Sunday, June 15, 2008
Salmon, pelargoniums and the Spread of Ich
I was reading a sad story in the LA Times today about salmon fisherpeople in Alaska and the trouble with ich. It seems the parasite Ichthyophonus hoferi has spread into the wild salmon population, infecting many of the fish and rendering them inedible or dead, due to the warming of the river water where the salmon spawn. You probably are familiar with this disease--known as Ich--if you've ever had aquarium fish. It seems to be a classic case of the spread of an organism into its prime niche as climate change is suspected of warming waters further north. In a similar way we in southern California find insect pests that used to be discouraged by our sorta cold winters and occasional frosts surviving the winter and building up harmful population levels. A great example of this was the spread of giant whitefly from Mexico through southern California from 1992 on. In fact, the population of giant whitefly has settled down to manageable levels for the most part as natural predators have adapted to use them as a resource (e.g. eat them); but for some they are still the scourge of hibiscus.
I noticed this helicoverpa caterpillar on the salmon-colored geranium, two years to the day from this post. Hardly significant since corn earworms can be found at many times during the year on this particular plant. Some people doubt the value of amateur observations of natural science since we, as amateurs, mostly aren't formally trained and might make a bad (or worse--redundant!) identification or observation of behavior. On the other hand, we have eyes in places where no professional naturalists are and might find something important. The Times story reports that back in the late 1980s a fisherman noticed something odd about the salmon and sent samples to be tested. He was brushed off. It wasn't until 2000 that any serious research started. Today, they are testing theories as to the extent of the disease and its effect on the salmon populations, and whether anything can be done to lessen the damage. Maybe if that fisherman had been taken seriously, or if there was a mechanism for observations of that sort to be disseminated to the scientific community, it wouldn't take 2 decades for meaningful research to happen.
I still don't like these salmon flowers, and I've never enjoyed eating salmon but I do think citizen science is good.