Distribution, movements and group size of the bottlenose dolphin (Tursiops truncatus) to the south of San Quintín Bay, Baja California, Mexico

Distribution, movements and group size of the bottlenose dolphin (Tursiops truncatus) to the south of San Quintín Bay, Baja California, Mexico

 Twelve boat-based photoidentification surveys were carried out along the coast to the south of San Quintín Bay, in Baja California, Mexico, from July 1999 to June 2000; effort was 276.76 km and 31.7 h at sea. Twenty-two schools were encountered and 12.9 h of total observation were spent wi...

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Autores principales: Morteo, E, Heckel, G, Defran, RH, Schramm, Y
Format: info:eu-repo/semantics/article
Sprog:eng
Udgivet: Iniversidad Autónoma de Baja California 2004
Fag:
distribution
movements
ecology
Tursiops truncatus
San Quintín
distribución
movimientos
ecología
Online adgang:https://www.cienciasmarinas.com.mx/index.php/cmarinas/article/view/122
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id repositorioinstitucional-20.500.12930-7354
record_format dspace
institution Repositorio Institucional
collection DSpace
language eng
topic distribution
movements
ecology
Tursiops truncatus
San Quintín
distribución
movimientos
ecología
Tursiops truncatus
San Quintín
spellingShingle distribution
movements
ecology
Tursiops truncatus
San Quintín
distribución
movimientos
ecología
Tursiops truncatus
San Quintín
Morteo, E
Heckel, G
Defran, RH
Schramm, Y
Distribution, movements and group size of the bottlenose dolphin (Tursiops truncatus) to the south of San Quintín Bay, Baja California, Mexico
description  Twelve boat-based photoidentification surveys were carried out along the coast to the south of San Quintín Bay, in Baja California, Mexico, from July 1999 to June 2000; effort was 276.76 km and 31.7 h at sea. Twenty-two schools were encountered and 12.9 h of total observation were spent with 242 dolphins in these schools. The average school size was 11 (SD = 8) dolphins, although it is possible that groups are actually smaller; nursing groups were significantly larger (P < 0.05), with frequent membership exchanges occurring among schools. Dolphins preferred a coastal strip between 250 and 500 m offshore (P < 0.05), at depths below 7 m, and with sandy substrates (P < 0.05). Greater sighting frequencies occurred in two coastal zones (P < 0.05) and feeding was common around the mouth of the bay. Dorsal fin photographs led to the identification of 169 dolphins, and 124 were different individuals. During the study period, the coast south of San Quintín was a pass zone for transient dolphins, since most of the animals (>70%) were sighted one time or stayed for short periods. A total of 220 different dolphins have been identified in the San Quintín area when these data are combined with those gathered by Caldwell (1992) in 1990; these dolphins probably represent a small part of a larger population. More research on the population biology of the bottlenose dolphin in this and adjacent geographic areas is needed to develop better conservation and management strategies for this important natural resource.
format info:eu-repo/semantics/article
author Morteo, E
Heckel, G
Defran, RH
Schramm, Y
author_facet Morteo, E
Heckel, G
Defran, RH
Schramm, Y
author_sort Morteo, E
title Distribution, movements and group size of the bottlenose dolphin (Tursiops truncatus) to the south of San Quintín Bay, Baja California, Mexico
title_short Distribution, movements and group size of the bottlenose dolphin (Tursiops truncatus) to the south of San Quintín Bay, Baja California, Mexico
title_full Distribution, movements and group size of the bottlenose dolphin (Tursiops truncatus) to the south of San Quintín Bay, Baja California, Mexico
title_fullStr Distribution, movements and group size of the bottlenose dolphin (Tursiops truncatus) to the south of San Quintín Bay, Baja California, Mexico
title_full_unstemmed Distribution, movements and group size of the bottlenose dolphin (Tursiops truncatus) to the south of San Quintín Bay, Baja California, Mexico
title_sort distribution, movements and group size of the bottlenose dolphin (tursiops truncatus) to the south of san quintín bay, baja california, mexico
publisher Iniversidad Autónoma de Baja California
publishDate 2004
url https://www.cienciasmarinas.com.mx/index.php/cmarinas/article/view/122
_version_ 1792609211282096128
spelling repositorioinstitucional-20.500.12930-73542023-05-09T14:30:34Z Distribution, movements and group size of the bottlenose dolphin (Tursiops truncatus) to the south of San Quintín Bay, Baja California, Mexico Distribución, movimientos y tamaño de grupo del tursión (Tursiops truncatus) al sur de Bahía San Quintín, Baja California, México Morteo, E Heckel, G Defran, RH Schramm, Y distribution movements ecology Tursiops truncatus San Quintín distribución movimientos ecología Tursiops truncatus San Quintín  Twelve boat-based photoidentification surveys were carried out along the coast to the south of San Quintín Bay, in Baja California, Mexico, from July 1999 to June 2000; effort was 276.76 km and 31.7 h at sea. Twenty-two schools were encountered and 12.9 h of total observation were spent with 242 dolphins in these schools. The average school size was 11 (SD = 8) dolphins, although it is possible that groups are actually smaller; nursing groups were significantly larger (P < 0.05), with frequent membership exchanges occurring among schools. Dolphins preferred a coastal strip between 250 and 500 m offshore (P < 0.05), at depths below 7 m, and with sandy substrates (P < 0.05). Greater sighting frequencies occurred in two coastal zones (P < 0.05) and feeding was common around the mouth of the bay. Dorsal fin photographs led to the identification of 169 dolphins, and 124 were different individuals. During the study period, the coast south of San Quintín was a pass zone for transient dolphins, since most of the animals (>70%) were sighted one time or stayed for short periods. A total of 220 different dolphins have been identified in the San Quintín area when these data are combined with those gathered by Caldwell (1992) in 1990; these dolphins probably represent a small part of a larger population. More research on the population biology of the bottlenose dolphin in this and adjacent geographic areas is needed to develop better conservation and management strategies for this important natural resource. Entre julio de 1999 y junio de 2000 se realizaron 12 navegaciones de fotoidentificación a lo largo de la costa al sur de Bahía San Quintín, Baja California, México. Se recorrieron en total 276.8 km de costa, en 31.7 h. Durante 12.9 h de observación se encontraron 242 tursiones agrupados en 22 manadas. El tamaño promedio de grupo fue de 11 (DE = 8) delfines; sin embargo, es posible que las agrupaciones más comunes sean de menor tamaño. Los grupos con crías fueron significativamente más grandes (P < 0.05) y las manadas intercambiaron individuos constantemente. Los tursiones prefirieron la franja entre 250 y 500 m fuera de la costa (P < 0.05), con profundidades menores a 7 m y sustratos arenosos (P < 0.05). Se establecieron dos zonas con mayor frecuencia de avistamientos (P < 0.05) y el comportamiento alimentario fue más común cerca de la boca de la bahía. Se identificaron 169 animales mediante fotografías de las aletas dorsales y 124 de ellos fueron individuos diferentes. La costa al sur de San Quintín representó una zona de tránsito durante el periodo de estudio debido a que la mayoría de los tursiones (> 70%) fueron vistos en una sola ocasión o por corto tiempo. El catálogo de aletas dorsales desarrollado en este trabajo, en conjunto con el realizado en 1990 por Caldwell (1992), contiene a la fecha 220 animales; posiblemente estos delfines representan sólo una pequeña parte de la población. En la medida en que se desarrollen trabajos científicos sobre la biología poblacional de los tursiones en esta área geográfica y en otras adyacentes, se contribuirá a mejorar las estrategias de conservación y manejo de este recurso natural. 2004-03-06 2021-06-03T03:55:01Z 2021-06-03T03:55:01Z info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion Peer-reviewed Article Artículo Arbitrado https://www.cienciasmarinas.com.mx/index.php/cmarinas/article/view/122 10.7773/cm.v30i11.122 https://hdl.handle.net/20.500.12930/7354 eng https://www.cienciasmarinas.com.mx/index.php/cmarinas/article/view/122/101 application/pdf Iniversidad Autónoma de Baja California Ciencias Marinas; Vol. 30 No. 1A (2004); 35-46 Ciencias Marinas; Vol. 30 Núm. 1A (2004); 35-46 2395-9053 0185-3880

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