Frequently Asked Questions

Credit: John Brouwer

SeaChoice receives many questions about ocean-friendly seafood and so we are sharing some of the most common questions with you below. Feel free to email us at if your question didn’t make the list!

1) What is sustainable seafood?
SeaChoice identifies sustainable seafood as fish or shellfish that is caught or farmed in ways that consider the long-term viability of harvested populations and the ocean’s health and ecological integrity.

2) Why is sustainable seafood important?
The world demand for protein is growing and the demand for seafood is growing with it. By ensuring that seafood is ocean-friendly, fisheries and seafood farms around the world will change their practices so that seafood is no longer overfished or fished/harvested using destructive methods.

The world’s fisheries peaked in the late 1980s and, despite increased fishing effort, catches continue to drop. More hours on the water are yielding fewer and fewer fish. On a global level, commercial fisheries are presently fishing at rates that are clearly unsustainable. There are real limits to the amount of marine life we can take from our oceans. We must not continue to exceed these limits.

Choosing to eat or source sustainable seafood will help ease pressure on overharvested ocean species to assure that we are able to enjoy seafood over the long term.  A 2011 study from WWF also reports that 91 per cent of Canadians feel sustainable seafood is important.

3) What are the most sustainable types of seafood?
There is no single seafood that is the best choice, but the most sustainable wild seafood to eat is typically:

  • A species whose biology is capable of withstanding fishing pressure (i.e., fast growth rates, low age of maturity and high fecundity or low trophic level);
  • Where the status of the stock is well understood; and
  • Where the fishing methods do not adversely impact other species or habitat.

The best farmed seafood options are typically herbivorous (plant-eating) animals grown in such a manner to minimize impacts to the surrounding ecosystem.

4) What are the least sustainable kinds of seafood?
The least sustainable wild seafood to eat is typically:

  • Comprised of species whose biology is vulnerable to fishing pressure (i.e., slow growth rates, high age of maturity, low intrinsic rate of increase and high on the food chain) where the status of the stock is poorly understood or known to be in decline;
  • Where the fishing methods  impact other species or habitat; and
  • Where regulation and enforcement management is poor or not present.

The worst farmed seafood options are typically carnivorous fish found high on the food chain that use large amounts of edible fish protein and are produced in open net-cages that impact the surrounding species and environment. The most infamous example is farmed Atlantic salmon.

Bluefin tuna, wild international caviar or sturgeon, large sharks and swordfish from certain fisheries are among the worst species you can choose to eat. Problems that these species face include over-fishing, high by-catch levels and poor regulations. In addition, many of these species are top predators in the food chain and are long-lived. These fish are therefore susceptible to high concentrations of mercury in their tissues.

5) Why is there mercury in fish?
Mercury occurs naturally in the environment and is also released into the air and water through industrial pollution from pulp and paper processing, mining operations, coal-burning plants and garbage incinerators. Mercury in fresh and marine waters is converted by bacteria into methylmercury, which is easily absorbed by animals as they feed and binds to fish protein. Methylmercury accumulates in fish tissue and becomes concentrated in fish higher on the food chain.

6) What types of fish have mercury?
Nearly all fishes and shellfish contain traces of methylmercury. However, older predatory fish have the highest levels of methylmercury, because they have had more time to accumulate it. Fishes such as swordfish, shark, king mackerel, tuna and tilefish pose the greatest risk. To learn more about mercury and other health issues, please refer to the health advisories generated by Environmental Defense.

7) What do national health organizations consider acceptable mercury consumption?
Health Canada’s guideline for total mercury content in commercial marine and freshwater fish is 0.5 parts per million (ppm). It was first set in the 1970s and, based on a recent re-evaluation, is still considered by Health Canada to be appropriate to protect the health of Canadians from the toxic effects of methyl mercury.

Health Canada literature states that Canadian limits are more stringent than in the United States. However, Canadian limits exceed only the 1.0 ppm limit set by the US Food and Drug Administration. In contrast, the US Environmental Protection Agency recommends a limit of 0.1 micrograms of mercury/kg of body weight/day. This value is five times less than the FDA limit (which equates to 0.5 micrograms of mercury/ kg/day) and two and a half times less than the present Canadian limit (which equates to 0.25 micrograms of mercury/kg/day). In July of 2000, the National Academy of Sciences (NAS) released their report entitled “Toxicological Effect of Methylmercury” to Congress, in which the NAS supported the EPA’s recommended limit of 0.1 ug/kg/day. This means that Canadian recommendations presently exceed the US EPA’s standards by 2.5 times, but are generally equivalent to the limit set by the US Agency for Toxic Substances and Disease Registry (ATSDR), which is 0.3 micrograms of mercury/kg/day.

Consumers should also be aware that the Canadian government allows fish to be marketed even if they regularly exceed the 0.5 ppm guidelines. These species, namely, shark, swordfish, and fresh and frozen tuna (but not canned tuna) regularly show mercury levels between 0.5 and 1.5 ppm, and are issued exemptions from the 0.5 ppm guidelines. Instead, the government chooses to issue advisories for these species, recommending appropriate restrictions on consumption, and leaving it up to consumers to inform themselves of this information.

Visit mercury advisories and information provided by Health Canada.

8) How do I figure out for myself how much mercury I can safely consume?
Visit a mercury calculator that can tell you whether your planned consumption of seafood exceeds safe-limits set by the US Environmental Protection Agency (EPA).

9) Why should women be concerned about methylmercury?
If you regularly eat fishes that are high in methylmercury it can accumulate in your body over time. Since methylmercury affects the nervous system, unborn babies and young children are particularly vulnerable to mercury during development. Methylmercury is removed from the body naturally, but it may take over a year for the levels to drop significantly. Thus, it may be present in a woman even before she becomes pregnant. This is the reason why women who are planning to become pregnant should avoid eating certain types of fish.

10) Are there other types of contaminants I should be concerned about?
Consumers should also be aware that persistent organic compounds such as dioxins, PCBs and arsenic present health threats when consumed. Residues of antibiotics and hormones used in aquaculture may be a cause for additional caution.

11)  Why are some fish called different names at my local fish market?
Ideally, labels should tell us the name of our seafood, how it is fished/harvested and where it comes from. Unfortunately current labelling legislation does not enforce this.

In Canada, distributors are required to use the common names of fishes on labels, as defined by the Canadian Food and Inspection Agency. Often these trade names bear little resemblance to local common names or to scientific names of the specific fish or shellfish species.

For example, did you know that rockfish from the Canadian Pacific coast are sold under the trade name of snapper?

According to the scientific community, snappers are found only in the tropics and sub-tropics and are a part of the family Lutjanidae. In contrast, rockfish are actually in the family Scorpaenidae/Sebastidae and are found from California to Alaska.

Differences between trade names and scientific common names, or local names, make it difficult for consumers to know what they are buying. Proper seafood labelling allows consumers to make more informed choices. Explain to your fish retailer that transparent, informative labelling is essential for making responsible and safe seafood choices.

12) Where can I find more information about the technicalities of labelling seafood in Canada?
The Canadian Food and Inspection Agency has a website that explains seafood labelling and provides a comprehensive FAQ section.

13) What does dolphin-friendly labelling on canned tuna really mean?
The intention behind dolphin-friendly labelling on tuna products is to certify that labelled tuna has not been harvested in a manner that kills or harms dolphins. However, dolphin-friendly labelling has no international certification body, and does not go through an independent auditing process. Labelling is almost always subject to the laws of the country of origin. To find a list of dolphin-safe approved processors, visit the website of the Earth Island Institute’s International Marine Mammal project.

14) Why is open-net farmed salmon not considered sustainable?
There are several reasons why open-net farmed salmon is not considered sustainable. The main concerns are transfer of disease and parasites to wild stocks, pollution and the net loss of protein. Penned salmon live at high density that makes them susceptible to disease outbreaks. Some salmon farming companies are investigating the use of closed-containment systems in order to address these impacts on wild salmon stocks. Sustainably farmed Kuterra Atlantic Salmon comes from a closed-containment operation and is a best choice.

Pollution comes in the forms of fish feces and uneaten food pellets, both of which may be contaminated with drug residues. This waste from the farms is not treated and simply spills through the cages and into the open ocean where it may impact the health of the surrounding marine ecosystems.

Another ecological concern is the net loss of protein in the production of the fish. Salmon need to eat other fish. The wild fish used for feed comes at the expense of marine food webs—and the people dependent on them—elsewhere in the world.

There are several additional conservation concerns associated with salmon farming including the effect of escaped farmed salmon and antibiotic use to control disease.

15) When I buy “salmon” in the store, what am I getting?      

The Canadian government produces a list of common names that may be used to label fish. On this “Fish List”, the only species that can be labelled as “Salmon” is Atlantic salmon, Salmo salar. The rationale for this is that Pacific salmon includes several species that have different market values. In effect, this means that any fish that only bears the word “salmon” is farmed salmon, as wild Atlantic salmon are endangered and not available commercially. On the other hand, Pacific salmon will be also be labelled with the name of their subspecies (e.g. sockeye salmon, coho salmon, chinook salmon etc). In almost all cases these will be wild, although some chinook and coho is now being farmed.

16) Am I unknowingly eating farmed salmon?

There are no commercially viable Atlantic salmon fisheries left in North America. If you are eating Atlantic salmon, it is from a farm. Atlantic salmon is the most commonly farmed species, but some B.C. farms raise Pacific chinook (spring or king), Atlantic, and coho salmon.

Retailers and restaurants often advertise “fresh” salmon. This usually means fresh from the farm – not from the fisher. Be sure to ask restaurants and retailers if their salmon is farmed or wild. If it is farmed, don’t buy it unless it is farmed responsibly with closed containment technologies.

17) What if farmed salmon has a label that says “Certified Sustainable”                                 

There are many third party organizations around the globe that are considered “seafood certifiers.” Some of these certifications are based on robust science, transparent processes, and stakeholder involvement. But some are less stringent. At this time, no certification for farmed-raised salmon has proven to address concerns raised by SeaChoice concerning sustainability. Farmed salmon raised in closed, contained facilities such as those operated by Kuterra are the only farmed salmon that we consider sustainably grown.

18) What is “organic”?

Photo credit CFIA

Photo credit CFIA

The Canadian government regulates organic production in Canada, and has developed standards for what meets “organic” production. The full standard can be found here. The Canadian Organic Standard (COG) states that “organic production is based on principles that support healthy practices. These principles aim to increase the quality and the durability of the environment through specific management and production methods. They also focus on ensuring the humane treatment of animals.” The COG notes that the standard does not represent a health claim, nor the safety or nutrition of organic products. To qualify as “organic”, farms of any kind may not use the following during production:

  • genetically modified materials or products
  • synthetic pesticides
  • synthetic allopathic veterinary drugs, including antibiotics and parasiticides (except as specified)
  • synthetic processing substances including sulphates, nitrates and nitrites (except as specified) among other criteria. In addition, organic producers must feed livestock with an organic feed.

19) What is organic aquaculture?

In Canada, organic aquaculture is the production of fish species (including fin fish and shellfish) that meet the standards outlined by the Government of Canada. The Canadian Organic Aquaculture Standard was published in 2012.

20) Does organic mean sustainable?

Not necessarily. While, in many cases, organic practices are environmentally superior to conventional production methods, the words are not interchangeable. Organic production methods may still be environmentally damaging.

21) Does SeaChoice recommend organic farmed salmon?

Not at present. While SeaChoice recognizes that achieving organic certification for farmed salmon is a step in the right direction, concerns remain from a sustainability point of view. SeaChoice bases our aquaculture recommendations on eight criteria: data, effluent, habitat, chemical use, fish feed, escapes and introduced species, disease, pathogen and parasite interaction, and source of stock. While the Canadian Organic Aquaculture standard addresses the chemical use criterion, organic farms may score negatively in other categories. A comparative study of the environmental benefits of different marine aquaculture standards conducted by a research group at the University of Victoria concluded that the draft Canadian Organic Aquaculture Standard were equivalent to conventional open-net pen salmon farming in Canada.