Program and Abstracts(PDF)

Presentation 8
SPAWNING AND LARVAL REARING OF YELLOWTAIL AMBERJACK (Seriola
laland) IN SOUTHERN CALIFORNIA
Kevin Stuart* and Mark Drawbridge
Hubbs-SeaWorld Research Institute 2595 Ingraham St. San Diego, CA 92109, USA
*Email: kstuart at hswri.org
Hubbs-SeaWorld Research Institute (HSWRI) has been rearing yellowtail amberjack (Seriola
lalandi), known locally as California yellowtail, at its laboratory in San Diego since 2003. The
broodstock have been spawning naturally in a 140 m 3 maturation pool since 2002. The sex ratio
has been close to 1:1 and spawning typically occurs between 16.5 and 22.0°C (April thru August).
The number of adults has ranged from 21 to 35 and associated individual weights from 8.2 to
20.8 kg. Our primary egg quality measures have shown inconsistent spawn quality within a
spawning season, with hatch rates ranging from 10 – 90% and survival to first feeding ranging
from 5 – 80%. Typically the highest quality spawns are seen early in the season. The numbers
of spawning events and eggs per spawn have increased in recent years due to increasing female
biomass and improvements to the broodstock feeding regime.
Recent research results on yellowtail have shown no significant differences in growth or
survival at 10 dph among egg stocking densities of 50, 100, and 200 eggs per L. Greenwater was
demonstrated to be beneficial to larvae up to 16 dph as was 24hr light and high light intensity of
5,000 to 13,000 lux. There were no significant differences in growth or survival when yellowtail
larvae were fed at rotifer densities of 15, 30, and 45 rotifers per ml. Larvae were able to consume
1 st instar Artemia (Artemia franciscana) as early as 6 dph. Finally, we determined that
greenwater rearing conditions created using either SanoLife ALG (INVE), algae paste, or live
algae all produced similar results.
Our current culture protocols for production include 1) stocking eggs at a density of 100 per
L; 2) maintaining water temperature at 21.0 – 22.0 °C; 3) providing rotifers (Brachionus
rotundiformis) from 2 to 9 dph at 20 per ml; 4) moving larvae from tall, narrow 1600L egg
incubators to shallow, wide 8,000L tanks at 10 dph; 5) providing 1 st instar Artemia (Artemia
franciscana) from 6 to 10 dph and 2nd instar Artemia from 10 to 35 dph; 6) providing 24hr light
at 5,000 to 13,000 lux above each tank; and 7) greening the water using SanoLife ALG from 2 to
17 dph.
These procedures yielded survival rates from egg to juvenile of up to 5% with a relatively
high degree of variability. High larval mortality, from unidentified causes at around 17 - 20 dph
and deformity rates as high as 40% are focal areas for improvement through future research.
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