Parasite Community Analysis of The Gray Snapper Lutjanus Griseus (Perciformes,Lutjanidae) in a Tropical Region of The Southern Gulf of Mexico.

The gray snapper Lutjanus griseus is a commercially important fish species along its distribution range in the western Atlantic Ocean. However, despite its importance, there is still little knowledge about its parasitic fauna for the Mexican coasts of the Gulf of Mexico. The aims of this research were to generate a list of the parasitic fauna present in juvenile gray snapper L. griseus from a coastal lagoon located in southeastern Mexico, to evaluate the infection levels of parasites and to determine the relationship between the abundance of parasites and the fish size and condition factor. Samples of L. griseus (12 - 29.2 mm) were obtained in two periods of the year (dry and rainy seasons) to examine the intra-annual variability of its parasitic fauna. A total of 17 parasite species were recorded belonging to six taxonomic groups (Myxozoa, Monogenea, Digenea, Cestoda, Nematoda and Acanthocephala). The highest levels of infection (abundance, prevalence and intensity of infection) were found for the monogeneans Euryhaliotrema griseus and Euryhaliotrema fastigatum. There were no significant correlations between the total abundance of parasites and the fish condition and size (total length) in not any of the two seasons studied, suggesting that the body size and the biological condition index of the host did not directly influence the abundance of parasites in early life stages of L. griseus. Moreover, the species of parasites found that could be zoonotic for humans through the consumption of raw or inadequately cooked fish were the nematodes Contracaecum sp. type 1, Contracaecum sp. type 2, Cucullanus pargi and Pseudoterranova sp. The presence of the monogeneans E. griseus and E. fastigatum was also highlighted because these ectoparasite species are known to cause harm to fish under culture systems. All the parasite species found in this study, except nematodes, were new records of geographic distribution.

Toxicidad letal y subletal del arsénico, cadmio, mercurio y plomo sobre el pez Parachaeirodon innesi neon tetra (Characidae) / Lethal and sublethal toxicity of arsenic, cadmium, mercury and lead on fish Paracheirodon innesi neon tetra (Characidae)

La contaminación ambiental es un problema global, siendo los metales pesados los de mayor importancia; como, por ejemplo, arsénico, cadmio, mercurio y plomo. El objetivo del estudio fue evaluar la toxicidad estos cuatro metales sobre el pez Paracheirodon innesi. Para esto se realizaron bioensayos estáticos en laboratorio empleando individuos juveniles y como agentes tóxicos: arseniato de sodio, cloruro de cadmio, cloruro de mercurio y nitrato de plomo. Se determinó la concentración letal media (CL50) y la concentración efectiva media (CE50) para dos efectos subletales (nado extraño y movimiento opercular acelerado) con los programas TRAP y Excel Probit; así como la Concentración sin Efecto Pronosticada (PNEC). Los valores de CL50 y CE50 disminuyeron de manera casi continua de 24 h a 96 h para los distintos metales. El grado de toxicidad, en orden descendente, fue: mercurio > cadmio > arsénico > plomo. Los valores de CE/L50 de TRAP fueron ligeramente mayores a los de Excel Probit. La CL50-96h de estos metales fue 0,129; 23,1; 60,3 y 278 mg.L-1 para Excel Probit y 0,137; 29,4; 65,5 y 282 mg.L-1 para TRAP; respectivamente. Al comparar los valores de PNEC estimados para los cuatro metales de interés con el Estándar de Calidad Ambiental Peruano de la Categoría 4 para ríos de selva (ECA Cat 4 - E2 ríos selva), se puede indicar que la concentración límite del ECA para arsénico no es apropiada y su cumplimiento no aseguraría la conservación del medio acuático

Envinronmental pollution is a global issue, being heavy metals the most important; such as, arsenic, cadmium, mercury and lead. The study object was to evaluate these four metals on fish Paracheirodon innesi. To meet the goal static bioassays were carried out at laboratory, using juveniles and as toxic agents: sodium arsenate, cadmium chloride, mercury chloride and lead nitrate, with high purity. There were determined the median lethal concentration (LC50) and the median effective concentration (EC50) for two sublethal effects (strange swimming and accelerated opercula movement); as well as the Predicted No Effect Concentration (PNEC). LC50 and EC50 values decreased continuously from 24 to 96 h for all metals. The four evaluated metals showed the next toxicity ranking: mercury > cadmium > arsenic > lead. TRAP's L/EC50 values were slightly higher than Excel Probit's values. LC50‑96h for these metals were 0.129; 23.1; 60.3 and 278 mg.L-1 for Excel Probit and 0.137; 29.4; 65.5 y 282 mg.L-1 for TRAP, respectively. When comparing PNEC's estimated values for the four metals of interest with Peruvian Environmental Quality Standard of Category 4 for jungle rivers (EQS Cat 4 - E2 jungle rivers), it can be indicated that ECA's limit concentration to arsenic is inappropriate and its compliance would not ensure aquatic environment conservation

Pseudohaliotrema paralonchuri sp. n. (Monogenoidea: Dactylogyridae), parasitic on Paralonchurus peruanus (Steindachner) (Teleostei: Sciaenidae) from the Peruvian coast.

Pseudohaliotrema paralonchuri sp. n., parasitic on the sciaenid fish Paralonchurus peruanus (Steindachner) from the Peruvian central coast, is described, illustrated and compared with related species of the genus. P. paralonchuri differs from other Pseudohaliotrema by the characteristics of the cirrus, accessory piece, anchors and bars. This is the first record of Pseudohaliotrema from the South American Pacific Ocean.

The metazoan parasites of Stellifer minor (Tschudi, 1844): an ecological approach.

A quantitative and qualitative analysis of the parasite fauna of the sciaenid Stellifer minor (Tschudi) from Chorrillos, Perú, was made. Some characteristics of the infectious processes, in terms of intensity and prevalence of infection, as a function of host sex and size, are given. Moreover, comments on the characteristics of the parasite fauna, related with host role in the marine food webs are included. The parasite fauna of Stellifer minor taken off Chorrillos, Perú, include the monogeneans Pedocotyle annakohni, Pedocotyle bravoi, Rhamnocercus sp. and Cynoscionicola sp., the digenean Helicometra fasciata, the adult acantocephalan Rhadinorhynchus sp. and the larval Corynosoma sp., the nematode Procamallanus sp., the copepods Caligus quadratus, Clavellotis dilatata and Bomolochus peruensis and one unidentified isopod of the family Cymothoidae. A distinctive characteristic of the parasite fauna (Metazoa) of S. minor is the almost absence of larval forms.