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Migrating Whales vs Offshore Wind Farms

December 7, 2023

by Richard Bates

Question: Can floating offshore wind farms and migrating whales coexist?

The saving from extinction of the East Australian humpback whale has been one of humanity's great environmental success stories. By the mid 1960s a hundred years of commercial whaling had driven the population down to somewhere between just 100 to 150. We only had to stop killing them but once we did, in 1963, they thrived and for the last 30 years they have been increasing in numbers by about 10% annually.

Now during the migration season about 40,000 humpbacks travel up the east coast, hundreds streaming past all day and night, close enough to the coast that the annual count is done from vantage points on headlands. Anyone who goes out to such a spot for an hour or so in the season has a better than even chance of seeing whales as they migrate on their timeless path through the ocean, north from Antarctica between May and August then back south again from September to November. At this year’s annual whale census on June 25 over 5,000 whales were sighted in daylight hours on that one day. Whales of all types but mostly humpbacks. It is an amazing sight and one that eco-tourism businesses have been quick to benefit from.

Breaching Humpback whale in Jervis Bay
Humpback whale breaching of the coast of Jervis Bay, a majestic icon of our oceans. Photo credit: Chris Senior

The migration occurs in order for the whales to mate and give birth in the warm waters of the Coral Sea. Gestation takes 12 months so the females mate one year and give birth the next. On the way north they make use of the Inshore Northern Current which should mean that most of the humpbacks will swim within 6 kilometres of the coast. However on the return trip they mostly (mothers and newborns may stay close to the coast for rest stops) use the East Australian Current flowing southwards 10 to 30 kilometres off the coast – and this is where the problems arise.

From the moment I first heard about the giant offshore wind farm proposed for the Illawarra coast, slap bang in the middle of the whale migration route, I have wondered - how will the whales negotiate it? There was barely a mention of whales during the community consultation process; there didn't seem to be much of a concern with the effects on migrating whales of a massive industrialisation of the coast just offshore from Wombarra to Kiama. Most of the objection shown has been over the visual amenity of the coast but my main concern is over this huge floating steel barrier to migrating marine animals, especially the whales.

In our headlong if belated rush to embrace renewable energy, let us be sure that we do not do so at the expense of the natural environment and other species who also live on this planet.

Having swum this route for countless thousands of years and it being encoded in their genetic memory, what are 40,000 whales going to do when confronted with first the building of then the reality of a possible 300 massive wind turbines? Connected to offshore sub-stations by floating and fixed power cables and anchored by a network of steel cables to the ocean floor, they will occupy an area 10 to 30 kilometres off the coast (exactly in the path of the East Australian Current) for a distance of 60 kilometres, a total area of nearly 1500 square kilometres. How can such a massive obstacle NOT impact on the whales? All 300 turbines are not going to appear overnight but the construction phase may be the most dangerous time.

Location map of proposed floating offshore wind farm in the Illawarra
Map of proposed area of off shore wind farm Illawarra. Image credit:

Those whales which can be expected to travel into this zone (most of them) will find their migration path obstructed. What do we expect them to do? Swim out to sea for 20 kilometres hoping to find a way around (can whales even behave like that?). Divert through the 10 kilometre gap on the landward side against the current and their instincts? Turn around and go back to Queensland? Seriously - what do we expect them to do? It is highly likely that the whales will swim up to the constructions then either be repelled or try to swim through. How will they avoid getting trapped in all the cabling and structures right in the middle of the whales' highway? How will they avoid getting trapped in all the cabling and structures right in the middle of the whales' highway?

This issue has not even been touched upon in the application process that I can see, there are certainly no studies provided from elsewhere relating to the impact of floating wind farms on migrating whales. There are suggestions of what might happen and how the impact can be minimised, but they are just suggestions and so far untested. A theoretical bio-energetic model for migrating humpback whales was developed by researchers from the University of Western Australia to look at how human activity in general affects the whales. The model is from 2015 and does not include offshore wind farms, but it provides some insight of how whale migration behaviour might change when faced with manmade obstacles. There is a lot we have to learn.

Humpback whale traveling past Point Perpendicular in Jervis Bay NSW
Humpback whale traveling past Point Perpendicular, Jervis Bay, NSW. Photo credit: Chris Senior

Is this what we have to trade - the health of our marine environment and the amenity of ocean life for a way out of dependence on coal and gas? We know that whales are sensitive to changes in their environment in ways that we don't understand. We still have no idea why whales beach themselves. But we know that they are very sensitive to noise, especially sonar sound waves, which will be used in the construction phase. Will construction be limited to the summer months when the whales are in Antarctica?

It is up to the proponent, BlueFloat Energy, to demonstrate that there will be no to little impact, not the community's responsibility to prove that there will be. The duty of care is firmly with the Department of Climate Change, Environment, Energy and Water (DCCEEW - neatly placing all of the issues in one basket) and in the absence of evidence the precautionary principle must be applied. Once the project is built and the impacts known it will be too late.

Conventional media suggest that opposition to the project is made up of a ramshackle coalition of right and left wing extremists and ill-informed nimbys. It is an unusual coalition of individuals to be sure (including the pro-nuclear lobby and expressions of support from the likes of Peter Dutton! Oh the irony and talk about lack of credibility). Captain Paul Watson, ex Sea Shepherd, has said he is 100% opposed. Greenpeace and the Climate Council are in favour saying that on balance it is better for the whales that we address global warming of the oceans; they do not mention the issue of blocked migration. If any of those organisations with a history of protecting whales can explain to me how the wind farms planned for up and down the east coast will NOT impact negatively on migrating whales I would love to hear from them.

A row of floating offshore wind turbines
Row of floating offshore wind turbines, they surely look like being an obstacle. Photo credit: Max Topchii/

The mainstream media readily proclaim that the opposition is based on misinformation – that no whales have been killed by wind farms worldwide. But how do they know? Where are the studies? The media appear biased against the protestors and why? There are no studies because there are only four operational floating wind farms in the world, in Japan, China and Spain. Being floating means that they can be in deeper water and more acceptable because of the lesser impact visually. But none of the four are on whale migration routes although there are several proposals being developed in the US which are, so time will tell there.

So this is new technology with the humpbacks as guinea pigs. Just exactly how will the offshore wind farms be built to accommodate the whale migration? These turbines will not be your usual land-based type wind farm with heights half of these proposed. They truly will be massive – up to 300 of them 1.5 kilometres apart with blade tip height reaching 280 metres and the installation requiring six floating sub-stations. Underwater cables will anchor each turbine to the seabed, connecting each turbine to the other, then connecting each circle of turbines into the offshore sub-stations, creating a complicated maze that could entangle marine life - a threat acknowledged by the DCCEEW.

Huge parts of a wind turbine blade lying on the sand waiting for assembly
Huge parts of a wind turbine blade waiting for assembly, UK. Photo credit: Ian Dyball/

There are many, many arguments for and against wind farms, both on land and offshore, and whilst renewable energy is essential to our future my concern with this project is with the whales. It is not sound to jeopardise their existence in order to protect the ocean they live in by attempting to mitigate climate change with a renewable energy project like this. The DCCEEW's own website acknowledges that the "presence of OWF infrastructure can alter the natural movements and behaviours of marine fauna (e.g. create barrier effects along migration routes, or to and from areas that are important for breeding and foraging) or deter species from using areas of the marine environment that they currently use (e.g. for breeding, resting or foraging). Impacts of this nature may impede the recovery of threatened species such as blue whales and southern right whales."

The Illawarra is not the only region on the east coast to be facing the prospect of an offshore wind farm. An even larger proposal is for off the Hunter coast and there is a lot of opposition, especially from conservation groups that have been trying to save the Gould’s Petrel from extinction. Until recently this vulnerable bird, Australia’s rarest endemic seabird, had just one nesting site in the world - Cabbage Tree Island off Port Stephens. For the last 30 years National Parks and conservationists have been successfully introducing the birds to other nearby islands. Imagine their dismay to learn of a proposal to build a massive wind farm right next door.

Gould's Petrel nesting on Cabbage Tree Island
Gould's Petrel on Cabbage Tree Island, 2020. Photo credit: Jayden Walsh/

Some of the key negative impacts on marine life and birds that the DCCEEW acknowledges are likely to occur during the construction and operation of an offshore floating wind farm include injury, mortality, behavioural changes, disruption to navigation and migration, pollution and seabed disturbance at the lowest level of the ocean.

There is also a list drawn up by BlueFloat of the threatened species likely to have a “potential significant impact” from this proposal. They include petrels, albatrosses, several types of shorebirds, swift and orange-bellied parrots (although the latter is highly unlikely) - all at risk of turbine strike; whales and turtles subject to entanglement and the effects of underwater noise, as would be sharks. It is a long list, absent from which are the shearwaters which are not a threatened species, or the dozens of other seabirds that will be at risk of turbine strike – so obviously the list is not exhaustive.

Both the proponent and DCCEEW admit that there is the risk of significant entanglement of whales or at the very least a barrier to their migration. The potential future impact on whales from this industrialisation of the ocean off our coast is worrying and the onus on studying this impact is on the developers. One way or another they must be able to demonstrate that their proposal will have no ill effect or impediment to the whale migration at the very least.

The latest round of public comment (by means of a limited and limiting survey) has now closed but Chris Bowen is the minister and there is nothing stopping you telling him or your local federal member what you think. There will be plenty of opportunity with more rounds of public submissions to come. In response to community concerns the proponent - Spanish company BlueFloat Energy – in early November temporarily withdrew their environmental referral, the proposal being announced and presented to the community before the government had even declared where their operating zone would be. We need to hold them all to account.

Chris Bowen, the minister responsible, at <> or on 6277 7120

Tanya Plibersek, the environment minister, at <> or on 6277 7920

Alison Byrnes, the federal member for Cunningham, at <> or on 4228 5899

Stephen Jones, the federal member for Whitlam, at <> or on 4297 2285

Fiona Phillips, the federal member for Gilmore, at <>  or on 4423 1782

Feature photo: Offshore wind farm turbines. Photo credit: chinasong/

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