Total mesozooplankton biomass was measured as dry weight on a fresh sample. Samples were sieved on 200 ?m nitex, briefly rinsed with distilled water to remove salt, transferred on pre-weighted alluminium foil and placed in an oven at 60°C. The samples were weighted on a microbalance after 24 hours and again 2-3 times within the following seven days, until the weight was constant. This latter value was considered as dry weight.