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Laboratory studies of ingestion and food utilization in lobate and tentaculate ctenophores 1
Author(s) -
Reeve M. R.,
Walter M. A.,
Ikeda T.
Publication year - 1978
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.1978.23.4.0740
Subject(s) - predation , zooplankton , phytoplankton , biology , ingestion , population , nutrient , ecology , biomass (ecology) , zoology , biochemistry , demography , sociology
Ctenophore ingestion rates are linearly related to food density up to concentrations much higher than those usually assumed to be representative of the natural environment. Daily rations in excess of 1,000% of their body weights at high prey densities are matched by growth rates characteristic of phytoplankton (daily doublings). Digestive efficiencies >70% were recorded at moderate prey densities. Growth efficiencies rarely exceed 10% because the bulk of assimilated food (up to 80% of that ingested) is required for the energy metabolism of these organically dilute (carbon 2% of dry wt) creatures. Ctenophores may be at a competitive disadvantage at low food densities compared to predators such as chaetognaths, but at high food densities the reverse is true. Population explosion among ctenophores, and consequent decimation of’ other zooplankton, is well within their physiological means. In addition to regulating herbivore excesses and stimulating recovery of phytoplankton (by predation and rapid remineralization of nutrients), ctenophores are self‐regulated by being unable to maintain themselves when food supplies drop hack to moderate levels.