Tissue‐specific stable isotope ratios of shortfin mako (Isurus oxyrinchus) and white (Carcharodon carcharias) sharks as indicators of size‐based differences in foraging habitat and trophic level | Semantic Scholar (2024)

A positive relationship between shortfin mako length and δ15N values is found, indicating ontogenetic changes in diet based on prey or locality, and suggest shared resource use between these shark species and potentially high consumption of prey from SVB and other similar coastal regions in southern Baja.

The main objectives of this study were to analyze the differences in trophic ecology of juvenile S. lewini from coastal nursery areas of Jalisco by sex and size, through stomach content and stable isotope analyses, and analyze changes in muscle and liver δ15N and δ13C values with shark size.

This study provides relevant information regarding young white shark feeding preferences, reinforces the importance of coastal areas as critical habitat for the development and the successful foraging of this species, and also provides indirect insights on the feeding habits of the adult female of white sharks.

The importance of coastal demersal prey heavily targeted by local fisheries for the diet of young white sharks and the importance of Bahía Sebastián Vizcaíno as a nursery habitat is highlighted.

There was low trophic niche overlap between species and individuals, due to different individual foraging strategies, according to the carbon and nitrogen isotopic profiles obtained.

The isotopic values obtained suggest that I. paucus give birth in coastal waters and then migrate towards oceanic zones, while the level of isotopic enrichment could be an indicator of the food sources and trophic level of the mother.

This multi-proxy approach characterises an animal’s isotopic niche in greater detail than traditional isotope analysis alone and shows that δ^66Zn_en analysis can highlight intrapopulation dietary variability thereby informing conservation management and, due to good δ^66Zn_en fossil tooth preservation, palaeoecological reconstructions.

It is concluded that blue sharks capture prey ranging from neritic to mesopelagic animals through diel vertical migration.

These data demonstrate that dermis yields valuable isotope data to examine the trophic ecology and feeding/movement behavior of sharks, but further work is required to address dermis-specific turnover rates and diettissue discrimination factors.

The habitat use and migratory history of young White Sharks (Carcharodon carcharias), a highly protected species, is reconstructed by utilizing natural chemical tracers (element:Ca ratios and stable isotope analysis, SIA) in vertebral cartilage growth bands.

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Stable isotope analysis can provide insight into the trophic ecology and migratory behavior of marine predators, especially when coupled with electronic tagging data, and mixed model results indicated that sharks foraged at a higher relative rate in coastal habitats.

The close relationship between the juvenile bluefin δ15N values and those of suspension feeders suggests that nektonic crustaceans or zooplankton may contribute significantly to the diet of bluefin tuna, a food source previously overlooked for this species in the northwest Atlantic Ocean.

Paired differences between isotopic values of tissues were relatively small but varied significantly with shark total length, suggesting that shark size can be an important factor influencing the magnitude of differences in isotope values of different tissues.

It is found that liver and blood are more useful than muscle as shorter-term dietary indicators for summer flounder and other migratory fishes.

Nitrogen stable isotope values of skate blood and skate and dogfish white muscle were not affected by tissue urea content, suggesting that available diet–tissue discrimination estimates for teleost fishes with similar physiologies would provide accurate estimates for elasmobranchs.

Consideration of the maternal signal and measuring its loss are necessary when analyzing the stable isotopes of young animals, as there is potential to misinterpret feeding strategies, over-estimate trophic position and incorrectly assign carbon source.

In contrast to previous studies of juvenile fishes, C and N incorporation was primarily driven by catabolic tissue turnover as opposed to growth rate, and suggested that P. disjunctivus could not assimilate refractory polysaccharides.

The aim of this study was to evaluate the utility of 14C age validation for a wide-ranging species with a complex life history and to use stable isotope measurements in vertebrae as a means of resolving complexity introduced into the 14C chronology by ontogenetic shifts in diet and habitat.

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