“Mackerel and chips, twice please, with salt and vinegar.”

Does that sound right? (On reflection, go easy on the salt – we don’t want to negate the benefit of the mackerel, as an oily fish rich in omega-3, credited with a role in healthy brain and nerve development and possibly in heart health.) So there are certainly health benefits in that mackerel order, but the main point here is you are not asking for cod and chips, the default order in chip shops down the years.

It is simple truth is, we can’t carry on asking for cod, because stocks are plummeting and it is essential we look for alternatives. There are certified sustainable stocks of cod, but few fish and chip shops tell you where their fish comes from. (Some Atlantic cod and haddock fisheries now carry MSC certification, which demonstrates their sustainability to customers. ASDA is one place where you can buy them.)

There is growing consumer unease about buying cod, and the campaign to direct us to alternatives was given a mighty boost this week in a series of Channel 4 programmes, The Big Fish Fight (January 11 12 and 13).

Chef Hugh Fearnley-Whittingstall focussed on the practice of discarding fish. Once fishermen have caught their quota of restricted fish, such as cod, any more  they take in their nets while they fish for other species cannot be landed.  His campaign, Hugh’s Fish Fight , www.fishfight.net/, gathered 150,000 followers in a day. (By the following Monday, it was up to 500,000.)

There are already some well-established alternatives to cod and haddock in the fish and chip shop. In my student days I was intrigued by (although I never tried it) the deceptively attractive-sounding rock salmon and  chips. later I discovered this was dogfish, or huss .

Fearnley-Whittingstall didn’t bother about devising some fancy euphemism for mackerel. He’s been persuading fish and chip shops to put it straight on the list, and it seems to be working. The owner of Enoch’s fish and chip shop in Llandudno Junction North Wales was inspired to start selling mackerel, although his previous attempts to push more ethical eating practices had not gained consumer support.  He put mackerel on the menu this month (January 2010) and already people were buying it.

“I persuaded some regulars who normally have cod to try it and they were very impressed.”

Find a  mackerel-serving fish shop on the “Mackerel Mission” pages (www.fishfight.net/about-mackerel-mission/).  There is a map encouragingly overlaid with little mackerel pins showing you where they are.

Mackerel lives right across the North Atlantic but it is a seasonal fish, found in shallow waters in the summer months and in deeper waters in the winter. Most of the mackerel fisheries in the north-east Atlantic have been certified as environmentally responsible by the MSC.  To ensure the mackerel you buy is from the most sustainable fisheries, look for handline or drift net fisheries. These traditional methods are highly selective and catch low volumes of fish compared to the larger pelagic trawlers and purse seiners.

Making seafood sustainable has been named by chefs as one of the top ten trends of the coming year. This is Greenpeace’s definition of sustainability: “A particular seafood is sustainable if it comes from a fishery with practices that can be maintained indefinitely without reducing the target species’ ability to maintain its population and without adversely impacting on other species within the ecosystem by removing their food source, accidentally killing them, or damaging their physical environment.

“Identifying which fish come from sustainable sources is extremely hard. Because of the difficulties in accurately assessing fish populations and because it is very difficult to trace the supply of fish from the ocean to the shop there is no one, truly effective ‘green label” that consumers can look for on fish products, as there is with wood products for example (the FSC logo).

“Always ask the person you buy fish from where and how their fish is caught – if they can’t tell you or if you are not completely satisfied with their answer, don’t buy the fish!”