It is often an ill-defined term but in the case of New Zealand seafood it is well aimed.
The vast majority of wild caught fish in New Zealand waters is sustainable, that is stocks are carefully managed to ensure that the overall health of the fishery is maintained.
That is why the London-based Marine Stewardship Council (MSC) has certified New Zealand's deepwater fisheries as among the world's best managed.
Some 97 percent of the overall catch by weight is sustainably fished, according to Fisheries NZ scientists.
That is a fact, even if the anti-commercial fishing lobby prefers not to want to recognise it.
In September New Zealand hoki, hake, ling and southern blue whiting fisheries were recertified against the MSC Fisheries Standard, a global third-party certification standard and market-based program that recognises and rewards sustainable fishing practices.
The New Zealand hoki fisheries have been certified since 2001 and are the longest standing MSC certified whitefish fisheries in the world. New Zealand southern blue whiting fisheries were first certified in 2012 and those for hake and ling in 2014.
The assessments were carried out over a 12-month period by independent auditing body Lloyds Register (Acoura), attesting that each of these fisheries are well managed with health stocks and harvest strategies in place.
It is a testament to the combined efforts of the New Zealand government and industry that fisheries for eight species are now MSC certified (hake, hoki, ling, orange roughy, southern blue whiting, albacore tuna, skipjack tuna, and Ross Sea toothfish). This commitment to independent certification of fisheries sustainability places New Zealand amongst leading sustainably managed fishing nations in the world, alongside the USA, Canada, Denmark, Norway and Iceland, each of which has 50 percent or more of their commercial marine wild catch MSC certified.
A no doubt well-meaning addition to the sustainability bandwagon is a just published book, Truth Love & Clean Cutlery that purports to be an international guide to restaurants that behave in "ethical, organic and environmentally sustainable ways". It lists 15 restaurants in New Zealand, selected by Listener food columnist Lauraine Jacobs, that supposedly qualify.
The inference is that if an establishment is not on the list, it somehow doesn't measure up.
In the case of seafood, this is, of course, nonsense.
Every restaurant that serves fish and every fish'n'chip shop in the land is rightly able to declare that it serves sustainable seafood, whether it be hoki, shark, warehou, mussels or any other species.
It is commendable that consumers increasingly want to know where their food comes from.
Retailers are increasingly sensitive to sustainability, traceability and locality as a result.
But cost, practicality and truth also need to be essential ingredients in the sustainability recipe.
Eat New Zealand, a self-described New Zealand food movement, meeting in Christchurch last month, was totally mislead by recreational fishing group LegaSea about the state of our fisheries.
"Our fisheries are in a state of sustainable extinction," spokesman Scott McIndoe cried.
Such a contradiction is laughable, followed by the equally ludicrous claim that our "fish are currently out of reach for New Zealanders, with the bulk being exported for a poor price".
And how is it that despite the many millions in advertising spent by American-based chicken and hamburger fast food chains, fish'n'chips remain New Zealand's number one takeaway?
New World supermarkets are currently promoting fish for Christmas, caught from their own quota.
"Our New Zealand seafood is something the business is particularly proud of," New World head of marketing and customer experience Dominic Quin said.
"We know the fishing boats by name and the fishing families that own them, so we only select the best."
At Wellington's celebrated Capitol restaurant they also get it right.
On a recent night the waiter knew immediately the provenance of the fish of the day (tarakihi).
What's its name?, one of the diners facetiously asked.
"Gerald," he deadpanned.
Not a fish named Wanda then.