Intensive production of juvenile Artemia A' I' Olsen1 and Y' Attramadal2 1 Nesna University College,

1
Intensive production of juvenile ArtemiaA. I.
Olsen1 and Y. Attramadal2 1 Nesna University
College, N-8700 Nesna, Norway/NTNU
Trondheim.E-mail ao_at_hinesna.no2 Risørfisk AS,
Kranveien 60C, N-4950 Risør, Norway.

• Introduction
• Feeding fish larvae increasing sizes of feed as
  they grow according to their
• preferences results in faster growth and higher
  survival (Olsen et al. 2003),
• and may also give improved quality of juveniles
  compared with the use of
• enriched Artemia nauplii (Olsen et al. 1999).
  However, because of high
• production costs and problems with culture
  crashes and unsatisfactory
• nutritional value of the feed, juvenile Artemia
  has had a limited use as feed
• compared to enriched nauplii. Here we report on a
  new improved method for
• the production of high quality 3-4 day old
  juvenile Artemia.
• Materials and Methods
• Both EG (GSL) and RH quality Artemia from INVE
  were used. The food was
• the fishmeal based Micro Norse (now produced by
  Tromsø Fiskeindustri AS,
• Tromsø, Norway, distributed by EWOS) with a
  particle size of mainly 10-50µm.
• The food was distributed continuously into the
  tanks using a belt automat
• (Fig. 1). Some of the batches (totally 26
  batches) of Artemia produced were
• enriched with DC DHA Selco (INVE). The
  cultivation tanks (Fig. 1) used were
• 4.5m3 from BIA MILJØ (Herdla Norway) with a
  rounded bottom, and a plankton
• mesh covered outlet close to the tank top.
  Artemia density was kept at 50-100

Figure 2. Growth of juvenile Artemia when fed the
high food ratio, compared to what was previously
reported with this food (Olsen et al. 1999)
Table 1. Daily feeding in gram/million Artemia.
Half of first dose (day 1) was added directly
into the tank, the rest on feeding automat. Later
all food was given by automat.
The nutritional value of especially 3-day old
juvenile Artemia can be considered good with a
relatively high DHA content and DHA/EPA ratio,
and a low lipid level compared to short term
enriched Artemia nauplii that normally have a
lipid content of up to 30 (Table 2). Numbers of
bacteria associated with 3-day old Artemia
varied, but was in general around 20,000-30,000
CFU/Artemia. The percentage of Vibrios (4-19)
and bacteria with haemolytic activity (6-25) was
lower than previous reported (Olsen et al. 1999).
The 4h enrichment with DC DHA Selco gave only a
5-35 reduction of total numbers of bacteria. The
method described by Olsen et al. (2000) to
improve the microbial quality of Artemia could
also be adapted for 3-4 days old juveniles, but
it demands live algae.
Table 2. Content of total lipids ( of dry
weight), DHA (mg/g DW) and DHA/EPA ratio in 3-
and 4-day old Artemia juveniles, before and after
4h enrichment. N 2 (mean SD). Different
letters (a, b) in rows indicates significant
differences (Plt0.05) in lipids, and in the column
for Artemia (x, y) significant differences for
all values.
Conclusions and Applicability for the Aquaculture
Industry The method is labour and cost efficient
Artemia is ongrown at high density, with very
good survival and low occurrence of culture
crashes. No daily cleaning of tank bottom are
necessary because of minimal sedimentation. Apart
from transferring Artemia in/out of the ongrowing
tank, the daily tasks are filling automats and
counting Artemia. Approximate price of 10g dry
weight ongrown Artemia is 9 Nkr, assuming Micro
Norse price of 150 Nkr/kg and Artemia cyst price
of 500 Nkr/kg. The corresponding price of short
time enriched Artemia is approximate 15 Nkr.
Considering the beneficial effect of ongrown
Artemia, the scarcity and varying price of
Artemia cysts and the shortcomings of first dry
feeds, the method should have great applicability
to aquaculture.
Figure 1. Culture tanks with belt automats

• Results and discussion
• A manual point feeding immediately led to drop
  in oxygen level and the
• Artemia became less active and showed reduced gut
  filling. If repeated, this
• led to increased mortality. In tanks fed
  continuously, the Artemia showed no
• signs of reduced vitality and oxygen levels
  remained high. Cultures
• performed best at temperatures lower than 23C.
  Higher temperatures
• invariably resulted in mass mortality from day 3
  onwards. 7 batches with
• continuous feeding and temperature lt23C had
  92-99 survival after 4
• days. The obtained growth was better than
  previously reported with this
• food (Fig 2.). Also, growth depended on amount of
  food given, and
• powerful feeding for 4 days gave an increase in
  dry weight from 2.1 to
• 12 µg/ind. Approximately 50 of the dry feed was
  regained as biomass.

Acknowledgements This work was supported by the
LU project 048 Kostnadseffektiv videredyrking av
Artemia and the NUMARIO project K1-6069/2000
Vannkvalitet og videredyrking av
Artemia. References Olsen, A.I., Y. Attramadal,
A. Jensen Y. Olsen. 1999. Influence of size and
nutritional value of Artemia franciscana on
growth and quality of halibut larvae
(Hippoglossus hippoglossus) during the live feed
period. Aquaculture 179, p. 475-487. Olsen, A.I.,
Y. Olsen, Y. Attramadal, K. Christie, T.H.
Birkbeck, J. Skjermo O. Vadstein. 2000. Effects
of short term feeding of microalgae on the
bacterial flora associated with juvenile Artemia
franciscana. Aquaculture 190, p. 11-25. Olsen,
A.I, A. Hagiwara Y. Sakakura. 2003. Size
Preferences of Marine Fish Larvae Among
Cultivated Live Feed. Beyond Monoculture.
European Aquaculture Society Special Publication
No. 33, p. 278-279.