As with many species of seahorses, Hippocampus hippocampus wild populations are being subjected to uncontrolled exploitation in their natural environment. Thus, aquaculture could contribute to satisfy the commercial demand for animals while promoting the recovery of wild stocks. The present study was conducted to compare the e¡ect of the substituting Artemia nauplii with rotifers for ¢rst feeding seahorse juveniles. Survival, growth and biochemical composition of prey organisms and ¢sh were studied during the feeding trial. In addition, to help the biometric study, an anaesthetic test was also carried out using clove oil. The results showed excellent survival (average 60%) in juveniles exclusively fed with Artemia, with better values than those reported previously obtained by other authors for this species. By comparison, high mortality and poor growth were observed during ¢rst feeding with seahorses fed on rotifers. This could have been related to the lower energy intake and poorer nutritional value of the rotifers. Furthermore, clove oil concentrations of 25 ppm were found to work well as an anaesthetic for seahorse juveniles. Overall, ¢rst feeding Artemia alone was found to be an e⁄cient and simpli¢ed method for feeding young H. hippocampus fry, building the principles for their culture for ornamental or restocking purposes.

The importance of a suitable diet for reproduction has been recognized as one of the major factors in ornamental aquaculture. In seahorses, mysids have been described as preys in the wild. Also, Artemia has been usually employed for rearing fish, including syngnathids. Therefore, the aim of this work was to evaluate the effect of these live preys on the spawning quality of Hippocampus hippocampus. After 108 d, no differences were found in adults concerning all biological parameters evaluated, but broodstock fed on mysids showed better results than Artemia regarding number of spawning events (12 vs. 3), brood sizes (233.50 ± 59.04 vs. 68.00 ± 57.97 juveniles), and newborn seahorses standard length (10.61 ± 0.64 vs. 8.75 ± 1.32 mm). The better nutritional quality of mysids, overall in Docosahexanoic acid, could be one of the main responsible factors. However, mysids stock is conditioned by natural catches and rearing techniques are little known. Another alternative would be to combine them with Artemia in mixed diet. Further research must be done concerning mysids breeding techniques to delineate their employment as a sustainable prey for seahorse aquaculture. This trial showed for the first time the effect of mysids to enhance reproduction efficiency in H. hippocampus.

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This paper presents the preliminary results of different trials carried out with two species of mysids from Gran Canaria: Leptomysis lingvura (G.O. Sars, 1866) and Paramysis nouvel. Experiments lasting 21 days showed significantly higher fecundity and survival in L. lingvura than in P. nouveli (P<0.05). We also report the biochemical profile of both species fed 48‐h‐Artemia nauplii enriched with Easy‐DHA‐Selco® for 7 days. A comparison of our results with those of for Artemia and rotifers, organisms frequently used as live food in aquaculture, showed that mysids have a high percentage of protein per dry mass (73.38% in P. nouveli, and 74.19% in L. lingvura). Furthermore, the percentage of docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA) and arachidonic acid (AA) in total fatty acids was higher in both species than that reported by Roo and colleagues for rotifers and Artemia. In addition to the content of these fatty acids, their ratios between them are also important for normal growth and larval development. We found that the ratio, DHA:EPA, was 0.85 0.02 and 0.89 0.01; the ratio, DHA: AA, 6.25 0.26 and 4.74 0.14; and the ratio, EPA:AA, 7.32 0.26 and 5.32 0.2, respectively, for P. nouveli and L. lingvura in cultures and these ratios do not significantly differ (P>0.05) from organisms in the wild. Here, we argue that as mysids are prey for many commercially important fish, cephalopods and rays, it is likely that the biochemical composition of mysids in their natural environment is “optimal” for these predators. Therefore, we studied the lipid profile of both species as they naturally occur in their environment. The results indicate that these mysids could be used to develop high quality live fish food.

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