The importance of using fish as a bio-indicator during bio-monitoring is often undervalued. The study of fish community structures highlight long term impacts associated with a particular reach or bio-monitoring point. Fish communities are mainly impacted by two aspects: habitat availability and stress which is a response associated with a particular stimulus.

Fish stresses can be divided into three main responses:

Primary: neuroendocrine responses – which causes particular species to migrate as soon as they are exposed to a new stressor this may be chemical or when threatened by a new predator (Alien invasive fish species);

Secondary: Metabolic responses – which may have an effect on the nutrient cycling of fish species; and

Tertiary: Dessication – where the stressor or impact is too large resulting in fish kills.

At Envass we realise the importance of using a multi-disciplinary approach in our bio-monitoring projects. Please contact us at info@envass.co.za for a free quotation.

Alien Gambusia affinis (Mosquito fish)

Electroshocking capture method

Staightfin Barb (Enteromius paludinosus)