New Zealand has a strong social commitment to environmental protection. It has the 6th largest marine area, and a tradition of enacting world-leading legislation, e.g. the Marine Reserves Act 1971 (MRA), and the Resource Management Act 1991 (RMA). But despite this background New Zealand has struggled to halt the decline of indigenous biodiversity. Notwithstanding baseline state of the environment reporting since 1997, there has been political resistance to preparing national policy statements regarding indigenous biodiversity to assist with interpreting the law, and attempts to replace the MRA with modern up to date legislation have stalled since 2002. This paper will therefore focus on the Fiordland coastal marine area, and the largest global submarine forest of black coral trees found in that area, as a mechanism for evaluating the effectiveness of New Zealand’s marine protection laws. Generally, an empirical approach is used in the following sections to interrogate what environmental practice would look like if carried out in a sustainable way, what government entities and the private sector are doing to foster sustainable outcomes, and what should be done to promote sustainability. The overall thesis of the paper is that different evaluation approaches (constitutional, emprical, and governance) are useful in exposing any gaps between policy and practice within the legal system.