Ecology and Fish Data Explorer — freshwater macroinvertebrates

What is measured

• Atlantic salmon density · fish/100m²
• Brown and sea trout density · fish/100m²
• EPT family richness · count
• European eel density · fish/100m²
• LIFE flow index (family level) · index
• Proportion of sediment-sensitive invertebrates · %
• WHPT average score per taxon · index
• WHPT number of scoring taxa · count

How current it is

Partial record held

EA ecology offers more than Hydrionis currently holds. The newest value here covers 2026-07; the gap is a deliberate limit on what has been collected, not a limit on the source. The Agency publishes 7.6 million taxon records across 280,630 samples. Hydrionis computes one number from them — the count of distinct EPT families per sample — at the same 2,611 long-record sites the community indices are held for, and stores no taxon list. Total abundance is published alongside and not held: a three-minute kick sample is designed to find what is present rather than to count it, and the published values reach 333,372 individuals in a single sample against a median of 79. Odonata richness was computed and refused, the median sample containing any dragonfly holding exactly one taxon.

The Agency publishes 7.6 million taxon records across 280,630 samples. Hydrionis computes one number from them — the count of distinct EPT families per sample — at the same 2,611 long-record sites the community indices are held for, and stores no taxon list. Total abundance is published alongside and not held: a three-minute kick sample is designed to find what is present rather than to count it, and the published values reach 333,372 individuals in a single sample against a median of 79. Odonata richness was computed and refused, the median sample containing any dragonfly holding exactly one taxon.

Partial record held

EA ecology offers more than Hydrionis currently holds. The newest value here covers 2026-07; the gap is a deliberate limit on what has been collected, not a limit on the source. The Environment Agency publishes 369,381 species-survey rows across 126 species and several fishing methods. Hydrionis holds three flow-dependent species from non-selective electrofishing depletion surveys of at least 50 m² — 25,952 rows — at site-species pairs with at least five years of survey. Single-catch surveys, seine netting, fixed traps and species-selective surveys are excluded because none of them yields a number comparable with a depletion estimate. Length and weight measurement archives published alongside are not held.

The Environment Agency publishes 369,381 species-survey rows across 126 species and several fishing methods. Hydrionis holds three flow-dependent species from non-selective electrofishing depletion surveys of at least 50 m² — 25,952 rows — at site-species pairs with at least five years of survey. Single-catch surveys, seine netting, fixed traps and species-selective surveys are excluded because none of them yields a number comparable with a depletion estimate. Length and weight measurement archives published alongside are not held.

Partial record held

EA ecology offers more than Hydrionis currently holds. The newest value here covers 2026-07; the gap is a deliberate limit on what has been collected, not a limit on the source. The Environment Agency publishes sites, per-sample indices and full taxon lists for 280,630 macroinvertebrate samples at 30,693 sites. Hydrionis holds four indices — WHPT ASPT, WHPT NTAXA, LIFE and PSI — at the 2,611 sites with at least 30 samples across at least 15 years, which is about 42% of all samples and the part of the archive long enough to show change. The 804 MB taxon file is deliberately not held: a taxon list is a species database rather than a time series. Diatom, macrophyte, phytoplankton and marine benthic archives published alongside are also not held.

The Environment Agency publishes sites, per-sample indices and full taxon lists for 280,630 macroinvertebrate samples at 30,693 sites. Hydrionis holds four indices — WHPT ASPT, WHPT NTAXA, LIFE and PSI — at the 2,611 sites with at least 30 samples across at least 15 years, which is about 42% of all samples and the part of the archive long enough to show change. The 804 MB taxon file is deliberately not held: a taxon list is a species database rather than a time series. Diatom, macrophyte, phytoplankton and marine benthic archives published alongside are also not held.