Here at ASBTIA we are opposed to drilling for oil in the Great Australian Bight and are extremely worried about the consequences on Southern Bluefin Tuna.
Studies exposing the embryo and larval stages of pelagic fish (with buoyant eggs) to crude oil resulted in uncoordinated rhythm, and deformities that can ultimately lead to death from heart failure (NOAA 2015). The small pelagic (herring) fishery exposed to the Exxon Valdez oil spill showed heart deformities and developmental abnormalities consistent with those of other species exposed to crude oil; this fishery has not recovered even 30 years after that event (NOAA 2015).
Exposure of tuna larvae to crude oil adversely affects heart development and ultimately results in acute and delayed mortality (Incardona et al., 2014). Hatchery reared SBT in South Australia were experimentally exposed to weathered crude oil collected from the Gulf Of Mexico, Deepwater Horizon accident and showed this species is acutely susceptible to very low concentrations of 1 to 15 parts per billion oil derived Polycyclic Aromatic Hydrocarbons (PAH) (Gardner, Stanford Universitypers.com. 2015).
NOAA have shown from work in the Gulf of Mexico that fish surviving transient crude oil exposure with only mild effects on the still-forming heart have permanent changes in heart shape that reduce swimming performance later in life (NOAA 2015).
Recent research (eg Klinger et al., 2015) is showing that short term exposure to oil (hours/days) physiologically compromises (older) juvenile pelagic fish – so at the very least any oil escaping in the GAB can impact on SBT performance in the wild and in the farms. As juvenile SBT return to the GAB every year, repeated exposure is highly likely and increases the potential for “population level” impacts.
In the case of an oil spill at sea, Equinor has proposed the use of chemical dispersants. Chemical dispersants enhance the natural break up of oil into small droplets that enter the water column (Grote et al., 2018). Chemical dispersants may pose an increased risk to SBT because they increase the concentration of toxic chemicals in the water column, which is where SBT are situated.
To listen to some of ASBTIA’s members speak up about drilling in the Great Australian Bight, visit this page.
Brette, F., Machado, B., Cros, C., Incardona, J.P., Scholz, N.L., Block, B.A., (2014). Crude oil impairs cardiac excitation-contraction coupling in fish. Science 343(6172): 772-776
Grote, M., Bernam, C., Bohme, B., Callies, U., Calvez, I., Christie, B., Colcomb, K., Damian, H., Farke, H., Grabsch, C., Hunt, A., Hofer, T., Knaack, J., Kraus, U., Le Flock, S., Le Lann, G., Leuchs, H., Nagel, A., Niew, H., Nordhausen, W., Rauterberg, J., Reichenbach, D., Scheiffarth, G., Schwichtenberg, F., Theobald, N., VoB, J., Wahrendorf, D., (2018). The potential for dispersant use as a maritime oil spill response measure in German waters. Marine Pollution Bulletin: 129, 623-632.
Incardona, J.P., Gardner, L.D., Linbo, T.L., Brown, T.L., Esbaugh, A.J., Mager, E.M., Stieglitz, J.D., French, B.L., Labenia, J.S., Laetz, C.A., Tagal, M., Sloan, C.A., Elizur, A., Benetti, D.D., Grosell, M., Block, B.A., Scholz, N.L., (2014). Deepwater Horizoncrude oil impacts the developing hearts of large predatory pelagic fish. E1510-E1518, DOI: 10.1073/pnas.1320950111
Klinger, D., Dale, J.J., Machado, B.E., Incardona, J.P., Farwell, C.J., Block, B.A., (2015). Exposure to Deepwater Horizon weathered crude oil increases routing metabolic demand in chub mackerel, Scomber japonicus. Marine Pollution Bulletin 98(1-2): DOI: 10.1016/j.marpolbul.2015.06.039
NOAA (2015). National Oceanic and Atmospheric Administration (USA). http://www.noaa.gov
(2019) Draft Environmental Plan – Stromlo-1 Exploration Drilling Program.