The State of World Fisheries and Aquaculture 2020

particular significance for aquatic biodiversity. 
The preliminary results of the analysis covered 
87 identified basin areas, which produce 
95 percent of the global inland fish catch (
Table 21
). 
At the basin scale, the highest threat scores facing 
inland fisheries, arise from a combination of loss 
of hydrologic connectivity, water abstraction, 
low gross domestic product and high population 
density (this will tend to drive fishing for food), 
and land-use change and associated runoff. 
These threats may be more relevant to riverine and 
floodplain systems rather than large lake systems. 
Only two of the basins score below 3, reflecting 
either low population densities and relatively 
low agricultural pressures, or regions where 
environmental management places some limits 
on the threat to freshwater environments and 
their fisheries. However, these two basins 
produce a negligible amount of inland fish. 
The majority of the world’s inland fishery catch 
comes from basins that score 4–5 (47 percent) 
or higher at 6–7 (38 percent). The latter category 
represents some of the world’s most productive 
inland fisheries that have rather high threat 
scores, underlining the fact that, in these basins, 
high population densities and nutrient loadings, 
coupled with abundant water resources, might 
drive their productivity. Only 10 percent of global 
inland fish catch comes from the basins with the 
highest threat scores. 
The threat maps may be more representative of 
fisheries in large, shallow lakes (e.g. Tonlé Sap) 
and riverine floodplains, wetlands, deltas and 
reservoirs, than those in very large waterbodies 
(e.g. Caspian Sea, Laurentian Great Lakes, Lake 
Malawi, Lake Tanganyika and Lake Victoria). 
This may be due to the high residence time 
and slow water exchange of large lake systems, 
allowing them to absorb or accumulate impacts, 
through processes that occur over a period of 
many years, before reaching a tipping point. 
Hence, a “low-impact” basin, could surround 
a large lake where significant eutrophication 
effects are seen (e.g. Lake Victoria). 
»
TABLE 21
THREAT SCORES OF BASIN AREAS THAT SUPPORT INLAND FISHERIES
Threat score
Number of basins
Share of global inland fish catch (%)
1–3 (low)
2
< 1
4–5 (intermediate)
37
47
6–7 (moderate)
33
38
8–10 (high)
15
10
Total
87
95
SOURCE: FAO.