Kenneth C. Stuck

Population Structure and Variation in Red Snapper (Lutjanus campechanus) from the Gulf of Mexico and Atlantic Coast of Florida as Determined From Mitochondrial DNA Control Region Sequence

The mitochondrial DNA control regions of red snapper (Lutjanus campechanus) from the Gulf of Mexico (n = 140) and Atlantic coast of Florida (n = 35) were sequenced to generate a prestocking genetic baseline for planned stock enhancement. Intrasample haplotype and nucleotide diversities ranged from 0.94 to 1.00 and 1.8% to 2.5%, respectively. All population analyses were consistent with the hypothesis that red snapper constitute a single, panmictic population over the sampled range. A ubiquitous, predominant haplotype, shared by 23% of the specimens, appeared to be evolutionarily recent, in contrast to previous findings based on restriction fragment length polymorphism data. Tajima’s D values were suggestive of a recent bottleneck. Mismatch distributions from Gulf samples were smooth and unimodal, characteristic of recent population expansion. However, the Atlantic sample exhibited a comparatively broader, possibly multimodal distribution, suggestive of a more stable population history. Additional control-region data may clarify potentially disparate demographic histories of Gulf and Atlantic snapper.

Seasonal Variability in Morphology of Blue Crab, Callinectes sapidus, Megalopae and Early Juvenile Stage Crabs, and Distinguishing Characteristics Among Co-Occurring Portunidae

Abstract Declines in abundance of the commercially important blue crab Callinectes sapidus have led fishery managers to search for new management strategies. Assessing year-class strength at megalopal or early juvenile stages may contribute to this effort, but separation from co-occurring species is difficult in many areas because morphological characteristics vary with season and published descriptions do not adequately distinguish C. sapidus from C. similis and other related species. Callinectes sapidus and C. similis megalopae were collected monthly and cultured in the laboratory to a size at which positive identification could be made. Measurements on intact megalopae and early crab exuviae of both species revealed seasonal differences, with spring megalopae having larger carapaces, longer rostral spines and antennae and more setae on some mouth parts than fall megalopae. This seasonal pattern of morphological variability was verified through examination of samples collected from MS (1976–1979) and NC (2005) coastal waters. Rostrum length, total carapace length and rostrum length as a percent of total carapace length of NC megalopae were negatively correlated with water temperature 2–4 weeks prior to collection. Callinectes sapidus and C. similis megalopae can be rapidly separated within locations and seasons by: 1) the shape of the antero-lateral carapace margin, 2) rostral length as a percent of total carapace length, and 3) the combined length of the distal eight segments of the antenna. Such rapid separation is essential for fisheries studies requiring identification of large numbers of individuals. Molecular analyses or more detailed morphological analyses remain necessary for definitive separation regardless of season. Keys to common coastal portunid megalopae and first crab stages were compiled to aid investigators in separating C. sapidus megalopae and early juvenile stages from co-occurring portunids.

Fishery-Related Morphometric Characteristics of Menippe adina from the North-Central Gulf of Mexico

Abstract Fishery-related morphometric characteristics of the recently described gulf stone crab Menippe adina were measured, providing data applicable to managing the species. Because data used in managing crab stocks have traditionally been based on carapace width, we examined the relationship between propodus length (PL) and carapace width and compared it to similar data for the heavily exploited Florida stone crab M. mercenaria. Claws for M. adina reach harvestable size (70 mm PL, minimum legal size in Florida) when carapace widths are 82 mm for males and 92 mm for females. Menippe adina exhibits allometric growth, and the transition point (carapace width) at which differential growth occurs appears to be related to sexual maturity. Males and females exhibit similar relationships of propodus length to carapace width below the transition point. Above the transition point, males display a greater increase in propodus length per incremental increase in carapace width and enter the fishery at a smaller siz...

Larval and Early Postlarval Development of Lepidopa Benedicti Schmitt, 1935 (Anomura: Albuneidae) Reared in the Laboratory

The complete larval development of an Atlantic Lepidopa from a known parental female is described for the first time. The ovigerous L. benedicti was collected at Horn Island, Mississippi (Gulf of Mexico). The larval development consisted of 4 zoeal stages, and one megalopal stage which was reached 14-17 days after hatching, at 25?C and 26%0 salinity. Zoeae of L. benedicti are very similar to those of other known Atlantic Lepidopa; there are differences among the corresponding zoeal stages in abdominal spination, and in zoeae II and III, differences in setation of the antennule and exopods of maxillipeds 1 and 2. The megalopa of L. benedicti is compared with other known megalopae of Lepidopa, 1 from the Atlantic and 2 from the Pacific. All megalopae are separable using setation of the antennular ventral flagellum, and the megalopa of L. benedicti can also be separated from the other Atlantic species by segmentation of the antennular dorsal flagellum. The development of selected adult key characters of L. benedicti (carapace frontal margin, eyeshape and pigmentation, posterior dorsal carapace groove, and pereiopod 2 dactylus shape) is illustrated and described through crab 4. In crab 4, all selected characters became diagnostic except for the pereiopod 2 dactylus which has not yet attained adult shape. Abele and Efford (1971) and Efford (1971) recognized 17 species of sand crabs, genus Lepidopa, from both coasts of the Americas and adjacent islands, including six species from the western Atlantic. Lepidopa benedicti Schmitt, 1935, and L. websteri Benedict, 1903, are the only western Atlantic species known from the nearshore waters of the southeastern United States (Efford, 1971). In the Gulf of Mexico, these species are sympatric at least from Grand Isle, Louisiana, to Petit Bois Island, Mississippi (Efford, 1971; Felder, 1973). In the Atlantic, L. benedicti is reported only as far north as central eastern Florida (Gore and Van Dover, 1980) and L. websteri only as far south as Sapelo Island, Georgia (Kurata, 1970; Williams, 1984). The four other western Atlantic species, L. dexterae Abele and Efford, 1971, L. distincta Gomes, 1968, L. richmondi Benedict, 1903, and L. venusta Stimpson, 1860, are known as adults only from the Caribbean coast of Panama, the eastern Antilles, and the eastern coast of South America (Abele and Efford, 1971; Efford, 1971; Gore and Van Dover, 1980). Information on the larval development of species of Lepidopa is scanty. Johnson and Lewis (1942) described zoea I, and Knight (1970) the entire zoeal series and megalopa from laboratory-hatched eggs of females attributed to L. myops Stimpson, 1860. Based on Effords (1971) revision of Lepidopa, Johnson and Lewis (1942) and Knight (1970) actually described developmental stages of L. californica Efford, 1971 (Sandifer and Van Engle, 1972). Knight (1970) also described four zoeal stages of an unidentified species, and Sanchez and Aguilar (1975) described the entire zoeal development and the megalopa of L. chilensis Lenz, 1902, from laboratory-reared larvae. In the Atlantic, Kurata (1970) partially described zoea I of L. websteri hatched in the laboratory, and three other zoeal stages and the megalopa (from plankton samples) that he assumed were L. websteri. Sandifer and Van Engle (1972) described zoeae I-III of putative L. websteri from plankton samples taken in Virginia waters. At that time L. websteri was not known as an

AMATHIMYSIS BRATTEGARDI, A NEW PERACARID (CRUSTACEA: MYSIDACEA) FROM CONTINENTAL SHELF WATERS OFF TAMPA BAY, FLORIDA

ABSTRACT An undescribed species of mysid belonging to the genus Amathimysis was obtained from box core samples taken at 11 to 45 m depth off Tampa Bay, Florida. This new species, Amathimysis brattegardi, can be distinguished from the three other species of Amathimysis by the presence of strong posteriorly directed mucronations on the abdominal pleura and spination of the telson. The description of A. brattegardi, new species, and a key to the species of Amathimysis are presented.