Puzzling flotsam washed in by the tide

Stan Rivett and his 4-year-old affenpinscher dog, Lili, examine the numbered plastic jar tops which have been appearing mysteriously on the Ocean View, Dunedin, beach. Photo by Stephen Jaquiery.

While walking their dogs along the beach last week, Stan and Heather Rivett discovered several numbered plastic bottle and jar tops.

Along with the other rubbish they found on the beach, the couple threw the tops - numbered 375 and 357 - in the rubbish bin and thought nothing of it.

But they kept on discovering more of the mysterious items.

Now, with a dozen caps which include the numbers 11, 341, 396, 412 and 563, the couple would like to discover their origin.

Rubbish often washed up on the beach from Kaikorai Stream after heavy rain, but this was not the case over the past week.

"The number caps kept coming and we're curious about where they came from.

"Is it some sort of experiment or has someone's precious bottle top collection been lost in a flood?"