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A captive population of California yellowtail ( Seriola lalandi) was used to document spawning patterns, including measures of egg production, population fecundity and egg and larval quality from 2007 to 2010. Spawned eggs were also used to document larval development and to develop rearing techniques for aquaculture in the region. Broodstock growth and condition factor were best when feeding rations were maintained at 10-15% body weight week−1 during the warm summer months. A winter ration based on satiation feeding was typically 4% body weight week−1. During the 4-year study period, the only broodstock health issue was an infestation by the parasitic gill fluke Zeuxapta seriolae, which was readily treated. Spawning occurred naturally in the 140 m3 tank when the ambient water temperature reached 16°C and ended when the temperature exceeded 22°C. Egg production reached a maximum in 2010 when 43 spawn events were recorded from a pool of nine females yielding 36.8 million eggs in total. The average female size at this time was 20 kg, which equated to a total annual population fecundity of approximately 226 000 eggs kg−1 female year−1. Larval rearing trials yielded survival rates as high as 5.8% from egg to 50 days post-hatch (dph). Successful larval culture methods included the addition of algae paste for green water culture, rotifers (20 rotifers mL−1) at 2 dph and Artemia (5 Artemia mL−1) at 6 dph. Larvae were transferred from the incubation tank at 10 dph to a shallower tank with 33% greater surface area to accommodate the larvae's strong orientation to surface waters. This research represents the first documentation of successful spawning and larval rearing for S. lalandi in the eastern Pacific. [ABSTRACT FROM AUTHOR]

It is likely that Seriola spp. have nutritional requirements for long-chain polyunsaturated fatty acids (LC-PUFAs) and are unable to meet physiological demand for these nutrients via biotransformation of C 18 polyunsaturated fatty acids (C 18 PUFAs). However, it is unclear whether 20:4n-6 (arachidonic acid, ARA), 20:5n-3 (eicosapentaenoic acid, EPA), and 22:6n-3 (docosahexaenoic acid, DHA) are each required or, as in other fish, EPA is comparatively unimportant in maintaining performance of Seriola spp. Accordingly, we assessed growth performance and tissue fatty acid composition of juvenile California Yellowtail Seriola dorsalis (formerly Seriola lalandi ) fed a fish oil-based positive control diet (FISH), a soybean oil-based negative control diet (SOY), or experimental diets based on soybean oil supplemented with ARA, EPA, DHA, ARA and DHA, or all three of these fatty acids combined to achieve 50% or 100% of the concentrations typically observed in fish oil (SOY + 50% ARA, SOY + 100% ARA, SOY + 50% EPA, SOY + 100% EPA, SOY + 50% DHA, SOY + 100% DHA, SOY + 50% ARA and DHA, SOY + 100% ARA and DHA, SOY + 50% ALL, SOY + 100% ALL). As expected, fish fed the SOY diet exhibited significantly reduced growth relative to those fed the FISH diet. Supplementing with ARA alone had no effect on growth performance, and independent supplementation with EPA or DHA did not yield predictably positive effects on growth. However, fish fed the SOY + 100% ARA and DHA feed grew as well as those fed the FISH diet, and those raised on the SOY + 50% ALL and SOY + 100% ALL diets outperformed all others. Fatty acid composition of the fillet, liver, eye, and brain tissues was significantly affected by dietary treatment. As expected peripheral tissues were more modified than central tissues, and tissues of fish fed the soybean oil-based feeds exhibited higher levels of 18:2n-6 and lower levels of LC-PUFAs than those fed the rest of the experimental feeds. This effect was less overt among feeds supplemented with ARA and DHA or all three fatty acids. Results indicate that soybean oil can completely replace fish oil in California Yellowtail diets, assuming adequate levels of DHA and ARA are provided. Furthermore results illustrate the value of supplementing fish oil-free feeds with ARA, EPA, and DHA, but suggest that ARA and DHA are the primary drivers of LC-PUFA essentiality in this species. Statement of relevance The current manuscript provides valuable insights for fish nutritionists, for the aquafeed and aquaculture industries regarding fatty acid essentiality for marine carnivorous finfish. Our study supports the hypothesis that some LC-PUFAs are more physiologically important than others, with DHA and ARA being the primary drivers of fatty acid essentiality for juvenile California Yellowtail. [ABSTRACT FROM AUTHOR]