COPEPODS AND FISHES IN THE BRAZILIAN AMAZON

The Amazon basin comprises the largest river ecosystem in the world (7 million km(2)) with annual high and low water peaks and a constant te mperature near 29 degrees C. Some 2000 fish species and 40 species of free-living copepods are known to occur in Amazonia. The free-living f orms serve as food for most larval fishes and some adults, but they al so transmit several parasites including representatives of the nematod e family Camallanidae. About three dozen species of parasitic copepods have been described from the Brazilian Amazon. Females of Amazonian p arasitic copepods are found on skin, gill filaments, gill rakers or wi thin the nasal fossae. Parasitic copepods are found on fishes that are from a few millimeters long up to those over 2 m in length and they a re usually quite host specific. All have body pigmentation in differen t patterns and colors (frequently blues, such as cerulean, cobalt, spe ctrum, smalt or campanula). It is suggested that the coloration serves to attract specific host fish. Copepods have evolved adaptations for attachment and feeding, especially in the second antennae and endopods . Examples of progenesis, phoresis and commensalism are shown. Some sp ecies produce pathology such as a tourniquet effect, hyperplasia, bloo d loss and anemia, and can kill fishes by limiting their respiration. (C) 1998 Elsevier Science B.V. All rights reserved.