Comportamiento diurno de cetáceos en el Área de Conservación Guanacaste, Costa Rica

Introducción: Tres especies de cetáceos, el delfín manchado pantropical (Stenella attenuata attenuata), el delfín nariz de botella (Tursiops truncatus) y la ballena jorobada (Megaptera novaeangliae) son un componente importante de la fauna marina del Área de Conservación Guanacaste. Sin embargo, la información biológica básica sobre el comportamiento y la presencia de estas especies sigue siendo escasa. Objetivo: El objetivo de este estudio es determinar el comportamiento diurno de los cetáceos en el sector marino de la ACG y en sus áreas adyacentes. Métodos: Se muestreó el Pacífico norte de Costa Rica desde Bahía Salinas hasta las Islas Murciélago, incluyendo el Golfo de Santa Elena, entre mayo de 2005 y mayo de 2006. Se utilizó el método de escaneo de comportamiento para identificar el comportamiento general de los grupos. Resultados: Se registraron encuentros para tres especies en un total de 36 avistamientos, pero solo con un tiempo considerable para dos especies, S. attenuata y M. novaeangliae. Los delfines manchados exhibieron una amplia variedad de comportamientos en la temporada de lluvias. La búsqueda de alimento (X2 = 29.42; g.l. = 1; P < 0.001) y los viajes (X2 = 38.33; g.l. = 1; P < 0.001) aumentaron significativamente en la época de lluvias. Los comportamientos predominantes para la ballena jorobada fueron la asociación madre-cría, social y de viaje; este último fue mayor en la época de lluvias (X2 = 78.16; g.l. = 1; P < 0.001). Conclusiones: En la zona, los cetáceos presentaron comportamientos como forrajeo y madre-cría, lo que significa que el área puede clasificarse como un hábitat crítico para estas especies de cetáceos, de mayor importancia para especies altamente migratorias como las ballenas jorobadas.

Introduction: Three species of cetaceans, the pantropical spotted dolphin (Stenella attenuata attenuata), the bottlenose dolphin (Tursiops truncatus) and the humpback whale (Megaptera novaeangliae), are important components of the marine fauna of the Guanacaste Conservation Area (ACG). However, basic biological information on the behavior and occurrence of these species remains scarce. Objective: The objective of this study is to determine the diurnal behavior of the three-mentioned species in the ACG. Methods: The north Pacific of Costa Rica, from Bahía Salinas to the Marine Sector of ACG was sampled between May 2005 and May 2006. The behavior scanning method was used to identify the general behavior of the cetacean groups. Results: Encounters were recorded for the three species, in a total of 36 sightings, but only for S. attenuata and M. novaeangliae for considerable periods of time. Stenella attenuata exhibited a wide variety of behaviors, being foraging (X2 = 29.42; d.f. = 1; P < 0.001) and travelling (X2 = 38.33; d.f. = 1; P < 0.001) significantly higher during the rainy season. Predominant behaviors for the humpback whale were mother-calf association, social and travelling; being the latter higher during the rainy season (X2 = 78.16; d.f. = 1; P < 0.001). Conclusions: Behaviors such as foraging and mother-calf were the most representative among species and the most frequent. This suggests that the area can be considered as a critical habitat for these species of cetaceans, with particular importance for highly migratory species such as humpback whales.

Human Pathogens in Marine Mammal Meat

Background: Norway conducts commercial hunts for seals and whales, and since marine mammal meat and products are distributed to the public, these products are covered by the general hygiene control regulations. The control of meat from marine mammals is based primarily on organoleptic and microbiological spot tests. There is a general lack of knowledge available on the presence of potential zoonotic pathogens in marine mammal meat and products and on the potential risk for humans. The Norwegian Scientific Committee for Food Safety (Vitenskapskomiteen; VKM), Panel of Biological Hazards (Faggruppe hygiene og smittestoffer) took the initiative to develop this risk assessment in order to identify possible risks associated with human consumption of meat and products from seals and whales. The risk assessment is based on scientific publications and reports, and documents that have been used for training of veterinary personnel in meat control. Animal welfare is not within the scope of this assessment. Main Conclusions: It is documented in this assessment that marine mammals may harbour several pathogens with the potential of giving disease in humans, and there are some reports on the transfer of such agents via meat from seals and whales. The Panel of Biological Hazards has not been able to document that human consumption of meat from seals and whales is associated to a risk of exposure to human pathogens in Norway, but the data on which this conclusion is build, is scarce and are too limited to draw firm conclusions. There are almost no data documenting the microbiological status of seal and whale meat that is distributed for human consumption and the control is ad hoc, based on spot tests and few animals. The general trend of increased consumption of raw or lightly cooked food may increase the risk for transmission of pathogens to humans. Considered suboptimal conditions for hygienic treatment of meat on board, as compared to abattoir conditions, as well as a long storage time in a non-frozen state (whale meat), it is crucial to secure the hygienic quality of the meat. The training of personnel in slaughter hygiene should be strengthened, and if meat is not frozen, an unbroken cold-chain should be documented through the production line from the slaughter to the retail level. A more systematic meat control practice (routine control) should be established. Broad-scale research projects, focusing on human pathogens in seals and whales, as well as monitoring and collating of data on contamination, are needed to further explore the risks of transmission of human pathogens from marine mammal meat.

Cetáceos del pacífico de Guatemala: cincuenta años de historia / Guatemala's pacific cetaceans: fifty years of history

En Guatemala el estudio de los cetáceos inició en la década de los sesenta con los primeros registros de vara-miento y captura incidental. Sin embargo, pocos trabajos científicos con datos de cetáceos han sido publicados. Con el objetivo de centralizar la información de cetáceos y obtener conocimiento biológico para el desarrollo de planes de manejo y conservación, se realizó una revisión bibliográfica de cetáceos en Guatemala que recaba información de los últimos 50 años. Se obtuvo un total de 1,014 registros de avistamiento (1979-2011), 62 registros de captura incidental (1961/85) y 16 registros de varamientos (1975, 2007-2012), los cuales se analizaron en mapas batimétricos y en mapas de presiones antropogénicas. Se identificaron diecinueve especies pertenecientes a cinco familias de cetáceos, incluyendo Balaenopteridae, Delphinidae, Ziphiidae, Kogiidae y Physeteridae. El esfuerzo y área de muestreo varió durante 1961-2012. Se identificaron diferentes patrones de distribución especie-específicos. La mayoría de avistamientos se registraron cerca de zonas con topografía compleja. Aunque los eventos de captura incidental se registraron únicamente en alta mar, los resultados sugieren que especies de distribución costera se encuentran en zonas con mayor riesgo antropogénico. Se reportaron ocho especies de cetáceos varados, eventos ocurridos principalmente en el departamento de Escuintla desde el año 2007. Debido a la gran diversidad en los patrones de distribución, comportamiento y uso de hábitat de los cetáceos, combinado con los riesgos antropogénicos de la zona, es necesario que se considere un enfoque integral cuando se implementen planes de manejo y conservación marina en Guatemala.

Cetaceans have been studied in Guatemala since 1960s, but only a few scientific works based on the collected cetacean data were published. We reviewed literatures about cetaceans in Guatemala for the past fifty years to gain the biological knowledge for conservation and management plans. A total of 1,014 sighting records (1979-2011), 62 tuna fishery by-catch events (1961-1985) and 16 stranding records (1975, 2007-2012) were obtained and analyzed with bathymetric maps and plot against maps with different anthropogenic pressures in the area. Nineteen species belonging to five different families of cetaceans, such as Balaenopteridae, Delphinidae, Ziphiidae, Kogiidae, and Physeteridae, were identified. Data sampling areas have been changed during 1961-2012. We identified several species-specific-spatial-distribution patterns. Species occurrence was higher in areas with complex topography. Although, all by-catch events were recorded offshore, species with coastal distribution occurred in areas with higher anthropogenic risk. Stranding events were reported for eight species, and occurred mainly in the department of Escuintla from 2007. Due to the great diversity in spatial-distribution patterns of cetacean in Guatemala, behavior and habitat use of cetaceans in the areas, combined with different anthropogenic risks, an integrative approach should be considered when conservation and management plans are implemented in Guatemala.

Cetáceos de las aguas costeras del Pacífico norte y sur de Costa Rica

Inshore cetaceans from the North and South Pacific coast of Costa Rica. Twenty nine cetacean species occur in Costa Rican waters but extensive research has been conducted only for three species. The latter shows there is a lack of general and local information about these mammals, even when the country, has shown a remarkable growth in whale watching activities. The increasing use of marine resources in coastal areas has also developed the need to determine the occurrence of cetaceans in areas showing high tourist presence, in order to propose sound conservation measures. In this study, environmental variables were determined and subsequently related to the presence of the species recorded, out of 166 sightings, between 2005 and 2006. The species with highest proportion of sightings were Stenella attenuata (68%), followed by Megaptera novaeangliae (13%) and Tursiops truncatus (10%). The presence of spotted dolphins is related to changes in salinity and water transparency, while that of the humpback whale was related to wave height (Beaufort scale) and water temperature. The presence of seven species of cetaceans was confirmed in two coastal areas of the Pacific coast of Costa Rica, from which three are present throughout the year. Environmental variables were found related to the presence of at least two species. Rev. Biol. Trop. 59 (1): 283-290. Epub 2011 March 01.

De las 29 especies de cetáceos presentes en Costa Rica, se han realizado investigaciones exhaustivas solamente para tres especies. Lo anterior evidencia la poca información general existente sobre cetáceos, a pesar de que Costa Rica posee un notable crecimiento de actividades de avistamiento. Debido al uso que se está generando en las zonas costeras, cada vez se hace más necesario determinar la ocurrencia de cetáceos en zonas de alta actividad turística, con el fin de proponer medidas de conservación. En el presente estudio, se determinaron variables ambientales que estaban relacionadas con la presencia de especies registradas, a partir de 166 avistamientos entre el 2005 y 2006. Las especies con mayor proporción de avistamientos fueron Stenella attenuata (68%), seguida por Megaptera novaeangliae (13%) y Tursiops truncatus (10%). La presencia del delfín manchado se relaciona con cambios de salinidad y trasparencia del agua, mientras que la de la ballena jorobada estuvo relacionada con el oleaje y la temperatura superficial del agua. Se confirma la presencia de 7 especies de cetáceos en dos zonas costeras del Pacífico de Costa Rica, de las cuales tres están presentes a lo largo del año. Se encontraron variables ambientales relacionadas con la presencia de al menos dos especies.