Jean-Claude Krynicki, Alban Benoist, Damien Bouchon
MEASUREMENT PLAN FOR THE DIAGNOSE OF AQUATIC ECOSYSTEMS
This paper is relating the effort to organize a pertinent measurement plan to analyze 2 aquatic ecosystems, a canal and a lake, where the issue is to improve the natural surviving of fishes for the benefit of local angling clubs.
The first case is a 4 century old canal, located in a castle, built from its very beginning for French king entertainment and trout rising; the issue is related to the massive introduction of new fishes every November which are disappearing during winter while trout, fishes very sensitive to pollutions, are surviving.
The second case is a more recent lake dedicated to fly fishing, where the issue is quite the opposite: introduction of trout is resulting, after a month, into a complete disappearance of these fishes while other alien species are still alive with a good reproduction rate. In both case there is no trace of dead bodies or other visual evidences of the changes.
The measurement plan is considering over 1000 different parameters that may explain the lethal for life situation of aquatic ecosystems and is creating a typology and hierarchy of these parameters to build a measurement sequence. A set of abiotic specifications was created with a scale compared to Nisbet & Verneaux abiotic inventory of French lakes and rivers.
The paper will cover the different techniques used for that purpose and what we have learned to obtain reliable results for physical measurements (flow, laminar flow, volume and water renewal rate, temperature etc¡K), abiotic (pH, redox, conductivity, hardness, dissolved gas etc¡K), biotic index, and comparison to biological history (sclerochronology ).
The presentation will show several tools we have developed for mass sampling, continuous surveillance and GPS driven measurements.
The conclusion will show the need for a systemic approach to integrate all these measurements into a consistent model for overall behavior and productivity prediction.