Ecosystem and Habitat Interactions

By-Product

Fishers are only authorised to retain scallop species, so by-product only consists of queen (Equichlamys bifrons) and doughboy (Mimachlamys asperrima) scallops, of which very little is retained. Scallop fishers are required to record any retained by-product.

By-Catch

By-catch in the recreational fishery are effectively nil as scallops are hand collected. Vessels usually anchor at dive locations but anchors are deployed on unconsolidated sediment so there is no concern with habitat interation.

By-catch impacts of the commercial fishery are low because volume is low and the majority of bycatch is returned alive and healthy. Common bycaught species are molluscs such as dog cockles (Glycymeris sp.) and the native oyster (Ostrea angas). Diogenid hermit crabs (Paguristes tuberculatus) and the introduced screw shell (Maoricolopus roseus) are also taken as by-catch. Below is a list of scallop bed species retained in commercial gear during two scallop dredge surveys conducted at White Rock in 2006.

Category	Common Name	Scientific Name
Commercial Scallop	Commercial Scallop	Pecten fumatus
Bivalves	Doughboy Scallop	Mimachlamys asperrima
	Queen Scallop	Equichlamys bifrons
	Mud Oyster	Ostrea angasi
	Mussel	Mytilus edulis
	Dog Cockle	Glycymeris striatularis
	Razor clam	Atrina tasmanica
Other Molluscs	New Zealand Screw Shell	Maoricolpus roseus
	New Holland Spindle Shell	Fusinus novaehollandiae
	Tulip Shell	Pleuroploca australasia
	Triton Shell	Charonia lampas
	Cowrie	Cypraea hesitata
	Pale Octopus	Octopus pallidus
	Southern Keeled Octopus	Octopus berrima
Crustaceans	Hermit Crab	Strigopagurus strigimanus
	Unidentified Hermit Crab	Unidentified sp.
	Spider Crab	Leptomithrax gaimardii
	Hairy Shore Crab	Pilumnus tomentosus
	NZSS Hermit Crabs	Unidentified spp.
Seastars	11-Arm Seastar	Coscinasterias muricata
	Astropectinid	Bollonaster pectinatus
	Oreasterid	Nectria ocellata
Urchins	Common Urchin	Heliocidaris erythrogramma
	Pencil Urchin	Unidentified sp.
Fish	Crested Flounder	Lophonectes gallus
	Lachet	Lepidotrigla vanessa
	Shaw’s Cowfish	Aracana aurita
Rays	Tasmanian Numbfish	Narcine tasmaniensis
	Banded Stingaree	Urolophus cruciatus
Other Species	Pumpkin Sponge	Unidentified sp.

Threatened, endangered or Protected Species

Interactions with threatened, endangered or protected species (TEPs) are rare. There are low levels of interactions with sygnathids (seahorses and related species) observed, but these are usually released unharmed and interactions with sygnathid populations are limited. Given that most of the fishing effort takes place in habitats that are not generally favoured by sygnathids (i.e., sandy bottoms with low levels of habitat structure). Gear is towed at low speed so interactions with mobile protected species like seals, sharks cetaceans and seabirds are not observed.

Scallop fishers are required to record any interactions with TEPS. Fishers do not record bycatch caught in the dredge. Scallop fishers participating in state-wide surveys may make notes and observations about bycatch in log sheets, but this is not compulsory. For targeted surveys, where there are observers on board, the observers (IMAS or NRE Tasmania staff) may make some more detailed observations, including any interactions with TEPS, but the bycatch from each dredge tow is not quantified. More detailed collection of bycatch information during surveys should be considered, given that these are the only means of collecting this data for the fishery.

Ecological Interactions

Habitat interaction from the commercial fishery has been of some concern when gear interacted with sponge habitat. This problem has been addressed with the system of smaller spatial boundaries for beds opened in the TSF. This process takes account of sensitive habitats to ensure reduced gear interaction.

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