Beachcombing and Snorkelling at Watermans Bay

NS Branch March Golly Walk

A small but enthusiastic group gathered at Watermans Bay for our annual beachcombing and snorkelling morning. We chose Watermans Bay as it was likely to provide an opportunity to look at many aspects of natural history.

Our meeting point offered us with views of the cliffs and dunes, so Don started the morning by explaining the origin of the Tamala Limestone and the Spearwood and Quindalup Dune systems. He then narrowed down to the effects of climate change over the last 20,000 years before leading us to a spot on the beach about 2 metres above the current seal level where we were able to observe large fragments of coral—an indicator of both warmer temperature and higher sea level.

Our path down to Watermans Bay beach provided an opportunity to look at the naturally occurring and planted coastal vegetation. We saw Rhagodia baccata, Olearia axillaris, Westringia dampieri, Frankenia pauciflora, Spinifex longifolia and Myoporum insulare but could not determine whether the pigface was the native species (Carpobrotus virescens) or the South African species (C. edulis).

Marilyn Zakrevsky discussed the method she used to propagate Spinifex from seed and Don explained the way to tell native Marine Couch (Sporobolus virginicus) from the common couch grown in lawns—helicopter blades versus spears—ask Don if this hint doesn’t help!

Although there was a considerable amount of sea wrack, we were unable to find anything unusual on the beach. Maybe the very numerous Ghost Crabs that must live on the beach—based on the number of freshly dug burrows—were nature’s very efficient garbage collectors?

Apart from a few Silver Gulls, a Kings Skink was the only fauna we saw.

Unfortunately a moderate south-westerly was blowing by the time we returned to our starting point, so only one person ventured into the water.

Don Poynton

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