Adapted to past, present and future aquatic environments: a review of the biology and ecology of the eurytopic Indo-Pacific tarpon Megalops cyprinoides
摘要
Megalops cyprinoides belongs to an ancient fish family (Megalopidae) that has an elopiform lineage dating back to ray-finned teleost origins more than 200 Ma. In this review, the characteristics that have ensured the past and present success of M. cyprinoides are examined, with the possible future impact of climate change and associated altered environmental drivers also being assessed. The attributes that have most enabled this remarkable species to exploit a diverse array of marine, estuarine and freshwater habitats during its predominantly catadromous life cycle include euryhalinity, a wide eurythermal tolerance, an air breathing capacity to cope with dissolved oxygen values < 1 mg L−1, a pH range from 5 to 9, occupation of both clear and highly turbid aquatic environments, occurrence in lentic and lotic habitats, and a diverse diet that includes insects, zooplankton, nektonic crustaceans and fishes, depending primarily upon fish life stage and prey availability. The end result is a species that occupies both Indian and Pacific Ocean coastal areas located over more than half the globe and a taxon that has survived continental drift and climate change over geological time scales that span millions of years. These attributes will also ensure that M. cyprinoides is well adapted to global warming and associated alterations in environmental conditions and precipitation patterns that are likely to accompany climate change in the future.