Association silure africain-tilapia : polyculture ou contrôle de la reproduction ?

Abstract

The use of police fish in tilapia culture for controlling overpopulation is nowaday an increasing practice by African fish farmers. Data from mixed Clarias gariepinus -0reoc.hromis niluticus culture show that a large amount of Clarias gariepinus is required in order to control totally the reproduction of initially stocked O. niloticus fingerlings for market size production and, morcover, C. gariepinus is a competitor versus the available food in the pond (both artificial and natural). In ordcr to control a 1200 0. niloticus (males and females) population in 10-are ponds, 260 C. gariepinus of individual mean weight over 150 g are required. In addition, growth (and yield) of tilapias is reduced compared with a polyculture using a strictly ichthyophagous fish such as Hemichromis fusciatus. These data, confirmed with another African catfish, Heterohranchus isopterus, lcad to advisc in Côte d'Ivoire the polyculture using 3 species: 0. niloticus, a strictly police fish (Hemichromis fasciatus or Parachanna obscura) and a catfish, H. isopterus which is aimed, not at controlling the reproduction of tilapia, but at contributing to the final yield, in quality and quantity. Another species of catfish Heterobranchus, H. longijilis, has too high a growth rate for such purpose: it feeds on tilapia and police fish stocked fingerlings. Yields of H. isopterus can reach 1 t.ha-'..year-l with an average individual weight of 500 g after a 6 month culture cycle. Based on these data, obtained on a large scale basis, this type of polyculture has already been developed in Côte d'Ivoire and appears to be a good mode1 for African fishculture.

La pisciculture des tilapias

“…Concernant la production de chair, cette prolificité constitue, en revanche, un handicap majeur pour l'élevage en étangs, car elle y conduit à une surpopulation et à un nanisme, et donc à une production de médiocre qualité (nombreux individus de petite taille). Deux techniques sont aujourd'hui largement utilisées pour y remédier : l'association d'un prédateur à la phase de grossissement (Lazard et Oswald, 1995) et le monosexage (élevage de populations monosexes mâles, les mâles ayant, en outre, une croissance en moyenne de 50 % supérieure aux femelles). L'élevage en cage ou en enclos ne présente pas cet inconvénient (ponte impossible sur le fond en filet des cages ou fuite des alevins en dehors du périmètre des enclos) mais pour des raisons de productivité, l'élevage monosexe est aujourd'hui devenu la règle.…”

Case study of innovations in commercial West African family fish farming that led to an ecological intensification

“…To fill in this analysis grid, we compare the additional contributions of the three innovations to the fish farming in dam pond. The considered initial situation is the one that preexisted in rural areas: dam ponds with little or no feed with a surplus tilapia population and some catfish, mostly Heterobranchus isopterus (Lazard and Oswald, 1995;Oswald, 2015). The factual elements from all the collected information were used, with particular attention paid to the producers' perceptions, in order to understand what motivated their choice Table 1.…”

Tilapia polyculture: a global review

“…(), 19 Da Silva et al . (), 20 Fischer and Grant (), 21 Lazard and Oswald (), 22 Shrestha et al . (), 23 Tahoun et al .…”

“…Another model for the production of Nile tilapia in mixed sex and all-male polyculture, with a predator (African catfish, Clarias gariepinus or African snakehead, Parachanna obscura), has been developed in African countries (de Graaf, Dekker, Huisman & Verreth 2005). African catfish was a competitor for the available food in the pond and large numbers of African catfish were required to control the reproduction of Nile tilapia fingerlings (Lazard & Oswald 1995). In Nepal, sahar (Tor putitora) was cultured with Nile tilapia to control recruitment.…”

“…Increased total production6 , 7 Minor species Prawn Principal species Shrimp Controlled luminous bacteria 8,9,10 Reduced phytoplankton biomass, improved the water quality 11,13,14 Higher shrimp production 12,13 Minor species Tilapia (2000), 6 dos Santos and Valenti (2002), 7 Uddin, et al (2007a) and Uddin, et al (2007b), 8 Tendencia et al (2004), 9 Tendencia (2003, 10 Tendencia et al (2006), 11 Sun et al (2011), 12 Li and Dong (2002), 13 Akiyama and Anggawati (1998), 14 Wang et al (1998), 15 Brummett and Alon (1994), 16 Ponce-Marb an et al (2006), 17 Papoutsoglou et al (1992), 18 Papoutsoglou et al (2001), 19 Da Silva et al (2008), 20 Fischer and Grant (1994), 21 Lazard and Oswald (1995), 22 Shrestha et al (2011), 23 Tahoun et al (2013), 24 Cruz and Laudencia (1980), 25 Xu (2013). species, stocking rates, input types and rates, and other management strategies according to different local conditions: climate, quality of water supply and pond fertility, availability of fish fry and fingerlings, availability of feeds and fertilizers, and market requirements.…”