Northeast Gulf Science Volume 12 Article 3 Number 2 Number 2 10-1992 An Investigation of the Reproductive Mode of the Pinfish, Lagodon rhomboides Linnaeus (Osteichthyes: Sparidae) Richard P. Cody Louisiana State University Stephen A. Bortone University of West Florida DOI: 10.18785/negs.1202.03 Follow this and additional works at: https://aquila.usm.edu/goms Recommended Citation Cody, R. P. and S. A. Bortone. 1992. An Investigation of the Reproductive Mode of the Pinfish, Lagodon rhomboides Linnaeus (Osteichthyes: Sparidae). Northeast Gulf Science 12 (2). Retrieved from https://aquila.usm.edu/goms/vol12/iss2/3 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]. Cody and Bortone: An Investigation of the Reproductive Mode of the Pinfish, Lagodon Northeast Gulf Science Vol. 12, No. 2 October 1992 p. 99·110 AN INVESTIGATION OF THE REPRODUCTIVE MODE OF THE PINFISH, Lagodon rhomboides Linnaeus (Osteichthys: Sparidae) Richard P. Cody Museum of Natural Science Louisiana State University Baton Rouge, LA 70803 and Stephen A. Bortone Dep<irtment of Biology University of West Florida Pensacola, FL 32514 ABSTRACT: The majority of spa rids studied have shown evidence of hermaphroditism. The reproductive mode of the pinfish was investigated using museum and field collections of pinfish (n =974) distributed in size from 13 to 276 mm SL. The observed female to male sex ratio of 1.3:1.0 was not ~niflcantly different from uniformity. Males were distributee! in size from 63 to 252 mm SL (x = 127 mm); females were distributed from 57 to 276 mm (x = 119 mm). Individuals of undetermined sex occurred to 178 mm SL. Although the mean lengths of the sexes differed significantly, overlapping length·frequency distributions suggested gonochoristic development. Gonadosomatic indices (GSI) indicated spawning occurs between October and March in pinfish. Contrary to the predominance of hermaphroditism in sparids, histological investigation of the gonads of 106 specimens supported gonochorism as the reproductive mode in pinfish. The diversity of reproductive Mehl, 1973; Malo-Michelle, 1977; Coetzee, "strategies" among sparids (Table 1) is 1982; Waltz et al., 1982; Garratt, 1986). In unrivalled by any other perciform family general, testicular and ovarian portions with the possible exception of the are completely separated by connective serranids (Smith, 1975). Types of sparid tissue. This germinal configuration has reproductive modes include protandry, been referred to by Sadovy and Shapiro protogyny, non-functional herma­ (1987) as a "delimited" type. In phroditism, and gonochorism. Evidence protogynous individuals, testicul~r tissue of simultaneous hermaphroditism is becomes enlarged and envelops limited to a few isolated cases within degenerating ovarian tissue which populations (Waltz et al., 1982; Cody, remains as a narrow strip on the medial 1989). Of 43 species examined to date, surface of the gonad. Remnants of over 80% show evidence of sex change. testicular tissue in protandrous Although the pinfish has been shown to individuals may be detected as be an important component species of longitudinal flaps positioned laterally on estuarine fish communities of the eastern the ovary (D' Ancona, 1949a). The United States and the Gulf of Mexico "delimited" type configuration ·of the (Stoner, 1980) information on its reproduc­ sparid ovotestis has allowed sex­ tive mode is sparse (Muncy, 1984). changers to be detected in many cases Morphological descriptions of the by gross visual inspection of the gonad sparid ovotestis indicate consistency in rather than histological examination of form (Kinoshita, 1936, 1939; D'Ancona, gonadal structure (Penrith, 1972). 1941, 1949a; Pasquali, 1941; Lissia-Frau It has been established that most 1966, 1968; Lissia-Frau and Casu, 1973; sparids are hermaphroditic and as such, 99 Published by The Aquila Digital Community, 1991 1 Gulf of Mexico Science, Vol. 12 [1991], No. 2, Art. 3 100 Cody, R. P. and S. A. Bartone the failure to uncover evidence of hook-and-line and beach seine specimens hermaphroditism in a population should were collected from the Northwest coast not be confused with the failure to accept of Florida. Larger pinfish were acquired hermaphroditism (or gonochorism) as a from day-cruise headboats and longliners valid reproductive "strategy". Care should operating 17-25 km offshore from Panama be taken with methodology so that if sex­ City and Destin, Florida. These changers are present in a population in specimens were fixed in 10% Formalin low frequencies, they are likely to be for up to 72 hours and subsequently detected. Caldwell (1957) believed that a transferred to 40% Isopropanol for size or sex-associated change in body storage. shape may occur in pinfish but did not Standard length (SL) and body depth demonstrate such a relationship. Such a (BD) were measured to the nearest mm. change in body shape may be associated Body weight was measured in grams and with sex-change. Winstead (1977) examin­ gonad weight was measured to the ed the possible homology between cyst nearest mg. Sex was determined by gross epithelial cells in pinfish testes and inspection of the gonad. Gonads were mammalian Sertoli cells. Although not classified according to the criteria of alluded to in the study, isolated early Orange (1961): stage 1S- gonads elongate stage oocyte-like cells were found in pin­ and ribbonlike in appearance, sex, not fish testes (Winstead, pers. comm.). discernible by gross inspection; stage 1 Winstead's and Caldwell's observations -elongate, sex recognizable by color and in addition to the predominance of textural differences; stage 2 - slightly hermaphroditism as a reproductive mode enlarged, ova not visible to the naked eye in sparids were considered sufficient correspohding to an early maturation criteria to warrant examination of sex­ phase; stage 3 - late maturation phase, change as a possible reproductive mode individual ova distinguishable; stage 4 - in pinfish. The hypothesis of ripe ova loose from follicles; stage 5 - hermaphroditism in the pinfish was undergoing atresia, resorption evident. tested using size distribution of the sexes Entire gonads were extracted from and sex ratio data in addition to 537 individuals and stored in 40% macrocscopic and histological examina­ isopropanol. Subsamples of the extracted tion of gonadal structure and maturation. gonads for each month were examined The establishment of standardized histologically. A base sample of 72 criteria to detect hermaphroditism was gonads consisting of three ovaries and also an objective of this study. three testes representing small (mean SL = 87 mm), medium (mean SL = 115 mm), MATERIALS AND METHODS and large (mean SL = 145 mm) individuals from each month was Specimens were obtained from supplemented with additional tissue, catalogued collections of the University comprised of 34 gonads from months of South Alabama, Mobile, Alabama; the preceding and following the peak Florida State Museum, University of spawning period. An estimate of Florida, Gainesville, Florida; University of spawning period was made from calcula­ West Florida Ichthyology Collection, tion of gonadal index (GSI), where GSI = Pensacola, Florida; and from uncataloged (wet gonadal weight I wet body weight) X 2 collections of the Department of 10 • Descriptive terminology for oogonial Biological Sciences, Florida State Univer­ and spermatogonial development sity, Tallahassee, Florida. In addition, followed Hayashi (1972), Coetzee (1983), https://aquila.usm.edu/goms/vol12/iss2/3 2 DOI: 10.18785/negs.1202.03 Cody and Bortone: An Investigation of the Reproductive Mode of the Pinfish, Lagodon Reproductive mode of pinfish 101 and Selman and Wallace (1986). no significant difference was found Transverse sections 6J.im • 1OJ.im were between females (SUBD = 2.44) and taken from anterior, medial, and posterior males (SLIBD = 2.47), immature portions of the gonad. Entire gonads from specimens (SL BD = 2.37) were found 10 specimens were serially sectioned. In to differ significantly from both males and larger individuals where serial sectioning females using a Student-Newman-Keuls of the gonad was not practical, 5 mm · 7 test (a = 0.05). mm cubes were removed and embedded Poor fixation and preservation of for sectioning. Dehydration and infiltra­ some of the specimens made thorough tion followed criteria described by analysis of gross gonadal morphology Humason (1972) for paraffin embedding. and development difficult. For this Sections were progressively stained in reason, descriptions of gonadal hematoxylin (gills formulation 2) and morphology and development 't:'er13 only counterstained in eosin-y. Statistical briefly summarized. In appearance, the analysis was performed using SAS pinfish gonad was elongate and bilobed, (Helwig and Council, 1979). positioned dorsal to the intestine, with each lobe attached anteriorly to the body RESULTS wall. The lobes united posteriorly, anterior to the genital opening. In immature A total of 974 specimens were specimens, the gonad was thread-like. In distributed from 13 mm to 276 mm SL. developing females it was larger and Females comprised 31% (n = 304) and thicker than in similar-sized males, in males 24% (n = 233) whereas immatures which the testes were thin and ribbon­ accounted for almost 45% (n = 437) of like. Vascularization