Nematode production in artificial ponds: a long-term perspective

What is it about?

Nematodes are the most abundant multicellular animals on Earth and play an important role in energy fluxes in terrestrial, freshwater and marine ecosystems. By monitoring the nematode species composition, abundance and biomass over several years in a set of outdoor ponds, we could estimate a substantial contribution of nematodes. During the first 3 years of colonisation of the pond bottom, nematodes quickly reached impressive numbers (up to 21 million individuals per square meter), thus representing a net yearly biomass gain of up to 928 Kg of fresh weight per Hectare of pond, which is fairly substantial in order to sustain aquaculture, knowing that many benthivorous fish juveniles (such as carp and tilapias) feed voraciously on nematodes. However, we also observed that anoxic events can dampen nematode production to very low levels without clear resiliency. The comparison of different models to estimate nematode secondary production helped to formulate general recommendations in order to popularize the use of nematode secondary production as a sound ecosystem diagnostic tool.

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