There are many present and potential threats to the marine environment that need to be addressed. Impacts from fishing, aquaculture, species introductions, coastal developments and pollution are briefly reviewed. With one notable exception, remedial measures for these impacts are not well developed. The exception is the establishment of marine reserves in which all marine biota is totally protected. Since the mid 1970s, New Zealand has set up 10 of these marine reserves. Further initiatives in marine reserves, and in other forms of conservation such as active habitat restoration and species enhancement, can be expected in the years ahead.