Área de ocupación y estructura social del bufeo costero Tursiops truncatus (Montagu, 1821) (Cetacea: Delphinidae) en la Puntilla de Santa Elena (Ecuador) desde Noviembre 2015 hasta Julio 2016
Fecha
2017
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Facultad de Ciencias Naturales. Universidad de Guayaquil
Resumen
Entre Noviembre 2015 y Julio 2016 se estimó el tamaño poblacional por medio
de observación directa, se evaluó la estructura social y el área de ocupación
del bufeo costero (Tursiops truncatus), en la provincia de Santa Elena y áreas
circundantes al área protegida (REMACOPSE).
De un total de 46 salidas y 271 horas de observación, se cubrió
aproximadamente 1.363 km de muestreo y se estimó un tamaño poblacional
de 9 individuos para esta población, de los cuales, 5 son registros nuevos.
El área de ocupación registrada es de 3.100 ha (31 km²). Se utilizó el programa
Presence para comprobar la confiabilidad de esta estimación, dando como
resultado que el 70% (EE: 0.15) de los sitios muestreados está siendo utilizado
por la especie para actividades de alimentación, socialización y tránsito.
La estructura social fue analizada con el programa SOCPROG 2.7 el cual nos
indicó que la mayoría de los animales presenta un índice de asociación alto
(0,8) y cuatro de estos presentan un índice de 1,00 por ser vistos en el 80%
de los avistamientos en el mismo grupo. El rango de interacción nos indica
que la mayoría de individuos presenta rangos altos, entre 9 y 12, afirmando
así que el grupo es residente para el área, con excepción de dos individuos
con menor rango de interacción con el grupo principal.
Se registraron factores antropogénicos importantes que a corto o largo plazo
pueden estar afectando a esta población en la puntilla de Santa Elena, entre
5ellos tenemos la interacción con pesquerías, la contaminación del hábitat y la
acústica, siendo estos, factores que son necesarios de examinar para una
mejor conservación de la especie. Un posible deterioro genético podría estar
ocurriendo debido a que la población es pequeña y esto produciría
complicaciones al momento de tener que adaptarse a otro tipo de situaciones
climáticas o de hábitat.
Between November 2015 and July 2016, population size was estimated through direct observation method, the social structure and occupation area of the coastal bottlenose dolphin (Tursiops truncatus) were evaluated in the province of Santa Elena and areas surrounding the protected area (REMACOPSE). Approximately 1,363 km of sampling was covered from a total of 46 surveys and 271 hours of observation, obtaining a population size of 9 individuals, in which 5 of them are new registers for the area. The registered occupancy area is 3,100 ha (31 km²). The program Presence was used to verify the reliability of this estimate, resulting in 70% (EE: 0.15) of the sampled sites being used by the species for feeding, socialization and transit activities. The social structure was analyzed with the SOCPROG 2.7 program, which indicated that most of the animals had a high association rate (0.8) and four of them presented an index of 1.00 for being seen in 80% of sightings in the same group. The range of interaction indicates that the majority of individuals present high ranges, between 9 and 12, thus affirming that the group is resident for the area, except for two individuals with lower range of interaction with the main group. Significant anthropogenic factors that may be affecting this population in the Santa Elena peninsula were recorded that can affect in short or long term, among them we have interaction with fisheries, habitat contamination and acoustics, which are necessary factors to examine for better conservation of the species. A possible genetic deterioration could be happening because the population is small and this would produce complications when having to adapt to another type of climatic situations or of habitat.
Between November 2015 and July 2016, population size was estimated through direct observation method, the social structure and occupation area of the coastal bottlenose dolphin (Tursiops truncatus) were evaluated in the province of Santa Elena and areas surrounding the protected area (REMACOPSE). Approximately 1,363 km of sampling was covered from a total of 46 surveys and 271 hours of observation, obtaining a population size of 9 individuals, in which 5 of them are new registers for the area. The registered occupancy area is 3,100 ha (31 km²). The program Presence was used to verify the reliability of this estimate, resulting in 70% (EE: 0.15) of the sampled sites being used by the species for feeding, socialization and transit activities. The social structure was analyzed with the SOCPROG 2.7 program, which indicated that most of the animals had a high association rate (0.8) and four of them presented an index of 1.00 for being seen in 80% of sightings in the same group. The range of interaction indicates that the majority of individuals present high ranges, between 9 and 12, thus affirming that the group is resident for the area, except for two individuals with lower range of interaction with the main group. Significant anthropogenic factors that may be affecting this population in the Santa Elena peninsula were recorded that can affect in short or long term, among them we have interaction with fisheries, habitat contamination and acoustics, which are necessary factors to examine for better conservation of the species. A possible genetic deterioration could be happening because the population is small and this would produce complications when having to adapt to another type of climatic situations or of habitat.
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DELFIN NARIZ DE BOTELLA, ALETAS DORSALES, FOTO IDENTIFICACIÓN, MARCADO - RECAPTURA, FACTORES ANTROPOGENICOS