The Preservation of Fish Species Through Artificial
Propagation
by Mitchell McKenzie
Aquarticles
Introduction -
The appropriate management of genetic resources is essential in halting the worldwide
decline in the biodiversity of fish species. The decline is due to a number of factors
including the uncontrolled introduction of alien species into fragile ecosystems. An
example is the Nile perch which is an important food fish and has been introduced to many
regions of Africa where it has become very successful, to the detriment of other native
species. Witte et al (1997), states that since its introduction to Lake Victoria in the
1980's species of Mochokid such as Synodontis victoriae and S. afrofischeri have suffered
heavy predation, to the point where intervention is required. Over fishing, farm and
industry related pollution and the constant threat of disease (Mijkherjee et al, 2002) all
contribute to a worsening problem.
Ideally the breeding of endangered fish species would involve replicating and
maintaining correct environmental parameters such as pH, nitrates, nitrites, temperature
and substrate composition at levels appropriate to the natural spawning season of each
species involved, in order to induce breeding behavior. Unfortunately in many cases there
is not a great deal known about a particular species to make this a viable option. 0r, as
is often the case the species is critically endangered and there is no time to acclimatize
or condition the fish in readiness for breeding, a process which (assuming that the fish
is of breeding age) may take considerable time.
In species such as the catfish Corydoras melini where the breeding behavior is
understood, a mature pair may be induced to spawn simply by raising the water level, this
action mimics the rainy season when the species naturally breeds. Many species can be
triggered into spawning by a simple replication of environmental conditions. Haniffa et al
(2000), describes a method of artificial reproduction in which mature male and female
Channa striatus were chosen, based on morphological characteristics and induced to spawn
via intramuscular injections of Ovaprim®. Ovaprim® is a patented formula which contains
Salmon gonadotropin releasing hormone which stimulates the production of follicle
stimulating hormone and luteinising hormone, which in males stimulates spermatogenesis and
in females encourages ovulation. The solution also contains domperidone which is an anti
emetic, this is necessary as many catfish species are prone to regurgitate food when under
stress. This method is of particular use where there is insufficient knowledge of natural
breeding behavior and will form the basis of our proposed project. The species used will
be Synodontis angelicus which was recently considered threatened, but is now recovering
due to artificial propagation (Burgess, 1989).
Proposed Protocol -
Materials -
1 Kaycee fish injector MK1
2 X2 glass/acrylic tanks - 12'x15'x48' =2x130liters
3 X2 Heaters - 300 watt
4 X1 Eheim professional 2022 external filter - pre seeded with
nitrogen fixing bacteria. The filter
should also be attached with a dual connector hose to
feed both tanks
5 Ovaprim® - 3 x 20 microliters
6 Saline solution (control) 3 x 20 microliters
7 Finquel® (tricaine/MS - 222) - 0.85 grammes
8 Dechlorinator - 21mls Chlorine/chloramine reduces the potency of
Finquel and will cause
unnecessary respiratory distress to the specimens.
9 X2 Plastic/glass containers - 10liter capacity
10 Oxygen cylinder (3 liters approx) and slow release regulator plus a 3 meter
air line
Preparation -
All specimens should be in perfect condition, ie no split fins, skin ulcers or signs of
parasitic infestation (Ichthyophthirius, anchor worm, velvet etc). Year old specimens are
generally considered to be mature.. 2 mature females will be chosen on the basis of egg
release on the application of light pressure to the ventral region. The species displays
no visual sexual dimorphism. Similarly 4 males will be chosen on the basis of milt release
on the application of light pressure to the ventral region.
Water parameters in holding tanks -
1 Temperature - 25°C - 77F
2 pH - 6.8 - 7.5 - Local water = 7.4 - No adjustment
required
3 Nitrates/nitrites - nil - Ensured through adequate bacterial
filtration - Denitrification process
4 Ammonia - nil - Ensured through adequate bacterial filtration S
angelicus is a naturally shy species
which is nocturnal by nature
Anesthetic & hormone preparation -
1 Anesthetic bath - Finquel® (Tricaine) - chosen for its fast
action and quick recovery rate - 85mg per
liter = 10x85 = 0.85 grammes - Dissolved in 1 liter
of water and added to 9 liters of water to
produce the required solution for the anesthetic
bath.
2 Recovery bath - composed chiefly of identical water composition
to that of the holding tanks with
the addition of an oxygen injection system - Pure
Oxygen flowing over the gills speeds recovery
3 Hormone (test) - Ovaprim® - 1 female and 2 male's will be
receive an intramuscular injection of 20
microliters to the dorsolateral region using the
Kaycee fish injector, which will be set to 20
microliters.
4 Saline (control) - 1 female and 2 males will receive an
intramuscular injection of 20l to the
dorsolateral region using the Kaycee fish injector, which
will be set to 20 microliters.
Procedure -
Both the control and the test holding tanks will contain 1 female and 2 male's. This
ratio encourages the natural pairing process.
1. Begin with the control - Net one fish and place in the anesthetic bath. The effects
are rapid and so care must be taken to avoid over exposure which is indicated by a total
loss of equilibrium. ie fish losses its balance and cannot remain upright. Exposure should
only be enough to reduce movement and resistance 2. Make an intramuscular injection of
saline to the dorsolateral region
3. Immediately revive the specimen in the recovery bath. Gently rock the fish back and
forth to aid water/oxygen movement across the gills. Recovery is often rapid and is
indicated by a sudden burst of energy (care should be taken at this point to avoid injury
from the dorsal and pectoral spines).
4. Carefully return the specimen to the holding tank
5. Continue the process with the remaining specimens ensuring that control fish are
returned to the control holding tank and test (hormone injected) specimens to the test
tank The fish are now allowed to spawn naturally. The onset of spawning is not immediate
but may take up to 24 hours to start and a further 24 hours to be completed. Around 3000
eggs may be gained by one female using this process. The adults will relish the option of
eating the eggs and should therefore be removed soon after spawning. There should be no
spawning in the holding tank as S. angelicus has never spawned naturally in captivity. The
resulting fry may be donated to institutions undertaking conservational breeding
programmes.
Hazards -
Finquel®, tricaine, MS-222 -
Potential Hazards
Inhalation
May be harmful - Remove to fresh air. Contact doctor
Ingestion
May be harmful - Wash mouth out with water
Eye contact
Flush out with water for at least 15 minutes May be harmful
Skin contact
Immediately wash with soap and water May be harmfu
Solubility in water
Readily soluble
Stability
Stable
Flammable
No
Conditions and materials to avoid
Oxidisers
Control measures
---
Respiratory protection
Wear approved respirator
Protective clothing
Chemical resistant gloves
Eye protection
Tight fitting chemical safety goggles
Disposa
Use a licensed professional waste disposal service
Ovaprim® - Potential Hazards
Inhalation
May be harmful - Remove to fresh air. Contact doctor Ingestion
May be harmful - Wash mouth out with water
Eye contact
May be harmful - Flush out with water
Skin contact
May be harmful - Rinse with watre
Solubility in water
Miscible
Stability
Stable
Flammable
---
Conditions and materials to avoid
Oxidisers
Control measures
Use in ventilated areas
Respiratory protection
Wear approved respirator
Protective clothing
Chemical resistant gloves
Eye protection
Tight fitting chemical safety goggles
Disposal
Burn in chemical incinerator
Warning - Oxygen is highly combustible -
1 Absolutely no naked flames
2 Ensure adequate ventilation
3 Protect from extremes of temperature
4 Ensure regulator seal is intact
Cost (£) -
1 X2 130 liter glass tanks = 2x100
2 X2 plastic 10 liter containers 2 x 10 = 20
3 X1 Kaycee fish injector MK1 = 95
4 Finquel® (tricaine) = 35 per 1ml
5 Ovaprim® = 185 per Kg
6 Eheim professional = 110
7 3 liter oxygen cylinder + regulator = 45+
8 Specimens (excluding donations) = 6 x 55 = 330
9 Dechlorinator (500mls) = 12
10 Net = 1
11 X2 heaters = 2 x 20 = 40
Total = £ 1,073
Ethics -
Every possible measure will be considered to ensure that the specimens involved are
treated with the care and compassion which they deserve. All injections should be carried
out by a registered animal technician (Prof J. Lockheart) holding a current license. The
ultimate aim of this experiment is not to further scientific knowledge or for personal
gain but to illustrate an option which may help to perpetuate the species.
N.B - If the species used was still considered under C.I.T.E.S to be threatened (as it
once was) then a GN11 permit would be required for legal import. An article 30 (annex A)
document would also be required to work on threatened species
Bibliography -
Electronic journals -
1. Haniffa MA, Merlin T, Mohamed J (2000) Induced spawning of the striped Murrel Channa
striatus using pituitary extracts, human chorionic gonadotropin, Leutenising hormone
releasing hormone analogue and Ovaprim. Acta Ichthyologica et Piscatorial Vol 1, pp 53-60
(Available online at - http://www.aiep.pl/2000/pdf.gif)
[Accessed - 18/4/06]
2. Mijkherjee M, Praharaj A, Das S (2002) Conservation of endangered fish stocks
through artificial propagation and larval rearing techniques in West Bengal, India Office
of the deputy director of fisheries (Microbiology & Parasitology) (Available online at
-
3. Witte F (1997) The catfish fauna of Lake Victoria after the Nile perch upsurge.
Environmental Biology of Fishes, vol.49. (Available online at: http://www.springerlink.com/openurl.asp?genre=article&id=doi:10.1023/A:1007311708377)
[Accessed – 17/4/06]
Books -
Burgess WE, 1989, An atlas of freshwater and marine catfishes, A preliminary study of
the Siluriforms, NJ, United states, TFH publications inc
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