The Endemic Species Flock of Labeobarbus spp. in L. Tana (Ethiopia) Threatened by Extinction: Implications for Conservation Management

Abstract

The endemic Labeobarbus species in Lake Tana are severely affected by anthropogenic pressures. The implementation of fisheries management is, therefore, vital for their sustainable exploitation. This study aimed at investigating the catch distribution and size at 50% maturity (FL50%) of the Labeobarbus species. Samples were collected monthly from May 2016 to April 2017 at four sites. The relative abundance, catch per unit effort (CPUE), and size distribution of these species was computed, and logistic regression was used to calculate FL50%. Of the 15 species observed, five species constituted 88% of the total catch. The monthly catch of the Labeobarbus spp. declined by more than 85% since 1993 and by 76% since 2001. Moreover, the CPUE of Labeobarbus has markedly decreased from 63 kg/trip in 1991–1993 to 2 kg/trip in 2016–2017. Additionally, large size specimens (≥30 cm fork length) were rarely recorded, and FL50% of the dominant species decreased. This suggests that the unique species flock may be threatened by extinction. Given the size distribution of the species, the current social context, and the need for a continuous supply of fish for low-income communities, a mesh-size limitation represents a more sustainable and acceptable management measure than a closed season. This paper illustrates the tension between sustainable development goal (SDGs) 1—No Poverty, 2—Zero Hunger, and 8—Decent Work and Economic Growth in Bahir Dar City on the one hand, and SDG’s 11—Sustainable Cities and Communities, 12—Responsible Consumption and Production, and 14—Life Below Water on the other hand. A key for the local, sustainable development of the fisheries is to find a balance between the fishing activities and the carrying capacity of the Lake Tana. Overfishing and illegal fishing are some of the major threats in this respect.

Pesticide concentration in three selected fish species and human health risk in the Lake Tana sub-basin, Ethiopia

“…The fish species of the genus Labeobarbus are the most numerous and endemic to Lake Tana. Two of the five Labeobarbus species most frequently caught for commercial fishing are L. tsanensis and L. megastoma (Gebremedhin et al, 2019).…”

Sustainability of Lakes and Reservoirs: Multiple Perspectives Based on Ecosystem Services

“…(2) hydropower [3][4][5]; (3) sediment cycling [6]; (4) water storage and supply [7][8][9]; (5) climate change [10]; (6) flood control [5]; (7) fisheries [11] and (8) tourism [12]. Together with a description of these ES, a brief summary of these papers is provided below.…”

“…Lake Tana in Ethiopia is not only the largest lake of the country, but the associated basin is moreover home to more than 90,000 inhabitants and plays a crucial rule in local economic activities [11]. Unfortunately, the ecosystem of Lake Tana has undergone a very severe pressure resulting from the diverse exploitations and human development, mainly because the conservation management of natural resources has often been neglected in this waterbody.…”

“…Unfortunately, the ecosystem of Lake Tana has undergone a very severe pressure resulting from the diverse exploitations and human development, mainly because the conservation management of natural resources has often been neglected in this waterbody. Gebremedhin [11] indicated the issues of overfishing and illegal fishing which have strongly affected the population of the endemic Labeobarbus species in Lake Tana. Specifically, the monthly catch of this species has decreased by 76% since 2001 as the catch per unit effort (CPUE) declined from 63 kg trip −1 to only 2 kg trip −1 from 1991 to 2017.…”