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MEPS prepress abstract   -  DOI: https://doi.org/10.3354/meps13315

Effect of diet on breeders and inheritance in syngnathids: application of isotopic experimentally derived data to field studies

Miquel Planas*, Alexandro Chamorro, Alex Paltrinieri, Sara Campos, Arturo Jiménez, Killian Nedelec, Jorge Hernández-Urcera

*Corresponding author:

ABSTRACT: Syngnathids are vulnerable ovoviviparous fishes with repeated brooding of males within a reproductive season. The isotopic effects of diet on both breeders (pooled sexes) and parent–egg transmission have been demonstrated in a few fish species but never in syngnathids. Quantifying isotopic changes due to diet is necessary to assess parent–newborn conversions and to estimate accurate trophic enrichment factors (TEF). We assessed the isotopic (δ13C and δ15N) effects of 3 experimental diets on TEFs in seahorse Hippocampus guttulatus breeders and isotopic inheritance. Our results suggest that H. guttulatus follows an income-capital continuum pattern for parent–egg transmission. The isotopic variability in diets for breeders and the resulting experimentally derived TEFs were compared with fixed TEFs from reviews to estimate their impact on the relative contribution of potential prey sources in syngnathids from Cíes archipelago (Atlantic Islands National Park, NW Spain). We estimated source contributions using stable isotopes mixing models (SIMMs) by combining prey sources into ecologically informative groups and incorporating informative priors. We demonstrate that (1) most frequently used TEFs from reviews might not be suitable to all fish species, particularly to syngnathids, and (2) dietary source variability has a great effect on source contribution estimates. This study is also the first to provide specific TEFs for syngnathids.