SAEON Elwandle applies expertise to marine protected area management in Amathole

By Moraea Phillips and Albrecht Götz, SAEON Elwandle Node Tweet

The stereo-BRUV system is ready to be deployed. The light housing is above the pole that supports the bait container. On either side the camera housings are focused on the bait container. A healthy looking reef in the Gonubie MPA. Large and mature individuals of reef fish species gather around the bait container.

The Amathole district in the Eastern Cape incorporates one of the most unspoilt and beautiful coastlines in South Africa, from just below Hole in the Wall to the mouth of the Fish River.

The rocky shoreline is continuous, with reefs extending all the way out to massive drop offs and canyons at the edge of the continental shelf. The area boasts some of the best fishing in the country and is a stronghold for a number of overexploited reef fish species such as Seventyfour (Polysteganus undulosus) and Red Steenbras (Petrus rupestris).

In the 1980s local fishermen noticed a decrease in line-fish catches and realised the need to establish refuges where fish stocks could recuperate. They set aside three areas of inshore reef near the Gxulu River mouth, Gonubie point and the Kei River mouth as voluntary sanctuaries and lobbied for them to become official reserves. Despite being declared closed areas in 1984, it was still left largely up to the local fishing clubs to enforce restrictions and bring offenders to prosecution.

Amathole marine protected areas

The areas were declared marine protected areas (MPAs) in 2011 and their management is now a responsibility of the Eastern Cape Parks and Tourism Agency (ECPTA), who benefit from the continued support of the fishing clubs.

MPAs are an example of ecosystem-based fisheries management, where fish are protected not only by regulating their capture, but by protecting the rest of the ecosystem on which they depend as well. This entails setting aside relatively unspoilt areas as a refuge where they can recover to carrying capacity and eventually replenish stocks in adjacent areas by spill-over of fish. This form of protection is particularly successful if the reserve is larger than the movement range of the species of interest, as is often the case with resident reef fish.

The Amathole MPAs extend three nautical miles (about 5.5km) out to sea, taking them to depths of up to 80 m. Larger individuals of species such as Red Steenbras and Seventyfour are known to frequent depths of up to 200 m, and it is these larger individuals which are reproductively active.

In addition to this, the reserves are split into three separate areas, protecting 45 km out of the 100 km of coastline they span. Fish with larger ranges are likely to venture between these reserves, putting them at risk of capture. These limitations raised the question as to whether the reserves had been adequately designed to boost local populations of vulnerable and threatened reef fish species.

Using stereo-BRUVs to evaluate fish communities

With this in mind, Megan van der Bank of the ECPTA approached Dr Albrecht Götz of the SAEON Elwandle Node and Dr Anthony Bernard, now of the South African Institute for Aquatic Biodiversity (SAIAB), regarding their work using stereo-BRUVs (baited remote underwater stereo-video systems) to survey MPAs.

The stereo-BRUVs consist of two cameras, a light system and a bait container all mounted to a steel frame, which is deployed to the sea floor. The cameras are calibrated to film fish from two different angles as they pass the bait container, permitting measurement of individuals that swim within the overlapping fields of view. This means that in addition to species composition and abundance, the size structure, and therefore maturity of individuals and spawner biomass can be compared between sites.

As a result, it was decided to use these stereo-BRUVs to evaluate fish communities in the Amathole MPAs. Communities from different depths will be compared to see if there is indeed a tendency for larger fish to reside in deeper parts of the reef and, if so, how far the reserves would need to be extended in order to include such crucial habitats. In addition, fish communities from inside the MPAs will be compared with those from adjacent, exploited sites.

The Amathole MPAs are split into three separate areas, protecting 45 km out of the 100 km of coastline they span.

Although the MPAs were only officially declared in 2011, they had already benefited from some level of protection for over 30 years, thanks to the efforts of the fishing clubs.

As yet only one fishing survey has been carried out to assess the status of fish stocks in the area, but the methods and conditions made the results inconclusive. The comprehensive survey carried out for this project will serve not only for the present evaluation, but also as a starting point for long-term monitoring to be carried out in the MPAs by the ECPTA.