Saturday, January 12, 2013

Guilty pleasures: smoked salmon and unagi

Since it’s New Year’s resolution time, I’ve been pondering what this year’s resolution should be. Last year, I borrowed my husband’s idea of resolving to eat only “good” meat (i.e. organic, grass-finished, meat formerly named Polly/Charlotte/etc.). As a fisheries biologist, I try to do the same thing with fish by following the Monterey Bay Aquarium Seafood Watch recommendations. However, this can be hard when it comes to occasionally denying myself, especially two particular kinds of fish – salmon and freshwater eel (aka unagi to sushi enthusiasts). While wild Alaskan is a good option for salmon, many places (restaurants especially) carry farmed Atlantic salmon, which is better to avoid. And as for eel, I’ve been putting off (with dread, since I don’t think there are any at this point) looking into unagi alternatives.

Since my favorite food is smoked salmon—and since it also happens to be my study species—I’ve decided to look into the purported ills of farmed salmon. Smoked salmon at the grocery store is often farmed Atlantic salmon. But first, a quick aside to illustrate why this issue (e.g. finding good smoked salmon to eat) is so close to my heart. I was about 9 when I first read C.S. Lewis’s The Lion, the Witch, and the Wardrobe. In the scene when the White Witch offers Edmund any food he desires, he chooses Turkish Delight, and receives a bottomless tin full of (enchanted) confection. Since, at age 9, I had no idea what Turkish Delight was, I imagined a bottomless tin of smoked salmon – nothing could be better – and to this day, any mention of Turkish Delight automatically makes my mouth begin to water (and not for the candy). So, while I don’t think I’ve actually been enchanted, I find it about as difficult to resist buying a package of smoked salmon as Edmund found it to resist going back to the White Witch for more Turkish Delight.

Edmund fantasizing about Turkish Delight
Turkish Delight (a far cry from smoked salmon)
So what is wrong with farmed salmon? There are several problems with it, ranging from environmental impacts to serious health concerns. As with raising beef cattle, it takes a lot of food to raise meat. But unlike cows, which eat corn (well, not naturally, but that’s a whole other story), salmon eat fish, so there’s a large impact on the marine food chain. It takes about 3 pounds of other fish (mostly small pelagic fish) to produce 1 pound of salmon. In addition, many studies have found that salmon feed is highly contaminated with toxins, including PCBs and mercury, and this high toxin load gets transferred to the farmed salmon (at much higher levels than are found naturally in wild salmon populations).

Most farmed salmon, at this point, come from large aquaculture operations in Norway and Chile. In general, the salmon are raised in large netpens in near-shore ocean, a design resulting in pollution of ocean waters through fish and feed waste. Pens can contain up to 90,000 fish. Overcrowded conditions mean that disease and parasites run rampant, and can then be transferred to wild salmon populations due to the open netpen set-up. In particular, sea lice (a marine copepod) are a major concern (google image search them if you have a strong stomach—I couldn’t bring myself to put the pictures up on my blog). There have been studies showing the transfer of sea lice from salmon farms to wild pink salmon, causing infection and mortality in the wild populations.

However, there are some promising innovations in aquaculture that may mean better farmed salmon in the future. Closed, re-circulating systems prevent many of the environmental problems, such as pollution and disease/parasite transmission to wild salmon. There has also been some success rearing coho in freshwater pens in the US—these farmed salmon are now listed as a “best choice” by Seafood Watch (success!). In addition, innovations in net design are helping prevent some of the disease and parasite problems by using antimicrobial copper alloy netting.

So, after looking into salmon farming, I bit the bullet and did a little research on why freshwater eel are listed as “avoid” by Seafood Watch. After all, the first step to many things is knowledge. It turns out freshwater eel have a fascinating life cycle. They are catadromous—this is the opposite of anadromous (salmon’s life cycle), where the eels spend their life in freshwater, but go to the ocean to spawn. They find their way to rivers as small, immature, transparent eel (referred to as “glass eels”), and it’s at this stage that they are caught in droves in order to supply eel farms raising unagi. Basically, instead of raising eels from scratch (starting with eggs, as salmon hatcheries do), eel farms find it easier to go catch the young wild eels, and use these as a constant supply, thereby continually depleting already declining wild populations.
Glass eel, the life stage when they're caught to bring to eel farms.

Declines in wild eel populations
So, herein lies one of the hardest personal debates about being a good environmental steward. Do I completely deny myself a food I love, or allow myself to have it very occasionally? There is a fine balance between enjoying and living life, and also trying to live according to certain values. Where do you draw the line? As with purchasing carbon offsets for air travel, can we go out and do something proactive to protect fish populations every time we indulge in another round of unagi sushi? This is a balance I, and many people I know, continually struggle with.

1 comment:

  1. Great post Kim.....I always heard that farmed fish wasn't always the most Eco-friendly solution, but never took the time to figure out why. Thanks for doing the research and the great write-up. I hope you are doing well!!!