Tinned or frozen fish may be better for the planet than expensive fresh options

You might assume fresh seafood is better for the environment than a frozen fish finger.

But fish lovers should consider buying from the frozen section if they want to help the planet, a leading charity has said.

The Good Fish Guide, updated twice a year by the Marine Conservation Society, recommends Alaska pollock, often found in fish fingers and Icelandic cod, which can be bought fresh or frozen, as best choices.

Stocks of British cod are very low so local cod is one to avoid, though other UK fish such as herring caught in the north Irish sea, plaice from the North Sea and sprat from the English channel are all recommended.

The charity rates different types of fish caught in different parts of the world according to a traffic light system.

"Red"- rated varieties are "fish to avoid" while those rated "green" are the most sustainable options.

Fishing methods, specific catch locations and certifications can all affect the ratings, which are used to guide consumers through the complex process of choosing the most sustainable fish.

'Green'-rated fish

Many freezable products are rated "green", the charity said, with the added benefit that they keep for longer, avoiding food waste.

Charlotte Coombes, Good Fish Guide Manager, said shoppers often wrongly assumed that more expensive products were more sustainable.

"There are plenty of tinned and frozen options that can be a sustainable choice.

"It's something that people should be more aware of, because obviously it's really important at the moment to be budget-friendly when shopping, but that doesn't need to come at the cost of the environment," she said.

Jack Clarke, sustainable seafood advocate at the MCS said: “Most major retailers offer green rated options for breaded fish, from fingers to fillets.

"Freezing fish extends its shelf life and makes it easy to knock up a delicious, sustainable seafood dinner."

Tinned fish, which has become more popular in recent years, is also a sustainable product because of its long shelf-life, the charity said.

Tinned herring is a good option if caught in the North Sea or MSC-certified, while shoppers can also look out for anchovies caught in the Bay of Biscay or albacore or skipjack tuna caught by pole and line.

Farmed fish can also be more sustainable than wild-caught for some species, including halibut farmed in open pens in Norway, which moved from amber to green in the latest update because of stricter requirements for sourcing the food used in the fish farms, and Scottish farmed halibut, which remains green. Wild halibut is a threatened species rated red on the guide.

Farmed mussels are both cheap and good for the environment and can be bought fresh or tinned.

Wild seabass is slowly recovering from critically low levels and still has an amber rating, and farmed seabass tend to be more sustainable.

Arctic char and oysters

Other good farmed options are arctic char and oysters, as well as farmed tilapia certified to standards set by the Aquaculture Stewardship Council, an independent certification which measures environmental and social impact.

Dawn Purchase, aquaculture programme manager at the charity, said: “It’s a common misconception that farmed seafood is not as responsible a choice as its wild-caught counterpart.

"However, this season’s update to the Good Fish Guide has shown that for some species it is often a more ocean-friendly option.”

Next month the Government is due to publish its Joint Fisheries Statement, which will set out its plans for environmentally-sustainable fishing practices in the UK.

Draft versions have been encouraging, the charity said, but it warned that a trend towards "deregulation" was putting progress under threat.

Kenneth Bodles, head of fisheries and aquaculture at the MCS said: “With environmental laws recently under attack, we cannot afford to let the Joint Fisheries Statement be derailed."