There is a parallel world to ours. It too has a volcanic mountain like Mount Warning, formed 20 million years ago as the Australian continent drifted north over a hot spot, though it is four times as high. It too has gorges carved into the rock by the Tweed and Brunswick rivers, though rather than being 100–200 metres deep its canyons are 1,000–2,000 metres deep. While people once wandered around the head of the canyons, its atmosphere has now become so dense that they would implode. Since people left, new weird and wonderful creatures have taken over.
It is hard to fathom how this parallel world can exist with most of us only being vaguely aware of its magnificence. Even the few who study it only have a vague idea of the creatures that inhabit it. Yet humans have come to rely on its bounty, with devastating consequences.
We now have an opportunity to protect a small part of this parallel world, though only if you want to. The Commonwealth government is now deciding which parts of its Temperate East Marine Region it will protect to establish its promised Comprehensive Adequate and Representative (CAR) marine reserve system. The region extends from Bermagui on the south coast to past Fraser Island and out to beyond Norfolk Island.
The reserve system is required to include a full range of ecosystems, reasonably reflect the biotic diversity within those ecosystems, and have the required level of reservation to ensure the ecological viability and integrity of populations, species and communities. The evidence is that this will require 20–50 per cent of each population and ecosystem to be fully protected from fishing.
In November 2011 the Commonwealth released proposals for 25 per cent of this region to be incorporated into marine reserves, though most reserves are still available for most forms of fishing, with only 4.3 per cent fully protected in Marine National Park zones.
The proposed outcomes are far worse for coastal ecosystems. For the Commonwealth controlled waters of the continental shelf a mere 1.6 per cent is proposed for reservation, with only 0.01 per cent fully protected. Similarly for the continental slope only eight per cent is proposed for reservation with none fully protected. This is one of the worst outcomes in Australia. We have been dudded.
Numerous ecosystems, key ecological features, biologically important areas and severely depleted species have been excluded.
The Commonwealth originally identified the Tweed Area for Further Assessment for consideration as a reserve, though dropped this without justification. Conservation groups are seeking its restoration by proposing the creation of the 15,000km2 Tweed-Byron Commonwealth Marine Reserve covering Commonwealth waters off the Tweed and Byron coasts. It extends from the existing NSW Cape Byron Marine Park (5.5km offshore) out for 220km to encompass massive 4km high volcanic mountains rising from the Abyssal Plain. The proposed reserve encompasses about one per cent of the Temperate East Marine Region.
The aim of this proposal is to protect a sample of waters central to the overlap between Australia’s tropical and temperate species, with its own unique ecosystems, that will function as a stepping stone between proposed reserves to the north and south, and contribute to a genuine CAR marine reserve system.
Key features of the proposed Tweed-Byron Commonwealth Marine Reserve are:
• The continental shelf consisting of river valleys, cemented dunes, and ancestral shorelines drowned by rising seas from around 15,000 years ago, and now mostly smothered by sand and silt. Grasses and trees have been replaced by sponges and corals, birds by fish, and humans by dolphins and whales.
• The off-shore Windarra Banks reefs and pinnacles rising 30m from the continental shelf, an aggregation site for a plethora of fish, home to giant cod, kingfish and rays, and habitat of the critically endangered Grey Nurse Shark.
• The continental slope dropping from around 220m (24km from Cape Byron) down to the 4,600m deep Abyssal Plain. The descent takes you from the world of sunlight to the black depths where animals generate their own light. From the southerly flowing tropical waters of the East Australian Current, to an underlying cool sub-Antarctic current flowing northwards over beds of sponges and deepwater corals.
• The 2km deep Tweed Canyon eaten into the continental slope by the ancestral Tweed and Brunswick Rivers. A refuge for species, an area of enhanced productivity, an aggregation site for fish and predators, and a key ecological feature.
• The 4.6–4.9km deep Tasman Abyssal Plain, 84km from Cape Byron, formed by seafloor spreading associated with the breakup of the ancient supercontinent of Gondwana over 50 million years ago. Little is known of its inhabitants.
• The 20-million-year-old volcanic mountains of Britannia 170km from Cape Byron. Part of the Tasmantid Seamount chain rising up 4km from the abyssal depths to within 400m of the surface. These are refuges, aggregation sites and places of speciation for unique species.
Canyons such as the Tweed and seamounts such as Britannia are biodiversity hotspots. We know that when we get around to looking properly a large proportion of the species we find will never have been seen before. These are the sites we know should be targeted for reservation.
As you descend over the edge of the continental shelf and down the slope light rapidly diminishes; by 200m photosynthesis stops and by a kilometre down light can no longer penetrate. Knowledge of fish and seafloor organisms diminishes with the light.
Many species of the deep have long lives, slow reproduction and slow maturity, and thus are particularly vulnerable to over-fishing. Populations of many higher-order predators, along with some targeted commercial fish, have declined by more than 90 per cent off NSW in the last few decades. Complex seafloor communities, including sponge and deepwater coral reefs, are being systematically eliminated by trawling. These are the ecosystems and species most urgently in need of the reservation the Commonwealth is denying them.
Please show your support for marine conservation and the proposed Tweed-Byron Commonwealth Marine Reserve by emailing [email protected]. On its own this proposal does not rectify the manifest deficiencies in the Commonwealth’s proposed reserve network, though it is a worthwhile start. The full proposal is available at http://ncec.files.wordpress.com/2012/01/proposed_tweed_byron_marine_reserve.pdf