Enhancing the watershed of Melo River and fish stock of Rib Reservoir to assist the migratory Labeobarbus spp. of Lake Tana, Ethiopia
The following activities will take place at the Melo River and Rib Reservoir. Melo River is one of the major tributaries of Rib River. 1. Reforestation program at Melo River, one of the major tributaries of the Rib River and which is a major spawning site 2. Restocking of the Rib Reservoir with juveniles of indigenous Nile tilapia (Oreochromis niloticus) to reduce the pressure that could otherwise be exerted on the cutoff population of Labeobarbus spp. in the reservoir.
An irrigation dam was recently completed on Rib River, which blocks the migration of the Labeobarbus spp. It is hypothesized that a cut-off population of Labeobarbus spp. may be established in the reservoir, but status of any such populations is unknown. Moreover, there is an irrigation weir (with 6.5m height and a length of 40 m) constructed downstream of the dam to distribute the water to irrigation canals, and a second is under construction. These weirs are obstacles to fish migration and likely entrain and kill large numbers of downstream migrating juvenile fishes.
The conservation and human well-being consequences of this new water infrastructure on Rib River are unclear, but of great concern. Questions that need to be addressed include:
i. Can / do Labeobarbus spp. spawn downstream of the dam in the Rib River?
ii. If below dam spawning occurs, do young-of-year reach natal rearing grounds in the lake or are they lost to irrigation canals?
iii. Is there a self-sustaining community of Labeobarbus in the reservoir above the dam?
iv. How will alterations in Rib R. Labeobarbus production influence the Lake Tana Labeobarbus community and the fishery, e.g., if Rib River production falls, will young of year (YOY) survival of progeny from the other spawning rivers see an increase in survival (i.e., a compensatory response) or will the lake population decline proportionately?
Addressing the above questions above will yield important insights essential for the long-term management of the Lake Tana Labeobarbus flock and will establish the necessary pre-conditions for subsequent study regarding fish and human lake-wide responses.
Online Event - No
Country - Ethiopia
Name of contact person - Abebe Getahun and Minwyelet Mingist