Saucer Scallop

Latin name: Amusium balloti

Common names: Scallop, Scallops

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Wild Caught


Key Facts

  • Trawl fisheries targeting scallop in WA operate over sandy sea floor and are not permitted in sensitive habitats, such as seagrass beds and fish nursery areas.
  • Area closures in marine parks also provide additional protection for marine habitat and protected wildlife.
  • Stocks are monitored every year before the start of fishing to ensure numbers are adequate to support fishing effort.
  • The majority of stocks have rebuilt to acceptable levels following depletions as a result of a marine heatwave in 2011.
  • The fisheries catch small numbers of protected seahorses and pipefish; devices that enable turtles to escape are mandatory. A lack of independent observer coverage is of concern.

More information

  • WA Shark Bay Scallop Managed Fishery, Abrolhos Islands and Mid-West Trawl Managed Fishery, South West Trawl Managed Fishery, South Coast Trawl Fishery  (959t in 2016)

Saucer scallops are caught in a number of different trawl fisheries in WA, with the largest fishery operating in Shark Bay. Trawling may have some effect on the seafloor, but the impact is considered low as trawling mainly takes place over sandy sea floor that is naturally resilient to disturbance. Vulnerable habitats such as seagrass and fish nurseries are closed in order to protect them from the effects of trawling.

WA trawlers catch some threatened species, including seahorses and seasnakes, but in very low numbers that are unlikely to have population level impacts on these species. While the majority of fishing effort occurs in waters that are too cold for sea turtles, devices that allow turtles to escape are mandatory on boats where interactions could occur. However, there is no independent observer coverage in the WA-managed fisheries, and reported protected species interactions require verifying.

Marine parks provide significant protection for both marine habitat and protected wildlife in the largest saucer scallop fishery in Shark Bay, and state and commonwealth marine parks protect other areas close to saucer scallop fisheries.

Scallop populations are complex to assess, as scallop stocks are heavily influenced by factors such as water temperature. In WA, saucer scallop stocks were severely impacted by a three-year marine heatwave event that began in 2011, and the fishery has been in a rebuilding phase since then. Catches have recovered to pre-heatwave levels in some areas in 2018.

In WA, populations of saucer scallop are closely monitored, for example, independent surveys to determine scallop numbers are made at the beginning of the fishing season and areas are then opened if populations are adequate to support fishing activity. The fishing season is timed so that saucer scallops spawn before the fishing season, which helps protect stocks.

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Wild Caught


Key Facts

  • Saucer scallops are overfished in QLD, with numbers reduced to around 5% of historical levels.
  • Some area closures are in place to protect the stock and support recovery, and scallops that are caught throughout winter months must be returned to the sea. It is unclear whether these measures will be sufficient to support the recovery of an overfished species.
  • The fishery interacts with threatened species, including critically endangered species of sawfish, sea snakes and pipefish. Efforts have been made to reduce the impact of fishing on these species; catches remain significant but are not thought to be driving further declines in population numbers.
  • The fishery observer program in QLD was cancelled in 2012, meaning there is no independent record of the impact of this fishery on threatened species. Observation of the fishery is considered essential to the management of a sustainable fishery. It is highly likely that the impact of this fishery on endangered wildlife is higher than currently recorded.
  • Saucer scallops are caught using otter trawls that operate over the seafloor. Trawling is conducted over sandy and muddy seafloors in and around the Great Barrier Reef Marine Park. Zoning closes 66% of the marine park to fishing and the impact of trawling over previously trawled habitat is not thought to be of high risk to the marine environment.
  • The fact that no issues were picked up with the stock, until they had been reduced to 5% of historical levels, points to issues with the management framework currently in place. The broad reforms currently underway should deliver the effective management needed to identify issues in the fishery prior to reaching a critical point.

More information

  • QLD East Coast Otter Trawl Fishery (260t in 2017)

Concerns over the status of saucer scallops in QLD were noted in 2015. There were significant problems in this fishery, highlighted by a decline in catch and the high catch of small scallops. For example, the rate of scallop catch, an indicator of how easy it is to catch the species, was the lowest in the nearly 40-year history of the fishery.

A stock assessment undertaken in 2016 indicated that saucer scallop stocks were down to around 5% of levels when fishing began. Saucer scallops are overfished in QLD.

In response to this situation, fishery managers closed some areas to protect the stock but fishing continues in the majority of historical fishing grounds. In an effort to support rebuilding no scallops can be retained for a 6-month period over winter, which is when scallops spawn and reproduce. It is unclear whether these measures will be successful in recovering the species.

The framework used to manage the stock of saucer scallops was inadequate to pick up significant issues in the stock. The broad reforms currently underway should deliver the effective management needed to identify issues in the fishery prior to reaching a critical point.

Trawl fisheries generally catch a high number of species other than that targeted, which can result in a high volume of discarding of unwanted catch. Discarded catch is not required to be reported in QLD, meaning there is no information on the impact of the fishery on marine animals that have no commercial value.

Independent fishery observer programs are an important method of verifying protected species interactions, as well as other fishery impacts, such as the type and volume of discarded catch. Unfortunately the QLD Government has closed the observer program for all QLD managed fisheries in 2012. In the intervening six years, there has been no independent on-vessel monitoring of the impact of the fishery, which is unacceptable for fisheries operating in the ecologically sensitive regions of the Great Barrier Reef. Concerns have been raised regarding under-reporting of endangered species caught in the fishery in logbooks; as there is no record of actual protected species interactions over time, the ecological impacts of the fishery cannot be measured or managed.

Trawling occurs over sandy and muddy within the Great Barrier Reef and Moreton Bay Marine Parks, where habitats are relatively well understood, as well as to the south of the marine park. Zoning closes 66% of the Great Barrier Reef and 44% of the Moreton Bay marine park to trawl fishing, protecting a significant proportion of marine habitat. Assessments of the impact of fishing to marine habitats showed that trawling presents a relatively low risk of long-term or significant damage to habitats within the marine park. In addition, all boats operating in the fishery have location monitoring devices, which means that authorities can ensure fishing is only taking place in areas open to fishing.