Aquaculture: Fishing for answers

October 19, 2009

Halibut

Photo credit: Angela Y. Martin

A few weeks ago I was a guest at the Canadian Aquaculture Industry Alliance‘s Farmed Seafood Extravaganza held at Starfish Restaurant in Toronto. The food was fantastic and spokespeople representing every aspect of the industry were present to tell their story and answer questions. While I learned a lot, I left the event feeling unsure about how to evaluate the many aspects of aquaculture. After all, it’s not really just one topic but dozens since different methods and species face different challenges.

I turned to Theodora (Teddie) Geach, Ocean Wise’s Eastern Coordinator, to help sort out my thoughts. Not only was she eager and able to answer my questions, she did such a great job that I’m excerpting her email here so that you can learn more about the pros and cons of Aquaculture, too!

“Aquaculture is the fastest growing food production system in the world and definitely has benefits if done correctly. It has the potential to relieve the pressure from over-exploited aquatic resources; however, it also has the potential to negatively impact the surrounding environment and wild fish stocks.

Five main criteria need to be taken into consideration:

1. Use of marine resources: This would be for example, the amount of wild fish used in fishmeal. If you’re feeding your farmed fish with more wild fish than you’re producing, you’re still putting pressure on the wild fish stocks. Ideally more fish protein is produced using aquaculture, than is used to facilitate it.

2. Risk of disease and parasite transfer to wild stocks: Since farmed fish are confined, they generally live closer together than they would in the wild. This increases the risk of disease and parasites. Therefore, the stock density needs to be considered. As I’m sure you know, with farmed salmon there is the issue of sea lice which can be transferred to juvenile wild salmon, increasing their mortality. In order to reduce this risk, antibiotics are sometimes added to the water which can result in stronger more resistant strains. However, today in BC, you need to get approval from a veterinarian before using any antibiotics. (I’m not sure if this is the case on the east coast as well.)

3. Risk of escapes to wild stocks: Most salmon farms are open-net pens or floating net pens in the ocean, therefore there is the risk of escape. These escaped fish can then compete with wild stocks for resources and may reproduce with wild stocks, thus reducing their genetic viability.

4. Risk of Pollution and habitat effects: These open-net pens can have a significant impact on the surrounding environment since anything added to the water is able to leach out. There can be a build-up of excessive fish feed and feces, which pollute the water and creates a very anoxic environment where nothing can grow except for sulfur loving bacteria. These open-net pens are usually in sheltered coves to protect the nets from extreme weather, but this also means that there is no current flowing through to flush out all the build-up of chemicals and feces, etc.

5. Effectiveness of the management regime: As with any fishery, there needs to be an effective management system in place to ensure that aquaculture practices favour conservation of the environment. For example the use of licensing to control the location, number, size and stocking density of farms; the existence of better management practices; and regulations for release of chemicals into the environment.

So for Atlantic salmon and cod farms, if they are able to address all these issues and support their claims with the data and sound science they would be considered sustainable. However, it is difficult for any open-net pen farm to address all these issues sufficiently.

6. The best option for farmed fish is a land-based, closed containment system. This way there is no risk of transfer of disease to wild stocks, no risk of escapes and you are able to treat and control the effluent water. An excellent example of one of these farms is in Agassiz, B.C. where Bruce Swift as created a land based Coho salmon farm. He is able to treat the effluent water and collect the solid waste, which is then used as fertilizer for garlic and bean crops. The wastewater is used to grow wasabi, watercress and algae. The algae are then used to feed his freshwater crayfish.

In addition to the land based farmed salmon that Bruce Swift is doing, there are some species of fin-fish which are better candidates for farming than others. Other examples of sustainable-farmed fish would include raceway-raised rainbow trout, land based arctic char and land based catfish

Tilapia offers and excellent case study: tilapia provides more protein than it takes to raise it and are relatively resistant to disease. Tilapia are also vegetarian and can be raised on soy protein and rice, which obviously does not put any pressure on the wild fish stocks. However, you still have to be careful where you get farmed tilapia. The best choice is tilapia farmed in the US, which generally uses land-based, closed containment systems. Farmed tilapia from Central America can also be found in our markets. In CA, regulations can vary and the farms may not always be land based; likewise, farmed tilapia from Asia would generally always be considered unsustainable since they are mostly produced in open-net pens.

7. In general farmed shellfish is considered sustainable. This is because they are filter feeders, eating the plankton out of the water column, so they don’t need supplemental feed and don’t put pressure on wild fish stocks. They can even improve the water quality as they clear excess plankton. Shellfish such as oysters and mussels are often grown on suspended cages or in bags off the seafloor so there is little damage when they’re harvested. (This is called off-bottom culture.) Clams can be farmed on-bottom and there can be an issue if they are harvested by dredge. However, the impact of farmed dredging is far less than dredging wild clams.”

Thanks Teddie! I think my readers will agree that you’ve done a great job explaining the benefits and pitfalls of current aquaculture practices!

Do any of you have questions about seafood? If so, jot them below and I’ll invite folks from the CAIA and Ocean Wise to pop in and answer your concerns.

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Goodbye to bycatch

October 14, 2009

bycatch_img_large

Image Credit

You may not believe me, but I dislike always being the bearer of bad news; it seems like I’m constantly telling you horror stories and asking you to make tough choices about fish and seafood. Regrettably, today is no exception.

By now most people are aware that making a choice at the fish and seafood counter is much more complicated than deciding what you’d like to eat for dinner. From aquaculture controversies to concerns about certain species becoming extinct, there is a lot to consider before you make a final choice.

And, more confusingly still, while some fish are plentiful and still live up to the adage that there are plenty of fish in the sea, the way that they are caught is harmful to other species. Such is the case with monkfish, a delicious white fish that is caught using bottom trawling (a method that can damage seafloor habitat and often results in high bycatch) or gillnets (which can result in the accidental bycatch and death of sea turtles and other marine mammals).

What’s bycatch you ask? It’s the unintentional harvest of sea, lake or river life, which was not the intended harvest species that results when nets are cast into the water. In some cases, bycatch can be sold as food which is fine if the species involved aren’t endangered or vulnerable; however, often fishermen discard their bycatch which is a terrible waste whether the species involved are vulnerable or not. In fact, according to the United Nations Food and Agriculture Organization, one in four of all animals caught in as bycatch is discarded.

So, before you make that final purchase choice next time you’re buying fish and seafood, ask the fishmonger about the bycatch associated with your choice. And, if he doesn’t know what the heck you’re talking about, send him here so that he can click on these links to find out more:

Before today, were you aware of the bycatch issue? If so, has it influenced your shopping and restaurant choices?


Hot weather cooking: easy shellfish salad

June 25, 2009

shellfish salad

It’s so awful, but for me, good food is sometimes a burden. For instance, the other day we needed clams and mussels in a bowl for a photo shoot. They were to serve no other purpose than to be themselves for 5 minutes.

At the end of the day they were up for grabs on our food trolley (we basically do a little grocery shop on our way to our cars each day, taking the food that was made between 9 and 5 home for ourselves or others). No one, including me, wanted the seafood. I’d eaten enough during the day and really, I just couldn’t see myself cooking them up into a chowder. But I felt guilty about wasting these creatures for the sake of a 5-minute TV segment so I took them home, steamed them and shucked the meats from the shells and made this little salad. Then, I packed it into a plastic container and put it in the fridge.

Sabrina and I ate it the next day for lunch and you know what? My efforts were well worth the pay off. And, given how hot it is here in Ontario right now. I can see myself making this salad again late one evening so that I have a cold, yummy, protein dish on reserve for dinner.

Here’s how to make one yourself:

Steam a combination of clams and mussels in a large pot of salted water.
Drain cooked shellfish in a colander and refresh under cold running water
Remove meats from opened shells and discard any unopened shellfish.
Pat the shucked shellfish dry on paper towel.
Combine drained shellfish, diced red pepper and a handful of chopped parsley in a bowl.
Drizzle with lemony-dill dressing; toss and let stand for at least 15 minutes.

What are your hot weather entree favorites?