Wednesday, August 13, 2014

Bluecliffs Beach

 A few weeks ago we had a trip to Bluecliffs Beach. The tide was out and the going was easy. Five years ago we made an interesting discovery here – a Leopard seal and a Hector’s dolphin. This time we found just a bit of a Hectors dolphin, six vertebrae still connected, enough for DoC to add another dot to the database that indicates one less Hector’s dolphin. There were a few odd seal bones as well, the humerus with a characteristic shape, and a shoulder blade.

 I was half looking for any of the remains of the nine Killer whales that had stranded and died much further to the west; whales can drift a long way before the carcase strands or sinks. When it loses buoyancy and slowly drops we have what is called a whale-fall. The carcase can feed a little ecosystem for 25 years or more, firstly with the flesh, then the oil in the bones and when the skeleton is gone there can remain the teeth and the earbones which are very dense and durable.

 You can see why it is called Bluecliffs. The clay banks, twenty metres high are bluey-grey, composed of sediment that settled on the ocean floor some millions of years ago. In places there are bands of fossil shells, mostly small clams. The cliffs are eroding back but that’s an ongoing process. Waves sweep up the gravel beach and gnaw at the soft base of the cliff. I wouldn’t want to be under when it collapses. Years ago there was an old grader on the beach, probably a relic from the time when the road ran along the top of the beach. Not much there now – we found part of the chassis; it’s being ground away each tide as the rocks are tumbled over it.

This sort of beach has the least marine life of any shoreline. The wave action is too strong for shellfish to live in the sand without being scoured out, the rocks are too small for anything to grow on them without being ground off and there are no rock pools, so the interesting part of the beach for a beachcomber is along the high tide line. That were you find the bones, the dried carcases of fish and birds, crab shells, driftwood and a few seaweeds.

 Next trip I plan to walk from the mouth of the Waiau to Rowallan. I haven’t done that stretch and it’s about the last bit of coast I haven’t walked between Port Craig and Waikawa Harbour.