Roman Rock, A-Frame and Batsata Rock collections, False Bay

Ecklonia maxima.
Ecklonia maxima.

Romans Rock

GPS coordinates: Syy.yyyyy° Exx.xxxxx°

Divers visited this site on 10 April 2015, and the dive for kelp collections was from 10:23 to 10:33 (Robert S, Robert W, Sam; Eric as surface swimmer). The rocks around the lighthouse come up to the surface. The rocky outcropping from which these kelp were sampled came up to 3 m below the surface with gullies going down to 7 m before the entire rock dropped to 16 m rapidly. Only Laminaria was collected as Ecklonia was not present. The bottom topography is a round rock dome covered with thick old growths of redbait. Some almost a metre long. Nothing else grew on the top of the rocks other than these ascidians. The Laminaria grew on the edges of the rock dome at a depth of 5.5 to ~8 m on the hard rock outcroppings. The kelp were only sampled between 5.5 – 6.5 m. No sand was present but anemones and urchins could be found in the gullys. The rocky outcroppings on which the healthiest and largest Laminaria could be found had a more diverse assemblage of life.

Kelp on the boat.
Kelp on the boat.

A-Frame

GPS coordinates: Syy.yyyyy° Exx.xxxxx°

Divers visited this site on 10 April 2015, and the dive for kelp collections was from 10:45 to 11:05 (Robert S, Robert W, Sam; Eric as surface swimmer). The kelp bed behind the well known dive site A-Frame was sampled. The rocky outcropping from which these kelp were sampled came up to 1 m below the surface with the largest boulder sitting well above the surface. Laminaria and Ecklonia were sampled from similar depths (6 m?). The bottom topography is a few large boulders forming a reef. Ecklonia grow at the shallowest 1 m depth on top down to ~6 m, with the sand in between the boulder reef systems starting at 7 m. Sparse Laminaria forming a border around the denser Ecklonia beds were sampled from ~6 m. Reefs were not heavily populated by grazers or other organisms. Saw a few small shy sharks.

Batsata Rock

GPS coordinates: Syy.yyyyy° Exx.xxxxx°

Divers visited this site on 10 April 2015, and the dive for kelp collections was from 11:53 to 12:16 (Robert S, Sam; Robert W and Eric as surface swimmers). The Ecklonia were harvested at 6 m while the sparse Laminaria could only be found below 10 m and were sampled between 10 – 12 m. The bottom topography where the Ecklonia was sampled was a smooth reef sloping down with some larger boulders. The reef was populated with other large algal species, crustose corallines, sponges, anemones, rock lobsters, crabs and other reef goers. Several small shy sharks and a few large pyjama cat sharks were seen, too. This has been the most species rich site thus far. The reef ended at ~12 m in sand and this lower portion had many smaller rocks from which Ecklonia and Laminaria were found. The Ecklonia were still far more prevalent than the Laminaria, though the later were in very good condition. The kelp became denser the deeper the reef went. We had seals playing with us while sampling the Laminaria.

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