Velocity estimation of valve movement in oysters for water quality surveillance

The measurements of valve opening activity in a population of oysters under natural environmental conditions are used to estimate the velocity of their valve movement activity. Three different differentiation schemes were used to estimate the velocity, namely an algebraicbased differentiator method, a non-homogeneous higher order sliding mode differentiator and a homogeneous finite-time differentiator. The estimated velocities were then used to compare the performances of these three different differentiators. We demonstrate that this estimated velocity can be used for water quality monitoring as the differentiators can detect very rapid change in valve movements of the oyster population resulting from some external stimulus or common input.