Scallop Ecosystem Interactions

Ecosystem and Habitat Interactions


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 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.

CategoryCommon NameScientific Name
Commercial ScallopCommercial ScallopPecten fumatus
BivalvesDoughboy ScallopMimachlamys asperrima
Queen ScallopEquichlamys bifrons
Mud OysterOstrea angasi
MusselMytilus edulis
Dog CockleGlycymeris striatularis
Razor clamAtrina tasmanica
Other MolluscsNew Zealand Screw ShellMaoricolpus roseus
New Holland Spindle ShellFusinus novaehollandiae
Tulip ShellPleuroploca australasia
Triton ShellCharonia lampas
CowrieCypraea hesitata
Pale OctopusOctopus pallidus
Southern Keeled OctopusOctopus berrima
CrustaceansHermit CrabStrigopagurus strigimanus
Unidentified Hermit CrabUnidentified sp.
Spider CrabLeptomithrax gaimardii
Hairy Shore CrabPilumnus tomentosus
NZSS Hermit CrabsUnidentified spp.
Seastars11-Arm SeastarCoscinasterias muricata
AstropectinidBollonaster pectinatus
OreasteridNectria ocellata
UrchinsCommon UrchinHeliocidaris erythrogramma
Pencil UrchinUnidentified sp.
FishCrested FlounderLophonectes gallus
LachetLepidotrigla vanessa
Shaw’s CowfishAracana aurita
RaysTasmanian NumbfishNarcine tasmaniensis
Banded StingareeUrolophus cruciatus
Other SpeciesPumpkin SpongeUnidentified sp.
List of scallop bed species retained in commercial gear during two scallop dredge surveys conducted at White Rock in 2006.

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.