To help improve knowledge of African freshwater clams in the wild, the ecology, growth and reproduction of the endogenous clam Galatea paradoxa (Bruguière, 1797) were studied in the lower Sanaga river (LN: 3 ° 14 ’- 3 ° 50’ and LN: 9 ° 34 ’- 10 ° 03 ’) in Cameroon. A total of 4095 clams were collected monthly from March 2018 to March 2019 in Bolounga-Moulongo, Mpombo-Boloy and Maldjedou-Bonapembe. Physico-chemical characteristics and the chlorophyll a of water; the particle size of the substrate; the phaneroptic characteristics and morphological measurements of clam were taken in situ and in the laboratory, then evaluated. A significant variation (p˂0.05) was observed in the main physical characteristics: TDS (19.0 ± 3.5 ppm), temperature (29.6 ± 1.7 °C), conductivity (35.0 ± 6.8 µs/cm) and chemical (mg/l): phosphate (2.3 ± 1.9), nitrate (13.6 ± 5.6), calcium (2.8 ± 2.2), and chlorophyll a (1.03 ± 0.94). The proportion of sand (89.5 ± 12.7%) predominated over that of clay (6.9 ± 7.0%) and silt (3.6 ± 6.2%) in all sites. Bolounga-Moulongo and Mpombo-Boloy have similar habitat characteristics but different from those of Maldjedou-Bonapembe, which influenced the biological characteristics. In fact, almost all the growth parameters were influenced by sites and seasons (p˂0.05). Bolounga-Moulongo and Mpombo-Boloy were very close by their growth characteristics while Maldjedou-Bonapembe differed from the other two by the values of its higher biometric and bromatological characteristics. Reproductive characteristics varied depending on site and period (p˂0.05). Five stages of maturation were observed in both males and females with 36 mm and 40 mm respectively as size at sexual maturity (L50). These clams are gonochoric with protandrous hermaphroditism, sex ratio in favor of females and significantly influenced (p˂0.001) by period and site. The mode of reproduction is iteroparous with asynchronous oogenesis with the emission of gametes between May and November. The results of this study may contribute to the development of a domestication program and sustainable management measures of Galatea paradoxa.
Key words: ecology, growth, reproduction, Galatea paradoxa, lower Sanaga, Cameroon