The reproductive biology of the Kapenta (Limnothrissa miodon), that supports the main commercial ... more The reproductive biology of the Kapenta (Limnothrissa miodon), that supports the main commercial fishery in Lake Cahora Bassa (Mozambique) was investigated using monthly samples collected during 2003 and 2004. This species was initially introduced in Lake Kariba in 1967/68 with the objective of filling up the pelagic environment that was created with dam closure. The fish is believed to have been able to negotiate the Kariba dam wall and became established in Cahora Bassa, some 250 km downstream, as well. The reproductive biology of Kapenta is known from Lake Tanganyika, where it is indigenous, and from Kariba, but no research has been performed, so far, in Cahora Bassa. Since many important biological attributes may vary from place to place, depending on the local environmental factors, it was thought important to investigate and compare the reproductive biology in Cahora Bassa. Samples of about 250 g of fish (approximately 150 individuals) were taken each sampling day and preserved in 10% formalin. Once in the laboratory, individual weight (in grams) and fork length (in mm) were measured. Then the fish was dissected for macroscopic assessment of the gonads. The results indicate that this species matures at 39 mm, which is less than half of its size at maturity in Lake Tanganyka and Kivu, but comparable to findings made in Lake Kariba. The reproduction seasonality was assessed through analysis of percentage of mature individuals and gonadossomatic index. As in Lake Kariba, Kapenta seem to reproduce year around, but peaks of reproduction were observed from December to January.
The distribution and diet of the elephants of the Maputo Elephant Reserve were studied using dung... more The distribution and diet of the elephants of the Maputo Elephant Reserve were studied using dung counts, satellite tracking and faecal analysis. The results were compared with earlier data from before the civil war in Mozambique. The elephant population decreased during the civil war, but 180 animals still remain. Earlier studies described the elephants as preferring the grass plains. Currently, the elephants prefer the dense forest patches over the high quality forage found in the grass plains. Water salinity affected distribution; elephant dung piles were found closer to fresh water in the dry season. A total of 95 different plant species were identified in the faeces. The percentage of grass was relatively low compared with other studies, increasing at the beginning of the rainy season. At the end of the dry season, elephants concentrated on the few available browse species with young leaves, but generally preferred grass species to browse species. Diet composition was mainly affected by season and less by habitat. The elephants have changed their habitat preference in reaction to poaching, and probably increased the contribution of browse species in the diet. The presence of forest patches has been vital for the survival of the elephants.RésuméOn a étudié la distribution et le régime alimentaire des éléphants de la Réserve áéléphants de Maputo en utilisant le comptages des crottes, le tracking par satellite et l'analyse des excréments. On a comparé les résultats avec des données recueillies avant la guerre civile au Mozambique. La population d'éléphants a baissé pendant la guerre civile mais il reste 180 animaux. Des études antérieures montraient que les éléphants préféraient les plaines herbeuses. Actuellement, ils préfèrent les ı^lots de forêt dense au fourrage de haute qualité qui se trouve dans les plaines herbeuses. La salinité de l'eau modifie la distribution; on trouvait les crottes d’éléphants plus près de l'eau douce en saison sèche. On a identifié un total de 95 espèces végétales différentes dans les excréments. Le pourcentage d'herbes était relativement bas par rapport aux études antérieures, il augmentait au début de la saison des pluies. A la fin de la saison sèche, les éléphants se concentraient sur les quelques espèces de buissons comestibles ayant des jeunes feuilles, mais ils préféraient généralement les espèces herbeuses aux buissons. La composition du régime était surtout affectée par la saison et moins par l'habitat. Les éléphants ont changé leurs préférences en matière d’habitat en réaction au braconnage et ont sans doute ainsi augmenté la contribution des espèces buissonnantes dans le régime alimentaire. La présence des ı^lots forestiers a été vitale pour la survie des éléphants.
The reproductive biology of the Kapenta (Limnothrissa miodon), that supports the main commercial ... more The reproductive biology of the Kapenta (Limnothrissa miodon), that supports the main commercial fishery in Lake Cahora Bassa (Mozambique) was investigated using monthly samples collected during 2003 and 2004. This species was initially introduced in Lake Kariba in 1967/68 with the objective of filling up the pelagic environment that was created with dam closure. The fish is believed to have been able to negotiate the Kariba dam wall and became established in Cahora Bassa, some 250 km downstream, as well. The reproductive biology of Kapenta is known from Lake Tanganyika, where it is indigenous, and from Kariba, but no research has been performed, so far, in Cahora Bassa. Since many important biological attributes may vary from place to place, depending on the local environmental factors, it was thought important to investigate and compare the reproductive biology in Cahora Bassa. Samples of about 250 g of fish (approximately 150 individuals) were taken each sampling day and preserved in 10% formalin. Once in the laboratory, individual weight (in grams) and fork length (in mm) were measured. Then the fish was dissected for macroscopic assessment of the gonads. The results indicate that this species matures at 39 mm, which is less than half of its size at maturity in Lake Tanganyka and Kivu, but comparable to findings made in Lake Kariba. The reproduction seasonality was assessed through analysis of percentage of mature individuals and gonadossomatic index. As in Lake Kariba, Kapenta seem to reproduce year around, but peaks of reproduction were observed from December to January.
The distribution and diet of the elephants of the Maputo Elephant Reserve were studied using dung... more The distribution and diet of the elephants of the Maputo Elephant Reserve were studied using dung counts, satellite tracking and faecal analysis. The results were compared with earlier data from before the civil war in Mozambique. The elephant population decreased during the civil war, but 180 animals still remain. Earlier studies described the elephants as preferring the grass plains. Currently, the elephants prefer the dense forest patches over the high quality forage found in the grass plains. Water salinity affected distribution; elephant dung piles were found closer to fresh water in the dry season. A total of 95 different plant species were identified in the faeces. The percentage of grass was relatively low compared with other studies, increasing at the beginning of the rainy season. At the end of the dry season, elephants concentrated on the few available browse species with young leaves, but generally preferred grass species to browse species. Diet composition was mainly affected by season and less by habitat. The elephants have changed their habitat preference in reaction to poaching, and probably increased the contribution of browse species in the diet. The presence of forest patches has been vital for the survival of the elephants.RésuméOn a étudié la distribution et le régime alimentaire des éléphants de la Réserve áéléphants de Maputo en utilisant le comptages des crottes, le tracking par satellite et l'analyse des excréments. On a comparé les résultats avec des données recueillies avant la guerre civile au Mozambique. La population d'éléphants a baissé pendant la guerre civile mais il reste 180 animaux. Des études antérieures montraient que les éléphants préféraient les plaines herbeuses. Actuellement, ils préfèrent les ı^lots de forêt dense au fourrage de haute qualité qui se trouve dans les plaines herbeuses. La salinité de l'eau modifie la distribution; on trouvait les crottes d’éléphants plus près de l'eau douce en saison sèche. On a identifié un total de 95 espèces végétales différentes dans les excréments. Le pourcentage d'herbes était relativement bas par rapport aux études antérieures, il augmentait au début de la saison des pluies. A la fin de la saison sèche, les éléphants se concentraient sur les quelques espèces de buissons comestibles ayant des jeunes feuilles, mais ils préféraient généralement les espèces herbeuses aux buissons. La composition du régime était surtout affectée par la saison et moins par l'habitat. Les éléphants ont changé leurs préférences en matière d’habitat en réaction au braconnage et ont sans doute ainsi augmenté la contribution des espèces buissonnantes dans le régime alimentaire. La présence des ı^lots forestiers a été vitale pour la survie des éléphants.
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