| This research evaluates the potential for rearing three southern California abalone species, namely Haliotis cracherodii (black), H. rufescens (red), and H. fulgens (green), in an aquaculture setting, with special attention to how different macroalgal diets impact their growth and fecundity.;The first experiment investigated how various macroalgal diets affect growth, consumption, and Feed Conversion Efficiency (FCE) in adult H. cracherodii, H. rufescens, and H. fulgens. These diets consisted of either monospecific or mixed species of brown algae ( Macrocystis pyrifera and/or Egregia menziesii), red algae (Gracilaria spp.), and/or green algae ( Ulva spp.). Weekly weight changes of all abalone, their rates of macroalgal consumption, and daily water temperatures were recorded during the experiment. Additionally, the FCE of each diet were calculated. Results indicated that H. cracherodii exhibited its greatest growth when fed a monospecific diet of M. pyrifera or a mixed diet of M. pyrifera and/or E. menziesii with the red algae Gracilaria spp. Most (ca 85%) H. rufescens and H. fulgens, exhibited slightly higher, albeit non-significant, growth when fed a diet of M. pyrifera, Gracilaria spp., and Ulva spp. compared to a diet of M. pyrifera and Gracilaria spp. Regardless of diet, H. rufescens growth rates declined once ocean water temperatures exceeded 20°C, but such detrimental temperature effects were not observed for H. cracherodii or H. fulgens.;The second experiment examined how the different macroalgal diets described above impacted egg quantity and quality in adult female H. fulgens . Individuals fed a three-species mixed diet exhibited a three-fold increase in egg production compared to individuals fed a two-species mixed diet. However, egg and yolk sizes and fatty acid methyl ester classes were not different between these diets. Thus, adding green algae to the abalone diets may result in increased egg production, and thus should be considered for culturing broodstocks. Together, these findings demonstrate that H. fulgens is an ideal candidate to culture in southern California waters due to increased growth when fed locally available macroalgae and their ability to tolerate warmer summer temperatures when coastal waters can reach 23°C. |
