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AHYAUD1N B. ALI

ton unsuitable as larval lood (Hashim and Ali 1989).

This essentially restricts catfish seed produc-tion toareasclose to Moinaiarms toensureavaila-bility of fresh zooplankton. However, by utilizing production ponds to raise fish fry to suitable stock-ing size, we should be able to solve zooplankton availability problem and optimize pond use through integration. Catfish larvae which require live zooplankton as initial exogenous food, can be held over in suitable mesh-size hapas in production ponds to takeadvantage of the zooplankton popu-lation. Largerfrycan begrown to marketable size with commercial food _twhereasexcess and uneaten food provides nutrient for zooplankton popula-tions which can then be utilized bysmaller-size fry. Thus by utilizing the different feeding habits be{-ween the recently hatched and larger fry, and intergrating the same ponds for both seed and maket-size fish production, farmerscan optimise pond use and obtain extra money through the sale of catfish seed.

However, this production technique requires proper pond management as well as the under-standingof the dynamicsof zooplankton commu-nities in ponds. The dynamics observed in this study, resulted from the competition and pre-dation among the zooplankton,other invertebrates such as insects, and fish. Management of zooplankton communities by eradicating potential competi-tors and predators such as insects by using dylox (masoten), dipterex or diesel fuel-motor oil could result in greater abundance of the morę desired zooplankton speciessuch as rotifers and cladocer-ans (McCraren and Phillips 1977;Opuszynski etal. 1984).Thusfurtherstudiesare needed on this type of catfish farming integration, especially on pond management to produce desirable zooplankton for catfish fry.

ACKNOWLEDGEMENT

This study was supported by a Universiti Sains Malaysia Short I erm Research Grant and research facilitieswere provided by theSchoolof Biological Sciences. The help and cooperation of pond owner, En. Ahmad Idrusisgratefullyacknowledged.

AHYAUDIN B. ALI

School of Biological Sciences

Universiti Sai ns Malaysia

*

11800Minden_t Penang, Malaysia

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PERTANIKA VOL. 14 NO.l, 1991