ROLE OF LIGHT IN LARVICULTURE OF RED DRUM
From: Fred Chambers regenerative@earthlink.net
To: AQUA-L@killick.ifmt.nf.ca
Sent: March 08, 2000
QUESTION:
I'm a volunteer intern at a marine fish hatchery near San Diego, CA, and
I'm planning a project comparing lights. My experiment will compare larval
success/behavior/growth under different colors and intensities of light.
The species is a big drum: king croaker or white seabass Sciaenidae
family (croakers and drums) Atractoscion nobilis (previously known as
Cynoscion nobilis).
Salt water, plankton, detritus, and dissolved compounds in the
natural
larval nursery water absorb red and blue wavelengths. In the
hatchery,
the lights appear to be white, usually mimicking day light: full
spectrum with a little extra red. Larval culture tanks are crystal clear
re-circulating and shallow, not filtering much blue or red wavelengths.
Perhaps the reds and blues are artificially stimulating anti-social
behavior, like cannibalism.
The poultry industry doesn't use white light in their growout
operations. It makes the birds fight. They find that the birds are calmer
and grow faster under blue light when young, and under green light as they
grow older.
What's going on biologically is important. The retinas in chordate
eyes
produce melatonin under illumination. That melatonin signals the
pineal gland and the superchiasma in the brain, producing melatonin,
dopamine, and other neurotransmitters that flow throughout the body. It
works in fish, chickens, and humans. The unnatural levels of blue and red
wavelengths in the larval tanks may cause higher somatic levels of "flight
or fight: neurotransmitters.
I'd like to use electronic ballast compact florescent lamps in
various
colors. I can probably get a couple-dozen T-8 or T-12's donated with
some timer/controllers enabling different photoperiods and outputs for
different trials.
What do you think about the project? Any experience with colored
lights in your hatcheries?
Fred Chambers
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COMMENTS 1:
I'm interested in the ability of the larvae to 'see' their prey under
different light, and what this does for survival. We use white lights, and
in the species that we do (cod, haddock and flatfishes), I don't think
anti-social behaviour (canibalism) is a feature of the
rearing until actually quite late on, like at weaning.
Of possible interest is that we used blue lights for
Halibut (Hippoglossus hippoglossus) early larval rearing in
the hatchery where I used to work. Quite why, I forget,
though it was definitely thought to improve survival in
some way.
Rob Blyth
Port Erin Marine Laboratory
Port Erin
Isle of Man, IM9 6JA, UK
Tel: +44 (0) 1624 831037
Fax: +44 (0) 1624 831001
e-mail: rblyth@liverpool.ac.uk
******************************
COMMENTS 2:
Don't know about the drum. I know they use fluorescent lighting in Texas
for red drum Sciaenops ocellatus for induction of spawning. I'm not sure
which bulbs they use.
I am using fluorescent figures with one cool (blue) and one warm
(red)
bulb to give a broad spectrum lighting. It has worked well for
induction of spawning of crayfish during the winter when they would not
normally spawn. I have to put them on a long photophase of about 14-15
hours of light.
Bill Daniels
Research Associate Professor/ Extension Specialist, Aquaculture
1200 N. Dupont Hwy.
Dept. of Agriculture & Natural Resources
Delaware State University
Dover, DE 19901-2277, USA
Tel. (302)-857-6436
Fax (302)-857-6430
e-mail: wdaniels@dsc.edu
*******************************
COMMENTS 3:
Fluorescent lighting does not (I believe) produce a continual spectra
(blackbody), but instead a series of shark spikes which roughly
simulate a continuous spectra. So your data may be accurate in terms of
effect, but determining cause (i.e intensity, temp, spikiness, flicker,
etc) will be difficult to tease out. You would get more accurate data by
using filters on full-spectrum (true blackbody) lamps (i.e. incandescent).
But if your ultimate goal is to decide which brand/type fluorescent
light to use, then your plan would be fine.
Brand and type of ballast also affect the results, as does age of
lamp.
Also, there is very little selection of color in compact fluorescent
- you
will need filters regardless.
Keith Redfield
e-mail: goodfish@ecovitality.org
********************************
COMMENTS 4:
I'm extremely interested in your finds on the light colours.
I build live fish and live lobster holding systems and have always
been
concerned about tank colours and light lux strengths. For lobster we
leave lights on at night at a low lux, all our tanks are a shade of blue.
But all our facilities are built within insulated cool room panel
buildings which are white or a cream colour.
John Seccombe
Aquahort Ltd
Auckland, New Zealand
Tel. +64 9 5366201
Fax: +64 9 5366362.
Australian toll Free.Tel.1800 146784
Fax1800 145668
e-mail: jseccombe@clear.net.nz
http://www.angelfire.com/az/aquahort/