HOW DOES human rubbish reach one of New Zealand’s sub-antarctic islands? Uninhabited and remote, the Cambell Islands are protected as National Nature Reserves and collectively form a World Heritage Area. DOC is engaged in restoring these somewhat-modified islands by removing introduced animals such as sheep, cattle and rats. This is helping return the islands to their pre-human glory. Vegetation is burgeoning on Campbell Island and small birds such as pipits and snipe are breeding again on the main island, having survived the rat era by living on small offshore stacks. The Campbell Island teal, a flightless duck, was bred in captivity and these are now being released back on the island.
But despite these gains, the negative influence of humans is still felt on the islands. Peter and Stacy Moore of DOC have visited Campbell Island for several years studying the southern royal albatross population. They report that long-line hooks and plastics are brought back to the island by the albatrosses.
Because they are scavengers, albatrosses investigate any floating object they see. “They are attracted to plastic rubbish which they eat when they mistake it for food,” says Stacy. “We find weird and numerous pieces of plastic such as bottle tops, pens, cigarette lighters, and squid lures, even childrens’ toys, beside albatross nests.” These items have been regurgitated by chicks or their parents along with other indigestible hard parts. “If too much plastic material is fed to chicks they could starve or dehydrate as there is no room for food, or be poisoned by organochlorines and other toxic substances in the plastic,” says Stacy.
One estimate is that 5 tonnes of plastic are fed to 500,000 Laysan albatross chicks each year on Midway Atoll in the North Pacific and thousands of birds die as a result. Those birds fly in search of food over what has been described as the world’s largest rubbish dump—a huge rotating gyre full of plastic flotsam. “Although things are not as dire in New Zealand, judging by the amount of plastic we find on Campbell we can’t be complacent about our own throw-away society,” Stacy says.
Albatrosses, those magnificent denizens of the open ocean, need every help they can get to ensure they continue to grace our waters for generations to come. “We can help the albatrosses now by continuing to encourage fishers to reduce the chance of accidentally catching seabirds,” says Peter. “Casual littering on land or from boats will harm marine life, even at our remote islands, so we can all do our bit to keep our oceans clean,” says Stacy.
UBE-NOSED ALBATROSSES AND petrels, or Procellariiformes, have a keen sense of smell. They also eat more plastic than other species. Scientists from the University of California, Davis have linked this behaviour to the presence of a delicious-smelling algae that naturally adheres to floating objects in the ocean, such as floating plastic particles.
The sulfurous smell given off by the algae - dimethyl sulfide (DMS) - is a foraging cue for the birds. Algae release it when grazed on by creatures such as krill. The birds, which love krill, can track this food source by sniffing for DMS as it wafts up from a visually stark ocean surface.
When scientists floated plastic beads in the California current for three weeks, they found the amount of DMS the beads emitted afterwards was four times the known minimum that Antarctic prions can sense.
According to a 2014 global analysis in PLOS ONE, the ocean contains an estimated quarter of a billion tonnes of tiny, plastic, floating particles, in more than five trillion pieces. Researcher Matthew Savoca says seabirds aren’t the only species that use DMS as a foraging cue—certain reef fish, whale sharks and loggerhead turtles are also tuned into it.
Article from Forest and Bird July 2018:
New Zealand is known as the ‘seabird capital of the world’, with 36 species that only breed on New Zealand islands. The country with the next highest number of endemic species is Mexico, which has just five.
As well as a very high rate of birds that only breed here, New Zealand is a ‘sometimes home’ to one third of all seabird species in the world.
Ms Baird says plastic makes up 78% of rubbish on New Zealand beaches, and most of it is fishing lines, plastic bags, or small fragments.
“Floating plastic can also carry pest species from other parts of the world, so the risk is not just environmental, but economic as well. The Ministry of Primary Industries should be very concerned that plastic pollution has the potential to harm our primary industries.”
The Guardian has reported that marine scientists documented 38 million pieces of plastic on the remote, uninhabited Henderson Island in the South Pacific. The human garbage they found originated from all over the world. They found samples from Germany, New Zealand, Canada, and elsewhere, amounting to about 18 tonnes. A lot of this plastic is not even visible. In a single square-metre of sand, digging down 10 cm the researchers found over 4,000 tiny bits of plastic.
The North Pacific gyre creates the largest garbage site in the world: 700,000 to a million square kilometers of floating plastic. The gyre contains six kilograms of plastic for every kilogram of plankton. In Hawaii, south of this gyre, a dead turtle was found with over a thousand pieces of plastic in its stomach.
Pieces of plastic are sharp, brittle, toxic, and routinely found in the stomachs of dead fish, turtles, and marine mammals. Plastics can come with a range of hazardous additives and can act as a chemical sponge, soaking up and concentrating other pollutants. Marine species, including fish, seabirds, and even marine mammals, can end up eating pieces of plastic, and at the same time get an additional dose of toxic chemicals.
Researchers have found plastic in the stomachs of 44% of all seabird species, 22% of cetacean species, and in ALL sea turtle species. Among seabirds, the Procellariiformes (albatross, petrels, shearwaters) are most vulnerable due to their small gizzard and inability to regurgitate the plastics. Plankton eaters – birds, fish, and mammals – often confuse plastic pellets with their food; copepods, euphausiids, and cephalopods.
The plastics obstruct the animals’ intestines, block gastric enzyme secretion and there are growing fears that they might also disrupt hormone levels or cause other biological effects as a result of the chemical burden they carry. It is estimated that up to about one million seabirds and 100,000 marine mammals die each year from ingesting plastic or by getting tangled in nylon fishing line, nets, six-pack plastic can holders, and plastic rope.
Things you can do to help:
- Use your “consumer power”. Reject anything that “in itself is junky, made of plastic or single-use”
- If it didn’t come in a recyclable container, don't buy it.
- At the supermarket, buy milk in glass or ask for the refillery option at forward-thinking supermarkets.
- shop at Goodfor Refillery - They have pantry staples at supermarket prices and free delivery over $100
- Start baking your own bread
- Buy local, farmers market, fair trade or ecologically friendly alternatives.
- Ask for your meat to be wrapped in paper at the grocery store or take containers for easy and quick storage when you get home.
- Reduce, reuse, rehome, recycle.
Links:
“38 million pieces of plastic waste on uninhabited island”: Guardian
2017 “Production, use, and fate of all plastics ever made,” Roland Geyer, Jenna R. Jambeck, and Kara Lavender Law
Science Advances, 19 July 2017
https://www.nzgeo.com/stories/life-is-no-picnic-for-albatrosses/ 2008
https://www.nzgeo.com/stories/a-taste-for-plastic/ 2017
