gonad maturity determination in the field practice

when we practice about fish breeding, we learn how to identifying and selecting of fish gonad maturity. the best technique for this kind based on nucleus migration. egg should be taken using intra ovarian biopsy by canulator or flexible tube. after immersed in serra/clearing solution for 3-5 minutes, nucleus migration could be observed under microscope. usually, nucleus position uniformity of 80% used as reference for gonad maturity judgment.

other way, we might measure eggs diameter under microscope completed with micrometer. compared to eggs diameter standard (different in each species), we could to determine of gonad maturity.

in the field practice, serra solution and microscope often un-available. So, we couldn’t use both nucleus migration and measured eggs diameter. in the point of view aquaculture dissemination to small scale fisherfolk, it’s important to introduce of practical method to judgment of gonad maturity which representative for fish breeding.

using flexible tube (feeding tube that available for human), eggs might be taken by intra ovarian biopsy. it’s easy but should be carefull. instead observed under microscope, eggs spread on hand and estimate of eggs diameter uniformity, direct visually (fortunately, most of tropical people have dark color in hand, so easier to observe eggs).

if most eggs (about 80%) seen uniform (independent from how width eggs diameter), gonad has be mature and ready to breed. if there are transparant eggs (estimate up to 20%), gonad has be over-ripe. and if there are too many small eggs (estimate up to 20%), gonad has been growing. brooder with over-ripe or growing eggs should not be used for breeding. in the case of over-ripe, usually easy to strip for eggs release but low in fertilization/hatching rate. and growing eggs, usually failure in eggs discharge or, if released, low in fertilization hatching rate.

note: thanks to aquaculture officer in Fish Seed Center of Gorontalo Province that warmly collaborate to practice of siamese catfish breeding. good luck to you!

juragan@9300i.gto

3 thoughts on “gonad maturity determination in the field practice”

  1. How are u juragan….
    Juragan Sunarma, i just want to ask u? what is a feeding tube (maybe a sample in indonesian language). Because i don’t know?
    Can we applied it for fish with a little size? Because it is really hard to take some eggs from fish with a little size.
    Just to make sure about gonad maturity, if we just look at its abdomen, can we conclude that the fish is already reach its sexual maturity by just looking at its abdomen (by defining sexual stages, stage 1, 2 etc)?

    Thank u

    in several area, feeding tube known as “selang sonde” but it may different in different drug store. depend on brooder size, feeding tube could be use in most of ‘consumption’ fish brooder. in smaller brooder, like ornamental fish, you should to try it using different size of feeding tube.
    as long as my experience, sexual stage couldn’t identified using visual observation of abdomen.

  3. Mohon bantuan juragan.
    Biopsi dengan cateter untuk lihat perkembangan oosit dan memasukkannya ke larutan serra memang teknik akurat untuk persiapan penyuntikan ikan. namun saya mengalami kesulitan pemakaian larutan serra untuk melihat inti dari telur ikan Tor soro, belida dan gurame. apakah juragan punya pengalaman dalam membuat komposisi serra dari yang biasa yaitu (alkohol 60: formalin 30 : asetic acid 10) karena dengan larutan tersebut inti dari telur ikan-ikan tsb tetap tidak dapat di lihat.
    terimakasih

    Sejauh ini Saya menggunakan serra dengan komposisi yang sama seperti itu dan belum mencoba penggunaan serra dengan komposisi lain. Karena itu, Saya menggunakan pendekatan keseragaman sebaran diameter telur untuk penentuan kematangan induk.

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