Toxic Algal Bloom Update and Fishery Closures
Levels of the toxic algal species, Alexandrium tamarense have unfortunately been increasing in several locations on the east coast since early August. Biotoxin testing of mussel flesh samples taken from Mercury Passage has returned results almost twice the maximum prescribed regulatory limit for bivalve shellfish. This is the same toxic algal species that impacted the east coast last spring / summer.
Paralytic Shellfish Toxin (PST) in lobster has potentially serious implications for the domestic and international export trade of Tasmanian rock lobster. It is critical that domestic and international markets are not compromised by the toxic algal event.
The Commonwealth Department of Agriculture, Fisheries and Forestry (DAFF) is closely monitoring this situation in regard to potential export restrictions and DPIPWE has been liaising closely with this Department regarding the latest developments.
The commercial rock lobster fishery on the East Coast between Eddystone Point (Red Rocks) and Marion Bay was closed from Thursday 22 August 2013 while rock lobster sample collection from the area and testing for paralytic shellfish toxins (PST) was undertaken.
This precautionary action was taken to ensure that export and domestic rock lobster markets were not potentially exposed to any lobster with high levels of PST while samples were being tested.
The paralytic shellfish toxin (PST) maximum permitted level for bivalve shellfish is 0.80 mg/kg (this limit is being used as a proxy for rock lobster). China applies the same maximum permitted level of PST for all seafood.
Summary of Rock Lobster Biotoxin Test results
One lobster viscera sample from north Maria Is was above maximum permitted level.
One lobster viscera sample from St Helens was below the limit but had a moderate PST level 0.43
All other lobster viscera samples had low – very low levels of PST
All lobster flesh (tail meat) samples returned PST levels of < 0.025mg/kg.
Detailed results – PST level mg/kg per lobster viscera sample
Ansons Bay (the Gardens)
Northern Maria Island
It is anticipated that another round of rock lobster sampling will take place in late October / early November 2013.
At this stage there are no changes to the recreational fishery.
As with the situation last summer, DPIPWE takes advice from the agency responsible for public health, the Department of Health and Human Services (DHHS) and any requests it may have in terms of management actions. DPIPWE is liaising closely with DHHS on this matter but at this stage it has advised that closure of the recreational rock lobster fishery on the east is not warranted. All the public health warnings associated with the east coast toxic algal bloom last summer advised not to eat rock lobster viscera (guts and organs) from wild harvested lobster. None of the samples of rock lobster flesh (meat) tested last summer had toxin levels above the maximum prescribed health limit for bivalve shellfish (this limit is used as a proxy for rock lobster).
For up-to-date information about public health alerts relating to this event, refer to the Director of Public Health's current Public Health warnings or phone the Department of Health and Human Services hotline on 1800 671 738.
There are currently no recreational fishery closures due to algal blooms, however, there are public health warnings in place for the eating of wild shellfish and the viscera of rock lobster in the Huon and Lower D’Entrecasteaux areas. The latest health warnings are summarised below, and are subject to change.
When is the last day I can pull my pots and do I have to unload these fish before continuing fishing in an open part of the fishery?
The east coast fishery between Eddystone Point (Red Rocks) 41 1’ 00” S and Marion Bay 42 49’ 00” S will be closed from Thursday 22 August 2013. Pots set in this area can be pulled until midnight on Wednesday 21 August.
You do not have to unload east coast rock lobster before continuing to fish in an open part of the fishery. The rock lobster catch and effort logbook provides a daily record of fishing location and date of harvest.
Why does this part of the fishery have to close prior to collecting the rock lobster samples?
If any of the rock lobster samples return results above the maximum prescribed regulatory limit for bivalve shellfish ( 0.8mg/kg*), then all rock lobster from that region of the east coast that has been harvested on or after the day the samples were taken (not the date of the test results) are potentially subject to a national or international recall. As there are serious questions on the capacity for full traceability of all rock lobster back to area and date harvest in many processing factories or domestic / overseas markets (i.e. through the full chain of supply), there is a risk that health authorities or the Commonwealth Dept of Agriculture, Fisheries and Food (DAFF) could recall all Tasmanian rock lobster no matter where it was harvested. This would be a disaster for the rock lobster industry. The only way to eliminate this risk is to close the relevant part of the fishery before samples are collected. Any recall of product would be harmful to the brand of southern rock lobster and Tasmanian seafood generally.
(*0.8 mg/kg of PST is the default maximum limit applied to rock lobster and the maximum level that is applied by the Chinese authorities to all seafood imported into China)
Where are samples being collected from and when are the results expected?
Subject to the weather, rock lobster samples will be collected from 5 east coast locations commencing Thursday 22 August, that is: Maria Island, Schouten Island, Bicheno, St Helens, and the Gardens. Sampling will take several days. Rock lobster samples will be prepared by IMAS staff and dispatched to the Sydney for analysis. This is the only laboratory in Australia that is accredited to undertake the required biotoxin testing. Results are expected in early September.
Why couldn’t the sampling be delayed until after 1 September when the southern part of the fishery was due to close anyway?
Data from last summer’s toxic algal bloom showed that rock lobsters can be over the maximum regulatory level within three weeks of mussels being over the maximum regulatory level. As this is a new issue, the understanding of update and depuration rates is limited.
Mussels from the Mercury Passage area returned results almost twice the maximum prescribed regulatory limit for bivalve shellfish on 8 August. High concentrations of the algae have also been sampled from inside Georges Bay. The Department, following consultation with DAFF, believed that leaving the fishery open until 1 September was too great a risk in terms of potential export restrictions and market confidence in Tasmanian rock lobster.
What current information is there about levels of toxic algae in the water and biotoxins levels in other species?
Since early August, levels of the toxic alga Alexandrium tamarense have been increasing on the east coast and detected at various locations including Spring Bay, Little Swanport, Bicheno and Moulting Lagoon (St Helens). This is the same toxic algal species that impacted the east coast last spring/summer.
Public Health warnings: www.publichealthalerts.tas.gov.au
Commercial Fishery season dates: www.fishing.tas.gov.au/com/seasons
Recreational Fishery season dates: www.fishing.tas.gov.au/rec/seasons
Recreational fishery enquiries: Ph (03) 6233 7042 or 1300 720 647 or subscribe to our email news service.
Commercial fishery enquiries: Ph (03) 6233 6797