The authors analyzed interview data from 1,020 fishers in the Mekong Delta in Vietnam in 2014 to identify trends in catch rates and the possible factors driving the trends. Most of the fishers (68–90%) reported that their catch rates had declined over the previous five years, although some fishers stated that their fish catches had remained stable or even increased. They identified eleven factors that they believed contribute to declines in fish catches, among which the use of illegal gears and overfishing were considered most important, with other factors relatively unimportant. Separately, long-term datasets (1995–2016) showed a general decline in commercial fish catches, which was positively correlated with peak water levels (which indicate flood levels), and negatively correlated with the intensification of rice farming, especially where flooding has been prevented to allow a third annual rice crop. Some data suggests that fishing effort has declined significantly in recent years, so an apparent downward trend in catches is not likely to be a result of overfishing as believed by fishers, which suggests that fishers are not aware of or under-rate the significance of hydrological and land-use/landscape changes.
Vu, A.V., K.G. Hortle, D.N. Nguyen
7 April 2021
capture fisheries; land use; Lower Mekong Basin; fish migration; flooding; habitat fragmentation; overfishing