Broadscale Environmental Monitoring

BROADSCALE Environmental Monitoring

Environmental consultants (Aquenal and Marine Solutions) travel to sites around Tasmania, frequently collecting water and sea floor samples. The purpose is to document broadscale environmental conditions over time.

The teams travel to over 40 different sampling stations throughout the state, including the D’Entrecasteaux Channel, Huon Estuary, Mercury Passage, Okehampton Bay, Port Arthur and Tasman Peninsula. There is also an environmental control site in Recherche Bay, which is sampled 15 times each year.

The marine scientists collect a range of samples from the ocean, which are then analysed and sent to the Environmental Protection Agency for review. It’s a regulatory requirement Tassal undertakes this farfield monitoring to provide a high level of confidence to ensure we are maintaining a healthy marine environment.

Both Aquenal and Marine Solutions employ local marine scientists – it’s great to have such highly qualified personnel assisting us with a range of environmental programs, from water monitoring to reef community and threatened species surveys.

Once each month, our scientific consultants survey the same monitoring locations regularly throughout the year.

Making sure the survey positions are sampled consistently is key to providing the most reliable data, a GPS is used to ensure each site is sampled in the same location for each survey.

Water samples provide a vast amount of information about the health of the ecosystem.

Through the Tasmanian Salmonid GrowersAssociation (TSGA), Tassal participates in aBroadscale Environmental Monitoring Program(BEMP) across multiple locations insouth-east Tasmania.

The monitoring program has a water qualitycomponent (surface and bottom water) and asediment component (sediment biology andchemistry). Water quality sampling is conductedby Aquenal (Environmental Consultants) every twoweeks in summer and monthly over winter.

From the boat, the team can collect significant data such as water temperature, depth, salinity, pH levels and dissolved oxygen levels using a Water Quality Meter. With ever-improving technology – the quality of sampling equipment is getting better by the year. So much data can now be stored automatically to be taken back to the lab and analysed for environmental trends. Sediment samples are also collected annually from the sea floor. The marine life collected in these samples are a key indicator of ecosystem health.

Other tests require further analysis and samples are sent to Analytical Services Tasmania to test for chlorophyll, microalgae (or phytoplankton) and nutrient concentrations. A range of different sampling apparatus are specially designed for collecting a range of different sample types, and at different depths in the water column.

The factors measured monthly are key in monitoring any changes in the environment. By developing a more intimate understanding of environmental patterns, we can predict how these changes may affect the health of our salmon, or the ecosystem. After all, we need a healthy, functioning marine ecosystem to produce healthy fish!

The Niskin bottle is used to collect water at different depths through the water column.

The water collected is transferred to sample bottles for nutrient analysis.

Some critters found in our marine environment

The water quality meter takes measurements throughout the water column and shows the team data on the salinity, pH, dissolved oxygen and temperature. Data is stored electronically for later analysis.

The surface sample is skimmed from the top of the water and placed into a sample bottle, where it will be later analysed for phosphorus, ammonium, phosphate, nitrate, nitrogen and silicate.

Sam Gray, Marine Scientist at Aquenal taking a closer look at the sample in the lab.

The Integrated Sampler (also known as ‘the snake’) travels 12 metres from the water’s surface to collect a sample, which is then placed into a separate bucket and further analysed for microscopic algae (phytoplankton).