Transcript Hybrid Striped Bass: Spawning Dr. Craig Kasper Hillsborough Community College FAS 1012 Aquaculture General Production • Intensive & Extensive • Enhancing Phase-I Fish • Ensuring Quality Products.

Hybrid Striped Bass:
Spawning
Dr. Craig Kasper
Hillsborough Community College
FAS 1012
Aquaculture
General Production
• Intensive & Extensive
• Enhancing Phase-I Fish
• Ensuring Quality Products
Morone spp.:Reproduction
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•
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Broodstock
Egg maturation
Fry management
Fingerlings
HSB: Broodstock
• Wild adults collected by electrofishing or angling.
• Spring spawning (55-68ºF.)
• hormones used
♀-IM 330 IU hCG/kg bwt.
♂- only 150 IU hCG/kg bwt.
Culture of Hybrid Striped Bass
In the U. S.
Striped Bass ( Morone saxatilis )
Popular sport fish caught in U. S. marine coastal waters
Distribution of Striped Bass in U. S.
Life History
Predacious
Food habits -
Reproduction - Lives in saltwater but spawning is
in freshwater ( anadromous ).
Migrates up coastal rivers in the
Spring. Several land-locked
populations are established in
U.S. Males and females reach
sexual maturity in 3 years and 4
years, respectively. Life span is 30
to 40 years.
Growth Reaches 32 kg in ocean
Commercial Fishery – Striped bass is a prized sport and
food fish. The commercial catch dropped from 15 million
lb in 1973 to less than 1 million lb in 1989. Presently, the
commercial catch is about 6 million lb/yr. Sport and
commercial fisheries are heavily regulated. Fingerling
stocking programs into fresh and salt water began in the
early 1970’s
White Bass ( Morone chrysops )
Life History
Food habits – predacious
Growth – 4 to 5 lb in freshwater lakes
Reproduction – Lives and spawns in fresh water.
Migrates up rivers and streams to shoal areas in Spring
to spawn. Males and females reach sexual maturity in 2
and 3 years, repectively. Life span is 5 to 6 years.
Distribution of white bass in U. S.
How to distinguish among striped, white and hybrid basses
Hybrid Striped Bass
Palmetto bass – Striped bass female x white bass male
Original cross first performed in the mid 1960’s
Sunshine bass – Striped bass male x white bass female
Both hybrid crosses are stocked into fresh waters to
improve sport fishing. Both crosses are fertile and will
reproduce in natural waters with adequate spawning
habitat. The sunshine bass is the most widely cultured
hybrid because it is easiest to produce fingerlings.
Hybrids are better for culture than striped bass because
they are more resistant to handling and warm water
temperatures in culture units. Hybrids grow faster than
white bass and will reach 20 lbs in natural waters.
Water quality for hybrid striped bass
Water temperature – 1 to 33o C; optimum for growth is 25 27oC
Salinity – 0 to 25 ppt
Dissolved Oxygen – optimum is 6 – 12 mg/l; can withstand 1
mg/l for short periods
Alkalinity and Hardness – grow best in waters above 100 mg/l
pH – 7.0 to 8.5 ideal
Salt is added to
freshwater with
low cloride ion
concentration to
improve growth
and survival
Reproduction in Captivity
Spawning water temperatures – 15 to 21oC
Obtaining broodfish
White bass – Some domestigated stocks but most are
captured from the wild with nets and hook and line.
Striped bass – Domestigated brooders not available,
all are captured from the wild. Only state and federal
agencies can use nets and electrofishing. Private producers
must catch brooders by hook and line and transport them to
the hatchery.
HSB: Egg Collection & Staging
• Sampling begins 16 hrs. post inject.(3 mm o.d. cath.)
•
• Check @ 2 hr intervals (narrow window)
-2 hr sb, 0.5 hr wb
•Look at eggs microscopically
- eggs = blood-free, oil droplet
coalesced (transparent)
& chorion intact
- eggs will be brownish
Bottom line...frequent all nighters!!
HSB: Stripping/Fertilization
• Wet method
-strip eggs into metal pan with H2O
-add milt (sperm)
-sperm is activated by salinity
shock due to water exposure
•Dry method
-strip eggs, add sperm,
stir eggs (turkey feather)
-add water
Striped bass eggs
shortly after fertilization
prior to cell division.
HSB: Incubation/Hatching
• Eggs are sticky (good in wild, but <fucundity)
-Add bentonite or tannic acid
• Incubate in MacDonald Jars/100K eggs/jar
• Continuous flow of O2 water
•2-4 days = hatch
• Fry “swim-up” and into traugh
•Stock @ 4 days post-hatch (250K/ha)
Future: Physiology and Biochemistry
• Broodstock
• Determination of Essential Fatty Acids (EFA)
• Egg Quality
• Fry Survivability
• Phase-I, II, III Fishes
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EFA’s
Isoflavones
α-Tocopherol
Phosphatidylcholine
• Metabolism
Spawning – Males and females are
injected with hormones to obtain
eggs and sperm. Eggs can be
checked to determine if they are
ripe and ready for fertilization.
Spawning - Eggs are stripped
from females and mixed with
sperm from the males. White
bass eggs are adhesive and must
be treated to remove
adhesiveness before placement in
incubators. Striped bass eggs are
non-adhesive and need no
treatment.
Egg incubation –
McDonald jars are used to
incubate the eggs. Eggs
hatch in 40 to 48 hr after
fertilization in 15 to 18o C
water. Fry begin to feed 4 to
8 days after hatch. Fry are
about 1mm at hatch.
Nursery Phase
First food:
Palmetto bass – large zooplankton
( daphnia )
Sunshine bass – small zooplankton
( rotifers )
Ponds must be carefully filled and fertilized to prepare the
proper food organizm for the type of hybrid fry stocked
Stocking rate – 250,000 to 500,000/ha
Nursery Phase
Survival to 35 to 50 mm in 3 to 4 weeks of culture:
Palmetto bass – 40 to 50 %
Sunshine bass – 10 to 25 %
Feed training:
In ponds – Crumbled feed can be fed to 14 to 21 day-old
fingerlings. Bass will learn to eat feed.
In tanks – Remove 4 week-old fingerlings from ponds
and stock them at high densities in tanks
receiving flowing
water. Feed them nutritionally complete
crumbled diets.
Growout Phase I
Grading – fingerlings must be graded to reduce cannibalism
before stocking.
Stocking density – 20,000 to 50,000/ha in earthen ponds
Feeding – Bass are feed a 40 % protein floating diet 1 to 3
times/day starting a 5% body weight/day, reduced to 3 %/day
as the bass grow.
Harvest – Bass are harvested in the winter
when water temperatures a cold. Survival is
85% and average weight is 125 to 225 g.
Growout Phase II
Stocking – Bass are graded and stocked at 3,000 to
4,000/ha into earthen ponds.
Feeding – Bass are fed 1 to 3 % body weight daily
with a
40 % protein floating diet.
Harvest – Bass reach 1.25 to 1.5 lb with a survival
of
90 % by October - November.
Yields – 4,000 to 5,000 kg/ha with aeration. 55%
of the
hybrid striped bass harvest in the U.
S. are
grown in ponds.
Growout Phase II
Hybrid striped
bass are also
grown in tanks at
high density
45 % of the hybrid
striped bass harvested in
the U. S. are from tanks
Markets - 1999
Live – 11 % of U. S. harvest is marketed live as
food fish or for fee fishing. Price to farmers is $3.30/lb (
$ 7.26/kg ).
Fresh – 89 % of U.
S. harvest is sold
whole on ice. Price
to farmers is
$2.53/lb
Constraints
1. Competition from striped bass commercial
fishery
2. High cost of production; high market price
3. Difficulty obtaining broodfish
4. Legal restrictions to sell cultured hybrid
striped bass in many states because it is
considered a sport fish. Each fish must be
individually tagged.
U. S. harvest - 1999
Weight - 9.7 million lbs
(4.4 million kg )
Value - $28 million
Hybrid striped bass is
5th in weight of food
fish harvested in the
U. S.
THE END