Degradation and in-use stability study of five marketed therapeutic monoclonal antibodies by generic weak cation exchange liquid chromatographic method ((WCX)HPLC/DAD).

Therapeutic monoclonal antibodies (mAbs) represent a very important class of the current biopharmaceutics. The great complexity of their structure made necessary the use of different analytical approaches for assessing different physico-chemical properties. In this work, weak cation exchange (WCX) high performance liquid chromatography with diode array detection ((WCX)HPLC/DAD) is used to assess the charge variant profile. The method here developed combined the effect of ionic strength and controlled pH gradient and allows for the charge variants analysis of the five mAbs studied, namely bevacizumab (BVZ), cetuximab (CTX) infliximab (INF), rituximab (RTX) and trastuzumab (TTZ), which are among the most used mAbs worldwide. The differences in the charge variants in the natural isoforms of the mAbs promoted characteristic WCX chromatograms for each of mAbs that can be also useful for identification purposes. These chromatograms have provided to be suitable for tracking changes in the charge variants of each mAb analyzed both in controlled degraded and in stabilities study along time of in-use samples solutions at 2 mg/mL in 0.9% NaCl stored refrigerated (at 4 °C) and frozen (-20 °C) for two months. The results obtained indicated different stabilities of these mAbs, all IgG1, against degradation by different stressed environmental conditions and in-use stability along two months.

Parasite communities of the spotted rose snapper Lutjanus guttatus (Perciformes: Lutjanidae) off the Mexican Pacific coasts: Spatial and long-term inter-annual variations.

A total of 802 individuals of Lutjanus guttatus (Steindachner, 1869) specimens were collected over a 10-year period (August 2012 to February 2021) from four locations on the south-central Pacific coast of Mexico. Their parasite communities were quantified and analyzed to determine if they experience significant spatial and inter-annual variations. Thirty-two taxa of metazoan parasite were recovered and identified: four species of Digenea, four Monogenea, one Cestoda, two Acanthocephala, seven Nematoda, one Hirudinea, and nine of Crustacea (six Copepoda, and three Isopoda). Species richness was greatest among the digenean group, which represented 25% of the total species recovered, followed by the nematodes (22% of total species). Species richness at the component community level (10 to 20 species) was similar to reported richness in other Lutjanus spp. The component communities and infracommunities exhibited a similar pattern: low species richness and diversity, and dominance by a single species, mainly the monogenean Haliotrematoides guttati. Parasite community structure and species composition varied through the years, as well as between sampling locations. Variations were possibly caused by a combination of biotic and abiotic factors which generated notable changes in the infection levels of several component species. However, the similarity in the parasite species composition was high locally for short-term periods (one or two years). This result, therefore, suggests that parasite communities of L. guttatus may be more predictable locally, but only for short-term periods.

Hábitos alimenticios de Caranx vinctus (Perciformes: Carangidae), especie de importancia comercial en la bahía de Acapulco, Guerrero, México / Feeding habits of Caranx vinctus (Perciformes: Carangidae), a commercially important species in Acapulco Bay, Guerrero

Introducción: Caranx vinctus es una especie importante en las pesquerías locales, utilizada como fuente de proteína para el consumo humano, sin embargo, su ecología trófica es poco conocida en las costas de Pacífico mexicano. Objetivo: Conocer los hábitos alimenticios de C. vinctus. Metodología: Se analizaron los contenidos estomacales de 268 ejemplares, capturados mediante el arte de pesca, chinchorro playero, en la sociedad cooperativa Playa las Hamacas, en la Bahía de Acapulco, Guerrero, México. Se aplicó el índice de importancia relativa específica de la presa (% PSIRI) para determinar las principales categorías alimenticias (ítems). La amplitud de la dieta se calculó utilizando el índice de Levin. Las posibles diferencias en la dieta por sexo, madurez sexual o temporada se identificaron a través del índice Morisita Horn y un análisis multivariado ANOSIM. Resultados: Los principales ítems fueron crustáceos representados principalmente por larvas megalopa de Portunoidae (16.51 %), Teleostei (12.7 %), materia orgánica no identificada (11.2 %), y Anchoa ischana (10.6 %) El índice de Levin indica baja amplitud del nicho trófico (Bi = 0.29) por lo que se le puede considerar como un depredador especialista con marcadas preferencias hacia algunos tipos alimentarios. El índice de Morisita Horn indicó que, se presentó un traslape entre las dietas por sexo (hembras y machos Cλ = 0.84), pero no entre madurez sexual (Juveniles y adultos Cλ = 0.56) y temporadas (Lluvias y secas Cλ = 0.03). Un análisis ANOSIM indicó que había diferencias significativas en la dieta de C. vinctus por sexo, madurez sexual y temporada. Conclusión: Se estableció que de manera general C. vinctus es una especie zooplantófaga e ictiófaga (Nivel Trófico = 3.39).

Abtract Introduction: Caranx vinctus is an important species in local fisheries, used as a source of protein for human consumption, however, its trophic ecology is little known on the Mexican Pacific coast. Objective: Know the feeding habits of C. vinctus. Methods: The stomach contents of 268 specimens, captured beach nets, in the Playa Las Hamacas cooperative society, in Acapulco Bay, Guerrero, Mexico, their food items were analyzed. The prey-specific index of relative importance (% PSIRI) was applied to determine the main food categories (breadth was calculated using Levin's index. Possible differences in the diet by sex, sexual maturity, or season were identified through Morisita Horn index and a multivariate ANOSIM analysis. Results: Crustaceans mainly represented by megalopa larvae of Portunoidae (16.51 %), Teleostei (12.7 %), unidentified organic matter (11.2 %), and Anchoa ischana (10.6 %) were the most important food items. The Levin index indicates low amplitude of the trophic niche (Bi = 0.29) so C. vinctus can be considered as a specialist predator with marked preferences towards some food items. The Morisita Horn index indicated that there was an overlap between sexes (females and males Cλ = 0.84), but not between sexual maturity (Juveniles and adults Cλ = 0.56) and seasons (Rainy and dry Cλ = 0.03). ANOSIM analysis indicated that there were significant differences in the diet of C. vinctus by sex, sexual maturity, and season. Conclusion: It was established that in general C. vinctus is a zoplantophage and ichthophagus species (Trophic Level = 3.39).

Temporal variation in infection levels and reproductive traits of the acanthocephalan Pseudoleptorhynchoides lamothei in the blue sea catfish Ariopsis guatemalensis (Günther, 1864).

Current data on reproductive biology and population dynamics of the acanthocephalans are scarce mainly in regions from the tropical Pacific. An analysis was done to identify possible factors that influence variation in infection levels of the acanthocephalan Pseudoleptorhynchoides lamothei Salgado-Maldonado, 1976 in its final host, the blue sea catfish Ariopsis guatemalensis (Günther, 1864), and describe its main reproductive traits. A total of 1,094 A. guatemalensis were collected from Tres Palos Lagoon from August 2014 to December 2015. Prevalence of P. lamothei varied from 1.47% to 38.33%, and mean abundance from 0.03 to 4.44 helminths per examined host. In female P. lamothei relative fecundity increased with total length. Temporal variations in P. lamothei infection levels were attributed mainly to changes in host feeding and reproductive behaviour in response to local environmental factors as climatic season, and variations in water temperature.

Feeding habits of the fishes Euthynnus lineatus and Scomberomorus sierra (Perciformes: Scombridae) in the Eastern Tropical Pacific / Hábitos alimentarios de los peces Euthynnus lineatus y Scomberomorus sierra (Perciformes: Scombridae) en el Pacífico Tropical Oriental

Introduction: Black skipjack, Euthynnus lineatus, and Pacific sierra, Scomberomorus sierra, are of great economic importance in the small-scale fishery of the Tropical Eastern Pacific and in particular in the study area. Objectives: The objectives of the present study were to assess the diet components of E. lineatus and S. sierra, as well as to evaluate the niche width, trophic level, and trophic overlap between the two species, by size and season. Methods: Biological samples were obtained weekly from small-scale fishery catches in Bahía de Acapulco, Mexico. The E. lineatus sampling period occurred from October 2016 to October 2017, whereas S. sierra was sampled from October 2016 to June 2018. The Prey-specific Index of Relative Importance (% PSIRI) was used to evaluate the importance of each prey item in the diet of the predator. Levin´s index (Bi) was used as a measure of niche width. The Morisita-Horn index was used to evaluate diet overlap by size (juveniles or adults), by season (dry or wet), and between the two species. The trophic level (TL) of predators was calculated using the Cortés´ method. Results: A total of 262 E. lineatus stomachs were analyzed (42 % were empty and 58 % contained food) and a total of 209 S. sierra stomachs were analyzed (74.6 % were empty and 25.3 % contained food). Of the total E. lineatus specimens sampled, 107 were juveniles and 155 were adults. Black skipjack juveniles fed on five food items and adults fed on 13 food items. Of the total S. sierra specimens sampled, 75 were juveniles and 134 were adults. Pacific sierra juveniles and adults fed on five food items. The diet of the two species comprised fish, mollusks, and crustaceans. The two species showed narrow niche width. The diet of juvenile and adult E. lineatus presented differences with growth, contrary to what was observed for juveniles and adults of S. sierra. There were no significant differences in diet by season for both species. The trophic overlap obtained between the two species was low. The trophic level calculated for both species indicated that are tertiary consumers. Conclusions: Black skipjack and Pacific sierra are tertiary predators and present a specialist behavior, feeding mainly on fish from the families Engraulidae and Clupeidae. Although a degree of similarity in the dietary food components of these species was observed, there was not a high degree of interspecific competition for food.

Introducción: El barrilete negro, Euthynnus lineatus, y la sierra del Pacífico, Scomberomorus sierra, son peces que presentan gran importancia económica en la pesca artesanal del Pacífico Tropical Oriental y de manera particular en el área de estudio. Objetivos: Los objetivos del presente trabajo son determinar los componentes alimentarios de la dieta de E. lineatus y S. sierra, así como determinar la amplitud del nicho, el nivel trófico y el traslape trófico entre ambas especies, por tallas y por temporada climática. Métodos: Las muestras biológicas se obtuvieron semanalmente de las capturas realizadas por las pesquerías de pequeña escala llevadas a cabo en la Bahía de Acapulco. El periodo de muestreo de E. lineatus se realizó desde octubre 2016 hasta octubre 2017, mientras que el de S. sierra de octubre 2016 hasta junio 2018. El Índice de Importancia Relativa Específica de la Presa (% PSIRI) se usó para evaluar la importancia de cada ítem presa en la dieta del depredador; el índice de Levin (Bi) se usó como una medida de la amplitud del nicho; el índice de Morisita-Horn se usó para evaluar el traslape entre las dietas por talla (juveniles y adultos), por temporada climática (seca y lluviosa) y entre las dos especies. El nivel trófico (TL) de los depredadores fue calculado usando el método de Cortés. Resultados: Se analizaron en total 262 estómagos de E. lineatus (42 % vacíos y 58 % con alimento) y 209 estómagos de S. sierra (74.6 % vacíos y 25.3 % con alimento). Del total de organismos muestreados de E. lineatus, 107 se consideraron organismos jóvenes y 155 adultos. Los jóvenes de barrilete se alimentaron de 5 ítems alimentarios y los adultos se alimentaron de 13. En el caso de S. sierra, 75 organismos se consideraron jóvenes y 134 adultos. Los jóvenes y adultos de sierra se alimentaron de cinco ítems alimentarios. La dieta de ambas especies se compone por peces, moluscos y crustáceos. Las dos especies presentaron una amplitud del nicho trófico estrecho. La dieta de jóvenes y adultos de E. lineatus presentó diferencias alimentarias de acuerdo con su crecimiento, contrario a lo observado entre jóvenes y adultos de S. sierra. Entre temporadas climáticas, la dieta no presentó variaciones significativas en ambas especies. Asimismo, el valor de traslape trófico obtenido entre ambas especies fue bajo. El nivel trófico determinado para ambas especies indicó que son consumidores terciarios. Conclusiones: El barrilete negro Euthynnus lineatus y la sierra del Pacifico Scomberomorus sierra son depredadores terciarios y presentan un comportamiento especialista, principalmente sobre peces de las familias Engraulidae y Clupeidae. Aunque se observó una similitud en los componentes alimentarios de estas especies, no existe un alto grado de competencia interespecífica por el alimento.

Validated reverse phase HPLC diode array method for the quantification of intact bevacizumab, infliximab and trastuzumab for long-term stability study.

The aim of the present study was to develop suitable and reliable method for quantification three of the most worldwide used therapeutic monoclonal antibodies (mAbs) -bevazizumab (BVZ), infliximab (INF) and trastuzumab (TTZ)- to be used in long-term stability studies. Reverse phase (RP) was selected by its greater sensibility and reproducibility comparing with other chromatographic modes. Then a high performance liquid chromatography with diode array detection (RP)HPLC/DAD method was checked. Since the three mAbs represent the active ingredient in the medicines in which they are formulated, the selected method was validated for each one in accordance with the International Conference on Harmonization (ICH) guidelines for pharmaceuticals for human use. Then method was validated in terms of linearity, accuracy, precision, (repeatability, intermediate precision) specificity (by forced degradation studies), robustness and system suitability. Spectral peak purity analysis strategy was used to test mAb degradations. Comparative study of the results indicated similar behavior for the three mAbs. Forced degradation studies also provided deep knowledge of these important bio-macromolecules. At last the method was successfully used to quantify BVZ, INF and TTZ in long-term stability studies performed under hospital conditions of use and they showed great stability regarding quantification during the time of the study.

Study and ICH validation of a reverse-phase liquid chromatographic method for the quantification of the intact monoclonal antibody cetuximab.

Cetuximab (CTX) is a potent chimeric mouse/human monoclonal antibody (mAb) approved worldwide for treatment of metastatic colorectal cancer. Among the various biological and physical analyses performed for full study on this biopharmaceutic, the determination of the concentration preparations throughout manufacturing and subsequent handling in hospital is particularly relevant. In the present work, the study and validation of a method for quantifying intact CTX by reverse-phase high-performance liquid chromatography with diode array detection ((RP)HPLC/DAD) is presented. With that end, we checked the performance of a chromatographic method for quantifying CTX and conducted a study to validate the method as stability-indicating in accordance with the International Conference on Harmonization guidelines (ICH) for biotechnological drugs; therefore, we evaluated linearity, accuracy, precision, detection and quantification limits, robustness and system suitability. The specificity of the method and the robustness of the mAb formulation against external stress factors were estimated by comprehensive chromatographic analysis by subjecting CTX to several informative stress conditions. As demonstrated, the method is rapid, accurate, and reproducible for CTX quantification. It was also successfully used to quantify CTX in a long-term stability study performed under hospital conditions.

Study and ICH validation of a reverse-phase liquid chromatographic method for the quantification of the intact monoclonal antibody cetuximab$ / 药物分析学报

Cetuximab (CTX) is a potent chimeric mouse/human monoclonal antibody (mAb) approved worldwide for treatment of metastatic colorectal cancer. Among the various biological and physical analyses per-formed for full study on this biopharmaceutic, the determination of the concentration preparations throughout manufacturing and subsequent handling in hospital is particularly relevant. In the present work, the study and validation of a method for quantifying intact CTX by reverse-phase high-perfor-mance liquid chromatography with diode array detection ((RP)HPLC/DAD) is presented. With that end, we checked the performance of a chromatographic method for quantifying CTX and conducted a study to validate the method as stability-indicating in accordance with the International Conference on Harmo-nization guidelines (ICH) for biotechnological drugs; therefore, we evaluated linearity, accuracy, preci-sion, detection and quantification limits, robustness and system suitability. The specificity of the method and the robustness of the mAb formulation against external stress factors were estimated by compre-hensive chromatographic analysis by subjecting CTX to several informative stress conditions. As de-monstrated, the method is rapid, accurate, and reproducible for CTX quantification. It was also suc-cessfully used to quantify CTX in a long-term stability study performed under hospital conditions.

Quantification of an intact monoclonal antibody, rituximab, by (RP)HPLC/DAD in compliance with ICH guidelines.

We studied the quantification of an intact therapeutic monoclonal antibody (mAb), rituximab (RTX), using (reversephase) high-performance liquid chromatography with diode array detection ((RP)HPLC/DAD). To this end, we developed a chromatographic method and validated it as stabilityindicating in accordance with the International Conference on Harmonization guidelines (ICH). A 300-Å C8 column (250 mm×4.6 mm, 5 µm) was used to perform the analysis, and the temperature was maintained at 70 °C. Although only one mAb was analyzed, it was necessary to apply a gradient to elute it with a complex organic mixture. Chromatograms were registered at several wavelengths, with λ =214 nm employed for quantification purposes. The method was developed to quantify marketed RTX under typical hospital administration conditions. Further dilution was avoided in order to prevent additional mAb modification, and in this way the method was shown to be linear from 60 to 5000 mg/L. The precision of the method (repeatability and intermediate precision, estimated as the relative standard deviation, RSD %), was less than 1.0 %. Accuracy, specificity, robustness, and system suitability were also evaluated as specified in the ICH guidelines.We conducted a comprehensive chromatographic analysis by submitting RTX to several informative stress conditions. These forced degradation studies were conducted for two reasons: to estimate the specificity of the method, and to evaluate the robustness of the mAb formulation against external stress factors when handling it in preparation for administration. Thus, we investigated the effects of acid, base, oxidation, ionic strength, temperature, and UV light. Although a slight modification to the intact mAb could not be distinguished chromatographically in the stress studies we conducted, the procedure proposed here to evaluate peak purity enabled us to detect it with a satisfactory level of confidence. The proposed method could therefore be considered stability-indicating for quantyfying the intact mAb since it is qualified to detect its degradation/modification. Finally, the method was used to evaluate RTX in a long-term stability study performed under hospital conditions of use.

Helminth communities of two species of piscivorous birds, Ardea alba (Linnaeus) and Nyctanassa violacea (Gmelin) (Ciconiiformes: Ardeidae), in two coastal lagoons from Guerrero state, Mexico.

The composition and species richness in helminth communities of two species of heron, Ardea alba and Nyctanassa violacea, in two coastal lagoons from Guerrero, Mexico were examined. Nineteen species of helminth (7,804 individuals) were identified in 43 adult birds: 15 digeneans, 1 acanthocephalan, 1 cestode, and 2 nematodes. Eight species co-occurred in herons of both species and lagoons. The prevalence values of seven species and the mean abundance of five species varied significantly between species of birds and between lagoons. The heterophyid, Ascocotyle (Phagicola) longa, was the helminth numerically dominant in the helminth community of A. alba in both lagoons, while the cestode, Parvitaenia cochlearii, dominated the community of N. violacea. At the component community level, species richness varied significantly: 10 species in A. alba from Coyuca to 16 in N. violacea (Tres Palos). All of the birds examined were infected with helminth parasites: three to seven species per host in A. alba from Coyuca, and two to eight species in A. alba and N. violacea from Tres Palos. The results indicate that even though species composition was similar between both species of heron, the structure of their communities was not the same. Differences in the feeding behavior of the birds (day/night habits), as well as local differences in the abundance of species of fish, and infection levels of helminths in each lagoon are suggested as being responsible for the variations registered in the structure of the helminth communities.

Parasite communities of the neotropical cormorant Phalacrocorax brasilianus (Gmelin) (Aves, Phalacrocoracidae) from two coastal lagoons in Guerrero state, Mexico.

The parasite community structure of the neotropical cormorant, Phalacrocorax brasilianus, from two lagoons (Coyuca and Tres Palos) from Guerrero state, México, was examined. Fourteen species of adult helminths (6,391 individuals) from 48 cormorants were identified: 9 digeneans, 1 acanthocephalan, 1 cestode, and 3 nematodes. A total of 11 species were collected in Coyuca Lagoon and 12 in Tres Palos Lagoon. Nine species co-occurred in cormorants of both lagoons but, with the exception of Contracaecum multipapillatum and Drepanocephalus olivaceus, species were not equally common in both lagoons. The prevalence values of six species of helminth and the mean abundance of four species varied significantly between lagoons, and C. multipapillatum was numerically dominant in both lagoons. The qualitative similarity between the two communities at the component level was 64%. All cormorants examined were infected, and parasite species richness was 3-5 in Coyuca and 4-9 in Tres Palos lagoon. The results indicate that both communities presented a similar structure at the component level, probably because the cormorants of both lagoons feed on the same species of fish and thus acquire almost the same species of parasites. Differences observed at the infracommunity level were attributed to variations in the degree of dominance of the particular species.

Six new and one previously described species of Pseudorhabdosynochus (Monogenoidea, Diplectanidae) infecting the gills of groupers (Perciformes, Serranidae) from the Pacific coasts of Mexico and Panama.

Six new and 1 previously described species of Pseudorhabdosynochus (Diplectanidae) are described and/or reported from the gill lamellae of 5 serranid (Perciformes) fish species from the Pacific waters in Guerrero State of Mexico and Panama City, Panama. These species are Pseudorhabdosynochus guerreroensis n. sp. from the Pacific mutton hamlet Alphestes inmaculatus Breder (type host), rivulated mutton hamlet Alphestes multiguttatus (Günther), and spotted grouper Epinephelus analogus Gill from Mexico; Pseudorhabdosynochus urceolus n. sp. from the Pacific graysby Cephalopholis panamensis (Steindachner) from Taboga Island in Panama; Pseudorhabdosynochus spirani n. sp. from the starry grouper Epinephelus labriformis (Jenyns) from Mexico and the Perlas Archipelago and Taboga Island in Panama; Pseudorhabdosynochus fulgidus n. sp. from E. labriformis from Mexico and the Perlas Archipelago and Taboga Island (type locality) in Panama; Pseudorhabdosynochus tabogaensis n. sp. from E. labriformis from Mexico and the Perlas Archipelago and Taboga Island (type locality) in Panama; Pseudorhabdosynochus anulus n. sp. from E. labriformis from Mexico and Taboga Island (type locality) in Panama; and Pseudorhabdosynochus amplidiscatum (Bravo-Hollis, 1954) Kritsky and Beverley-Burton, 1986 from E. analogus and E. labriformis from Mexico and the Perlas Archipelago and Taboga Island in Panama. All new species are mainly distinguished from other species of the genus by the shape and size of the sclerotized vagina and haptoral structures. The present specimens of Alphestes, Cephalopholis, and Epinephelus spp. represent new host records and Panama represents a new geographic record for species of Pseudorhabdosynochus. The apparent common feature supporting a close similarity of these diplectanids is a single, secondary ejaculatory bulb with thickened wall.

Factors determining parasite community richness and species composition in black snook Centropomus nigrescens (Centropomidae) from coastal lagoons in Guerrero, Mexico.

Species richness and composition were determined for parasite communities in the black snook Centropomus nigrescens collected from five coastal lagoons in the Guerrero state, Mexico. A total of 354 fish were collected between December 2007 and November 2008. Twenty-four species of parasite were identified: 2 monogeneans, 12 digeneans, 4 acanthocephalans, 1 cestode, 4 nematodes, and 1 pentastomid. The communities consisted mainly of autogenic parasites, and all were dominated by the digenean Paracrytogonimus yamagutii. Community species composition was similar among lagoons, although the influence of local conditions prevented them from being identical. Host traits such as predator feeding habits, body size, and vagility contributed to parasite community structure and species composition.

Metazoan parasite community of blue sea catfish, Sciades guatemalensis (Ariidae), from Tres Palos Lagoon, Guerrero, Mexico.

The seasonal dynamic of the metazoan parasite community of the blue sea catfish (Sciades guatemalensis) from Tres Palos Lagoon, Guerrero, Mexico, was studied at the component community and infracommunity levels. A total of 382 fish were collected during the regional dry and rainy seasons (a total of seven seasons) between April 2000 and September 2007. Nine helminths were collected: Neotetraonchus sp., Pseudoacanthostomum panamense, Austrodiplostomum compactum, Clinostomum complanatum, Metadena sp., Pseudoleptorhynchoides lamothei, Neoechinorhynchus cf. golvani, Hysterothylacium perezi, and Contracaecum sp. The infection dynamics of some dominant helminths was influenced by environmental changes generated by the dry/rainy season cycle. Nested (non-random) species composition was observed in the infracommunities during almost all of the sample period. Variation in the intensity of nestedness was attributed to a sequential colonization process over time by the dominant helminths.

Diplostomiasis in cultured and wild tilapia Oreochromis niloticus in Guerrero State, Mexico.

This paper is a comparative study of Diplostomum (Austrodiplostomum) compactum (Lutz, 1928) in Nile tilapia Oreochromis niloticus (Linneo) from two fish farms and two nearby coastal lagoons in Guerrero state, Mexico. The higher infections levels in cultured tilapia than wild tilapia is attributed to higher fish densities in the culture systems and higher abundance of the snail Biomphalaria cf. havanensis (Pteiffer), first intermediate host of this parasite in freshwater and brackish water systems.

Seasonal patterns in metazoan parasite community of the "Fat Sleeper" Dormitator latifrons (Pisces: Eleotridae) from Tres Palos Lagoon, Guerrero, Mexico

Dormitator is among the most important fish genera in the Mexican Pacific coastal lagoon systems. In Tres Palos Lagoon, the Fat Sleeper Dormitator latifrons is one of the most significant species based on catch volume, although it is only consumed locally. Very little information exists on this species’ parasitofauna. Composition and temporal variation in the metazoan parasite community structure of Dormitator latifrons from Tres Palos Lagoon (99º47’ W, 16º48’ N), Guerrero, Mexico, were determined using seasonal samples taken between April 2000 and June 2002. Ten parasite species (55 817 individuals) were recovered from 219 examined hosts. These species included eight helminths (Ascocotyle (Phagicola) longa, Echinochasmus leopoldinae, Clinostomum complanatum, Pseudoacanthostomum panamense, Saccocoelioides lamothei, Parvitaenia cochlearii, Contracaecum sp. and Neoechinorhynchus golvani) and two crustaceans (Argulus sp. and Ergasilus sp.). Five of the helminth species exhibited seasonal variation in their infection dynamics associated with environmental changes during the dry and rainy seasons. The variations in the infection dynamics generated changes in the community structure over time. Rev. Biol. Trop. 56 (3): 1419-1427. Epub 2008 September 30.

Entre abril del 2000 y junio del 2002 se efectuó un estudio para determinar la composición y la variación temporal en la estructura de la comunidad de parásitos metazoarios del popoyote Dormitator latifrons en la laguna de Tres Palos, Guerrero, México, a partir de muestras temporales. Se recuperaron diez especies de parásitos (55 817 individuos) de 219 hospederos examinados. Estas especies incluyeron ocho helmintos (Ascocotyle (Phagicola) longa, Echinochasmus leopoldinae, Clinostomum complanatum, Pseudoacanthostomum panamense, Saccocoelioides lamothei, Parvitaenia cochlearii, Contracaecum sp. y Neoechinorhynchus golvani) y dos crustáceos (Argulus sp. y Ergasilus sp.). Cinco de las especies de helmintos registraron variación temporal en su dinámica de infección, la cual fue asociada con cambios ambientales durante las estaciones de secas y lluvias. Las variaciones en la dinámica de infección de estas especies generaron cambios en la estructura de la comunidad a lo largo del tiempo.

Seasonal patterns in metazoan parasite community of the "Fat Sleeper" Dormitator latifrons (Pisces: Eleotridae) from Tres Palos Lagoon, Guerrero, Mexico.

Dormitator is among the most important fish genera in the Mexican Pacific coastal lagoon systems. In Tres Palos Lagoon, the Fat Sleeper Dormitator latifrons is one of the most significant species based on catch volume, although it is only consumed locally. Very little information exists on this species' parasitofauna. Composition and temporal variation in the metazoan parasite community structure of Dormitator latifrons from Tres Palos Lagoon (99 degrees 47' W, 16 degrees 48' N), Guerrero, Mexico, were determined using seasonal samples taken between April 2000 and June 2002. Ten parasite species (55 817 individuals) were recovered from 219 examined hosts. These species included eight helminths (Ascocotyle (Phagicola) longa, Echinochasmus leopoldinae, Clinostomum complanatum, Pseudoacanthostomum panamense, Saccocoelioides lamothei, Parvitaenia cochlearii, Contracaecum sp. and Neoechinorhynchus golvani) and two crustaceans (Argulus sp. and Ergasilus sp.). Five of the helminth species exhibited seasonal variation in their infection dynamics associated with environmental changes during the dry and rainy seasons. The variations in the infection dynamics generated changes in the community structure over time.

Hábitos alimentarios de los peces Lutjanus peru y Lutjanus guttatus (Pisces: Lutjanidae) en Guerrero, México / Feeding habits of the fishes Lutjanus peru and Lutjanus guttatus (Pisces: Lutjanidae) of Guerrero, México

Se analiza la composición de la dieta del huachinango (Lutjanus peru )y del flamenco (Lutjanus guttatus ) en la costa de Guerrero,México.Los ejemplares se obtuvieron mensualmente de las capturas comerciales en tres regiones de pesca y presentaron intervalos de talla comprendidos entre 130 y 684 mm de longitud horquilla (LH)para el caso de L.peru ,y de 120 a 550 mm para L. guttatus .A partir del número y del peso de los distintos componentes alimentarios,identificados hasta el taxon más bajo posible,se calcularon los porcentajes numéricos (%N),gravimétricos (%P)y de frecuencia de ocurrencia (%FO)que fueron sintetizados como valores de importancia relativa.En los estómagos de L.peru se identificaron 68 ítems alimentarios dentro de los cuales predominan los peces (%P =50.9),los crustáceos (%P =35.6)y los moluscos (%P =7.2)mientras que el espectro alimentario de L.guttatus estuvo integrado por 88 componentes que incluyeron principalmente peces (%P =50.8)y crustáceos (%P =43.4).Ambas especies son depredadoras generalistas,con un amplio espectro de presas.Los valores de los índices de traslape de las dietas de estas especies sugieren que no existe un alto grado de competencia intraespecífica por el alimento.Con el fin de encontrar similitudes en la dieta de estos lutjánidos en varias localidades de México y Costa Rica,se realizó un análisis de conglomerados con los valores de importancia relativa de las presas,publicados en varios trabajos.Se encontró más afinidad en la dieta de aquellas especies que habitan en una misma localidad, que entre organismos de la misma especie distribuidos en diferentes zonas.Se infiere que la disponibilidad de las presas,más que la selectividad por el alimento,determina la dieta de estas especies

Feeding habits of the fishes Lutjanus peru and Lutjanus guttatus (Pisces:Lutjanidae)of Guerrero, México.Diet composition of the Pacific snapper (Lutjanus peru )130-684 mm fork length (FL)and the spotted snapper (Lutjanus guttatus )120-550 mm FL,was analyzed.Monthly samples were obtained from commercial landings in three regions off the coast of Guerrero,Mexico.Percentage by number (%N),percentage by weight (%W),and percentage of occurrence (%O)were calculated for each prey and summarized as the index of relative importance.Both species are polyphagous predators feeding on a variety of prey:Sixty-eight prey items,mainly fish (%W =50.9),crustaceans (%W =35.6),and mollusks (%W =7.2),were found in the stomach contents of L.peru ,while 88 components were identified in the diet of L.guttatus ,the most important prey being fish (%W =50.8)and crustaceans (%W =43.4).Diet overlap between species is not significant (p<0.05),indicating that competition for food is unlikely.Based on published values of the relative importance index,the diets of these Lutjanidae were analyzed considering different regions of the Pacific coast of Mexico and Costa Rica,and similarities among sites and species were discussed.The cluster analysis showed that similarities among species inhabiting in the same area are more important than within organisms of the same species living in different zones.Results suggest that prey availability rather than food selectivity, conditions the feeding behavior of these fish species

[Feeding habits of the fishes Lutjanus peru and Lutjanus guttatus (Pisces: Lutjanidae) of Guerrero, México]. / Háqbitos alimentarios de los peces Lutjanus peru y Lutjanus guttatus (Pisces: Lutjanidae) en Guerrero, México.

Diet composition of the Pacific snapper (Lutjanus peru) 130-684 mm fork length (FL) and the spotted snapper (Lugjanus guttatus) 120-550 mm FL, was analyzed. Monthly samples were obtained from commercial landings in three regions off the coast of Guerrero, Mexico. Percentage by number (%N), percentage by weight (%W), and percentage of occurrence (%O) were calculated for each prey and summarized as the index of relative importance. Both species are polyphagous predators feeding on a variety of prey: Sixty-eight prey items, mainly fish (%W = 50.9), crustaceans (%W = 35.6), and mollusks (%W = 7.2), were found in the stomach contents of L. peru, while 88 components were identified in the diet of L. guttatus, the most important prey being fish (%W = 50.8) and crustaceans (%W = 43.4). Diet overlap between species is not significant (p<0.05), indicating that competition for food is unlikely. Based on published values of the relative importance index, the diets of these Lutjanidae were analyzed considering different regions of the Pacific coast of Mexico and Costa Rica, and similarities among sites and species were discussed. The cluster analysis showed that similarities among species inhabiting in the same area are more important than within organisms of the same species living in different zones. Results suggest that prey availability rather than food selectivity, conditions the feeding behavior of these fish species.