"This is clearly abnormal" says biologist James Nagler and I must agree.
Male salmon in the Columbia River are spawning as females. DNA testing shows that the Mr. mom fish started life as males and transitioned sometime before being found spawning as females.
Speculation centers on gender-bending chemicals as a cause, but nobody really knows what's going on. I suppose if it started happening to members of Congress, we'd have answers in a hurry. Tweet
3 comments:
I've seen evidence of increased "residualization" of salmon (males staying in rivers and never migrating, then spawning as trout-sized "jacks"). This seems to happen where good habitat is available in spawning streams but migration is hazardous due to dams, poor water quality, etc. Is this evolution in action?
I've been studying fate and effects of lost lead fishing sinkers on WQ in midcoast Oregon salmon streams. Freshwater mussels (Margaritifera falcata) are long-lived and can record a timeline of bioavailability history of metals on a site-specific basis. Other pollutants may be similarly recorded if we can learn how to read the clues. Lead, cadmium, and methylmercury NPS pollutants can affect many of the same physiologic pathways and thus become additive and even synergistic. Freshwater habitat can then have generally unrecognized limiting factors for salmonid diversity recovery. Some of these effects can leave fish looking 'normal' in the hand, but less than what they need to be to survive in the competition at near-ocean-entry.Some of these effects can probably be genderbending, especially when combined with PCB effects commonly contaminating salmon.
Thanks Ray, it's sad to hear that such harm can come from seemingly innocuous things like lost fishing sinkers. Devastating harm that is hard to detect is VERY hard to address.
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