Data: Carry-over effects of pre-breeding diets on seahorse (Hippocampus reidi) reproductive success

The effects of diet on reproduction success in fishes are fairly well known for many species. In syngnathids (seahorses, pipefishes and seadragons), almost nothing is known about how diet quality during the pre-breeding period might influence subsequent breeding performance and fry quality. In the present study, the influence of pre-breeding diet was assessed for the first time in seahorses. For that, adult seahorses Hippocampus reidi were submitted to three dietary treatments (based on Artemia and/or mysidaceans) including different timing schedules. The assimilation of the diets by breeders and subsequent newborn batches were evaluated isotopically (δ13C and δ15N). In newborn juveniles, the timing of brood release, brood size, and length, weight and survival were also evaluated. The species followed a mixed capital-income reproduction strategy and showed a higher breeding performance and larger newborn with a mixed diet supplied during the whole pre-breeding period (5 months). The enhancements were specially reflected on the second half of the breeding period. The isotopic steady-state in newborn batches was achieved beyond the second month of the breeding period (i.e., slow change rates), depending on the treatment and isotope considered. For the first time in syngnathids, this study also revealed an isotopic relationship between breeder’s diet and newborn. Three data sets are provided: general data on breeders (onset and end of the pre-breeding period), breeders isotopic data (onset and end of the pre-breeding period) and newborn general information and isotopic data