase female. 7. Gonads were prominent in all specimens examined except for a few very large yel1ow-phase fish and a few bluehead-phase fish. In these specimens, no gonads were found. 8. All ripe ova are located in the posterior portion of the greatly distended ovary and are free of unripe ova and ovarian tissue. 9. A size-frequency peak of opaque (unripe) ova is usually present in the ovary even before the transparent (ripening or ripe) ova are expelled. 10. Spawning occurs throughout the year. 11. There are periods of intensive spawning and periods of diminished spawning. 12. The periods of intensive spawning are about one and one-half to two months apart. 13. Ova ripen continuously throughout the year, with spawning intervals dependent on the rate of ripening. 14. The fecundity of females ranged from 800 ova in a 38.5 mm specimen to 3000 ova in a 53.9 mm specimen. 15. No relationship of ova diameter to fish size was noted. 16. Each egg contains a single yellow oil globule. 17. Sex reversal from female to male possibly occurs but no natural sex reversal has yet been discovered. 18. All sizes of juvenile and adult specimens are present on the reef throughout the year. 19. Means of size frequencies based on standard lengths of specimens in each collection showed much slower rates of increase than indicated by direct successive measurements on live individual fish. 20. Modes of females did not match with modes of males in size- frequency graphs, indicating different growth rates during some portion of the life history before adulthood is reached. 21. Yellow-phase fish attain maximum lengths of about 80 mm, while the largest bluehead-phase fish collected was 87.5 mm. 22. Yellow-phase specimens occasionally clean ectoparasites from other fish. This perhaps affords T. bifasciatum a partial immunity to predation. 23. Specimens are only active during the day. At night they either burrow into the sand or hide in crevices in the limestone. 24. Specimens smaller than 30 mm form small schools which remain 1965] Feddern: The Bluehead Wrasse 935 just above the bottom. Yellow-phase specimens larger than 30 mm form large loose aggregations, with individuals sometimes rising many feet above the bottom, but remaining within the area covered by the aggregation. Bluehead-phase fish are more solitary and range more widely. 25. Only the pectoral fins are used for propulsion, however, the caudal fin also is used in escape reactions. 26. The only mimic of T. bifasciatum known is Hemiemblemaria simulus (Clinidae). 27. This mimic resembles only yellow-phase fish, but reproduces all patterns of the phase. 28. Most often H. simulus remains in a burrow with its head exposed, but often it emerges and swims with specimens of T. bifasciatum. 29. As it swims, H. simulus mimics the particular pattern displayed by nearby T. bifasciatum, and also mimics their pectoral-fin method of swimming. 30. The egg of H. simulus contains oil globules, but eggs are attached to the substrate. 31. Young fishes form a major part of the diet of H. simulus. 32. Two probable advantages to H. simulus that result from mimicry are decreased predation on them and an increased opportunity to capture young fish.

SUMARTO ASPECTOS DE LA BIOLOGiA DE LA DONCELLA CABEZA AZUL Thalassoma bifasciatum (PISCES: LABRIDAE) Se investigaron aspectos de la vida del pez marino tropical Thalassoma bifasciatum durante un perfodo de dos anos en un arrecife de los Cayos de la Florida. Se puso enfasis en el desove y en el crecimiento. Dos tipos de desove: agregado y apareado, fueron observados; en ambos los huevos y el semen fueron expelidos en media agua. £1 analisis de la frecuencia de los tamanos de los huevos indica altas en las actividades de desove en los arrecifes de la Florida a intervalos de 1-1;2 a 2 meses durante el ano, con desoves individuales muchas veces durante el ano. El promedio de maxima longitud de 55 a 65 mm se obtiene alrededor de un ano, aunque hay individuos excepcionales que alcanzan 90 mm 0 mas. La frecuencia de tamano de la longitud promedio indica que la mayor abundancia de ciertos tamanos esta relacionada con el sexo, aunque no se pudo demostrar diferencia en la proporci6n de crecimiento entre adultos machos y hembras. Otms aspectos que se discuten son: coloraci6n, morfometria, alimentos y alimentaci6n, comportamiento general y mimetismo. Se incluye una sinonimia. 936 Bulletin of Marine Science [/5(4)

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