The return of the Columbia sturgeon George Gruenefeld
There isn’t much that bothers a fish the size of a white sturgeon, but tops on that short list is a charge of explosives going off in its immediate vicinity. When that happens, they have a tendency to float belly up to the surface. And there were enough explosive charges going off on the Columbia River and its tributaries in the course of a half century to nearly blow the stocks to oblivion. Big sturgeon—prime breeders, for the most part weighing hundreds of pounds and capable of producing close to a million eggs each—floated to the surface and washed ashore in alarming numbers.
The dams built during the 50-year frenzy to harness the hydro electric
potential of the 2,000 kilometre Columbia and its tributaries also had an
indirect impact on Columbia sturgeon, fracturing their habitat, blocking their
migrations up and down the system and, in many cases, barring access to spawning
grounds and nursery areas. Not only was the population of adult fish decimated,
but there were also far too few young fish in the upper basin to rebuild or even
hold the population for the future. With fewer than 1,000 adult fish in the
Canadian portion of the river, the white sturgeon of the Columbia’s upper basin
was designated in 2006 as an endangered population destined to die out within
the lifetime of most people living along its banks.
But poke around in the calm and shallow back bays near the West Kootenays
town of Trail of late and you’re liable to encounter these endangered relics
from the age of dinosaurs in surprising numbers. Granted, these fish aren’t
quite in the same size as the big adults, but they are sturgeon, they are
plentiful and, if participants in the Upper Columbia White Sturgeon Recovery Initiative
have their way, these foot-and-a-half-long, perfect miniatures, likely survivors
of a release of hatchery-reared juveniles at Beaver Creek in Trail several years
ago, will become cornerstones in the return of the Upper Columbia white sturgeon
population.
The cross-border organization, also known by the equally tongue twisting
acronym UCWSRI, has been releasing juvenile sturgeon in the Columbia since 2001
when somewhere between 10,000 and 12,000 fish the size of your hand were
released at several sites including the base of the Hugh Keenleyside Dam near
Castlegar and Beaver Creek. These days the annual releases are more modest,
numbering between 2,000 and 3,000 juveniles but the success ratio, initially
pegged at about 10 per cent, appears to be three times that.
It bodes well for the upper Columbia’s white sturgeon populations by the
middle of the current century, but what about the fish between now and then? The
presence of a few wild juveniles—recognizable by the absence of identifying
marks on their scutes or armour plating—represent half a percentage of the age
class in the river. That’s good new and bad. It means the adult females are
still producing young rather than absorbing the roe for lack of essential
spawning habitat or required water temperatures. And some of the eggs are
evolving into free swimming youngsters.
On the other hand, there’s the question of why the wild juveniles make up
such a skimpy proportion of the total population of immatures.
“If these prehistoric fish are to survive long-term, we need to understand
why younger age classes are not surviving to adulthood,” said James Crossman,
sturgeon biologist for BCHydro, one of the partners in the UCWSRI.
The key to that mystery may have something to do with water temperature and
quality, but with the overall population of white sturgeon in Canada’s portion
of the Columbia River numbering upwards of 10,000 fish, young and old, their
immediate survival, if not explosive, appears to be rock solid.
potential of the 2,000 kilometre Columbia and its tributaries also had an
indirect impact on Columbia sturgeon, fracturing their habitat, blocking their
migrations up and down the system and, in many cases, barring access to spawning
grounds and nursery areas. Not only was the population of adult fish decimated,
but there were also far too few young fish in the upper basin to rebuild or even
hold the population for the future. With fewer than 1,000 adult fish in the
Canadian portion of the river, the white sturgeon of the Columbia’s upper basin
was designated in 2006 as an endangered population destined to die out within
the lifetime of most people living along its banks.
But poke around in the calm and shallow back bays near the West Kootenays
town of Trail of late and you’re liable to encounter these endangered relics
from the age of dinosaurs in surprising numbers. Granted, these fish aren’t
quite in the same size as the big adults, but they are sturgeon, they are
plentiful and, if participants in the Upper Columbia White Sturgeon Recovery Initiative
have their way, these foot-and-a-half-long, perfect miniatures, likely survivors
of a release of hatchery-reared juveniles at Beaver Creek in Trail several years
ago, will become cornerstones in the return of the Upper Columbia white sturgeon
population.
The cross-border organization, also known by the equally tongue twisting
acronym UCWSRI, has been releasing juvenile sturgeon in the Columbia since 2001
when somewhere between 10,000 and 12,000 fish the size of your hand were
released at several sites including the base of the Hugh Keenleyside Dam near
Castlegar and Beaver Creek. These days the annual releases are more modest,
numbering between 2,000 and 3,000 juveniles but the success ratio, initially
pegged at about 10 per cent, appears to be three times that.
It bodes well for the upper Columbia’s white sturgeon populations by the
middle of the current century, but what about the fish between now and then? The
presence of a few wild juveniles—recognizable by the absence of identifying
marks on their scutes or armour plating—represent half a percentage of the age
class in the river. That’s good new and bad. It means the adult females are
still producing young rather than absorbing the roe for lack of essential
spawning habitat or required water temperatures. And some of the eggs are
evolving into free swimming youngsters.
On the other hand, there’s the question of why the wild juveniles make up
such a skimpy proportion of the total population of immatures.
“If these prehistoric fish are to survive long-term, we need to understand
why younger age classes are not surviving to adulthood,” said James Crossman,
sturgeon biologist for BCHydro, one of the partners in the UCWSRI.
The key to that mystery may have something to do with water temperature and
quality, but with the overall population of white sturgeon in Canada’s portion
of the Columbia River numbering upwards of 10,000 fish, young and old, their
immediate survival, if not explosive, appears to be rock solid.
