An Environmental Assessment of a Proposed Marine Farm Zone Extension at Butlers Point in Great Taylor Bay, South Eastern Tasmania

An environmental assessment of a proposed marine farm extension at the current Butlers lease in Great Taylors Bay was conducted in November 2013. Environmental data on substrate type, habitat distribution, bathymetry, benthic flora and fauna was assessed. The survey area covered 2.081 km2 where 1.989 km2 (95.58%) was comprised of sand habitat with a fringing hard substrate reef covering - 0.09 km2 (4.42 %) to the inshore side of the zone. The bathymetric profile of the site ranged from 1.6 m on the shoreward side of the lease (to the South West) to 20 m to the North West. The sandy substrate had a range of particle sizes from fine to coarse sands which correlated with depth. The sand substrate was characterised by screwshells (Maoricolpus roseus) both live and dead and numerous small burrows. The sediment grabs showed the presence of both live and dead New Zealand screwshells (Maoricolpus roseus), polychaete tubes, ghost shrimp (Callianassidae), Corbula gibba bivalves, Caulerpa scalpelliformis, Caulerpa trifaria, hermit crabs (Paguristes sp.), crabs (Hexapus granuliferus), dead scallop shell (Pecten fumatus) and squat lobsters (Munida haswelli). The fringing reef habitat was characterised by Caulerpa trifaria, Caulerpa longifolia, red algae, Macrocystis pyrifera, Sargassum sp. (which was covered with green filamentous algae), Phyllospora comosa, Ecklonia radiata, Caulerpa longifolia, Caulerpa trifaria, plate sponges, numerous Southern Hulafish (Trachinops caudimaculatus) and Blue-throat Wrasse (Notolabrus tetricus). These findings are consistent with the habitats described by the SeaMap Tasmania surveys conducted in 2000 at this site (Barrett et. al. 2001). Apart from Macrocystis pyrifera, no threatened, endangered or protected species were recorded or observed from the video or grab samples.