"We knew of this problem in New Zealand, we'd heard of people finding them, but we'd never seen it ourselves. It was a shocking illustration of the problem."
It was not the first time Howitt had seen rubbish affecting wildlife.
"We found a little blue penguin strangled by a plastic bottle ring on Great Barrier Island and, horribly, turtles have washed up dead in the Hauraki Gulf with plastic in their guts."
An estimated one million sea birds and 100,000 marine mammals are killed each year because they eat or get trapped in rubbish, he said.
Sustainable Coastlines head Sam Judd said 560 people joined the Coromandel clean-up recently and collected almost enough trash to fill a shipping container. So far this summer, 5263 volunteers have joined clean-ups around the country, removing 86,196 litres of rubbish.
The ZM Mr Whippy van will be at the Milford clean-up on Thursday, providing free ice-creams to volunteers.
YOUR CHANCE TO WIN BIG
Win a camera every week
Take a photo of your friends or family cleaning up your favourite beach and go in the draw to win a Sony Cyber-shot TX10, valued at $649.95. With an Underwater Sweep Panorama function and 16.2 Mega Pixels you'll be able to take stunning underwater photos, as well as crystal clear shots on land. We have one camera to give away every week for the next 10 weeks to the person who takes the best photo, as judged by Herald on Sunday illustrations editor Chris Marriner. Five runners-up will each receive a copy of the book Beached As - New Zealand Beaches Then and Now by Craig Levers.
GRAND PRIZE
At the end of our Beach Busters campaign, the overall winner will receive a grand prize package comprising:
* a Sony Tablet S valued at $749.95
* a dive, snorkel or sightseeing trip for two to the Poor Knights Marine Reserve courtesy of Dive! Tutukaka
* $400 worth of clothing from surf label Sitka.
Entries close each week at Friday noon, and the winning photo will be printed each Sunday. So get snapping, and email your best shot as a JPEG to pictures@hos.co.nz with 'Beach Busters' in the subject line. Make sure you include your name, address and daytime phone number. Include a caption giving the place and full names of the people in the photo.
Please see terms and conditions at www.nzherald.co.nz/HOScompetitions. APN New Zealand reserves the right to store electronically any pictures entered in the competition and to use the images in any of its publications.