Adolfo Gracia

Deep-Water Shrimp (Crustacea: Penaeoidea) Off the Yucatan Peninsula (Southern Gulf of Mexico): A Potential Fishing Resource?

ABSTRACT Shrimp fisheries in the Mexican Gulf of Mexico arc limited to the 100-m-depth contour. We investigated potential penaeoidean shrimp resources on the continental slope of the Yucatan Peninsula (southern Gulf of Mexico) during 2 research cruises conducted during spring 1999 (cruise 1; number of hauls, 21; depth range, 300–599 m) and 2007 (cruise 2; number of hauls, 27; depth range, 300–999 m). During both cruises, the catch included 6 penaeoidean species: Aristaeomorpha foliacea, Aristaeopsis edwardsiana, Pleoticus robustus, Aristeus antillensis, Penaeopsis serrata, and Parapenaeus politus. The first 3 species constituted 85% and 91% of the total catch in weight obtained during cruise 1 and cruise 2, respectively. During cruise 1, the mean (± SE) biomass (1.05 ± 0.25 kg/ha) and catch per unit effort (CPUE: 3.21 ± 0.75 kg/h) of the combined species did not differ significantly between 100-m-depth strata. During cruise 2, by contrast, mean biomass and CPUE differed significantly between strata, with the highest mean values at the 600–699-m stratum (biomass, 1.37 ± 0.61 kg/ha; CPUE, 5.14 ± 2.30 kg/h) and the lowest at the 300–499-m stratum (biomass, 0.03 ± 0.01 kg/ha; CPUE, 0.10 ± 0.04 kg/h). High CPUE values (≥5.0 kg/h) were more prevalent at depths of 400–499 m during cruise 1 and 600–699 m during cruise 2. Mean size of shrimp differed significantly between and within species, except for A. foliacea. On average, our CPUE values compare with values obtained in fisheries for deep-water penacoideans around the world, and also with current CPUE values from the shallow-water shrimp fisheries in the southwestern Gulf of Mexico, suggesting that these deep-water shrimp represent a potential fishing resource.

RELATIVE GROWTH AND SIZE AT FIRST MATURITY OF THE DEEP WATER SHRIMP, HETEROCARPUS ENSIFER (DECAPODA, PANDALIDAE) FROM THE SOUTHERN GULF OF MEXICO

The pandalid shrimp, Heterocarpus ensifer occurs on continental slopes over the eastern and western Atlantic, and over some portions of the Indian and Pacific oceans. Despite its wide distribution, studies on the biology of this species are scant. In particular, there is no information on morphometric relationships or reproductive issues from any western Atlantic population. Although the general morphology of males and females of H. ensifer appears similar, we hypothesized that size at the onset of sexual maturity (SOM) and sexual dimorphism of H. ensifer could be examined with morphometric analyses, using those body dimensions most commonly measured in shrimp: carapace length (CL), body length (BL), rostral length (RL), and body weight (BW). We examined 754 H. ensifer from the southern Gulf of Mexico. SOM, determined through sequential reduced major axis regressions of BL, RL, relative rostral length (RRL = RL/CL), and BW against CL, was 23-24 mm CL in females and 21-22 mm CL in males. These sizes closely matched those of the smallest ovigerous females and the smallest males with appendices masculinae. Juveniles of both sexes showed similar morphometry and allometries, but ontogenetic allometry and morphometric sexual dimorphism occurred after maturity. In particular, the positive relationship (with negative allometry) between RL and CL shown in juveniles was lost after SOM in females and changed to enantiometry in males, despite a wide dispersion of data. The rostral polymorphism may be related to the protracted, year-round reproductive activities of this Gulf of Mexico population. Morphometric techniques may be useful to compare populations of if. ensifer from disparate locations.

A new species of Munidopsis Whiteaves, 1874 (Crustacea: Anomura: Galatheoidea: Munidopsidae) from the Gulf of Mexico and Caribbean Sea

A new species of squat lobster, Munidopsis shulerae sp. nov., from the Gulf of Mexico and western Caribbean, is fully described and illustrated. This new species is named in honor of the late Barbara Shuler Mayo (1945-1988), who first recognized this new taxon in her 1974 unpublished doctoral dissertation, but never formalized it. This new species is placed in the Anoplonotus group based on the presence of simple, narrow rostrum, spineless eyes, fused sternites 3 and 4, well-marked carapace regions, unarmed pleonal tergites, and smooth dactyls of pereopods 2-4. Among western Atlantic congeners, M. shulerae sp. nov. is most similar to M. polita (Smith, 1883), from which it can be distinguished by the straight shape of the rostrum with a tuberculate dorsal carina extending to the epigastric region, coarse ornamentation of the carapace, and a conspicuous submarginal protuberance on each side of the carapace between the antennal and ocular peduncles.

DISTRIBUTION AND ABUNDANCE OF LARVAE AND ADULTS OF SOLENOCERA (DECAPODA, SOLENOCERIDAE) IN THE SOUTHWESTERN GULF OF MEXICO

The distribution and abundance of larvae of the genus Solenocera and adults of Solenocera vioscai (Burkenroad, 1934) were analysed. Factors affecting their distribution and abundance in Campeche Sound are discussed. We found the occurrence of a period of higher reproductive activity related with the time of maximal primary production during summer, that is, the rainy season when the supply of organic material is greater. A larval dispersion model related to the pattern of predominating water currents in each climatic period is given. During summer, larvae concentrate in front of the Terminos Lagoon, due to the presence of a middle-scale cyclonic gyre. During autumn, larvae are transported to the central region of the study area in front of the Grijalva-Usumacinta system and the Boca de Puerto Real at the outer shelf. Finally, in spring, an anticyclonic current is observed (in southwestern direction), which transports the larvae and tends to concentrate them in front of the coast of Tabasco.

Morphometry and relative growth of the swimming crab, Portunus Spinicarpus (Stimpson, 1871) from the southern Gulf of Mexico

The morphometric characteristics and relative growth of the swimming crab, Portunus spinicarpus collected in the southern Gulf of Mexico were examined. A total of 248 specimens was measured on 13 external variables, including measurements of carapace, chelae, and abdomen. For both males and females, each body character was adjusted to a power equation taking the carapace width as the independent variable, and comparisons in the growth parameter (b) between sexes were made. Discriminant Analyses (DA) were also applied to identify measurements characterizing sexes. The results obtained show the males to be larger than the females. The smallest individuals (<28 mm carapace width) were only females, and the only two specimens larger than 60 mm were males. The size of the smallest specimen (13 mm) presumably indicates that individuals recruit to the adult population around this size. The DA showed that the sex discriminating power of the abdomen width was absolute (100% of specimens well classified) only in combination with the carapace depth. The DA and t-test of the b parameter showed that secondary sexual characters corresponded to the lengths of chelae and spines, being larger in males. The statistical analysis of paired characters within sexes indicated a mirror-symmetry in this species, which provides more stability and balance to individuals. Symmetrical traits and body measurements in P. spinicarpus probably explain its ecological success in the western Atlantic. Se examinaron las caracteristicas morfometricas y el crecimiento relativo del cangrejo nadador Portunus spinicarpus recolectado en el sur del Golfo de Mexico. Se midieron un total de 248 individuos en 13 variables externas, incluyendo medidas del caparazon, quelas y abdomen. Cada caracteristica corporal en machos y hembras se ajusto a una ecuacion de tipo potencial tomando el ancho del caparazon como variable independiente, y se hicieron comparaciones entre sexos del parametro de crecimiento (b). Se aplicaron tambien Analisis Discriminantes (DA) para identificar las caracteristicas morfometricas de cada sexo. Los resultados mostraron que los machos son mas grandes que las hembras. Los individuos mas pequenos (<28 mm en ancho del caparazon) fueron hembras, mientras que los dos unicos especimenes mayores a 60 mm, fueron machos. La talla del especimen mas pequeno (13 mm) indica que probablemente los individuos se reclutan a la poblacion adulta alrededor de esa talla. El DA mostro que el poder para discriminar sexos del ancho del abdomen es absoluto (100% de los especimenes bien clasificados) solo en combinacion con la profundidad del caparazon. El DA y la prueba de t sobre el parametro b mostraron que las caracteristicas sexuales secundarias corresponden a la longitud de quelas y espinas, siendo mayor en los machos. Los analisis estadisticos aplicados a las caracteristicas pareadas dentro de cada sexo indicaron que la especie presenta una simetria en espejo, la cual provee una mayor estabilidad y balance a los individuos. Los rasgos simetricos y caracteristicas corporales en P. spinicarpus probablemente explican su exito ecologico en el Atlantico occidental.

Dispersal patterns of shrimp larvae and postlarvae of the genus Solenocera

Se analiza la abundancia y los procesos de dispersion de los primeros estadios larvales y postlarvales de Solenocera spp. (Burkenroad, 1939). Los datos obtenidos se basaron en tres campanas oceanograficas realizadas en el sur de la bahia de Campeche, Mexico, durante el verano y otono de 1993 y primavera de 1994. El verano fue el periodo de mayor abundancia con una densidad larvaria promedio de protozoeas, mysis y postlarvas correspondientes a 19,8; 22,1 y 1,9 organismos 100 m-3, respectivamente. Las larvas presentaron, en general, un tipico patron diario de migracion. Ellas se desplazaron de zonas de mayor profundidad hacia la superficie en la noche, mientras que durante el dia estas tendieron a dirigirse hacia las profundidades. Las protozoeas se distribuyeron con mayor frecuencia en los niveles superficiales mientras que las mysis y postlarvas fueron capturadas en mayor numero en los niveles mas profundos. En general, las protozoeas y mysis se distribuyeron en profundidades sobre la termoclina, haloclina y picnoclina. La disponibilidad de alimento parece ser el principal factor para determinar la distribucion vertical de Solenocera spp.

Bacterial diversity and the geochemical landscape in the southwestern Gulf of Mexico

Marine sediments are an example of one of the most complex microbial habitats. These bacterial communities play an important role in several biogeochemical cycles in the marine ecosystem. In particular, the Gulf of Mexico has a ubiquitous concentration of hydrocarbons in its sediments, representing a very interesting niche to explore. Additionally, the Mexican government has opened its oil industry, offering several exploration and production blocks in shallow and deep water in the southwestern Gulf of Mexico (swGoM), from which there are no public results of conducted studies. Given the higher risk of large-scale oil spills, the design of contingency plans and mitigation activities before oil exploitation is of growing concern. Therefore, a bacterial taxonomic baseline profile is crucial to understanding the impact of any eventual oil spill. Here, we show a genus level taxonomic profile to elucidate the bacterial baseline, pointing out richness and relative abundance, as well as relationships with 79 abiotic parameters, in an area encompassing ∼150,000 km2, including a region where the exploitation of new oil wells has already been authorized. Our results describe for the first time the bacterial landscape of the swGoM, establishing a bacterial baseline “core” of 450 genera for marine sediments in this region. We can also differentiate bacterial populations from shallow and deep zones of the swGoM based on their community structure. Shallow sediments have been chronically exposed to aromatic hydrocarbons, unlike deep zones. Our results reveal that the bacterial community structure is particularly enriched with hydrocarbon-degrading bacteria in the shallow zone, where a greater aromatic hydrocarbon concentration was determined. Differences in the bacterial communities in the swGoM were also observed through a comprehensive comparative analysis relative to various marine sediment sequencing projects, including sampled sites from the Deep Water Horizon oil spill. This study in the swGoM provides clues to the bacterial population adaptation to the ubiquitous presence of hydrocarbons and reveals organisms such as Thioprofundum bacteria with potential applications in ecological surveillance. This resource will allow us to differentiate between natural conditions and alterations generated by oil extraction activities, which, in turn, enables us to assess the environmental impact of such activities.

Diversity and distribution of Chirostyloidea and Galatheoidea (Decapoda, Anomura) in the Southern Gulf of Mexico.

Abstract We examined the diversity, abundance, distribution, and average size of squat lobsters collected during eight cruises conducted on the continental shelf and slope of the Gulf of Mexico (Mexican/USA border to the Caribbean Sea). Six species belonging to two genera of Chirostyloidea, and 25 species of four genera of Galatheoidea are reported. A total of 1513 specimens were obtained of which 95 were Chirostylidae, two Galatheidae, 285 Munidopsidae, and 1131 Munididae. Of the species collected, 13.8% were only known from Caribbean Sea. Three species of Chirostylidae—Gastroptychus salvadori, Uroptychus capillatus, and Uroptychus spiniger—as well two of Munidopsidae, Munidopsis bradleyi and Munidopsis riveroi, are recorded for the first time in the Gulf of Mexico. The upper bathymetric range of one species and the lower one for eight species are extended. Biological and ecological traits of squat lobsters in the southern Gulf of Mexico are also provided.

An unusual new species of paguroid (Crustacea, Anomura, Paguridae) from deep waters of the Gulf of Mexico

Abstract A new hermit crab species of the family Paguridae, Tomopaguropsis ahkinpechensis sp. n., is described from deep waters (780–827 m) of the Gulf of Mexico. This is the second species of Tomopaguropsis known from the western Atlantic, and the fifth worldwide. The new species is morphologically most similar to a species from Indonesia, Tomopaguropsis crinita McLaughlin, 1997, the two having ocular peduncles that diminish in width distally, reduced corneas, dense cheliped setation, and males lacking paired pleopods 1. The calcified figs on the branchiostegite and anterodorsally on the posterior carapace, and the calcified first pleonal somite that is not fused to the last thoracic somite, are unusual paguroid characters. A discussion of the affinities and characters that define this new species is included, along with a key to all five species of Tomopaguropsis.