Species density obtained for fish sampled with three seine nets hauled individually towards a stop net or a bank

Researchers continuously search for adequate and inexpensive fish sampling methods and, as such, it is worth remembering the quantitative seine method with three identical nets hauled individually towards a stop net or a bank. A sample obtained by three nets is the absolute minimum for any accurate estimate employing a removal technique, and this procedure provides an estimate of density with a known error, because it allows for calculations of the variance value. Density (the number of individuals calculated from the model, as per defined area or volume), a popular term in the previous century when a secondary production and bioenergetics budget studies were considered to be modern investigations, but now when it is used with different meanings, an attempt has to be undertaken to sort out this terminology.