Yep - that's the Grey River bar, apparently one of the worst in Australasia. The heavy seas and high river flow were a result of the same weather patterns that caused floods in Australia.
The bar moves about quite a bit due to the changes in flow and sea levels etc, so it's apparently never in quite the same place. Those fishing boats had been out for over a week and made their way from Bluff I think. The skippers didn't seem too worried about it all!