Optimisation de la reproduction de la carpe commune (Cyprinus carpio) par aération et substrat innovant dans les hauts plateaux de Vakinankaratra, Madagascar.

Abstract

Cyprinus carpio fish farming in Vakinankaratra (1,405 hectares, 7,835 farmers) suffers from chronic hypoxia (dissolved oxygen 5.4 mg/l), limiting production to 3 million fry per year. This study tests 4 treatments on 20 tracked females (F1-F20) in 12 ponds (100 square meters, 4 treatments x 3 replicates, 3 sites) for 30 full days (day 1 spawning to day 30 larvae to day 14). Treatment T2 dominated with stable dissolved oxygen at 6.9 mg/l, fecundity of 188,000 eggs per female (32% higher). Consolidated production: 4,206,000 eggs to 2,103,000 fry on day 7 (105,000 per female, 70% higher versus T1 64,000). Correlations of dissolved oxygen (r = 0.67 to 0.71) and transparency (r = 0.61 to 0.68) explained 68% of the variance. Site C FIA amplified T2 (16% higher fecundity versus farmer sites). High-density T3 inhibited it (12% lower in all phases). A 30-day trajectory showed dissolved oxygen levels in T2 from 7.2 to 6.2 mg/l (14% lower) versus T1 from 6.2 to 4.0 mg/l (35% lower). These results surpass Malagasy standards (50,000 fry per female) and position Vakinankaratra as a model of resilient highland aquaculture.