Estuaries – how challenging are these constantly changing aquatic environments for associated fish species?

Much has been written about the abundance of fishes in estuaries, and particularly the value of the littoral zone and associated macrophyte habitats as fish nursery areas. What has not been researched or discussed in the same amount of detail is that estuaries are demanding physico-chemical environments for fishes, yet each year millions of 0 + juveniles are recruited into these supposedly stressful nurseries. This review focuses on three primary variables; salinity, temperature and turbidity, and highlights the ability of estuary-associated fish species to withstand apparent extreme conditions associated with these physico-chemical drivers in order to benefit from the rich food resources and possible low predation rates present within most systems. However, there is increasing evidence that global change, including climate change, is resulting in these driving variables becoming more extreme, which will test even the most eurytopic estuarine species now and in the future.