Contribución al conocimiento de los hábitos alimenticios de Lepidochelys olivacea y Chelonia mydas agassizi (Reptilia, Cheloniidae) en el Pacífico Mexicano

Casas-Andreu, Gustavo; Gómez-Aguirre, Samuel

doi:10.1590/s0373-55241980000200019

Cited by 6 publications

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“…Bjorndal (1997) reported that East Pacific green turtles may have a more carnivorous diet than Chelonia of other regions. This might be a consequence of the low presence in the Eastern Pacific of sea grasses and a lack of algal diversity, but an abundance of other prey such as fish, fish eggs, molluscs, crustaceans, polychaetes and jellyfish (Casas-Andreu & Gómez-Aguirre 1980, Fritts 1981, Hays Brown & Brown 1982. The consumption of a diet with high protein content (tunicates) would result in greater nutrient gain for development to sexual maturity.…”

Section: Discussionmentioning

confidence: 99%

Feeding ecology of the East Pacific green sea turtleChelonia mydas agassiziiat Gorgona National Park, Colombia

Amorocho¹,

Reina²

2007

Endang. Species Res.

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The diet of 84 East Pacific green turtles Chelonia mydas agassizii, captured in 2003 and 2004 at Gorgona National Park in the Colombian Pacific, was studied through analysis of lavage samples collected from the lower oesophagus. We identified 5 food diet components, with rank in order of percent dry mass being: tunicates (Salpidae and Doliolidae), red mangrove fruits (Rhizophora mangle), algae (Rhodophyta, Chlorophyta, Cyanophyta), small crustaceans (shrimp larvae) and leaves (Ficus spp.). Three non-food diet items included coral fragments, shells, and sand/pebbles that were found in large amounts in most retrieved samples. Nutritional analyses were carried out to determine the contribution of diet components to the foraging turtles. Tunicates had the highest protein value (438 g kg -1), followed by algae (174 g kg ) and mangrove fruits (65 g kg -1). The frequency of retrieved components grouped in animal (including coral), vegetal and sand/pebbles categories did not vary between sampling seasons. The immature East Pacific green sea turtle population at Gorgona National Park showed an omnivorous behaviour, feeding on a range of animal and vegetal components with a bias towards tunicates (Salpidae and Doliolidae). In contrast to the generally herbivorous diet of juvenile green turtles (over 40 cm straight carapace length; SCL), Gorgona's immature population was composed of large juveniles, subadults and a few adults feeding mainly on animal matter. Mean SCL of 86 measured turtles was 58.4 ± 7.8 cm (ranging from 37.0 to 72.9 cm). Mean mass was 28.0 ± 10.7 kg (ranging from 7.5 to 50.5 kg). We speculate that this omnivorous strategy of Gorgona's immature green turtles might provide energetic benefits for continuing long distance migrations to further developmental or mating grounds in the Pacific basin.

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Section: Discussionmentioning

confidence: 99%

Feeding ecology of the East Pacific green sea turtleChelonia mydas agassiziiat Gorgona National Park, Colombia

Amorocho¹,

Reina²

2007

Endang. Species Res.

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“…Studies of stranded turtles report a high degree of durophagy and piscivory (Behera et al, ; Colman et al, ; Di Beneditto, De Moura & Siciliano, ; Spring & Gwyther, ; Wildermann & Barrios‐Garrido, ). Two studies of freshly killed turtles in Mexico corroborated these findings, but also revealed a high degree of gelativory (mostly salps, but also other tunicates) as well as other soft‐bodied prey including sipunculid worms and bryozoans (Casas‐Andreu & Gómez‐Aguirre, ; Montenegro Silva et al ., ). Its trophic morphology reflects this varied diet: L. olivacea has the most generalised rhamphotheca in terms of shape and function (Fig.…”

Section: Introductionmentioning

confidence: 76%

Beyond trophic morphology: stable isotopes reveal ubiquitous versatility in marine turtle trophic ecology

2019

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The idea that interspecific variation in trophic morphology among closely related species effectively permits resource partitioning has driven research on ecological radiation since Darwin first described variation in beak morphology among Geospiza.Marine turtles comprise an ecological radiation in which interspecific differences in trophic morphology have similarly been implicated as a pathway to ecopartition the marine realm, in both extant and extinct species. Because marine turtles are charismatic flagship species of conservation concern, their trophic ecology has been studied intensively using stable isotope analyses to gain insights into habitat use and diet, principally to inform conservation management. This legion of studies provides an unparalleled opportunity to examine ecological partitioning across numerous hierarchical levels that heretofore has not been applied to any other ecological radiation. Our contribution aims to provide a quantitative analysis of interspecific variation and a comprehensive review of intraspecific variation in trophic ecology across different hierarchical levels marshalling insights about realised trophic ecology derived from stable isotopes.We reviewed 113 stable isotope studies, mostly involving single species, and conducted a meta-analysis of data from adults to elucidate differences in trophic ecology among species. Our study reveals a more intricate hierarchy of ecopartitioning by marine turtles than previously recognised based on trophic morphology and dietary analyses. We found strong statistical support for interspecific partitioning, as well as a continuum of intraspecific trophic sub-specialisation in most species across several hierarchical levels. This ubiquity of trophic specialisation across many hierarchical levels exposes a far more complex view of trophic ecology and resource-axis exploitation than suggested by species diversity alone. Not only do species segregate along many widely understood axes such as body size, macrohabitat, and trophic morphology but the general pattern revealed by isotopic studies is one of microhabitat segregation and variation in foraging behaviour within species, within populations, and among individuals.These findings are highly relevant to conservation management because they imply ecological non-exchangeability, which introduces a new dimension beyond that of genetic stocks which drives current conservation planning.Perhaps the most remarkable finding from our data synthesis is that four of six marine turtle species forage across several trophic levels. This pattern is unlike that seen in other large marine predators, which forage at a single trophic level according to stable isotopes. This finding affirms suggestions that marine turtles are robust sentinels of ocean health and likely stabilise marine food webs. This insight has broader significance for studies of marine food webs and trophic ecology of large marine predators.Beyond insights concerning marine turtle ecology and conservation, our findings also have broader impli...

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Identifying critical foraging habitats of the green turtle (Chelonia mydas) along the Pacific coast of the Baja California peninsula, Mexico

López‐Mendilaharsu

Gardner

Seminoff

et al. 2005

Aquatic Conservation

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ABSTRACT1. The conservation of highly mobile and migratory species remains one of the most serious challenges to resource managers.2. Intense mortality of immature green turtles has been identified at principal developmentalfeeding habitats in Baja California, and is considered a great threat to the stability of the eastern Pacific population. Thus, coastal lagoons of the Baja California peninsula, such as Bah! ı ıa Magdalena, have been identified as high priority areas for their protection.3. Conservation efforts to date have focused on creating a sea turtle refuge in the northwestern part of the bay, but this area may not be sufficient for protecting all of the critical feeding areas used by green turtles.4. The diet of green turtles was investigated through analysis of digestive tract contents from 24 green turtles that were drowned incidentally in fishing nets at feeding grounds in Bah! ı ıa Magdalena and adjacent areas along the Pacific coast of the Baja California peninsula, Mexico.5. Mean straight carapace length (SCL) differed significantly between localities: mean: 55:5 cm (range: 47.7-76:9 cm, n ¼ 11) in Bah! ı ıa Magdalena; mean: 67:7 cm (range: 49-87 cm, n ¼ 11) in adjacent coastal waters.6. Green turtle diet consisted largely of marine algae and seagrasses, but food items varied spatially. The red algae Gracilaria pacifica, Gracilariopsis lemaneiformis and Hypea johnstonii were the most abundant diet items inside Bah! ı ıa Magdalena, and the seagrass Phyllospadix torreyi was the most commonly ingested food in coastal areas outside of the bay.7. Results indicate that green turtles utilize spatially distinct foraging habitats within this region. Therefore, it is recommended that any design of protected areas for sea turtles in Bah! ı ıa Magdalena

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Contribución al conocimiento de los hábitos alimenticios de Lepidochelys olivacea y Chelonia mydas agassizi (Reptilia, Cheloniidae) en el Pacífico Mexicano

Cited by 6 publications

References 0 publications

Feeding ecology of the East Pacific green sea turtleChelonia mydas agassiziiat Gorgona National Park, Colombia

Feeding ecology of the East Pacific green sea turtleChelonia mydas agassiziiat Gorgona National Park, Colombia

Beyond trophic morphology: stable isotopes reveal ubiquitous versatility in marine turtle trophic ecology

Identifying critical foraging habitats of the green turtle (Chelonia mydas) along the Pacific coast of the Baja California peninsula, Mexico

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