Will there be sea lettuce this summer? Probably.

Will it be knee deep at the Main Beach? Probably not, but then again, it all depends.

Large sea lettuce drifts at the main beach in 2013. Photo: Jamie Troughton, Dscribe Journalism.

'Giving you a prediction is going mean someone sticking their neck out, I think,” says regional council Tauranga harbour principle advisor Bruce Gardner.

Part of the problem is sea lettuce volumes in the harbour and on the ocean beach are separate, but related events.

Last year there was a huge dump of sea lettuce on the main beach, but not much in the harbour.

'The sea lettuce situation in the harbour at the moment, especially in the southern part of the harbour from Omokoroa down to the city, is still at relatively low levels compared with bad seasons,” says Bruce.

'But that could all change. Things can change really quickly and the climate predictions are that we are heading towards an El Nino summer.”

Indicators include the prolonged period of westerly winds and cooler ocean water temperatures.

'The puzzling thing about that is that normally translates into quite a lot of sea lettuce in the harbour,” adds Bruce.

'It may well happen late. That is still a possibility.

'Last summer for example when it was not a particularly bad year for sea lettuce, we still got quite a lot of it coming up on the beach at the Mount,” says Bruce.

'So there are some different factors in play. Wind direction and strength, and current and tide all play a part. So even though you may have a huge amount of sea lettuce in the harbour, it doesn't necessarily mean it's all going to end up on Mount beach.

'It can, at times, just go straight out and you never see it. You usually see some on the Mount beach, but not huge amounts

'And then in low years, like last year, we got quite a lot on the beach simply because we got quite a lot of onshore winds, and it was exiting out the mouth of the harbour with currents bringing it back around.

'Then two days later a nice full high tide and an offshore wind – and it all disappears. So it's really, really difficult to predict or to say what the situation will be.

Climate scientists are extremely cautious, adds Bruce. 'On the basis of the prolonged westerly weather, they would say we are already well and truly into a El Nino summer, and it could strengthen. Climate scientists are still saying it's trending.”

Meanwhile, local kayaker Nathan Pettigrew has posted footage of the harbour on his Facebook page, and asks the question: 'Have you ever wondered just how much sea lettuce is actually in our harbour? Well, come for a ride as I take you from Matua toward Pilot Bay, by kayak, in just over 3mins.”