Clarias gariepinus Broodstock (Premature/Mature)

Description

Broodstock (broodfish) are mature fishes used in aquaculture for breeding purposes and are often used for replacement for, or enhancement of, seed and numbers.

As fish are generally cheap, rich in protein and high in macro and micronutrients, they are a recommended alternative to other meat sources. Thus, the need to increase fish seeds result in the development of artificial propagation by induced breeding.

This not only helps to develop a larger quantity of fish seed but help introduce newer and comparably superior strains by selective breeding and hybridization of the parent stock.

Clarias gariepinus and Heterobranchus sp. are the two commonly cultured clariid fishes in Nigeria with good commercial value. Their attributes include

• Rapid growth rate, high resistance to disease, tolerance to adverse environmental conditions, ability to feed on a wide range of feed and capacity to withstand harsh environmental conditions.

Broodstock management

This covers three particular aspects of the rearing process:

1. The selection of fish with desirable hereditary qualities
2. The selection of fish with well-developed sexual organs.
3. The rearing of these selected fish to produce healthy potential spawners, with dormant eggs well developed in the females.

Broodstock production ensures maximum fry output by controlling environmental conditions such as photoperiod, temperature, and pH in artificial or natural habitats. It is a profitable venture whereby fishes can be offered for sale and also used for personal production of fingerling/juveniles.

Prospective breeders-who are often a suitable market for broodstock purchases- are often advised to run grow-out and broodstock production alongside. This will ensure quality seed production, good reputation for future customers as well as multiple sources of income.

Tips for broodstock management

• Separate males and females while stocking as this helps facilitate regular assessment of their performance.
• Provide well-formulated protein-rich diet for selected broodstock to enhance production of quality eggs and spermatozoa. Readily formulated broodstock feed should be purchased.
• Do not overstock fishes in a pond.

Broodstock sexes

The male and female of the hybrid can be easily recognized. The males have distinct sexual papilla (elongated with red tip and located on the ventral aspect). This penile shaft is leaner when compared with the H. longifilis broodstock males. A sexually primed female has a swollen, usually reddish genital opening. Gentle pressure on the belly (of a viable female) towards the genital opening releases the ripe eggs.