Marine Biology Commons^™

Distributional And Ecological Notes On The Halfbeaks Of Eastern Gulf Of Mexico, With A Provisional Key For Their Identification, S. Contreras-Balderas, M.L. Lozano-Vilano, M.E. Garcia Ramirez

Gulf and Caribbean Research

Several fishes of the halfbeak genus Hyporhamphus occurring in the Mexican Gulf of Mexico and Caribbean Sea have been misidentified or confused in the literature. Most of it has centered around the taxonomic status of H. unifasciatus (including its synonym H. roberti), which is shown to comprise a complex of three species, H. unifasciatus, the recently described H. meeki, from the western Atlantic region, and an undescribed species from the eastern Pacific Ocean. Another eastern Mexico halfbeak is the freshwater form H. mexicanus. Using Banford and Collette (1993), we examined specimens from collections at UANL, UNAM, …

Observations On Mass Mortalities Of The Sooty Eel, Bascanichthys Bascanium, And The Speckled Worm Eel, Myrophis Punctatus, Associated With A Fish Kill In The Mississippi Sound, James S. Franks, Ross P. Dodds

Gulf and Caribbean Research

Mass mortalities of the sooty eel, Bascanichthys bascanium, and the speckled worm eel, Myrophis punctatus, were observed in association with a fish kill which occurred the morning of 18 June 1994 on the south shore of Deer Island, a nearshore barrier island located off Biloxi, Mississippi. B. bascanium and M. punctatus, as well as other fishes, were found dead and dying near the shore in reddish-brown water and along a lengthy stretch of fringing sandy beach. Both species of eels are infrequently reported from Mississippi waters but were the most abundant fishes recorded from the kill. A …

Northern Record For The Zooxanthellate Scleractinian Coral Siderastrea Siderea (Ellis And Solander) From The Gulf Of Mexico, William W. Schroeder, Thomas S. Hopkins

Gulf and Caribbean Research

We report a northward range extension of the zooxanthellate scleractinian coral Siderastrea siderea (Ellis and Solander) in the Gulf of Mexico. Several small, living colonies of S. siderea have been obtained in dredge samples from a site located at 29º 55.5' N, 087º 28.4' W in the northeastern Gulf of Mexico. Prior to these collections the northernmost occurrence of S. siderea in the Gulf of Mexico was reported as 27º 54.5' N, 093º 35.8' W, on the East Flower Garden Bank, in the western Gulf of Mexico. In the eastern Gulf of Mexico, S. siderea is not reported occurring on …

Gonadal Maturation In The Cobia, Rachycentron Canadum, From The Northcentral Gulf Of Mexico, Jeffrey M. Lotz, Robin M. Overstreet, James S. Franks

Gulf and Caribbean Research

Gonadal maturation of cobia, Rachycentron canadum, was evaluated by examining 508 specimens from its recreational fishery. Specimens were collected off southeast Louisiana to northwest Florida by hook-and-line during February through October 1987-1991. Fork lengths (FL) of these fish ranged from 580-1,530 mm, with corresponding weights of 2.0-43.5 kg. The female:male ratio was 1:0.37. Using a combination of oocyte size frequency and histological assessment of many of the fish, we determined that females were ripe from May through September, with atretic oocytes occurring in some fish from July through October. Degenerating hydrated oocytes in July and October and the presence …

Food Of Cobia, Rachycentron Canadum, From The Northcentral Gulf Of Mexico, Gabriele H. Meyer, James S. Franks

Gulf and Caribbean Research

The stomach contents of 403 cobia, Rachycentron canadum, caught in the northcentral Gulf of Mexico recreational fishery from April through October of 1987-1990 were examined. Cobia ranged from 373-1,530 mm in fork length. Of the 403 stomachs, 287 (71.2%) contained at least one identifiable prey taxon. Crustaceans, consisting primarily of portunid crabs, were the predominant food. Crustaceans occurred in 79.1% of the stomachs and comprised 77.6% of the total number of identifiable prey. The second most important prey category was fish which was dominated by hardhead catfish, Arius felis, and eels. Fish occurred in 58.5% of the stomachs …

Cryopreservation Of Sperm Of Spotted Seatrout (Cynoscion Nebulosus), William R. Wayman, R. Glenn Thomas, Terrence R. Tiersch

Gulf and Caribbean Research

Cryopreservation of fish sperm has applications in preserving genetic resources from stocks of endangered fishes, replenishing fisheries, reducing the number of males needed in hatchery situations, and allowing repeated spawning of specific males. As part of a larger study on artificial breeding of sciaenid fishes, we developed procedures for collection, handling, refrigerated storage, and cryopreservation of spotted seatrout sperm. Hanks' balanced salt solution (HBSS) was used as an extender for collection and storage of sperm. Sperm motility in relation to graded concentrations of HBSS was used to determine the osmolality at which sperm were activated. Based on these findings, HBSS …

Distribution Of Loxothylacus Texanus (Cirripedia: Rhizocephala) Parasitizing Crabs Of The Genus Callinectes In The Southwestern Gulf Of Mexico, Fernando Alvarez, Jorge Calderon

Gulf and Caribbean Research

A preliminary study on the interaction between the parasitic barnacle Loxothylacus texanus and two of its host species, the blue crab Callinectes sapidus and the dark blue crab C. rathbunae, in the Gulf of Mexico is presented. Data were obtained from 923 crabs, 162 C. sapidus and 761 C. rathbunae, deposited in the Colección de Crustáceos, Instituto de Biologia, Universidad Nacional Autónoma de México (UNAM), that were collected in 14 coastal lagoons and sites along the Mexican coast of the Gulf of Mexico. The distribution of L. texanus parasitizing each one of the host species, mean host size …

Reproductive Strategies In A Population Of Gobiosoma Bosci (Osteichthyes: Gobiidae) With Slow And Fast Maturing Individuals, Candace H. Conn, David L. Bechler

Gulf and Caribbean Research

The reproductive biology of Gobiosoma bosci collected from November 1986 to October 1987 in the McFaddin Wildlife Refuge in southeast Texas was studied by using morphometric data. Males achieved greater weights per unit length than females, and longevity was about 12 to 13 months. GSI values and mean monthly ovum diameters indicated that the breeding season ran from April to September, with a major activity peak in May and a minor peak in September. Significant differences in male and female standard lengths (SL), ovum diameter, and egg number existed for sexually mature specimens between the first and second peaks of …

Seasonal Migration In The Southern Hogchoker, Trinectes Maculatus Fasciatus (Achiridae), Tanya L. Peterson

Gulf and Caribbean Research

Life history patterns often respond to local environmental conditions. The seasonal migration pattern of the northern hogchoker has been described, but the southern subspecies rarely has been studied. To document the migratory movements and the habitat characteristics of the southern hogchoker, long-term survey data and specimens collected during 1993 were examined. Moderate depth (5.8-6.4 m), low water clarity (0-1.2 m), moderate oxygen concentration (4-9 ppm), and sand-mud substrata generally defined hogchoker habitats. Hogchoker habitats only showed seasonal shifts in temperature and salinity characteristics. Hogchokers were only collected in low salinity (0-2 ppt) waters during the winter, but exhibited three abundance …

Observations On An Isolated Population Of Sagitta Hispida Conant (Chaetognatha) In A Tropical Lagoon System Of Northeast Yucatan (Mexico), Jose N. Alvarez-Cadena, Eduardo Suarez-Morales, Jerry A. Mclelland

Gulf and Caribbean Research

Monthly zooplankton collections were carried out from January to December 1991 at two sampling sites, Cuenca Norte and Bojórquez lagoon, in the Nichupté lagoon system, a partially enclosed network of interconnected waterways located in the northeastern region of the Yucatan Peninsula (Mexico) adjacent to the Caribbean Sea. Only one species of Chaetognatha, Sagitta hispida Conant, was present and was more abundant at Cuenca Norte (total density 450.6 organisms/m3) than at Bojórquez (138.6 organisms/m3). The latter site is smaller, more physically isolated, and more environmentally stressed than the former. From monthly gonadal and length-frequency analyses of 1390 specimens, it was found …

Aricidea (Allia) Bryani, A New Species Of Polychaete (Polychaeta: Paraonidae) From The Northern Gulf Of Mexico, Gary R. Gaston, Jerry A. Mclelland

Gulf and Caribbean Research

Aricidea bryani, a new species of polychaete (Polychaeta: Paraonidae) belonging to the subgenus Allia Strelzov 1973, is described from shallow subtidal sediments along the northern shore of Mississippi Sound, an estuary of the northern Gulf of Mexico. The new species is distinguished from other members of the subgenus by the presence of tuberculate neuropodial lobes in the anterior 15-20 setigers, a cirriform median antenna that extends posteriorly to setiger three, and by modified neuropodial setae that are abruptly tapered at mid-length, but lack terminal aristae.

Cholangioma In A Wild-Caught Sheepshead Minnow (Cyprinodon Variegatus) From The Northern Gulf Of Mexico, Lee A. Courtney

Gulf and Caribbean Research

A single case of ac holangioma occurred in the liver of a wild-caught sheepshead minnow (Cyprinodon variegatus). This is the first biliary neoplasm and second case of a hepatic neoplasm reported from a wild-caught specimen of this species. The findings further demonstrate the susceptibility of the sheepshead minnow to neoplasm development and add support to its selection as a subject for field monitoring of carcinogenic exposure.

First Sperm Whale (Physeter Macrocephalus) Record In Mississippi, Jon C. Peterson, Wayne Hoggard

Gulf and Caribbean Research

A sperm whale (Physeter macrocephalus) stranded on the south shore of Horn Island, Mississippi, represents the first record of this species in the state. The specimen, a neonate female, was euthanized at the stranding site. Tissue samples, blood samples, and stomach contents were analyzed following gross necropsy.

Pseudione Overstreeti, New Species (Isopoda: Epicaridea: Bopyridae), A Parasite Of Callichirus Islagrande (Decapoda: Anomura: Callianassidae) From The Gulf Of Mexico, Daniel L. Adkison, Richard W. Heard

Gulf and Caribbean Research

Pseudione overstreeti, new species, is a common bopyrid that infests the branchial chamber of the beach ghost shrimp, Callichirus islagrande, occurring along beaches of the Gulf of Mexico from Cape San Blas, Florida to Paraiso, Tabasco, Mexico. Like other members of the genus Pseudione that infest callianassid shrimps, the female of P. overstreeti is characterized by biramous terminal appendages which result from the combination of uniramous uropods with the closely associated lateral plates of pleomere 6. From the other members of the genus Pseudione occurring on callianassid hosts, P. overstreeti is distinguished by the distinctive development of the …

Observations On Extant Populations Of The Softshell Clam, Mya Arenaria Linné, 1758 (Bivalvia: Myidae), From Georgia (Usa) Estuarine Habitats, Erik Rasmussen, Richard W. Heard

Gulf and Caribbean Research

The softshell clam, Mya arenaria Linné, 1758, is reported from Georgia (USA) estuarine habitats based on studies conducted between 1969 and 1972. Observations on Georgia estuarine habitats where extant populations of softshell clams occurred are described. On several occasions, fresh shells with periostracum and tissue remnants were found in a brackish drainage system on Sapelo Island. These shells represent the first southern records of extant populations of softshell clams from such a specialized habitat type. Living specimens of M. arenaria from the benthos and specimens in the stomach contents of stingrays (Dasyatis sabina) were collected at four stations …

Trophic Structure Of Macrobenthic Communities In Northern Gulf Of Mexico Estuaries, Gary R. Gaston, Steven S. Brown, Chet F. Rakocinski, Richard W. Heard, J. Kevin Summers

Gulf and Caribbean Research

Trophic structure of estuarine benthic communities in the northern Gulf of Mexico was characterized according to the functional roles and geographic distributions of the macrobenthos. Macrobenthic organisms collected during two years of study were assigned to trophic groups to assess the relative utilization of detritus and other resources. Three groups of detritivores (surface-deposit feeders, subsurface-deposit feeders, and filter feeders) were numerically dominant among the benthos, each of which accounted for 25-30% of total abundance across regions. Carnivorous macrobenthos also comprised an appreciable portion (12%), while omnivores (<3%) and other groups (<4%) were poorly represented. Dominance by detritivores is consistent with current concepts regarding the role of macrobenthos in processing detritus of Gulf of Mexico estuaries.

A Study Of Factors Influencing The Hatch Rate Of Penaeus Vannamei Eggs. I. Effects Of Size, Shape And Volume Of The Spawning Tank, John T. Ogle

Gulf and Caribbean Research

The hatch rate of Penaeus vannamei eggs spawned by individual females in square and round tanks and in different volumes of seawater was determined. The mean hatch rates ranged from 17.3% to 64.9% and were not significantly different for volumes of 50, 100 and 200 L nor for square or round tanks of equal water volumes. Hatch rate was significantly affected by the size of the spawning tank.

Levinseniella Deblocki, New Species (Trematoda: Digenea: Microphallidae) From Salt Marshes Along The Eastern Gulf Of Mexico With Notes On Its Functional Morphology And Life History, Richard W. Heard, John M. Kinsella

Gulf and Caribbean Research

Levinseniella (Austromicrophallus) deblocki, n. sp., was collected during parasitologic studies of homeothermic vertebrates from salt marshes along the coast of the eastern Gulf of Mexico. Because L. deblocki lacks a femal epouch, it belongs to the subgenus Monarrhenos proposed by Deblock and Pearson (1970). However, since Deblock and Pearson did not explicitly designate a type species for Monarrhenos, it is not available and is a nomen nudum. The next available name, Austormicrophallus Szidat, 1964, a genus synonymized with Levinseniella Stiles and Hassall, 1901 by Deblock (1978), is reinstated as a subgenus to receive the species …

Gametogenic Cycle In The Non-Native Atlantic Surf Clam, Spisula Solidissima (Dillwyn, 1817), Cultured In The Coastal Waters Of Georgia, Christopher R. Spruck, Randal L. Walker, Mary L. Sweeney, Dorset H. Hurley

Gulf and Caribbean Research

This study describes the gametogenic cycle of the Atlantic surf clam, Spisula solidissima (Dillwyn, 1817), cultured from fall to spring in the coastal waters of Georgia, where it is non-native. Early active stages of gametogenic development began in November, with the majority (83%) of the animals in the early active stage by December. Gonadal indices increased to late active stages by March, with ripe individuals present in April. Spawning commenced in May and continued into June. Sex ratio (0.48 female to 1.00 male) was significantly unequal. Results of this study indicate that clams achieved sexual maturity and spawned when cultured …

A Study Of Factors Influencing The Hatch Rate Of Penaeus Vannamei Eggs. Ii. Presence Of A Spermatophore, John T. Ogle

Gulf and Caribbean Research

Eghty-three mated Penaeus vannamei females were sourced from a commercial sized maturation tank. The hatch rate was recorded for those shrimp based on the presence of a full spermatophore, a partial spermatophore or the loss of the spermatophore during sourcing and handling. The hatch rates were not significantly different among females for the three spermatophore conditions. The mean hatch rates were 48.8% for full spermatophores, 43.1% for partial spermatophores and 55.6% for lost spermatophores. The location of the sperm at fertilization and the precise mechanisms of fertilization are still unknown.

A Pugheaded Cobia (Rachycentron Canadum) From The Northcentral Gulf Of Mexico, James S. Franks

Gulf and Caribbean Research

A pugheaded cobia (Rachycentron canadum) captured in the northcentral Gulf of Mexico represents the first record of pugheadedness in cobia. The specimen, a 4-year-old gravid female, exhibited considerable distortion of the premaxillary and maxillary bones, with the length of the snout 46% shorter than that of a normal cobia of the same length. The anomaly had no apparent effect on feeding, since the stomach contained a substantial amount of food, and the fish was the same length expected of a normal 4-year-old cobia.

A Note On Bycatch Associated With Deepwater Trapping Of Chaceon In The Northcentral Gulf Of Mexico, Harriet Perry, Richard Waller, Christine Trigg, James Mcbee, Robert Erdman, Norman Blake

Gulf and Caribbean Research

Bycatch associated with deepwater trapping of Chaceon is reported for outer shelf and slope waters of the northcentral Gulf of Mexico. Bycatch was dominated by the isopod, Bathynomus giganteus. Other crustacean megafauna consisted of the majid crab, Rochinia crassa, and the portunid crabs, Benthochascon schmitti and Bathynectes longispina. Finfish bycatch included hagfish, Eptatretus springeri, deepwater shark, Centrophorus uyato and hake, Urophycis cirrata.

The Distribution And Abundance Of The Bay Anchovy, Anchoa Mitchilli, In A Southeast Texas Marsh Lake System, Scott A. Griffith, David L. Bechler

Gulf and Caribbean Research

A one-year distribution and abundance study on the bay anchovy, Anchoa mitchilli, was conducted in a southeast Texas marsh-lake system from March 1990 through February 1991. Day and night collections were conducted in backwaters, lake shores, and lake centers by seining and trawling. Bay anchovies were the second most abundant fish species collected, and exhibited seasonal, diet and habitat variations in abundance and distribution. Across the study area, seasonal abundance peaks occurred in May and August following migration into the marsh and seasonal recruitment. However, within each habitat type, peaks of abundance varied in time of occurrence. Within habitats, …

Estimates Of Harvest Potential And Distribution Of The Deep Sea Red Crab, Chaceon Quinquedens, In The North Central Gulf Of Mexico, Richard Waller, Harriet Perry, Christine Trigg, James Mcbee, Robert Erdman, Norman Blake

Gulf and Caribbean Research

Harvest potential, relative abundance, and geographic and bathymetric distribution are discussed for the red crab, Chaceon quinquedens, in the northcentral Gulf of Mexico. Harvest potential is expressed as the number of trapable crabs present on fishing grounds defined as depths ranging from 677 m to 1043 m between 87.5^o and 88.5^oW longitude. Using various estimates of the effective fishing area (EFA) of a trap, the number of trapable red crabs on the fishing grounds ranged from 3.7 x 10⁶ to 10.7 x 10⁶. Estimatesofcrabnumberssuggest there is a potential for commercial harvest in the …

A New Species And Two Known Species Of Free-Living Marine Nematodes (Nematoda: Monoposthiidae) From Northwest Florida, U.S.A., Edwin J. Keppner

Gulf and Caribbean Research

Two known free-living marine nematodes, Monoposthioides mayri Wieser and Hopper, 1967 and Monoposthia hexalata Chitwood. 1936 are redescribed from sediments in St. Andrew Bay and Lake Powell, Bay County, Florida, U.S.A. One new species of free-living marine nematode, Monoposthia baxteri n. sp., is described from nonvegetated sediments in St. Andrew Bay, Bay County, Florida. M. baxteri n. sp. differs from the other members of the genus in the shape of the gubernaculum which is more similar to that of the species of Monoposthioides than that of Monoposthia.

Namalycastis Abiuma (Müller In Grube) 1871, An Aberrant Nereidid Polychaete Of A Georgia Salt Marsh Area And Its Faunal Associations, Erik Rasmussen

Gulf and Caribbean Research

The morphology of the aberrant nereidid Namalycastis abiuma, Namanereidinae is described on the basis of material collected 1971-72 and 1976 in the brackish water drainage ditch system of Sapelo Island, Georgia, USA. The systematics of the species is briefly reviewed. The habitat and ecological conditions under which the species lives in these brackish ditches are described.

At various times, N. abiuma lives out of water under the bark of trunks and branches of fallen trees. Decaying wood is ingested. It is suggested that future studies should concentrate on the reproductive biology of the widely spread, mainly tropical populations of what …

Historic Trends In The Secchi Disk Transparency Of Lake Pontchartrain, J.C. Francis, M.A. Poirrier, D.E. Barbe, V. Wijesundera, M.M. Mulino

Gulf and Caribbean Research

A major environmental concern about Lake Pontchartrain is an assumed long-term increase in turbidity based on Secchi disk transparency observations. Regression of the available data on Secchi disk transparency versus time (1953 through 1990) reveals a statistically significant decrease in transparency of about 40%. However, the data set is biased in that it does not adequately represent the seasonal effects of salinity and wind speed. Two analytical procedures were undertaken to determine the extent to which the apparent long-term decrease in transparency was dependent on the seasonal bias. One procedure involved seasonal adjustment of the data for the effects of …

Fatty Acid Pattern Differences Among Individuals Of Two Estuarine Fishes (Leiostomus Xanthurus And Mugil Cephalus), Julia S. Lytle, Thomas F. Lytle

Gulf and Caribbean Research

Ten individual fish of two estuarine species, spot (Leiostomus xanthurus) and striped mullet (Mugil cephalus), were analyzed for fatty acids. Fish of similar size were obtained from a single collection to minimize variability due to age, size, location and season. Analysis of variance (ANOVA) of each fatty acid provided statistically similar groups for each acid that existed among individual fish. Fatty acids in the striped mullet provided a greater number of statistically similar groups than those in spot, indicating greater variability among individual striped mullet, which probably reflected a greater diversity in the feeding regime for …

Long-Term Study Of Benthic Communities On The Continental Shelf Off Cameron, Louisiana: A Review Of Brine Effects And Hypoxia, Gary R. Gaston, Kenneth A. Edds

Gulf and Caribbean Research

A long-term data set compiled from our studies and a variety of investigations was analyzed to determine the effects of nine years of discharged brine (concentrated salt water) on benthic organisms surrounding a brine diffuser off Cameron, Louisiana (USA). These investigations began three months before brine discharge was initiated in 1981. A preliminary summary by Giammona and Darnell (1990) relied on just three years of discharge data and gave misleading reports of brine impacts.

Brine effects over the nine years of study were minimal, in part because the fine sediments of the study area were numerically dominated by opportunistic species. …

Behavioral Ecology Of Two Teal Species (Blue-Winged Teal, Anas Discors, And Green-Winged Teal, Anas Crecca) Overwintering In Marshes Of Coastal Louisiana, Usa, Gary R. Gaston, Jeanne C. Nasci

Gulf and Caribbean Research

Feeding and other dominant activities of Blue-winged Teal (BWT, Anas discors) and Green-winged Teal (GWT, Anas crecca) were compared from October 1987 to March 1988 in southwestern Louisiana, USA. Three observation towers were constructed near similar intermediate marsh habitats in areas where BWT and GWT concentrated for feeding. These observation towers allowed activities of the two species to be compared throughout the nonbreeding season. Although BWT and GWT often fed together, time spent in various activities differed. Feeding was the most frequent activity of both BWT(64.5%) and GWT (55.3%), but BWT spent more time feeding (P < 0.01) and alert (P < 0.05), but spent less (P < 0.01) time resting than GWT. Within each species there were differences in activity budgets among daily time blocks and among months, but few differences among the three habitats studied. Temperature and light intensity were correlated with resting (+), feeding (-), locomotion (-), and preening (+). Daily and monthly activity budgets of BWT and GWT were similar, as were ingested foods, suggesting that these two species used the study areas primarily for foraging, and left the areas for other activities. Predation and diminished resources during late winter may have affected activities of BWT and GWT as well.