9 research outputs found
Hábitos alimenticios y la razón de isotopos estables de carbono (δ13 C) y nitrógeno (δ15 N) del tiburón Sphyrna lewini, (Griffith y Smith 1834) capturado en el área de Mazatlán, Sinaloa, México
No full textimpreso y digitalSphyrna lewini es un recurso importante en la pesca de tiburón para la zona de Mazatlán México, el objetivo de este estudio es conocer su dieta, establecer su posición trófica y llevar a cabo una comparación entre la dieta consumida (evaluada por contenido estomacal) y la dieta asimilada (estimada con δ13C Y δ15N). Durante los muestreos de octubre 2000 a abril 2004 se colectaron 556 estómagos correspondientes a tiburones entre 48 - 160 centímetros. de estos 449 estómagos presentaron alimento. En la evaluación del contenido estomacal se identificaron 88 especies presas. De acuerdo al índice de importancia relativa (IIR), la dieta estuvo constituida por el cefalópodo Loliolopsis dimedeae (IIR) = 49 %), y por lo peces de la familia carangidae ( IIR = 26 %) y gerreidae (iir = 7 %). De manera general se observo un valor bajo de amplitud de dieta (0.15). El índice Morisita-Horn indico un alto traslapo trófico entre sexos (C2 = 0.95), y traslapo medio al comparar la dieta entre tiburones mayores a 100 cm. y menores a 100 cm. (c2 = 0.44). para S. lewini los valores promedio (± 1.01 ‰ y -14.89 ± 0.44 ‰ y en hígado : 17.21 ± 1.03 ‰; y -17.46 ±1.71 ‰ respectivamente. al comparar el valor promedio de δ15n de S. lewini con el de sus presas más probables, se observo en el tiburón un enriquecimiento de aproximadamente 3 ‰ los cambios mensuales observados en el número de especies presa se reflejaron directamente en la variación del valor del índice de amplitud de dieta, el cual a su vez se reflejo en el valor de la desviación estándar de los valores del δ15N con retraso de un mes, es decir a valores altos de amplitud de dieta correspondió el mes siguiente un valor alto de desviación estándar y viceversa. a pesar de que los valores de amplitud de dieta en general fueron bajos, los cambios mensuales permiten plantear que S. lewini puede ser considerado como un depredador oportunista, con comportamiento de alimentación poco selectivo influenciado por la abundancia y disponibilidad de sus presas en el medio.
Finalmente se observo que los tiburones al inicio de la temporada presentan un valor promedio de δ15n bajo con respecto al enriquecimiento esperado de acuerdo a las presas encontradas en el contenido estomacal. Después del primer mes, el enriquecimiento es proporcional a las presas consumidas el mes anterior, lo que finalmente se mantiene a lo largo de la temporada; lo que nos permite suponer que la zona de Mazatlán es un área de alimentación y crianza para S. lewiInstituto Politécnico Nacional. Centro Interdisciplinario de Ciencias MarinasMaestría en Manejo de Recursos Marinosxiv, 107 h
Hábitos alimenticios y la razón de isotopos estables de carbono (δ13 C) y nitrógeno (δ15 N) del tiburón Sphyrna lewini, (Griffith y Smith 1834) capturado en el área de Mazatlán, Sinaloa, México
No full textimpreso y digita
Reproductive cycle of the sea cucumber Holothuria floridana in the littorals of Campeche, Mexico
No full textA global perspective on the trophic geography of sharks
No full textSharks are a diverse group of mobile predators that forage across varied spatial scales and have the potential to influence food web dynamics. The ecological consequences of recent declines in shark biomass may extend across broader geographic ranges if shark taxa display common behavioural traits. By tracking the original site of photosynthetic fixation of carbon atoms that were ultimately assimilated into muscle tissues of 5,394 sharks from 114 species, we identify globally consistent biogeographic traits in trophic interactions between sharks found in different habitats. We show that populations of shelf-dwelling sharks derive a substantial proportion of their carbon from regional pelagic sources, but contain individuals that forage within additional isotopically diverse local food webs, such as those supported by terrestrial plant sources, benthic production and macrophytes. In contrast, oceanic sharks seem to use carbon derived from between 30° and 50° of latitude. Global-scale compilations of stable isotope data combined with biogeochemical modelling generate hypotheses regarding animal behaviours that can be tested with other methodological approaches
Data from: A global perspective on the trophic geography of sharks
No full textSharks are a diverse group of mobile predators that forage across varied spatial scales and have the potential to influence food web dynamics. The ecological consequences of recent declines in shark biomass may extend across broader geographic ranges if shark taxa display common behavioural traits. By tracking the original site of photosynthetic fixation of carbon atoms that were ultimately assimilated into muscle tissues of 5,394 sharks from 114 species, we identify globally consistent biogeographic traits in trophic interactions between sharks found in different habitats. We show that populations of shelf-dwelling sharks derive a substantial proportion of their carbon from regional pelagic sources, but contain individuals that forage within additional isotopically diverse local food webs, such as those supported by terrestrial plant sources, benthic production and macrophytes. In contrast, oceanic sharks seem to use carbon derived from between 30° and 50° of latitude. Global-scale compilations of stable isotope data combined with biogeochemical modelling generate hypotheses regarding animal behaviours that can be tested with other methodological approaches. </span
A global perspective on the trophic geography of sharks
No full textSharks are a diverse group of mobile predators that forage across varied spatial scales and have the potential to influence food web dynamics. The ecological consequences of recent declines in shark biomass may extend across broader geographic ranges if shark taxa display common behavioural traits. By tracking the original site of photosynthetic fixation of carbon atoms that were ultimately assimilated into muscle tissues of 5,394 sharks from 114 species, we identify globally consistent biogeographic traits in trophic interactions between sharks found in different habitats. We show that populations of shelf-dwelling sharks derive a substantial proportion of their carbon from regional pelagic sources, but contain individuals that forage within additional isotopically diverse local food webs, such as those supported by terrestrial plant sources, benthic production and macrophytes. In contrast, oceanic sharks seem to use carbon derived from between 30° and 50° of latitude. Global-scale compilations of stable isotope data combined with biogeochemical modelling generate hypotheses regarding animal behaviours that can be tested with other methodological approaches.This research was conducted as part of C.S.B.’s Ph.D dissertation, which was funded by the University of Southampton and NERC (NE/L50161X/1), and through a NERC Grant-in-Kind from the Life Sciences Mass Spectrometry Facility (LSMSF; EK267-03/16). We thank A. Bates, D. Sims, F. Neat, R. McGill and J. Newton for their analytical contributions and comments on the manuscripts.Peer reviewe
Bird_etal_shark_trophic_geography
No full textCarbon isotope data compiled from muscle tissues of 5394 sharks from 114 species. Data provided include d13C values, latitude of capture, designation as shelf, slope or oceanic shark, length, depth of capture (where available), C/N ratios of muscle, and lipid extraction method if used. Also included are phytoplankton d13C data modelled from Magozzi et al 2016 (Ecosphere 8(5):e01763. 10.1002/ecs2.1763). Model data expressed as the median and standard deviation d13C value for the Longhurst Biogeographic province corresponding to the location of shark captur
