Young Naturalists Beach Sweep 2020

BEACH SWEEP 6 AUGUST 2020

The weather was not at all conducive to a beach excursion. However, eight people braved it, including four children, as well as our three leaders. The storm overnight had left piles of kelp and seagrass for us to fossick amongst. But with rain threatening, we retreated to the shelter of a member’s back car door to identify and discuss our finds.

The brown algae included the Common Kelp (Ecklonia radiata), and Sargussum Weed (Sargassum spp) with its floats which the children loved popping. The red algae included Jelly Weed (Betaphycus sp), and the green algae included Velvet Balls (Codium sp). The seagrasses included Wireweed (Amphibolis sp) and Ribbon Weed (Posidonia australis).

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Sponges (really sponge skeletons) were abundant among the sea-wrack, and there were several dried-up bluebottles (Physalia sp). These are colonial jellyfish, with polyps specialised for different functions. We found Sea Squirts (Ascidians or Tunicates) including bright red Sea Tulips on their stalks and various colonial species.

There were tiny specimens of Lace Coral (Bryozoa) adhering to the stems of the Wireweed, and goose barnacles on their stalks sticking to some of the Cuttlebones. Two small dead crabs were found – one of them a little sand crab, the size of a spider, and the other a ghost crab with its stalked eyes. Of the many Cuttlebones, one still had some of the flesh on, not quite rotted away, and some had the teeth-marks of predators. Other molluscs included turban shells.

If we had not had to rush back to shelter, we would have found much more, such is the abundance of marine life found washed up after a storm. However, there was plenty to interest the children and adults alike.

Coastwest has produced an app called Beachcombers Field Guide that is very useful in identifying marine organisms washed up in the flotsam. To download it to your phone, click above link.

Mike Gregson