TY - JOUR
T1 - Ecological patterns, distribution and population structure of Prionace glauca (Chondrichthyes: Carcharhinidae) in the tropical-subtropical transition zone of the north-eastern Pacific
AU - Vögler, Rodolfo
AU - Beier, Emilio
AU - Ortega-García, Sofía
AU - Santana-Hernández, Heriberto
AU - Valdez-Flores, J. Javier
N1 - Funding Information:
We extend thanks to the INAPESCA of México and especially to Dirección General de Investigación Pesquera en el Pacífico Sur (Manzanillo, Colima) for allowing the use of the databases used in this research. R.V. and E.B. are part of the SEP-CONACYT, Ciencia Basica project 103 898, “Investigaciones Oceanográficas del Sistema Frontal de Baja California Sur”. The National Council for Science and Technology (CONACYT) funded R.V. ( 269770/220070 ) through a scholarship to pursue graduate studies at CICIMAR-IPN. We thank the National Oceanographic Data Center of the NOAA for the Levitus database.
PY - 2012/2
Y1 - 2012/2
N2 - Regional ecological patterns, distribution and population structure of Prionace glauca were analyzed based on samples collected on-board two long-line fleets operating in oceanic waters (1994-96/2000-02) and in coastal oceanic waters (2003-2009) of the eastern tropical Pacific off México. Generalized additive models were applied to catch per unit of effort data to evaluate the effect of spatial, temporal and environmental factors on the horizontal distribution of the life stages (juvenile, adult) and the sexes at the estimated depth of catch. The presence of breeding areas was explored. The population structure was characterized by the presence of juveniles' aggregations and pregnant females towards coastal waters and the presence of adult males' aggregations towards oceanic waters. The species exhibited horizontal segregation by sex-size and vertical segregation by sex. Distribution of the sex-size groups at oceanic waters was seasonally affected by the latitude; however, at coastal oceanic waters mainly females were influenced by the longitude. Latitudinal changes on the horizontal distribution were coupled to the seasonal forward and backward of water masses through the study area. Adult males showed positive relationship with high temperatures and high-salinities waters (17.0°-20.0°C; 34.2-34.4) although they were also detected in low-salinities waters. The distribution of juvenile males mainly occurred beyond low temperatures and low-salinities waters (14.0°-15.0°C; 33.6-34.1), suggesting a wide tolerance of adult males to explore subartic and subtropical waters. At oceanic areas, adult females were aggregated towards latitudes <25.0°N, mainly associated to subtropical waters during summer. The distribution of juvenile females indicated its preference by lower temperatures and more saline waters. Presence of pregnant females suggests that the eastern tropical Pacific off México represents an ecological key region to the reproductive cycle of P.glauca.
AB - Regional ecological patterns, distribution and population structure of Prionace glauca were analyzed based on samples collected on-board two long-line fleets operating in oceanic waters (1994-96/2000-02) and in coastal oceanic waters (2003-2009) of the eastern tropical Pacific off México. Generalized additive models were applied to catch per unit of effort data to evaluate the effect of spatial, temporal and environmental factors on the horizontal distribution of the life stages (juvenile, adult) and the sexes at the estimated depth of catch. The presence of breeding areas was explored. The population structure was characterized by the presence of juveniles' aggregations and pregnant females towards coastal waters and the presence of adult males' aggregations towards oceanic waters. The species exhibited horizontal segregation by sex-size and vertical segregation by sex. Distribution of the sex-size groups at oceanic waters was seasonally affected by the latitude; however, at coastal oceanic waters mainly females were influenced by the longitude. Latitudinal changes on the horizontal distribution were coupled to the seasonal forward and backward of water masses through the study area. Adult males showed positive relationship with high temperatures and high-salinities waters (17.0°-20.0°C; 34.2-34.4) although they were also detected in low-salinities waters. The distribution of juvenile males mainly occurred beyond low temperatures and low-salinities waters (14.0°-15.0°C; 33.6-34.1), suggesting a wide tolerance of adult males to explore subartic and subtropical waters. At oceanic areas, adult females were aggregated towards latitudes <25.0°N, mainly associated to subtropical waters during summer. The distribution of juvenile females indicated its preference by lower temperatures and more saline waters. Presence of pregnant females suggests that the eastern tropical Pacific off México represents an ecological key region to the reproductive cycle of P.glauca.
KW - Blue shark
KW - By-catch
KW - Landscape ecology
KW - North-eastern Pacific
KW - Spatial-temporal distribution patterns
KW - Subtropical convergence
UR - http://www.scopus.com/inward/record.url?scp=84655164358&partnerID=8YFLogxK
U2 - 10.1016/j.marenvres.2011.10.009
DO - 10.1016/j.marenvres.2011.10.009
M3 - Artículo
SN - 0141-1136
VL - 73
SP - 37
EP - 52
JO - Marine Environmental Research
JF - Marine Environmental Research
ER -