Effects of pollutants on olfactory mediated behaviors in fish and crustaceans

Abstract

Streams, lakes and the sea are the final sinks of various pollutants which means that aquatic organisms are exposed to many different chemicals present in the ambient water. Several studies demonstrate that these pollutants may interfere with chemoreception of aquatic animals. Many aquatic vertebrates and invertebrates depend on chemical senses for their survival and reproduction. In fish and crustaceans, olfactory and taste receptors are exposed directly to the pollutants and their function can be disturbed. This can result in behavioral changes or lack of proper behaviors. Anthropogenic compounds can have detrimental effects on reproduction and survival of aquatic organisms. Relatively little is known about the effects of pollutants on crustacean chemoreception and behavior, but studies on fish might help elucidate the problems faced by crustaceans. This chapter gives examples of pollutant effects on pheromone detection in fish in connection with reproductive behavior, shoaling and dominance interactions, fright responses and effects on detection of food odors and foraging. Results from crustacean studies are compared to the examples given from fish studies. Various studies have shown that pesticides of different kinds affect the function of fish olfactory receptor cells. Crustaceans may face similar problems with less sensitive chemo-receptor cells. This will be especially problematic with compounds designed to combat insects and arthropods that are closely related to crustaceans. Many insecticides have direct effects on the nervous system and this will disturb chemoreception and behavior. Heavy metal ions are also problematic as they can be transported by chemosensory neurons into the brain and affect its normal functions. Crustaceans play important roles in aquatic ecosystems as well as in human food industry. Therefore, it is urgent to increase the knowledge about the effects of pollutants on crustacean chemoreception and behavior, especially compounds with direct effects on the nervous system that will affect the normal behavior and signal perception, disturbing social communication and reproduction. Such effects are serious for an individual as its growth and ability to compete and reproduce will be suppressed.