We used Tasmania as a case example to question the consensus that few marine species have recently become extinct or are approaching extinction. Threats to marine and estuarine species - primarily in the form of climate change, invasive species, fishing, and catchment discharges - are accelerating, fully encompass species ranges, and are of sufficient magnitude to cause extinction.
Our ignorance of declining biodiversity in the marine environment largely results from an almost complete lack of systematic broad-scale sampling and an over-reliance on physicochemical data to monitor environmental trends. Population declines for marine species approaching extinction will generally go unnoticed because of the hidden nature of their environment and lack of quantitative data. ¬©2005 Society for Conservation Biology.