Fish infochemicals alter life cycle and growth of a calanoid copepod

GUTIERREZ, FLORENCIA; PAGGI, JUAN CESAR; GAGNETÉN, ANA MARÍA

JOURNAL OF PLANKTON RESEARCH

Oxford Journals

Lugar: Londres, Inglaterrra; Año: 2009

0142-7873

In this study, we evaluate the effects of chemical signals present in exudates of the zooplanktivorous fish Cnesterodon decemmaculatus (Poeciliidae) on the life cycle and growth of the planktonic copepod Notodiaptomus conifer. Semi-static assays were carried out using five concentrations of fish water (0.41 - 3.3 fish L-1), and a control (without fish). Copepods subjected to fish water developed significantly faster. Adult body size was smaller at the highest fish water concentrations. The proportional duration of each larval stage was not modified in the presence of chemical signals, indicating that N. conifer mantained an equiproportional development according to the growth model proposed for copepods. High concentrations of fish conditioned water reduced the fecundity and time of formation of the first ovigerous sac. Some parameters of the copepod life history changed depending on fish water concentration while other response features were induced merely by the presence of fish exudates, regardless of concentration. The observed responses would be the result of physiological mechanisms acting directly on development and constitute an example of the importance of predator-prey interactions as a selective force in natural environments.