Macroalgae are good indicators of general pressures including, toxic substances and disturbance. They are ideally suited to monitoring as many are large, widespread and relatively easily identified. The method is based on the principle that pollution and disturbances from man-made activities can alter the number of species of macroalgae expected on a shore.
The intertidal rocky shore macroalgal index enables an assessment of the condition of the quality element macroalgae.
The method statement published in 2008 for the first river basin planning cycle has now been updated for the second cycle, linked below.