Estructura de la población del cambute Slrombus galealus (Gastropoda: Strombidae) en Cabo Blanco, Costa Rica
Fecha
1998
Tipo
artículo original
Autores
Arroyo Mora, Daisy
Mena Aguilar, Luis
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Resumen
EI gastrópodo Strombus galeatus, habitante de la costa Pacífica de Costa Rica, ha estado expuesto a una alta explotación, que ha causado una disminución de las poblaciones naturales, sin que haya estudios previos para entender su biología general. Se estudió una población natural en la laguna San Miguel de la Reserva Natural Absoluta Cabo Blanco, desde diciembre de 1993 hasta diciembre de
1997, y en la que se utilizó el sistema de marcado y recaptura para estudios biométricos. Esta población puede inmigrar y emigrar de dicha laguna por una entrada natural localizada en su parte más occidental. Del total de individuos marcados 627, el 70.3 % fueron adultos, 23.0% subadultos y solo 6.8% juveniles, y este patrón fue casi constante en los muestreos realizados. Los machos representaron el 51.4% de la población, 43 .7% fueron hembras y un 4.8% de individuos indeterminados. Un promedio de 69.9 % fueron recapturas (con un índice de recaptura medio de 14.7%), y solo un 30.1% de los caracoles fueron observados una única vez. Las longitudes medias de adultos, subadultos y juveniles fueron respectivamente 183.2 (d.c. 9.5). 162.8 (d.e. 5.7) y 132.1 (d.e. 15.0). La densidad se estimó en 500 caracoles/ha con un patrón de distribución agregada al azar.
The conch S. galeatus used to be a common gastropod in the Pacific coast of Costa Rica, but high exploitation levels have diminished natural stocks. A natural unexploited population was studied at San Miguel tidal pool at Cabo Blanco Absolute Reserve, from December 1993 through December 1997, using the mark-recapture method and biometrics. This population can inmigrate and emigrate from the mostly rocky-bottom pool by its westem natural entrance. From a total of 627 marked conchs, 70.3 % were adults, 23,0 % subadults and only 6.7 % were juveniles, and this pattem was constant throughout the survey. Males represented 51.4 % of the population, females 43.7% and undetemined individuals 4,8 %. An average of 74 % of the conchs were recovered during surveys (with a mean recapture index of 14.7 %), and only 26 % of the conchs were observed. Average adult, subadult and juvenile lengths were respectively 183.2 mm (S.D. 9.5), 162.8 mm (S.D. 5,7) and 132.1 mm (S.D, 15,0). Density was estimated as 500 conch/ha.
The conch S. galeatus used to be a common gastropod in the Pacific coast of Costa Rica, but high exploitation levels have diminished natural stocks. A natural unexploited population was studied at San Miguel tidal pool at Cabo Blanco Absolute Reserve, from December 1993 through December 1997, using the mark-recapture method and biometrics. This population can inmigrate and emigrate from the mostly rocky-bottom pool by its westem natural entrance. From a total of 627 marked conchs, 70.3 % were adults, 23,0 % subadults and only 6.7 % were juveniles, and this pattem was constant throughout the survey. Males represented 51.4 % of the population, females 43.7% and undetemined individuals 4,8 %. An average of 74 % of the conchs were recovered during surveys (with a mean recapture index of 14.7 %), and only 26 % of the conchs were observed. Average adult, subadult and juvenile lengths were respectively 183.2 mm (S.D. 9.5), 162.8 mm (S.D. 5,7) and 132.1 mm (S.D, 15,0). Density was estimated as 500 conch/ha.
Descripción
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Strombus galeatus, Population structure, Protected area