Fishing Friday: Is Salmon Sushi A Good Idea?
By: Mike Schoonveld
Some people relish salmon sushi and sashimi, but it should be made from frozen, not fresh salmon.
Other than slick-talking car salesmen and pretty girls selling raffle tickets, people don’t often “put one over on me” - especially, youngsters. I have nine younger brothers and sisters.
But a ten-year-old nailed me good one day after fishing with me on Lake Michigan. The youngster asked dozens of questions during the day about the fish, the lures, the tackle, so when I was filleting the salmon we’d caught, one more question didn’t seem out of place.
“Have you ever eaten raw fish?” he asked.
“I have,” I answered, then continued. “It wasn’t particularly good tasting, but it certainly wasn’t nasty, either.”
“Can salmon be eaten raw?” he asked.
“I suppose so,” I said.
“Want to try some?” he proposed. “I’ll try some if you will try some with me.”
“Why not?” I thought. That’s why, seconds later, we each had a freshly caught, freshly cut, bite sized piece of salmon in hand and on the count of three, we agreed we’d pop the salmon sashimi into our mouths.
One, two, three...I popped my piece past my teeth, he popped his towards his mouth but at the last second, purposely pitched the raw morsel over his shoulder. Then he laughed at me. I laughed too, but if he’d been one of my five younger brothers, I’d have had the last laugh.
Good golly! I could have gotten Diphyllobothriasis.
Salmon sashimi? Are you brave enough to try it?
I thought of this incident some time later when a friend posted on Facebook about a good day of catching salmon on Lake Michigan. He got the usual, “way to go” comments, plus one post from a jealous commentator wishing he had some lake-fresh salmon to use for salmon sushi. That prompted a follow-up comment saying “it’s unwise to make sushi with freshwater fish.”
I’d heard that before, but had never wondered why? I’m not being a regular consumer of raw fish other than on dares from ten-year-olds. Is that true? Is it an old wives’ tale?
Off the top of my head, I came up with three possible reasons - toxins, germs or parasites. So I researched the subject. What I learned revealed science, psuedo-science, and a few tales originating from old wives and now promulgated on Facebook.
Toxins - I found no evidence of poisonous freshwater fish, especially the species of fish most likely to be consumed raw, such as salmon, trout, walleye, or panfish. There is a toxic saltwater fish commonly eaten raw, a dish called Fugu is made from puffer fish, and almost all puffers contain a toxin over a thousand times more potent than cyanide.
Almost all fish, fresh or saltwater, contain some measure of chemical contaminants which can be passed on to consumers, whether cooked or uncooked. If these concern you, follow consumption guidelines.
Germs - Bacteria and viruses don’t normally exist inside fish or animal meat, whether it’s a steer from a feedlot, a carp from the Ohio River or a wicked tuna. Microbes can contaminate the surface of raw meat. The presence or absence of germs on the exterior of the sushi is determined by the handling of the fish and flesh by the fisherman and the sushi-chef. A clean freshwater filet is much better than a not-so-clean saltwater tuna steak.
Parasites - I took a course in college called parasitology. I’ve forgotten far more than I learned, but two things stuck. One is most parasites are host specific. That’s why you can eat those “pepper-flecked” panfish filets without harm. The pepper flakes are parasitic cysts which will only open and grow into a living worm if the fish is eaten by a bird.
Shallow water fish like panfish are much more likely to host the D. latum tapeworm.
The other thing I recall is that many parasites have a complex life cycle involving more than one host species. The life cycle of the trematode parasite causing pepper-flecked fish is from a fish to a bird to a snail and eventually back to a fish.
Diphyllobothriasis, mentioned earlier, is a condition humans get when they become the host to specific tapeworm called Diphyllobothrium latum. D. latums, like other many other parasites, have a complex life style.
Adult D. latums live in the intestines of fish-eating mammals such as mink, otters, humans and others. The eggs produced by the adult tapeworm are passed in feces, get into the water, hatch and are eaten by copepods (a type of zooplankton) which are eaten by minnows or baby fish. The larva grows in the muscle of the parasitized fish and, when eaten raw by a mammal, grows into a tapeworm.
Does this preclude ever eating uncooked Great Lakes salmon or other freshwater fish? Not in the least! Heat or cold kills the tapeworm larvae. Cooking fish until it flakes (145 degrees F, 63 degrees C) will kill any parasites. So will freezing - most sources suggest a week or longer in a home freezer.
Cold smoking, gravlax, salting, or making raw fish into ceviche doesn’t necessarily kill the D. latum larvae which could be present. It probably does, but to be sure, if walleye ceviche or salmon sushi or sashimi sounds good to you, freeze the fish for a week before making these treats. Then get out the lime, soy sauce or wasabi.
The author learned his lesson: never trust an inquisitive, 10-year-old fisherman!
The fish most often connected with D. latum are those living in shallow, weedy areas, like pike, bass, and panfish, not open water fish like Great Lakes salmon. That one bite of raw salmon did me no harm, but the experiment will never be repeated. I, for one, like my fish cooked; and realistically, do you think I’d let another ten-year-old dupe me like that a second time?
Capt. Mike Schoonveld can often be found fishing the Great Lakes and avoiding being sucked into eat raw fish. Find him online at: @brothernaturefishing
