Thursday, 7 April 2022

The science of buying sustainable fish - Irish perspective.


"What is certainly lacking in the sale of fish is the availability of coherent information upon which buyers can make their choice."

Stock assessments and quotas look at sustainability in terms of maintaining an exploitable population of 

Buying fish can be a mildly daunting experience. At a fishmonger’s stall salmon and shellfish are sometimes the only species discernible from the filleted cadavers arranged across beds of ice.

The scenario is further compounded when a sustainable purchase is on the agenda. Grabbing a frozen pack of fish fingers is a quick way to avoid those difficult questions around provenance and sustainability that we might otherwise feel compelled to ask. And to the majority of the population who are neither marine biologists or fishers, the answers are likely to leave us teetering on even greater uncertainty.

Sustainability is a growing priority for consumers but knowledge of fisheries and the ways they are regulated is not always accessible. Globally the Food and Agriculture Organisation estimates that over a third of fish stocks are being overfished, meaning they are being depleted at a rate that cannot be replenished.

A recent flurry of documentaries and books have depicted stern viewpoints on the fishing industry, but the reality may be more nuanced. Fishing is complex, with boats pursuing their quarry over vast portions of ocean that are difficult to interpret and manage.

Determining what is sustainable currently relies on a stringent mathematical approach, says Dr Anne Marie Power, a marine biologist at NUI Galway. “The way we solve or explain this overexploitation [of fish] is often using the analogy of a bank account. You have the capital, which is your healthy stock, and the capital grows because they’re breeding, and what’s added each year through breeding is the interest. So to fish sustainably you only fish the interest, you don’t eat into the capital.”

Data harvested from fish catches and population surveys are put into numerical models that spit out trends and predictions. It is an audit based on methodologies developed at the turn of the 20th century, when industry, capital, interest and growth were taking their place in our common vocabulary.

The fact that a dynamic ecological system can be understood through the lens of economic calculation is quite jarring, but it is currently the only method upon which policy decisions can be based.


Sustainability is determined purely in terms of fish as a stock, and whether the current rate of fishing allows that stock to maintain a steady capital. Quotas are the method of management, says Dr Ciaran Kelly, a director at the Marine Institute in Galway. Constantly reassessed in line with current fisheries data, they divide the stock of each fish species between fisheries and their boats.

“[Quotas] limit the impact of the industry on the environment, ensure the sustainability of the fish stock themselves, and ensure the continuity of supply of food into a market that is safe,” Kelly adds.

Stock assessments and quotas look at sustainability in terms of maintaining an exploitable population of fish. But a more holistic approach needs to be taken to ensure the longevity of local, small-scale fishing economies, says Alex Crowley, secretary of the National Inshore Fishermen’s Association,

“One of the issues that we’d have as small-scale boats is that a lot of the quota is allocated to mostly the bigger boats,” says Crowley, whilst acknowledging that “there are certain species, certain stocks, that you need big boats to harvest, so that’s appropriate in some cases”.

Mackerel is considered Ireland’s most important fishery in terms of economic value, with €48.3 million worth landed in 2020. Most of this was caught by larger boats, says Crowley, which is often necessary to ensure a sufficient yield that maintains food security. But he adds that the portion granted to smaller boats could be increased, doing more to support local communities.

It can be easy to assume that enormous fishing boats are pillaging the oceans and ruining the livelihoods of small-scale fishers, but the subtleties of creating a fair and sustainable industry make it difficult to draw hard lines between what is sustainable and what is not.

“It’s a simplification when we talk about small-scale fishing,” says Kelly. “Are we talking about the fish stock or are we talking about the fishing fleet, or are we talking about the fishing vessel?”

Wider variables

The way in which fishing quotas are determined makes sense in the context of a market economy, but it is perhaps a dangerous simplification with insufficient recognition for wider variables. And regardless of whether the method is sufficiently comprehensive, the way in which scientific findings are put to use ultimately comes down to a variety of demands from fishers, consumers and policy-makers.

An analysis in 2020 by Birdwatch Ireland found that there was a pattern of policy-makers going against scientific advice for allocating fish stocks, often in the interest of political expediency.

The same report found that fishing in Ireland was heavily dependent on a limited variety of stocks, leaving the sector vulnerable to crisis. Like any wild harvest, focusing on a limited number of species will disproportionately reduce their numbers.

It is true that several of our fish stocks are in a precarious place. According to the Marine Institute, the stock of whiting in the Irish Sea has collapsed, while North Atlantic Cod is listed as “threatened” by the International Union for Conservation of Nature.

“Cod is a problem in many cases,” says Power, adding that “lots of the cod you see in chippers isn’t actually cod because cod is overfished and it’s very expensive”. The fact that another white fish can be dressed up as cod demonstrated some interesting points; we have a preference for such a narrow selection of fish species that they have been driven to depletion; and our preference is potentially superficial.

“What is a desirable fish opposed to what is not a desirable fish is totally artificial,” says Power – arriving at the fundamental principle that “market price is driven by fashion and consumer ideas”.

Factors determining the sustainability of what we buy are perhaps as numerous as the fish in the sea. Everyday shoppers cannot be expected to keep up with the vast amounts of data being churned out by fisheries researchers.

Power recommends taking a look at the MSC Good Fish Guide, which distils masses of scientific information into an easy traffic light system of fish species. Wielding consumer power through this handy booklet might be a way to affect the fashion of fisheries.


Sustainable is a fluid term, and each buyer might have different priorities, including the geographical origin of their purchase, the subsequent carbon footprint, and its contribution to local economies. “No fishing type or method can be simply branded as sustainable or unsustainable,” Crowley says.

What is certainly lacking in the sale of fish is the availability of coherent information upon which buyers can make their choice. “The traceability in seafood is very poor,” Crowley adds. “You can go into a supermarket, pick up your fish and it’ll just tell you it’s caught in the northeast Atlantic. And it’ll tell you the type of fishing method, but it doesn’t really tell you much more than that.”

Perhaps it is a lack of interpretable information that makes the responsible purchase of fish such a puzzling task. We know that connecting with our food engenders a familiarity, and this in turn can prompt informed choices.

“We want to give them the choice: if this was caught by a small-scale fisher in Donegal or in Galway... let’s label it for what it is and then take a look at sustainability,” says Crowley.

Power reflects that familiarity is a key trait missing from our relationship with fish. “Ideally, we would all get out into the ocean... we would develop a respect for it, and then we would eat a diversity of seafood... there are lots of things to consider and it’s all confusing.”

What we need is not more information. That will only heighten the confusion and there are already expansive databases on fisheries. An awareness for sustainability is growing among fish buyers. What they need is appropriate access to key facts, clearly presented, that buyers can interpret. It is only when sustainability makes sense that it can be achieved.