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This paper describes and evaluates the mortality associated with the potential stressor effect induced by application of artificial photoperiods in rainbow trout (Oncorhynchus mykiss). After application of artificial photoperiods, high mortalities of trout subjected to this management were recorded (36% in LD 14:10 and 25% in LD 24:0) as compared to controls (7%). The recorded signology related to diseased trout included darkening, lethargy and erratic swimming. Among the morphological changes, skin lesions and ulcerative-type necrosis could be observed. Blood tests, histopathology and isolation of pathogens identified as Flavobacterium psychrophilum, associated with Aeromonas, Pseudomonas and Saprolegnia sp., were performed. The application of artificial photoperiods suggests that fish may be more susceptible to opportunistic diseases; thus, it is advisable to emphasize preventive measures in fish subjected to this management.

ABSTRACT. This report offers a macroscopic and histological description of ulcerative gastric lesions in Humboldt penguins associated with the presence of Contracaecum pelagicum. Parasites of this genus have been isolated from different species of marine mammals and birds, including penguins, demonstrating its capacity to generate ulcerative lesions in the gastrointestinal tracts of many hosts. A bibliographic review revealed no publications on gastric ulceration by nematodes in Humboldt penguins. Studies carried out in Chile concerning gastrointestinal parasitism by nematodes of the Contracaecum genus in S. humboldti only established the parasite's taxonomy. This is the first pathological description of a parasitic ulcerative manifestation in the stomach of S. humboldti in the world. The Humboldt penguin is a vulnerable species. Therefore, this study is relevant as it offers a better understanding of the diseases that affect S. humboldti and facilitates the development of strategies intended to recover the population. Keywords: Spheniscus humboldti, Humboldt penguin, ulcer, stomach, Contracaecum, Chile. Primera descripción patológica de úlceras gástricas parasitarias en el pingüinode Humboldt (Spheniscus humboldti) en la costa centro-sur de Chile RESUMEN. El presente trabajo ofrece una descripción macroscópica e histológica de lesiones gástricas de tipo ulcerativas en el pingüino de Humboldt asociadas a la presencia de Contracaecum pelagicum. Parásitos del género Contracaecum han sido aislados de diferentes especies de mamíferos y aves marinas, incluyendo pingüinos, en gran parte del mundo, demostrando una gran capacidad de generar lesiones ulcerativas en un número importante de hospederos. La revisión bibliográfica reveló la ausencia de publicaciones relativas a cuadros ulcerativos gástricos causados por nemátodos en el pingüino de Humboldt. Los estudios realizados en Chile concernientes a parasitismo gastrointestinal por nemátodos del género Contracaecum en S. humboldti sólo han abordado aspectos taxonómicos. Esta publicación constituye la primera descripción patológica de un cuadro de ulceraciones gástricas parasitarias en el pingüino de Humboldt. S. humboldti está catalogado como especie vulnerable por lo que este estudio es relevante en cuanto a incrementar el entendimiento de las patologías que afectan a la especie facilitando el desarrollo de estrategias tendientes a la recuperación de la población.

Since the late 1990s, European Association of Zoos and Aquaria (EAZA)‐member zoos have worked collaboratively to achieve a self‐sustaining population for gorilla through the European Endangered Species Programme (EEP). The Association of Zoos and Aquariums (AZA) in the United States has similarly worked through the Species Survival Plan (SSP). These populations are all registered in the International Studbook for the Western Lowland Gorilla Gorilla g. gorilla Savage & Wyman, 1847, which is updated annually. Demographic and genetic analyses of these data are carried out to monitor population development. This paper presents the results of the genetic and demographic analysis of EAZA and AZA populations of the Western lowland gorilla Gorilla gorilla gorilla, considering the individuals registered since the beginning of the studbook (1950) until 2014, and the analyses are mainly focused on the results for both populations around the last decade. The data have been gathered from the 2014 international studbook and data registered in the Single Population Analysis and Records Keeping System (Sparks). Genetic and demographic analyses were carried out using PMx software. The results of the demographic analyses show that the EEP population is growing, demonstrating positive life parameters; for example, a finite growth rate of λ = 1·007, an instantaneous growth rate of r = 0·007 and a net reproductive rate of R0 = 1·160. However, the results of the demographic analyses for the SSP population show a general tendency for population reduction; that is, a finite growth rate of λ = 0·992, an instantaneous rate of growth rate r = −0·008 and a net reproductive rate of R0 = 0·864. When comparing the results from both populations it would appear that the application of strict breeding policies in the SSP for a few years had a noticeable impact on the SSP demographic results.