Catfish Flashcards
what is the order of catfish for culture
Siluriformes
name two catfish that we’re looking at
- Ictalurus fureatus: blue catfish
- Ictalurus punctatus: channel catfish
3 sectors in the US industry
i) hatchery farms
ii) grow out (buy fingerlings and produce 0.5-1.5kg fish
iii) fee fishing ponds
Vietnam cultures what kind of fish?
Pangasinodon hypophthalamus
Pangasius boucourti
Europe cultures what kind of fish? for what?
wels, sheatfish.
- commercial, enhancement
- use to control excess reproduction in carp and trench ponds
SE Asia and Africa cultures what fish?
- clarias. walking catfish
- tolerate extreme densities, breathe air
- fast growth 10-500g in 6 months
- fair food, good CE
what fish does N.America culture?
- channel and blue : widely enhanced, big commercial
- Flathead catfish : Pylodictus olivaris. widely enhanced
Blue catfish:
- scientific name **
- general facts
Ictalurus furcatus
- biggest in N.A
- 150lbs max
- poorer growth and survival in the 1st year
- few growers, 5% US production
Channal Cats
- scientific name **
- general facts
Ictalurus punctatus
- identify by black spots
- up to 50lb
- no reproduction in culture
- easy spawning
- do well on pellets
- good CE
- high densities
- good disease tolerance
oxygen for catfish ponds
- 1-5ppm survive but grow poorly and dont spawn
- P.L (protection level) >5ppm
- Alkalinity - 50-400ppm
- Ca+2 10-160ppm
- iron <103%
- Temp 25-32*C ideal
4 steps of production cycle
i) spawn - spring and early summer
ii) fry stocked into nursery ponds, grow over summer and fall. Grade and over winter
iii) fryinto grow out in spring
iv) grow over summer and erarly fall, harvest in fall and early winter.
3 spawning options for catfish
i) pond method
- most common
ii) pens spawning - in ponds or raceways
- selective breeding or hybrids
iii) aquaria
- small scale and research
Brood care and selection
male fish mature at 2 years
female mature at 3 years
brood > 1.5kg up to 5kg
2 methods of sexing catfish
i) body confirmation (males bigger, wider heads, slim body at spawning. females narrower heads, and swollen body)
ii) UG openings: (males: sperm and urinary opening are the same, have UG papillae. females: separate urinary and genital openings in cleft or slit)
where do you select your brood from for catfish?
from all in all out growout
males and females from different stocks
where do you keep your catfish brood?
low density small pools
what do you feed catfish brood?
35% protein, fed at 3% bw/d in summer and less in winter. forage fish
low large are catfish brood ponds?
2-4ha
what is the sex ratio for catfish brood?
60%female, 40% male
female catfish egg production?
6500egg/kg
survival rate for catfish eggs-to-swimup?
egg to swim up 60-70% survival
suvival rate for catfish swim-up to fingerling?
60-70%
describe catfish pond spawning methods
- fish choose own mate
- must have spawning container
- container spaced 2-10m; shallow water
- 1 container/2-3 males
- marked with float or stake
- check every 3-4 days
- eggs removed and taken to hatchery
describe catfish pen spawning method
- selective breeding
- pens 1x2m -1m deep
- frames 2x4 driven into bottom and mesh sides
how do you induce catfish to spawn?
females 2 shots, males 1 shot
6-60mg carp pits/kg
1500 IU or HCG/kg
100ug LHRHa/kg
incubation for catfish:
- parental care?
- days till hatch?
- what temperature parameters dictate days till hatch?
- ideal temp?
- males fan eggs. paddle wheel simulate.
- also air stones and dipping eggs in and out of water.
hatch in 5-10 days
22-23C 10 days
28-30C 5 days
ideal 25-28*C
when do fry button up?
3-5 days
where are fry reared?
in troughs. reared 1-2 weeks then put in nursery pond
what are fry fed?
salmon starter, 50%; 40-50% fish meal
how often are fry fed?
every 2-4 hours, 24 hours a day
fry to fingerling;
- pond size
- filled?
- drainable?
- ponds usually small, 4-5ha. long and narrow, drainable
- ponds filled with ground water, just before stockimg
- undrainable ponds - eliminating insects and fish (??)
how do you eliminate air-breathing insects?
1L motor oil + 20L diesel/ha, apply on calm day
what do you use to kill fish in undrainable ponds?
Rotenone: 1mg/L most fish. dont stock 2-3 wks.
Chlorine Bleach: sodium hypochlorite, 10mg/L. stock in 2-3 days
Fintrol: antimycin A. 5-10ppb. far less toxic to catfihs.
when do you fill your pools for stocking?
at stocking to prevent macrophytes
when do you fertilize pools?
at filling and 2-3 weeks after. establish phytoplankton shades macrophytes
what are the general themes of stocking densities for catfish culture?
higher density = smaller fingerling produced. due to limits on feeding and resulting phytoplankton, oxygen decrease.
look at the fry size to fry/ha ratio.
what is the survival rate for fry to fingerlings?
50-80%
what is the initial rate for feeding fry based on?
what type of pellets?
how much feed a day/ha?
pond size, not biomass.
floating
20-30kg/ha/day
what time of day should you feed fry/fingerlings? why?
morning, ends by mid-afternoon. O2 consumption due to digestion. max feeding 100kg/ha/day must have back up aeration
name catfish fry/fingerling feed types.
- floating pellets - extruded
- sinking pellets - steam pelleted
- variety of sizes of crumbles - 6mm
- fish meal not critical for 15cm or >
what should catfish fry/fingerling feed include for protein?
protein most expensive ingredient . plants and animals.
- protein must have all essential AA (9-10). animals cant synthesize
- plant proteins lack lysine and methionine
Protein supplements:
- fish meal
- 60-80% proteins
- 50% of catfish fry foods
- 12% of fingerling foods
- 0.8% of growout foods
too much calcium will lead to what? what result will this cause in fish?
nephrocalcinosis. kidney stones. kill fish
haemochromatosis is caused by too much of what?
too much iron. kidney disorder.
name as many types of protein supplements as you can.
- fish meal
- meat and bone meal
- blood meal
- catfish offal meal
- poultry by-product meal
- hydrolized feather meal
- solvent extracted by soy bean meal
- solvent extracted cottonseed meal
- distillers dried grains and solubles
- canola meal
name as many types of energy supplements as you can.
- corn grain and screenings
- wheat grain
- wheat middlings
- animals and plant lipids
- formulation
what are the two types of growout ponds?
- all in and all out
- continuous cropping
describe all in and all out growout.
-fish all harvested in fall and early winter
-simple management
inventory
feed - all same size pellets
drain ponds - eliminates problem disease, predators, competitors
describe continuous cropping
- start like all in and all out
- 1st harvest graded fish (biggest), replace w fingerlings
- repeat every 2 months
- produces year round harvest and continuous cash flow
- ponds at max density increase standing crop
what are the problems with continuous cropping?
- pond not drainable
- no disease predator control
- feeding complicated and different pellets, poor inventory
- poor source of brood
- stocking ocntrolled by amount you can feed
- feeding controls oxygen
what is the max amount of food you can feed in continuous cropping pond without aeration?
greater or equal to 40kg/ha/day
what is the potential harvest per year?
20MT/pond/year
describe the seine net used for harvest
- size
- net type
- strand type
- 2x as wide and deep as pond
- nylon net coated with tar
- multiple strands 4-6 lb line
how is the seine reel conducted?
- trailer mounted, pulled by tractors
- 2 tractors
- flat bottom skiff.
- seine drain into inlet.
- hold fish in live cart
protocols for fish transport?
- fish starved 2 days or more
- transport water cooler, often ice is used.
- fingerlings sedated
how do you predict the need for aeration?
occurs at night
take O2 samples at dusk, 2 hours later, 2 hours later again.
-plot [O2] vs time
»> plot this. look at example in notes
describe ‘off flavor’
musty, mouldy, musky, earth flavor
what is off flavor caused by?
geosmin + 2 methyl isoborneal (2-mib)
-produed by antinomycetes, cyanophytes
what can be used to predict off flavor?
phytoplankton community
how long does it take off flavor to dissipate?
7-21 days
how do you prevent off flavour? (4)
i: minimize food near harvest
ii: reduce feeding well before harvest in the summertime
iii: have >1 pond to harvest
iv: check fish
