The ancients among us

Umatilla tribal member and fisheries biologist Aaron Jackson measures an adult lamprey that is migrating over Three Miles Falls on the Umatilla River.

Umatilla tribal member and fisheries biologist Aaron Jackson measures an adult lamprey that is migrating over Three Miles Falls on the Umatilla River.

One of the most uncharismatic animals in the Pacific Northwest also ranks among the most remarkable and most threatened. The Pacific Lamprey (Lampetra tridentate)– is one of the most ancient fish on the planet. And its dwindling numbers are about to vanish from our rivers.

The adult Pacific lamprey grows to about two feet in length. It is an unremarkable, boring, olive-drab green-brown. It has holes in its head/neck that function as gills, and although technically a fish, it lacks scales or bone. It makes do with a slick, mucusy skin and soft, flexible cartilage. This native fish has remained virtually unchanged since it first appeared in the Devonian period, 360 million years ago. The Pacific Northwest was then a string of volcanic islands far from Idaho’s shore. The continent has changed radically. The Pacific lamprey has not. It is as ancient as the fabled Coelacanth. Yet we know little about these natives.

Pacific lamprey are parasitic feeders in the ocean But unlike their rapacious and destructive cousins –the east-coast-based sea lamprey that is invasive into the Great Lakes–Pacific lamprey never kill their host fish. They feed briefly, and then drop off and swim free, attaching again only when they need more sustenance.

These ancient, seemingly drab fish share the anadramous lifestyle of more glamorous salmon. Pacific lampreys spawn in fresh water. The newly hatched lamprey spend up to seven years as larvae, feeding on algae while they rear in our streams. Then, like salmon, the young lamprey migrate to the sea. But once they get there, we don’t really know where they go. Fishermen in Hawaii have reported finding them on tuna they caught near the Big Island. Pacific lamprey may hitch rides far into the ocean. Or they may seek fish more endemic to coastal waters. We are just not sure. We don’t know how long Pacific lamprey remain in the Pacific before returning far upstream to spawn in the headwaters, though it would seem to be a year or two. But even if you are hitching a ride on the tuna express, it takes a long time to get to Hawaii and back.

The downfall of lamprey comes in their migration upstream. Salmon can navigate the rushing waters of fish ladders. Lamprey cannot. Instead of swimming up the ladder, lamprey must use their circular mouths to attach to the concrete sides via suction, and literally inch their way up the ladder. But when they encounter one of the thousands of right-angle bends in the ladder, they simply cannot get their mouths into a configuration to loosen on one side and re-attach on the other around the 90-degree bend. Pacific lamprey cannot make the turn. They are swept back down the fish ladder, and like Sisyphus, must try again. Eventually, they simply run out of energy and die. (Lamprey do not eat during their upstream migration. They rely on the fat they have stored up over their time in the ocean. Once their fat reserves are gone, they are done.)

This year we have a record run of Fall Chinook and Steelhead.—and more wild fish than hatchery. As of today, 1,300,000 fall Chinook salmon have navigated upstream through Bonneville Dam. (Yes, that’s one million three hundred thousand.) and 24,000 lamprey made it as far as Bonneville’s fish counting window. McNary Dam, 150 miles upstream, counted about 500,000 Chinook. And 1500 lamprey. On the Snake River, once a lamprey stronghold, only 19 Pacific lamprey were able to crawl past the Lower Granite Dam fish counter’s bright lights (lamprey are nocturnal, and passing through a counting window’s lights is traumatic.) and rushing water, 300 miles from the Pacific.

These ancient, elongate, odd, and now rare fish are important to PNW tribes and tribal culture. They provide important food sources for young salmonids, and many other components of PNW headwater streams. And while we are starting to recover wild salmon, we are loosing the much-needed lamprey.

The Corps of Engineers is slowly modifying some of its fish ladders-installing rounded metal flanges at sharp corners so lamprey can inch around the bends. The tribes are starting rearing programs, and programs to collect lamprey at Columbia River dams and truck them upstream to tributaries for their final celebratory spawn. (Lamprey are not as fussy as salmon about returning to their natal stream to spawn.) There is hope that we can save this remarkable, ancient, ancestral fish. I’m rooting for them.

See: http://www.oregonlive.com/environment/index.ssf/2013/06/with_new_ladders_at_columbia_r.html

One thought on “The ancients among us

  1. You really make it seem so easy with your presentation but I find this topic to be really something that I think I would never understand.
    It seems too complicated and extremely broad for me.
    I am looking forward for your next post, I will try to get the
    hang of it!

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