Recovery of fish stocks in Flemish watercourses is stalling
Only 7 per cent of the monitoring sites surveyed in Flemish watercourses achieve good ecological quality based on fish stocks. Furthermore, new figures show that the improvement seen in recent years has come to a standstill.
The European Water Framework Directive stipulates that our watercourses must achieve good ecological status. To assess this status, INBO examines, amongst other things, fish stocks. Based on this, we calculate an ecological quality ratio (EQR), with a score ranging from 0 (poor) to 1 (very good).
During the latest sampling cycle (2019–2024), we surveyed 347 monitoring sites. The results show that there is still work to be done:
- Only 7% achieve good quality.
- 36% are rated as moderate.
- 34% are of inadequate quality.
- 23% are rated as poor.
At no less than 93% of the sites surveyed, fish stocks therefore do not meet the target for good quality.
Previous progress has stalled
Between 2010–2012 and 2013–2018, the average fish stock quality in Flanders improved significantly: the EQR rose from 0.316 to 0.384. However, this positive trend has not continued in recent years. In the period 2019–2024, the average EQR stood at 0.383, virtually identical to that of the previous cycle.
A comparison of 342 monitoring sites for which data from both of the most recent monitoring cycles are available also confirms this picture. At 52 per cent of the sites, the quality remained virtually unchanged. At 24 per cent, it improved, whilst at an equally large proportion, it deteriorated.
Still a long way to go
Despite previous progress, the average ecological quality, based on fish stocks, remains in the ‘inadequate’ category. The results make it clear that further efforts are needed to improve the ecological quality of our watercourses.