Introduction

DOC is monitoring the changes in the Long Bay-Okura Marine Reserve to learn how the marine reserve status has helped sea life.

A range of monitoring has been carried out at the Long Bay-Okura Marine Reserve since its establishment, along with earlier surveys carried out at the time the reserve was proposed:

Investigating a rock pool, Long Bay-Okura Marine Reserve.
Investigating a rock pool, Long Bay-Okura Marine Reserve

Benthos and marine surveys 1990

In 1990, prior to the area being declared a marine reserve, a survey was carried out by divers on the reefs north and south of Long Bay. The survey looked at the rocky reef and sediment bottom habitats along with associated marine life.

To supplement the survey a dredge survey was carried out at Karepiro Bay and the Okura River Mouth investigating sediment biota.  

The results from these surveys indicate the Long Bay area is typical of the east coast of the Auckland region. The report notes that most Aucklanders would be surprised at the colourful beauty of the marine life of the rocky reef, "a paradise for close-up underwater photographers”.

Rocky reefs

Large brown seaweed dominated the tops of rocky reefs, with species of red and green seaweed beneath. 

A range of invertebrates were found to inhabit the reef including sea squirts, sponges, chitons, molluscs and echinoderms such as kina and starfish. The greatest diversity and species richness occurred under overhangs of reef edges which afforded protection from the elements and predators. 

A number of encrusting and filter feeding species were present including nudibranchs sponges, bryzozoans and small corals. Fish species included spotty, triplefin, parore, red mullet and snapper.

Reef fish and lobster surveys

In 2002 a baited underwater survey found 11 times as many snapper within the reserve when compared with surrounding areas. Abundance was highest in the centre of the reserve. Snapper inside the reserve were also of a larger size on average and the range in size was also greater within the reserve.

A 2011 survey carried out by divers found snapper occurred at higher abundances within the reserve and several legal-sized individuals were also observed within the reserve, but not outside.

Lobster abundance was extremely low across the majority of sites surveyed; only occurring at one reserve site and one non-reserve site. Higher lobster abundance at the non-reserve site is likely to be related to the presence of boulder reef habitat.

Reef fish assemblage composition was generally similar between reserve and non-reserve areas surveyed. Reef fish diversity was much lower relative to outer Hauraki Gulf Marine Protected Areas. Spotty, goatfish, parore and snapper were the most dominant reef fishes. Other species recorded include sweep, koheru, kahawai and leatherjacket. Kahawai and leatherjacket were only found within the reserve. 

Rock flats, muddy sediment and sand

A strip of sediment covered rock flats boardering the rocky reef was host to sponge gardens as well as numerous hermit crabs, starfish and bivalves.   Kina (sea urchin).
Kina (sea urchin)
 

In the sandy stretch of Long Bay populations of tuatua and scattered sand dollars could be found and in increasingly muddy sediment away from the surf zone numerous small invertebrates, mud crabs and the heart urchin, a staple food source for snapper, were present as well as occasional small scallops. 

Fish species observed included trevally and kingfish.

Long Bay Marine Monitoring Programme 1999-2011

The Long Bay Marine Monitoring Programme was designed to detect changes in intertidal beach communities, particularly in relation to the increasing urban development of the Long Bay catchment. The monitoring programme is undertaken by the Auckland Council (formerly Auckland Regional Council) and reports are available upon request.

Monitoring of subtidal communities of rocky reefs has been carried out at Long Bay and at five other nearby bays (Campbells, Torbay, Little Manly, Stanmore and Waiwera) since 1999. 

Due to the movement of sites into deeper water it is not possible to detect trends in temporal variation over the entire sampling period. However, monitoring suggests that the communities at Long Bay are broadly similar to those found at other bays e.g. Torbay and Campbells in the inner Hauraki Gulf. A total of 81 taxa have been recorded during quadrat sampling to date.

Other surveys

A baseline survey was done by Auckland University in 2000. An initial monitoring survey of the intertidal area and rocky foreshore was undertaken 2002, with a subsequent survey in 2004.

Details of surveys

Find out more about the objectives, techniques used and key findings of each of the surveys carried out on the Long Bay - Okura Marine Reserve, as well as where to obtain the reports:

Long Bay - Okura Marine Reserve research (XLS, 40K)


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