sgreport1

	Seagrass Beds and Fauna of St Kilda Harbour Continued

Report #1	By Marine Science - Queenscliff May 2000
	Guy Werner & Matthew McArthur
Introduction	This is the second investigation of the St Kilda Breakwater for Earthcare by the authors. It focuses on identifying the macro-organisms at different seagrass bed sites within the breakwater. Further aims were to identify eels seen in the area at night and note any other nocturnal species.
Method	Dives were conducted on 25/4/00 at various seagrass locations around the breakwater area. Dive site one was near the perimeter of the study area, outward from the marina pier and on a bearing of 65 (=245-180) degrees magnetic from the end of the breakwater. Dive site two was on a seagrass bed near and approximately north of the kiosk. Dive site three was on a seagrass bed closer to shore. A night dive was also conducted to identify eels seen in the breakwater and to observe any nocturnal organisms. The night dive covered the area between the kiosk and the beginning of the breakwater proper. All sites are shown on the faxed chart of the area. Two opera house traps were deployed in the area before the night dive (6:15 p.m.) and recovered after (8:10p.m.).
	Apart from the night dive, dives were limited to thirty minutes. Note was taken of all attached macroalgae and larger invertebrate species (>~2cm). Where on-the-spot identification was not possible, underwater photographs were taken and the specimen collected, if possible.
Results	The seagrass at all sites was Heterozostera tasmanica. Density was considered to be sparse, dense, and dense with bare patches at dive sites 1, 2, 3, respectively. The accompanying photographs illustrate the conditions.
	Species observed at each dive site are given in the following table. Similar numbers of species were observed at each site. The green algal genus Caulerpa was represented by the most species at each site. A number of species were represented at all sites e.g. Little Rock Whiting, Caulerpa scalpelliformis, Cunjevoi. Others were only observed at one or two sites. The introduced pest, Sabella spallanzanii was present at all sites while the Northern Pacific Seastar, Asterias amurensis, was not observed at the first dive site. Another pest species was Codiumfragile tomentosoides at site 2.
Site 1	Depth 2.3metres
Chlorophyceae	Caulerpa brownii Caulerpa scalpelliformis Caulerpa simpliciuscula
Phaeophyceae	Dictyota dichotoma
Rhodophyceae	Gracilaria secundata Wrangelia sp. (Family Ceramiaceae)
Phylum Chordata	*Telcosts* Acanthopagnus butcheri..... Black Bream Arenigobius bifrenatus..........Bridled Goby Neodax balteatus ..........Little Rock Whiting *Family Syngnathidae* .........Pipefish *Family Platycephalidae* Platycephalus speculator .......Yank Flathead *Family Pyuridae* Pyura stolonifera ........Cunjevoi
Mollusca	Ostrea angasi .................Mud or Flat Oyster Mytilus edulis planulatus ..........Blue Mussel
Polycheta	Sabella spallanzanii........ European Fan Worm Diopatra sp. ....................Onuphid worm
Cnidaria	Anthopleura aureoradiata ................Sand Anemone
	caulerpa species
Site 2	Depth 1.9metres
Chlorophyceae	Caulerpa longifolia Caulerpa scalpeliformis Chaetomorpha sp. Codium fragile tomentosoides ...........Green Sea-fingers
Rhodophyceae	Gracilaria secundata Jeannerettia sp. ? Laurencia filiformis Laurencia sp.
Phylum Chordata	*Telcosts* Acanthopagnus butcheri .......Black Bream Neodax balteatus ..............Little Rock Whiting *Family Monacanthidae* .............Leatherjacket sp. Pyura stolonifera ...........Cunjevoi Crustacea Philyra laevis.......... Pebble Crab Echinodermata Asterias amurensis........ Northern Pacific Seastar *Mollusca* Ostrea angasi ........Mud or Flat Oyster *Polychaeta* Family Onuphidae species Sabella spallanzanii ..........European Fan Worm
Site 3	Depth 2.2metres
	*Chlorophyceae* Caulerpa brownii Caulerpa scalpelliformis Caulerpa simplicuscula
	*Phaeophyceae* Colpomenia perigrina
	*Rhodophyceae* Champina sp. Jeannerettia sp.
	Phylum Chordata
	*Chondrichthyes* Trygonoptera testacea..... Common Stingaree
	*Family Odacidae* Neodax balteatus........ Little Rock Whiting Platycephalus speculator ........Yank Flathead
	Family Pyuridae Pyura stolonifera ........Cunjevoi
	Echinodermata Asterias amurensis ........Northern Pacific Seastar
	*Mollusca* Mytilus edulis planulatus........... Blue Mussel Anapella cycladea Nasarius pyrrhus
	*Polychaeta* Sabella spallanzanii ...........European Fan Worm Diopatra sp. .........Onuphid worm

Night Dive	No eels were observed on the night dive. However other animals were trapped or observed.
	Possibly the greatest change from day to night was the presence of phosphorescence in the water column. Disturbance by the divers caused the planktonic organism responsible to luminesce with a flash of weak blue-white light in the order of 10 to the litre.
	At least two species of anemone were more obvious at night as their tentacles were extended.
	A variety of fish were observed. These included Southern Sea Garfish Hyporhamphus melanochir, Yank Flathead Platycephalus speculator, one Cobbler Gymnapistes marmoratus, Southern Cardinal fish Vincentia conspersa, a shoal of stationary Black Bream Acanthopagrus butcheri (in shallows), a flounder, two small leatherjackets or toadfish, Smooth Toadfish Tetractenos glaber, Spiky Globefish Diodon nicthemerus and the ever-present Bridled Gobies Arenigobius bifrenatus.
	The traps yielded one Asterias amurensis, one crab Nectocarcinus integrifrons and one Bridled Goby.

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