he bluffs overlooking Horoirangi Marine Reserve are more than a dramatic landscape; they are also the source of rocks for the rugged boulder reefs below. A distinctive feature of the reserve, these reefs form a wide intertidal zone and extend offshore for up to 400m and to a depth of around 20m. The boulders on the upper shore, regularly moved by the waves, are mostly devoid of life. Lower down and subtidally the reefs are much more stable—a matrix of interlocking boulders, some in places measuring metres across, interspersed with occasional patches of bedrock. Bedrock is more common around Mackay Bluff and towards the north of the marine reserve, culminating in the spectacular rocky outcrops of Ataata Point.
While fishing is not allowed in the marine reserve, other forms of recreation are welcomed. Walking, exploring the intertidal zone, kayaking, snorkelling, diving, general boating and sightseeing are all popular activities.
Discovering Marine Life
Discover the diversity of marine life on the lower intertidal boulder reef. This is a fun place to explore and study, especially when there is a very low spring tide and the sea is calm. Take a close look, but remember this is a marine reserve so animals and plants should not be taken or harmed. If you do look around or under boulders, please be very careful not to crush any animals or plants. All boulders should be carefully returned to their original position.
Diving & Snorkelling
Some of the best diving and snorkelling is found towards the north of the reserve, especially near Ataata Point. Look out for crayfish lurking in overhangs and crevices, and some of the more common reef fish – wrasses, triplefins, goatfish, blue cod, blue moki, tarakihi, and perhaps an elusive snapper. Sponges, some quite large, are a notable feature to keep a watch for, particularly along the outer reef edge and on the deeper bedrock reefs. Over time (perhaps decades!) divers might witness gradual changes in the numbers of some species due to the cessation of fishing in the reserve.
Plan & Prepare
The southern end of the marine reserve at Glenduan is a short, 12km drive from Nelson. From here you can walk along the reserve, but watch for the incoming tide and take care over the boulders, as they can be unstable and slippery. Kayaks can also be launched and retrieved—with care—across the Boulder Bank. For larger boats, there are good launching facilities at Nelson and Mapua, before embarking on a 12km boat trip north along the outer Boulder Bank.
While out on the water, keep a wary eye on the weather and sea conditions; there is little shelter along this stretch of coast and stiff sea breezes regularly occur in summer. At the northern end of the marine reserve, and well worth the 21km drive, is Cable Bay. Although you cannot reach the reserve from here on foot, kayaks and small boats can be launched from Cable Bay beach for a pleasant trip across to Ataata Point and into the northern sector of the reserve.
Large yellow triangles onshore mark the northern and southern boundaries; offshore buoys mark the ends and the outermost corners of the reserve. [Note: these markers may not always be present due to operational requirements.]