In New Zealand, we commercially fish populations down to a level of between 20 to 25 per cent of naturally occurring populations to achieve the 'maximum sustainable yield' which has major ecosystem impacts (although the level for snapper is set to increase from 23 per cent to around 40 per cent).
Marine reserves help ecosystems to recover by creating healthy, biodiversity-rich reef environments while restocking surrounding areas. Less than one per cent of our coastline is protected (more if you include the Kermedec marine reserve) compared with 33 per cent of our land.
2. Buy plastic-free products
Scan the ingredients list of cleansers and handwash for innocuous-sounding 'moisturising beads' (actually a type of plastic called polyethelene). These miniscule plastic balls float their way through the waste-water treatment process, ending up in rivers and eventually the sea, attracting oleophilic (oil-loving; plastic is derived from oil) toxins and ending up in sea creatures' stomachs.
Other ocean-bound plastic ends up in one of seven huge gyres, like the enormous Great Pacific Garbage Patch (rumoured to be the size of Texas) where rubbish congregates in a 'soup'. Here it's swallowed by organisms mistaking bags for jellyfish and tiny nurdle pellets (used to make virgin plastic) for fish eggs.
How to help? Stop buying plastic - reuse plastic bags, bring your own glass containers to supermarkets and shops, and choose non-plastic drink bottles and lunchboxes.
3. Bin your butts
Around 35,000 cigarette butts are flicked onto the pavement each day. Rain funnels them down the drain, ending up in the sea. Filters contain acetate, a type of plastic, which takes years to break down and has been found in the stomachs of birds, whales, fish and other marine species.
4. Support renewable energy
Climate change is having major effects on the ocean, making it more acidic and therefore harder for shell-forming creatures to survive (and also causing coral die-offs around the world). The scientific consensus is that we needed to act yesterday to halt climate change.
Buy, support and create renewable, clean energy instead of supporting coal mining, oil drilling and fracking.
5. Ride your bike
Nearly 20 per cent of our national gross CO2 emissions come from transport. Cars are also responsible for about 70 per cent of stormwater pollution (pollutants, heavy metals and chemicals from petrol, engine oil, tyres, break linings, brake pads, anti-freeze and car-washed water).
Choose public transport or get on your bike.
6. Plant trees
Removing trees and clearing land releases soil and sediment, washing it into rivers, where it mixes with nutrients from fertilisers and farm effluent, tiny particles of heavy metals from roads and nasty bugs from septic tanks. It chokes up fishes' gills, smothers cockles and bottom-dwelling organisms and turns sandy beaches muddy.
Planting trees helps the soil to stay put while sucking up carbon, reducing the impact of climate change.
7. Grassy car wash
Lather up your car on the grass or somewhere that the water can soak in (or at a car-wash facility where they collect their own waste water) to avoid soapy, chemical-laden water running off roads into streams and the ocean.
Detergents (even the eco-friendly ones) burn our native fishes, change the acidity of the water and strip out the oxygen as they break down. Plus, chemicals just end up accumulating in estuaries and fouling the sea.
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