South Africa: Salmon farm threatens Gansbaai ecosystem

In a twist of fate a new threat to the unique marine ecosystem of Dyer Island and Gansbaai has been approved by Marine and Coastal Management authorities.

The South African government was one of the first in the world to offer protection to species like the Great white shark, Southern right whales and many more, yet it has chosen to proceed with plans to install a fish farm in an area famed for its populations of these, and several more, protected species.

Gansbaai, with Dyer Island lying 5 miles offshore, is an ocean paradise. It is the world's number one Great white shark hotspot, as well as home to seasonal visitors like the Southern right, Humpback and Bryde's whale, not to mention host to Bottlenose, Common and Hump-backed dolphins.

A breeding population of endemic African penguins live on Dyer Island, and share the Island with some of the world's rarest sea birds, like the African Black oystercatcher and the Roseate tern. Every species mentioned here, plus many more, are fully, and internationally, protected.

However, without a healthy ecosystem and food sources, these species cannot thrive. Instead of aiming toward making this area a Marine Protected Area as it should be, the SA Government has chosen to take another route and develop the area commercially, to the detriment of the resident species.

Salmon Salar Sea Farming, a Norwegian company, has combined with local businessman Bertie Rumsouer to create SA's first marine fish farming project. This is intended to be the first of many as a way of curbing the unemployment problem in South Africa. The project was quietly in development for some years before the green light was given by Marine and Coastal Management in 2001. It was not until 2005 that pens were hurriedly erected and placed about 1km offshore from Kleinbaai (Gansbaai). The pens are 20m in diameter and approximately 20m deep. They have a predator net surrounding them. Within weeks a reported 5000 Norwegian Salmon were placed in the awaiting pens. The companies involved claim that the salmon is for local consumption, although this is highly unlikely.

The position of the pens, as well as the imported salmon species, make for an ecological disaster waiting to happen. Having any sort of permanent nets or ropes in Gansbaai waters is a horrific idea to start off with. Southern right whales with their newborn calves are numerous here, the danger to them becoming entangled and drowning is huge. That goes for the other species of whale and dolphin found here.

The idea of having a pen full of fish in an area with such a high number of fish eating predators is like putting a sheep pen in the middle of the Kruger. The Salmon are packed densely, their waste, activity and smell will draw predators from all around, including Great white sharks, Cape fur seals, African penguins and cormorants. These fish eating birds can easily becoming entangled in the netting. Cape fur seals are highly intelligent and will make easy work of the netting by either finding a way in over the top or simply biting their way through.

The salmon have no where to run, the seals will quickly learn that it is worth the effort. A Great white shark will not think twice about taking a dead salmon lying at the bottom of the pen, biting from the outside, taking a chunk of netting as it does. A shark will also feed on animals entangled in the netting, like seals, potentially becoming entangled themselves. One has to question what the farm owners will do with a white shark in their nets – will they make any attempt to set it free?

The pens are anchored in a position open to the infamous Cape storms and high seas. Swell reaches 9m in the area in winter. Storms have already wreaked havoc on the pens this year, resulting in the loss of several hundred Norwegian salmon to the local ecosystem. Foreign species escapees, especially of a genetically modified species, pose a huge threat to a local ecosystem. The new arrivals compete for food and space with natural stocks, and are often able to reproduce much faster than wild fish.

The farm owners claim that the Norwegian salmon cannot breed in the local waters. To that, all I can say is that earlier this year I joined about 20 local guesthouse owners and residents in their annual Rooikrans culling expedition in Gansbaai. If you don’t know what Rooikrans is, how about the last time you saw a Eucalyptus tree here in SA?

Escapees create additional pressure and compete with local fish species like Yellowtail and Kabeljou for food. These local species are already at an all time low.

The caged salmon are fed fish pellets, and it has been claimed that the farm is using growth hormones and antibiotics, amongst others, like other fish farms. These artificial chemicals, as well as food excesses and fish waste are being released freely into the surrounding underwater ecosystem. Bad luck for any sedentary animals that may be residing underneath the pens, this waste will simply smother the sea floor.

When the current and sea conditions move it around, it is simply spread over the whole area. To pollute the sea bed in this manner will have knock-on effects all the way up the food chain.

Fish kept in such densities become a breeding ground for parasites. Farmed fish are infamous for their parasite load. Studies have shown these parasites are passed on to wild fish that are simply utilising the same water column or even by them swimming past the pens. The same goes for diseases.

The farm has so far lost all 5000 salmon originally placed in the pens. The death rate in the first few months was high, and storm damage allowed the rest to escape. The farm has already replaced those 5000 with new ones.

No amount of media coverage has had any effect thus far, and several companies and individuals have been 'warned off' speaking up against the farm. No Environmental Impact report was ever done for the farm and plans were not made available to the public as they should have been. There is currently no monitoring being undertaken. Is something unsavoury afoot in Gansbaai. If not, why are these people allowed to destroy our ecosystem and threaten our marine life

Source: www.sharklife.co.za