RESUMEN Se registraron los primeros avistamientos de elefantes marinos, probablemente elefantes marinos del sur, Mirounga leonina, en la costa Pacífica de Colombia. Un juvenil macho fue registrado en las playas de Piangüita y Magüipi (Valle del Cauca), del 23 al 25 de enero de 2018. Días después, el 22 de febrero de 2018, se reportó un juvenil macho, aparentemente el mismo individuo, más al norte en la playa de Guachalito (Chocó). Luego, entre el 29 de diciembre de 2019 y el 20 de enero 2020, en la playa de El Medio, desembocadura del río Yurumanguí (Valle del Cauca), se avistó un grupo de tres individuos subadultos; este avistamiento fue confirmado el 3 de enero de 2020, al registrar un individuo subadulto macho aparentemente en buena condición corporal. También fue registrado un individuo subadulto en estado avanzado de descomposición en el río Guapi el 8 de enero 2021. Estos registros están dentro de los más septentrionales para M. leonina con un desplazamiento de entre 5000-8000 Km desde su ámbito de distribución normal que comprende el sur de Chile y Antártida. La presencia del elefante marino en Colombia no había sido documentada y su arribo pudo deberse a búsqueda de alimento, así como el impacto del ENOS y cambios ambientales en el océano del sur.

ABSTRACT The first records of elephant seals, likely southern elephant seals, Mirounga leonina, are reported for the Colombian Pacific coast. A juvenile elephant seal was registered on the beaches of Piangüita and Magüipi (Valle del Cauca), from January 23-25, 2018. On 22 February 2018, a male juvenile, presumably the same animal, was also reported further north on the beaches of Guachalito (Chocó). Then, a group of three individuals was sighted on the beach of El Medio, the mouth of the Yurumanguí River (Valle del Cauca) from 29 December, 2019 to 20 January2020; this sighting was confirmed on January 3, 2020, by recording a subadult male individual apparently in healthy body condition. Also, a dead subadult in advanced state of decomposition was found in the river Guapi in January 8, 2021. These sightings are among the most northern extralimital records for this species with a large displacement covering 5000-8000 Km from its normal distributional range that includes southern Chile and Antarctica. The presence of the southern elephant seal in the Colombian Pacific had not been documented, and the arrival of this species could be linked to the search for food and the influence of eco-physiological processes, as well as the impact of the ENSO and ongoing environmental changes in the Southern Ocean.

We report the first record of a male Juan Fernández fur seal, Arctocephalus philippii (Peters, 1866), in the Colombian Pacific coast. The animal was mainly identified according to the external morphology of the head and snout. This observation is the first northernmost record for A. philippii in the Southeastern Pacific, with an extreme movement covering a total distance of approximately 3700-4600 km from its normal geographic range, including the Juan Fernández Archipelago and Desventuradas Islands (San Félix and San Ambrosio), Chile. This finding indicates that vagrant individuals can reach new sites in the Northern Hemisphere and could have a broader geographical displacement than previously thought.

Piolhos mastigadores foram coletados em pequenas aves marinhas (Charadriformes: Scolopacidae) que invernavam na zona de forrageamento na costa do Equador. Em 27 ocasiões, pelo menos um piolho (3,7%) foi coletado em seis espécies de hospedeiros. Com base em caracteres morfológicos externos, pelo menos duas espécies de piolhos mastigadores foram preliminarmente identificados (família: Menoponidae), incluindo Actornithophilus umbrinus(Burmeister, 1842) e Austromenopon sp. A. umbrinus foi encontrado em Pilrito-miudo (Calidris mauri), Pilrito-anão (C. minutilla), Pilrito-pernilongo (C. himantopus), Borrelho-semipalmado (Charadrius semipalmatus) e o Falaropo de Wilson (Phalaropus tricolor), enquanto Austromenopon sp. é, presumivelmente, o primeiro registro coletado na Ave-Surfista (Aphriza virgata). Esses resultados indicam que a distribuição dessas espécies de piolhos mastigadores abrange pelo menos as regiões ao redor do Equador (latitude 0°) até o Ártico, no Norte, mas provavelmente também inclui toda a área de distribuição de inverno essas espécies hospedeiras. Este é o primeiro estudo de piolhos de aves marinhas da área continental do Equador e mais pesquisas são necessárias para compreender a ecologia parasita-hospedeiro e ectoparasitose destas aves que invernam na região.

Chewing lice were collected from small shorebirds (Charadriformes: Scolopacidae) overwintering in foraging grounds of coastal Ecuador. On 27 occasions at least one louse (3.7%) was collected from six host species. Based on external morphological characters, at least two species of chewing lice could be preliminary identified (family: Menoponidae), including Actornithophilus umbrinus(Burmeister, 1842) and Austromenopon sp. A. umbrinus was found in the Western Sandpiper (Calidris mauri), Least Sandpiper (C. minutilla), Stilt Sandpiper (C. himantopus), Semipalmated Plover (Charadrius semipalmatus) and Wilson's phalarope (Phalaropus tricolor), whileAustromenopon sp. is presumably the first record collected from the Surfbird (Aphriza virgata). These findings indicate that the distribution of these chewing lice species covers at least the regions around the equator (latitude 0°) until the Arctic in the north, but probably also includes the entire winter distribution area of the host species. This is the first study of chewing lice from Ecuador's mainland coast and more research is required to understand the host-parasite ecology and ectoparasitic infection in shorebirds stopping over the region.

Introducción. La gnathostomiasis humana fue reportada en Ecuador en 1981 a partir del hallazgo del tercer estadio larvario de Gnathostoma en Hoplias microlepis. Debido a que esta zoonosis es transmisible a humanos, su vigilancia y estudio ecoepidemiológico en sus huéspedes silvestres son de particular importancia en salud pública y control sanitario en Ecuador. Objetivo. Contribuir con la evidencia más reciente de infección natural por Gnathostoma en el pez dulceacuícola Hoplias microlepis y su ciclo biológico en sistemas acuáticos de la provincia del Guayas, Ecuador. Materiales y métodos. Se examinaron 74 peces obtenidos en dos localidades (campo de arrozales y mercado de peces) del Cantón Samborondón, provincia del Guayas. La presencia de Gnathostoma fue investigada en músculos de Hoplias microlepis. Se estimaron la abundancia y la prevalencia parasitarias, así como la comparación estadística de la intensidad parasitaria en los dos sitios estudiados y correlaciones de la carga parasitaria versus la talla de los peces. Resultados. La prevalencia total de Gnathostoma fue de 69%, con una abundancia media de 1,70 larvas por pez. La prevalencia parasitaria fue relativamente mayor en los campos de cultivo de arroz (77%) en relación con el mercado local (62%). No se observaron diferencias significativas en las abundancias media de larvas y en las prevalencia entre los dos sitios de estudios (p>0,05). Se encontró una relación directa y significativa entre la carga parasitaria y la longitud del pez (Spearman p<0,05). Conclusiones. La gnathostomiasis sigue siendo prevalente en la zona costera de Ecuador y el agente patógeno es aún encontrado en el huésped intermediario. Diversos mamíferos neotropicales estarían actuando como huésped reservorio definitivo en el ciclo biológico de Gnathostoma en Ecuador.

Introduction. Human gnathostomiasis has been reported in Ecuador since the early 1980s, when natural infections by Gnathostoma third larval stages were found in muscles of the second intermediary host, Hoplias microlepis (tigerfish). In Ecuador, this zoonotic disease is occasionally detected in humans, and its monitoring and eco-epidemiological assessment is of particular interest for its detection and control. Objective. The most recent evidence is provided with respect to natural infections by Gnathostoma as it occurs in the tigerfish (Hoplias microlepis), including insights into its biological cycle. Materials and methods. A total of 74 fish were collected from two localities (rice fields-wetlands and local fish market) of Samborondón County (Guayas Province). Each was examined for the presence of Gnathostoma in muscle of Hoplias microlepis. The abundance intensity and prevalence of parasites was estimated. Statistical comparisons between the two sites and correlations of parasite load versus fish size were conducted. Results. The infection prevalence by Gnathostoma was 69% (95% CI: 57-78%). The overall abundance intensity of parasites averaging the 2 sites was 1.7 larvae per fish. The proportion of infected fish was higher in rice fields (77%) when compared to those from the local fish market (62%). No statistically significant differences between the abundance intensity and prevalence were found between the sites (p>0.05). Parasite load and fish length were significantly correlated (Spearman p<0.05). Conclusions. Gnathostomiasis is a prevalent zoonosis in coastal Ecuador, and its etiologic agent is commonly found in the second intermediary host. Several Neotropical mammals are candidates as definitive reservoir hosts in the Gnathostoma biological cycle.

ABSTRACT The role of cetaceans in marine ecosystems and food webs is scarcely known in the southeastern Pacific. Estimates of secondary and tertiary (carbon) production and daily food intake were deduced for five species of representative cetaceans for different marine habitats of the Galapagos by using associated calculations of annual primary production and carbon flux, as well as estimations of relative abundance, biomass, absolute density and trophic levels (TL) reported elsewhere. Under these premises, sperm (Physeter macrocephalus) and carnivore-generalist killer whales (Orcinus orca) for open ocean (i.e. no upwelling regions) had the lowest values of tertiary production at the top predator level (0.01-1.01 gC m-2 yr-1), while Bryde's (Balaenoptera edeni) and blue (B. musculus) whales from upwelling zone located at southwest Galapagos Island yielded the highest cetacean production (13.7 and 35.4 gC m-2 yr-1, respectively). Significant positive correlations at a 15% of efficiency transfer were found between the estimated annual primary production and tertiary production of baleen whales, and between annual primary production and tertiary production of toothed cetaceans. When both groups of cetaceans were combined a no significant correlation was observed between cetacean production and annual primary productivity. This outcome was influenced by their different trophic positions in the food chain and different scenarios values of annual primary productivity of the marine ecosystems selected. More research is needed to determine abundance, prey selection, feeding rates, and fecal matter sinking rates from marine mammals in Galapagos waters, as well as their function in the vertical carbon flux.

RESUMEN El rol de los cetáceos en la productividad y flujo de energía en los ecosistemas marinos es escasamente conocido en el Pacifico sureste. Este estudio propone estimar la producción secundaria y terciaria de cinco especies de cetáceos representativos de diferentes ecosistemas marinos de las Galápagos usando cálculos asociados de valores anuales de producción primaria y flujo de carbono, estimaciones de abundancia relativa, biomasa, densidad absoluta y niveles tróficos disponibles en la literatura. De acuerdo a las ecuaciones propuestas para el cálculo de productividad, se obtuvo que el cachalote (Physeter macrocephalus) y la orca carnívora-generalista (Orcinus orca) tuvieron el valor más bajo de producción terciaria al nivel de depredador tope para regiones del océano abierto sin afloramientos, mientras que las ballenas de Bryde (Balaenoptera edeni) y azul (B. musculus) alcanzaron los valores mas altos de producción terciaria (13,7 y 35,4 gC m-2 yr-1, respectivamente) en zonas de afloramientos localizadas al oeste y suroeste de las Islas Galápagos. La producción primaria anual se correlacionó significativamente con las producciones terciarias de ballenas barbadas y odontocetos, usando un nivel de transferencia de energía del 15%. Cuando se combinó a las especies de cetáceos considerados en este estudio, se encontró una correlación positiva, pero no significativa entre la producción primaria anual y la producción terciaria de cetáceos. Esta relación fue influenciada por los diferentes niveles tróficos en la cadena alimenticia y los valores anuales de productividad primaria de cada uno de los ecosistemas marinos seleccionados. Más investigación es requerida para determinar la abundancia, selección de presas, tasa alimenticias, y tasas de hundimiento de material fecal proveniente de mamíferos marinos en aguas marinas de las Galápagos, así como su función en el flujo vertical de carbón.

An assessment on the population ecology, distribution and habitat of the American crocodile (Crocodylus acutus) was conducted within the recent protected area “Reserva de producción de fauna manglares El Salado”, Gulf of Guayaquil, Ecuador. The study was developed along 15 km of mangrove channels and tidal creeks, using nocturnal spotlight boat surveys during the dry season (September to December, 2004). About four crocodiles, with a relative abundance of 0.45 ind./km, ranging 0.27-0.63 ind./km, were detected. Crocodiles were aggregated in the final extreme of a tidal creek (Estero Plano Seco), where the water salinity ranged 10.0-28.0 psu and releasing of effluents (>32.0°C) from electric power plants and run-off from urbanized centers have been evidenced. Most of the crocodile sightings occurred during low tide. The population was represented only by adults (50%) and juveniles (50%); subadults and hatchlings were not observed during the study period. The population density found in this study is one of the lowest densities for American crocodile in the American regions. The euryhaline ability and tolerance to inhabit elevated surface water temperature (thermoconformer) confirm the physiological adaptation of this reptile species. More ecologic and population studies are needed to elucidate some gaps and the environmental factors influencing on the species conservation, as well as the establishment of management strategies to ensure its survival.

We describe an unidentified species of the genus Neoechinorhynchus occurring in the intestine of the marine fish Micropogonias altipinnis using scanning electron microscopy (SEM). The genus Neoechinorhynchus occurs mostly in freshwater fishes; this may be the first report of its occurrence in the marine fish genus Micropogonias and the New World Sciaenidae. The specimens collected have characteristics typical of the genus. The mean length of the trunk is 9.5 mm. The proboscis is short and subcylindrical measuring 70 mm in length and 50 mm in diameter near the base. The proboscis has three rings of curved spines each with six spines. The anterior spines are long measuring a mean of 55 mm in length, 9 mm in width, and 7 mm in depth, and are supported by simple unmodified roots. The spines of the middle ring are smaller and equivalent to 70% of the roots of the anterior spines. The spines of the posterior ring are much smaller than those of the anterior ring. The body surface lacks spines and consists of a series of folds. The estuarine habits of M. altipinnis and its ability to tolerate fresh waters may have facilitated its infection with a species of the primarily freshwater genus Neoechinorhynchus, as well as the possibility that this parasite can infect human beings from the consumption of this kind of croaker

Se describe una especie de acantocéfalo no identificada del género Neoechinorhynchus presente en el intestino del pez marino Micropogonias altipinnis, conocido localmente como "corvinón" o "torno", usando microscopia electrónica de escaneo. Este género ocurre mayormente en peces de agua dulce y probablemente este es el primer informe de su presencia en el pez marino del género Micropogonias y peces de la familia Sciaenidae del Nuevo Mundo. La longitud media del tronco es 9,5 mm. La proboscis es corta y subcilíndrica, la cual mide 70 mm en longitud y 50 mm en diámetro, cerca de su base. La proboscis tiene tres anillos de espinas recurvadas, con cada anillo teniendo seis espinas. Las espinas anteriores son largas y tienen una longitud media de 55 mm, un ancho de 9 mm y una profundidad de 7 mm, mantenidas por raíces no modificadas en sus bases. Las espinas del anillo medio son pequeñas y equivalen al 70% de las raíces de las espinas anteriores. La superficie del cuerpo presenta escasas espinas y consiste de una serie de pliegues. El comportamiento estuarino de M. altippinnis y su habilidad para tolerar agua dulce puede haber facilitado la infección parasitaria con esta especie de acantocéfalo del género Neoechinorhynchus, el cual es primariamente dulceacuícola, así como la posibilidad de que este parásito infecte al hombre a partir del consumo de este tipo de corvina