Catfish

Question 1

what is the order of catfish for culture

Answer 1

Siluriformes

Question 2

name two catfish that we’re looking at

Answer 2

• Ictalurus fureatus: blue catfish

- Ictalurus punctatus: channel catfish

Question 3

3 sectors in the US industry

Answer 3

i) hatchery farms
ii) grow out (buy fingerlings and produce 0.5-1.5kg fish
iii) fee fishing ponds

Question 4

Vietnam cultures what kind of fish?

Answer 4

Pangasinodon hypophthalamus

Pangasius boucourti

Question 5

Europe cultures what kind of fish? for what?

Answer 5

wels, sheatfish.

• commercial, enhancement
• use to control excess reproduction in carp and trench ponds

Question 6

SE Asia and Africa cultures what fish?

Answer 6

• clarias. walking catfish
• tolerate extreme densities, breathe air
• fast growth 10-500g in 6 months
• fair food, good CE

Question 7

what fish does N.America culture?

Answer 7

• channel and blue : widely enhanced, big commercial

- Flathead catfish : Pylodictus olivaris. widely enhanced

Question 8

Blue catfish:

• scientific name **
• general facts

Answer 8

Ictalurus furcatus

• biggest in N.A
• 150lbs max
• poorer growth and survival in the 1st year
• few growers, 5% US production

Question 9

Channal Cats

• scientific name **
• general facts

Answer 9

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

Question 10

oxygen for catfish ponds

Answer 10

• 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

Question 11

4 steps of production cycle

Answer 11

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.

Question 12

3 spawning options for catfish

Answer 12

i) pond method
- most common
ii) pens spawning - in ponds or raceways
- selective breeding or hybrids
iii) aquaria
- small scale and research

Question 13

Brood care and selection

Answer 13

male fish mature at 2 years
female mature at 3 years
brood > 1.5kg up to 5kg

Question 14

2 methods of sexing catfish

Answer 14

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)

Question 15

where do you select your brood from for catfish?

Answer 15

from all in all out growout

males and females from different stocks

Question 16

where do you keep your catfish brood?

Answer 16

low density small pools

Question 17

what do you feed catfish brood?

Answer 17

35% protein, fed at 3% bw/d in summer and less in winter. forage fish

Question 18

low large are catfish brood ponds?

Answer 18

2-4ha

Question 19

what is the sex ratio for catfish brood?

Answer 19

60%female, 40% male

Question 20

female catfish egg production?

Answer 20

6500egg/kg

Question 21

survival rate for catfish eggs-to-swimup?

Answer 21

egg to swim up 60-70% survival

Question 22

suvival rate for catfish swim-up to fingerling?

Answer 22

60-70%

Question 23

describe catfish pond spawning methods

Answer 23

• 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

Question 24

describe catfish pen spawning method

Answer 24

• selective breeding
• pens 1x2m -1m deep
• frames 2x4 driven into bottom and mesh sides

Question 25

how do you induce catfish to spawn?

Answer 25

females 2 shots, males 1 shot 6-60mg carp pits/kg 1500 IU or HCG/kg 100ug LHRHa/kg

Question 26

incubation for catfish: - parental care? - days till hatch? - what temperature parameters dictate days till hatch? - ideal temp?

Answer 26

- males fan eggs. paddle wheel simulate. - also air stones and dipping eggs in and out of water. hatch in 5-10 days 22-23*C 10 days 28-30*C 5 days ideal 25-28*C

Question 27

when do fry button up?

Answer 27

3-5 days

Question 28

where are fry reared?

Answer 28

in troughs. reared 1-2 weeks then put in nursery pond

Question 29

what are fry fed?

Answer 29

salmon starter, 50%; 40-50% fish meal

Question 30

how often are fry fed?

Answer 30

every 2-4 hours, 24 hours a day

Question 31

fry to fingerling; - pond size - filled? - drainable?

Answer 31

- ponds usually small, 4-5ha. long and narrow, drainable - ponds filled with ground water, just before stockimg - undrainable ponds - eliminating insects and fish (??)

Question 32

how do you eliminate air-breathing insects?

Answer 32

1L motor oil + 20L diesel/ha, apply on calm day

Question 33

what do you use to kill fish in undrainable ponds?

Answer 33

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.

Question 34

when do you fill your pools for stocking?

Answer 34

at stocking to prevent macrophytes

Question 35

when do you fertilize pools?

Answer 35

at filling and 2-3 weeks after. establish phytoplankton shades macrophytes

Question 36

what are the general themes of stocking densities for catfish culture?

Answer 36

higher density = smaller fingerling produced. due to limits on feeding and resulting phytoplankton, oxygen decrease. look at the fry size to fry/ha ratio.

Question 37

what is the survival rate for fry to fingerlings?

Answer 37

50-80%

Question 38

what is the initial rate for feeding fry based on? what type of pellets? how much feed a day/ha?

Answer 38

pond size, not biomass. floating 20-30kg/ha/day

Question 39

what time of day should you feed fry/fingerlings? why?

Answer 39

morning, ends by mid-afternoon. O2 consumption due to digestion. max feeding 100kg/ha/day must have back up aeration

Question 40

name catfish fry/fingerling feed types.

Answer 40

- floating pellets - extruded - sinking pellets - steam pelleted - variety of sizes of crumbles - 6mm - fish meal not critical for 15cm or >

Question 41

what should catfish fry/fingerling feed include for protein?

Answer 41

protein most expensive ingredient . plants and animals. - protein must have all essential AA (9-10). animals cant synthesize - plant proteins lack lysine and methionine

Question 42

Protein supplements:

Answer 42

- fish meal - 60-80% proteins - 50% of catfish fry foods - 12% of fingerling foods - 0.8% of growout foods

Question 43

too much calcium will lead to what? what result will this cause in fish?

Answer 43

nephrocalcinosis. kidney stones. kill fish

Question 44

haemochromatosis is caused by too much of what?

Answer 44

too much iron. kidney disorder.

Question 45

name as many types of protein supplements as you can.

Answer 45

- 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

Question 46

name as many types of energy supplements as you can.

Answer 46

- corn grain and screenings - wheat grain - wheat middlings - animals and plant lipids - formulation

Question 47

what are the two types of growout ponds?

Answer 47

- all in and all out | - continuous cropping

Question 48

describe all in and all out growout.

Answer 48

-fish all harvested in fall and early winter -simple management inventory feed - all same size pellets drain ponds - eliminates problem disease, predators, competitors

Question 49

describe continuous cropping

Answer 49

- 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

Question 50

what are the problems with continuous cropping?

Answer 50

- 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

Question 51

what is the max amount of food you can feed in continuous cropping pond without aeration?

Answer 51

greater or equal to 40kg/ha/day

Question 52

what is the potential harvest per year?

Answer 52

20MT/pond/year

Question 53

describe the seine net used for harvest - size - net type - strand type

Answer 53

- 2x as wide and deep as pond - nylon net coated with tar - multiple strands 4-6 lb line

Question 54

how is the seine reel conducted?

Answer 54

- trailer mounted, pulled by tractors - 2 tractors - flat bottom skiff. - seine drain into inlet. - hold fish in live cart

Question 55

protocols for fish transport?

Answer 55

- fish starved 2 days or more - transport water cooler, often ice is used. - fingerlings sedated

Question 56

how do you predict the need for aeration?

Answer 56

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

Question 57

describe 'off flavor'

Answer 57

musty, mouldy, musky, earth flavor

Question 58

what is off flavor caused by?

Answer 58

geosmin + 2 methyl isoborneal (2-mib) | -produed by antinomycetes, cyanophytes

Question 59

what can be used to predict off flavor?

Answer 59

phytoplankton community

Question 60

how long does it take off flavor to dissipate?

Answer 60

7-21 days

Question 61

how do you prevent off flavour? (4)

Answer 61

i: minimize food near harvest ii: reduce feeding well before harvest in the summertime iii: have >1 pond to harvest iv: check fish