Backyard Aquaponics
A place to discuss aquaponics

breeding barra is a long term prospect. They change sex at about 5 years old and become female (all big barras are girls) (you have 250 little boys Monya)

250 boys, now that would be a handful.

So I guess in theory, if I kept a few till they were 5, they would be females, pair them up with some mature but younger men, then bam!

does anyone know at what age the males become sexually mature?

Er just prior to turning 5,................ from 18 months in captivity if your lucky longer in the wild.
That isn't too long to wait.
Bet u will be eating them in 6mths..
Have you done much/any smoked fish?
C1

Have never smoked fish, am a crumbed, bbq'd or baked man!

Mon, here's a little bit about barra sex!
(Some light reading)


3. BROODSTOCK DEVELOPMENT
Success of fish breeding depends primarily on the availability of mature brooders of high quality which produce high survival and fast growing fish. Normally it takes at least 3–4 years for a hatchery to have enough brood fish for the operation. The brood stock can be obtained either from the stock raising from the juvenile stage in ponds, netcages and/or caught from the wild.


5. SEX DETERMINATION
Sex of seabass can only be determined accurately in mature fish, even though the the fish has some dimorphic characters to enable sex determination. For seabass of the same age, males are generally smaller and with a more slender body and narrower body depth than the female. During the spawning season, the milt can be observed at the genital opening if slight pressure is applied on the abdomen of the mature male. The female can be recognized from the big soft round belly (Fig. 3) with the red-pink papilla extruding out at the urogenital aperture. If the female has a fully ripe egg, the egg will be visible when the abdomen is pressed by hand (Fig.4).


Fig. 3. Mature seabass brooder

{well the pix won't copy across}

6. STAGE OF MATURITY
In order to avoid using immature spawners, the potential female can be selected on the basis of egg size. The stages of maturity for male and female seabass are given in Table 3. Spawning takes place between stage V (fully ripe), and stage VI (spent).


Fig. 4 Checking the readiness of broodfish by pressing on abdomen of the fish

Table 3. Stage of gonodal development in seabass, Lates calcarifer.

Stage Female Gonadal condition male
I
Virgin Glassy, rounded and ¼ the body cavity in length Colorless thin strap lying along the blood vessel. One half body cavity in length.
II
Maturing virgin and recovering spent. Definite gonadal appearance. The same length as stage I Whitish and has assumed a definite gonadal appearance. The same length as stage I.
III
Developed gonad Yellowish and easily detectable as female. Ovary about ⅔ of body cavity. Whitish with gonadal appearance.
IV
Developing Fills half the body Eggs can be distinguished separately. Fills half the body cavity. Whitish.
V
Fully ripe Eggs are separate and fill the entire body cavity Milt fills the body cavity and can be expelled without difficulty White and sticky.
VI
Spent Ovary flaccid. May have some eggs remaining. Testes thin although not as flaccid as female. Some spawner may have the testes remain and fill to one half of body cavity.
VII
Resting Ovaries reddish and small. Easily confused with stage II. Identification under microscope may be necessary. Testes are small and thin. They are sharp viewed from the edge.

(Modified from Broadhead, 1953)

http://www.fao.org/docrep/field/003/AB8 ... 01.htm#ch6.

Interesting Jaymie, I think there's a lot of reading to do, but it certainly would be fantastic to be able to have your own hatchery

we did some of this stuff at college, squeezing the fish to see what stage they were up to

right click on photo
save as....... (Monya's fish educator)
open in ACDsee or similar and save as jpeg
then post picture

that's one way
ell

Table salt should be ok if it is not iodised. cheapest alternative.

marine salts will give you a greater range of trace elements while you're at it.

to smoke a fish which end do you light maybee steve can light one

was going to reply, but deviates like AM would take advantage of my answer

Got aquarium salt. On the packet it says never add to an aquarium that already has fish in it. Comments?

i use rock salt to hatch artemia, as that is supposed to be evaporated sea water with no treatment.... (it works well, and we use the same salt in salt grinders at my house)

Not sure about aquarium salt....

"Aquarium salt" is usually a mix of different "salts" including magnesium sulfate etc. etc. Used to condition the water to the right GH and the like.

Marine salt is a differnt thing, and would be fine to use as i mentioned earlier, although it may raise hardness too far.

I've always used rock salt.

hope it didn't cost you too much, stu.

if you dose it at even 1 PPT your GH will be OFF THE CHARTS.