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Mimiwhangata - the story so far!

Mimiwhangata – the story so far

A national treasure exists between Whangarei and the Bay of Islands, on the east coast of New Zealand.  A wide variety of wildlife is found below high tide. Over the 40 years that biologists have been surveying the waters of Mimiwhangata, over 70 species of fish have been recorded, including subtropical species such as combfish, spotted black grouper, foxfish and rare invertebrates such as the red-lined bubble shell. Mimiwhangata Coastal Park and Marine Park is valued by the people of New Zealand for its spectacular scenery, cultural heritage and history. Mimiwhangata has a complex history of pre European utilisation and is of importance to local Maori and iwi- Ngatiwai. 

From 1960 Lion Breweries owned Mimiwhangata and commissioned Bill Ballantine, Roger Grace and Wade Doak to conduct a marine survey of the Mimiwhangata area in 1973. This was the first known survey of its kind to be conducted in New Zealand. The study revealed the diversity of habitats within the Mimiwhangata area. Concerns were expressed in the report that increasing fishing pressure may threaten the areas ecology. The Marine Reserves Act 1971 had just come into force and the authors of the 1973 marine report recommended a marine reserve for the Mimiwhangata study area. In 1978 the Hauraki Gulf Maritime Park Board (HGMPB) became involved. In 1982 a report by Dart et al. for the HGMPB proposed a marine park to adequately protect the area (as a marine reserve was viewed as extreme). In 1984 the Mimiwhangata marine park was established. The marine park extends 1000 metres off shore between Paparahi Pt and Ruatahi Island and extends beyond Rimariki Islands. Special fishing regulations enforceable by Ministry of Fisheries were put in place including reduced commercial fishing and method requirements for recreational fisherman. Paua and rock oysters are totally protected. Permitted species include Kingfish, snapper, trevally, blue maomao, mussel, tuatua and crayfish. The vision of the Park was to preserve and enhance one of NZ’s special environments for people to visit and enjoy.
mimipool.jpg After a complex debate about the marine park land ownership issues, Lion Breweries made a swap, for crown land in Wellington and Mimiwhangata became public land. Although species regulations were in place, they were hard to enforce, due to poor drafting of regulations back in 1984. Effectively the marine park has had no commercial fishing since 1994 with apparently unenforceable limited recreational fishing. Historic monitoring of marine species established at Mimiwhangata in 1976 was repeated at the original sites. The original methods of data collection were also followed. The species surveyed were; fish, kina, crayfish, rock oysters, tuatua and scallops. Results of this survey showed overall lack of improvements in the marine species studied over the period the Marine Park fisheries regulations had been in place. There was concern over continued decline in some habitats notably the algal forests of shallow sub-tidal areas and evidence of decline, in species such as snapper, tuatua, packhorse crayfish, red crayfish and rock oyster.

 

mimi_comparison_70_200.jpgThe 1950 aerial photo shows lush dark-coloured tangle kelp forest around the reef at Pa Point.  The same area in 2003 shows dramatic reduction of kelp cover and its replacement by pale-coloured "kina barrens".

Although monitoring was initially carried out on a regular basis, monitoring became more irregular and intermittent through the early 1980's, until a comprehensive survey again in 1986 and then there was a 17 year gap until 2001, when monitoring of intertidal sites was carried out in winter 2001, then a full survey of sub-tidal sites in 2002. View the Grace & Kerr progress report.

legal_cray_chart.jpgCrayfish have been so depleted at Mimiwhangata that on the transects it is now rare to see a legal-sized cray. Small numbers of juveniles are still seen. Decadal trend can be seen on this diagram.  The red shows a steady decline at Mimiwhangata over the last 4 decades, while the yellow shows a dramatic increase at Tawharanui. Crayfish are totally protected at Tawharanui Marine Park, where a policy of no-take has been observed since 1981. Crayfish have also shown dramatic increases in the numbers inside New Zealands oldest marine reserve at Leigh. Crayfish are not currently protected by the marine park at Mimiwhangata. Crayfish are a predator of kina, and since the 1970’s there has been an increase in kina barren areas. 

marinereserve_in_out.JPGA comprehensive fish survey in 2002 revealed that there was little change in the abundance and diversity of reef fish since the early survey work in the 1970’s. The survey found no significant difference in diversity and abundance of most fish species between sites inside and outside the Park. Snapper numbers were overall low compared with other study sites and also showed no real difference between in and outside of the Park. There was evidence that in some species and habitats there has been continued decline. It is likely that recreational fishing is now the major impact on Mimiwhangata marine species, as commercial fishing was discontinued in 1994.

It was becoming apparent that the current marine park status may not be adequate to sustain marine biodiversity.

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Partial protection  did not work at the Poor Knights either, and from 1998 the Poor Knights become completely no take, with rapid recovery of snapper, to take just one example as a result. Degraded or ‘fished down’ populations struggle to recover if fishing continues even at a reduced rate. We know recreational fishing pressure has increased over the years and is likely to continue to increase, but we have no actual measure of how much this is. It is a form of ‘blind management in the context of a local place like Mimiwhangata.  We have learned a lot from the marine reserve at Leigh.

The findings of survey work at Mimiwhangata indicated that the Marine Park concept as implemented has fallen short of protecting the marine species and habitats of Mimiwhangata, despite the positive intentions and aims the original Marine Park concept.

historic_survey_sites.<span class=View some of the video from the historic survey sites, such as F1, F3 and F6.

As a result of the 2002 survey, the Department of Conservation contracted Vince Kerr and Roger Grace to conduct deep reef surveys and found stunning biodiversity, including species of gorgonian fans, soft corals and black coral. Habitat information for the Mimiwhangata reefs was extended to 4 km offshore to include the significant area of rich biodiversity and important deep reef habitat.


 

black_coral.jpgThey established that rich diverse deep reef   complements the complex shallow reef habitats. Recent technology has allowed the deep reef to be surveyed beyond the reaches of a SCUBA diver, using remote operated video (ROV). Other modern survey methods were introduced such as side scan sonar and manta boarding to develop the 2004 habitat map . This rich biological assemblage of benthic communities could be significant to the fisheries productivity.


In 2004 the Department of Conservation published a proposal, calling for a marine reserve to be put in place at Mimiwhangata to allow the full recovery of all species and protect the full range of marine biodiversity. There was an extensive community consultation effort carried out at that time. The proposal attracted significant support and some opposition from fishing interests and some tangata whenua.
In total, the Department received 1109 submissions to the Mimiwhangata Marine Reserve proposal and Community Discussion Document. Of these, 763 supported the proposal, while 332 opposed it, and 14 were unclear. There was also a petition opposing the proposal.
A 2004 visitor use report and the proposal submissions provided valuable insight into how people use the proposed marine reserve area and how they might be affected by a change in protection status. Of particular interest  is the diverse ways people currently use the Mimiwhangata area for recreation and enjoyment. Many submitters also commented on the proposed marine reserve areas and their associated boundaries.

Overall, the submissions signalled support for the proposal in the community. However, it was also evident that fishers are concerned about the impacts of a marine reserve at Mimiwhangata.

In 2009 the government announced that the Department of Conservation would no longer be an applicant for marine reserves.  DOC still has mandate to support marine reserves and applications that arise out of the governments Marine Protected Area policy. Under the New Zealand Biodiversity Strategy (2000) there is a target of having 10 percent of the marine environment in a network of Marine Protected Areas by 2010.

If Mimiwhangata was to become a marine reserve, it would be interesting to monitor the likely reversal of reduction in algal forest (as observed at Leigh marine reserve), as there is a trend in other marine reserves along the North Eastern Coast, that exploited species  such as crayfish and snapper recover, kina become more cryptic and primary production increases. The effectiveness of partial protection for snapper at Mimiwhangata over a long time scale (commercial long lining has not occurred for 17 years) was investigated in 2009 by Paul Buisson of the Department of Conservation . The study again concluded no significant difference between snapper inside the Mimiwhangata Marine Park to outside using the sampling method of Baited Underwater Video. Numbers were also compared to areas open to fishing and there was no significant difference .
Mimiwhangata is rich in habitat diversity and this diversity is likely to benefit species such as crayfish by providing optimum opportunity for recovery with so many diverse feeding grounds. Mimiwhangata marine reserve would present numerous opportunities for future studies. We have few examples of marine reserves that include the diverse habitats of Mimiwhangata. We could learn so much!

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