According to a blog post on the home page of the tourism giant Mantra Group, a “family holiday in Queensland would be incomplete without a visit to the beautiful Great Barrier Reef, the largest coral reef system in the world”.

Which raises the question, why isn’t the Mantra Group – one of Australia’s largest hotel and resort operators, with more than $8bn in asset management including a string of resorts in north Queensland – vociferous in demanding action to save the reef?

The question could not be more pertinent given the return of the threat of coral bleaching.

Mantra and other huge hospitality companies with interests on the reef, including Marriott and Accor, were conspicuously muted during the great bleaching of 2015-16. Nor have any of these companies spoken out strongly against the Carmichael coalmine proposal – despite the mortal threat that fossil-fuel expansion poses to the reef their businesses depend on.

As the Queensland Tourism Industry Council boss, Daniel Gschwind, told the Monthly: “It’s hard to see how the further development or expansion of the coal industry can support or in any way contribute positively to the future of the reef … There is no denying that the further extraction and burning of fossil fuels is a negative for the reef.”

Port Douglas sits at the hinge of the central and northern sectors of the Great Barrier Reef. Presumably a large number of those who choose to stay in resorts like the Mantra Aqueous – or the Accor-owned Sea Temple or the Marriott-owned Sheraton Mirage, both also in Port Douglas – have been drawn there by the promise of the reef.

And while the vast majority of the reef experienced some damage, it is the northern sector that experienced the worst. Last November a team of experts from James Cook University led by Prof Terry Hughes estimated that two-thirds of the corals in the reef’s northern part had died.

I snorkelled some of the impacted areas. I’d seen plenty of images and vision but nothing really prepares you for the scale of the carnage when the algae-covered remains spread out beneath you, all around, in every direction, as far as your goggled eyes can see.

Gschwind believes that most tour operators are not just on the reef “to make a buck” but rather “have a deep, almost spiritual, connection to the places they visit and take their visitors to” so “their interest is very much also in conservation”. The 170 tourism operators who wrote an open letter to the prime minister last year opposing the Carmichael coalmine are no doubt in this category.

But in the fight for the reef’s future, the big end of the tourism street has gone missing. The likes of Mantra, Accor and Marriott profit from the astonishing beauty of the fish and the coral – but where is the much-vaunted corporate leadership when the Great Barrier Reef needs defenders?

Mantra is a case in point. The company’s public corporate social responsibility statement on environment is short and generic, containing no concrete or measurable targets. Nor is there any clear recognition that the company has an advocacy role to play in demanding action to save the reef.

Yet the Mantra Group’s self-stated philosophy is “to be the favourite by knowing what matters”. The group acknowledges that its “stakeholders place us in a position of trust” and vows to “act with the integrity this trust reserves”.

If the Mantra Group – and the rest of big tourism – wants the trust of stakeholders, then it cannot be silent about the state and fate of the reef. It must speak out against the expansion of the coral-killing coal industry and demand decisive government action on global warming and other threats.

One wonders what discussions are taking place at a board level about Mantra’s commercial and reputational risks and responsibilities apropos the reef. How are the chief executive, Bob East, the chair, Peter Bush, and the rest of the Mantra Board handling the question?

We know that East in particular – who also chairs the Tourism and Events Queensland Board – has a personal connection to the reef. East told an interviewer from Executive Style magazine that “his family loves the tropics during the Christmas season” and so they were off to “explore the Great Barrier Reef, Green Island and the world heritage-listed Daintree rainforest”.

What our reef needs is for big tourism to provide a determined business counterweight to the destructive agenda of the coalminers. Silence is complicity in the reef’s destruction.