Deschutes Wild Steelhead Contribute More To The Fishery Than Hatchery Steelhead
CONSERVATION AND SCIENCE REPORT
By Bill Bakke
A recent letter from the Oregon Department of Fish and Wildlife (ODFW) includes information on steelhead catch over 27 years from 1986 to 2012. In Table 4 there is information on the Deschutes River, Oregon sport catch, comparing the wild steelhead catch to that of hatchery fish. From 1986 to 2012 the catch of hatchery fish and wild fish shows that wild steelhead contributed 1.942 fish to the fishery for every hatchery fish caught for a ratio of wild to hatchery of 1.9:1.
If one removes the four low years of wild contribution (1994-1997) where wild fish contributed less than hatchery fish to the fishery the wild run size was 7,422 fish compared to 69,881 hatchery fish, the contribution of wild fish to the Deschutes fishery is 2.13 fish for every hatchery fish caught in the sport fishery. Even in the low contribution years the wild fish contributed nearly one fish for every hatchery fish harvested. In the years 1994-1997 the ratio of hatchery steelhead to wild steelhead was 10.4:1.
Wild summer steelhead of the Deschutes are threatened with extinction and stray hatchery fish, most from hatcheries in the Snake River, were the “primary factor for determining the Endangered Species Act listing of Mid-Columbia steelhead,” ODFW says.
“In some years, these (stray) hatchery fish comprise from one half to two thirds of the fish migrating past Sherars Falls,” says ODFW. And these strays “were and still are observed on spawning tributaries including Bakeoven, Buck Hollow, and Trout creeks, and the Warm Springs River. Reducing the incidence of stray hatchery steelhead spawning in the wild in the lower Deschutes basin has been identified as a high priority action item in the Mid-Columbia Steelhead Recovery Plan, the Columbia River BiOp (Biological Opinion for species recovery by NOAA Fisheries), and ODFW’s Lower Deschutes River Fisheries Management Plan,” ODFW says.
Wild steelhead have limited spawning and rearing habitat in the lower Deschutes, for they are confined to a few dinky desert tributaries that are often affected by drought conditions and some have reduced flows due to irrigation diversions, so these streams are less than ideal for maintaining wild steelhead populations.
Many steelhead spawning and rearing streams in their lower mile are dusty dry, filled with burning hot rocks in the intense summer sun. Many anglers drive across these streams, causing a rough dip in the road, on their way to a favorite run on the Deschutes, and do not realize they had just bounced over a wild steelhead spawning stream. But in the upper reaches of these streams there are springs and the creek’s pools are filled with juvenile steelhead, but they are landlocked because the water flow is not strong enough to reach the Deschutes during the summer and sub-out. In late winter and spring, if there has been a wet winter, these streams flow into the Deschutes. One can see adult steelhead splashing up them and smolts moving down to the river to reach the ocean. This unique life history selects for steelhead that are adapted to these desert rearing streams, but stray hatchery fish also use them and hybridize with wild steelhead, reducing their reproductive success and threatening their survival.
If one were to get excited about doing something to help Deschutes wild steelhead, it would be their protection for they are contributing more to the fishery than the hatchery fish, yet the hatchery fish are increasing the risk to wild steelhead in the river. A campaign to reduce hatchery fish to possession or to fertilize the river or provide food to wildlife would help reduce some of the risk the hatchery fish impose on wild steelhead.
Aquatic Playground Can Turn Water Tanks Into Fish Schools Juvenile Atlantic salmon raised in tanks with hiding places and floating artificial plants showed signs of improved brain function and could better navigate mazes than the salmon reared in standard hatchery tanks. The discovery may help fish hatcheries raise a smaller number of fish that can better survive in the wild. (Credit: Anne Gro Salvanes)
July 30, 2013 — Raising fish in tanks that contain hiding places and other obstacles can make the fish both smarter and improve their chances of survival when they are released into the wild, according to an international team of researchers.
"It's a key problem in that we are very good at rearing fish, but we're really not very good at releasing those animals in the wild such that they survive," said Victoria Braithwaite, professor of fisheries and biology, Penn State. "There's a mismatch between the way we raise them and the real world."
Juvenile Atlantic salmon raised in tanks that including pebble and rock hiding places and floating artificial plants were better able to navigate mazes and showed signs of improved brain function compared to the salmon reared in standard hatchery tanks, Braithwaite said. This may help conservation fish hatcheries raise and release fish that are better adapted to survive in the wild.
Conservation fish hatcheries raise cod, salmon, trout and other types of fish and release them in places where their species may be threatened, or where their populations are declining.
"The philosophy of most fish hatcheries is to rear a large number of fish and hope some survive," said Braithwaite. "What this study is suggesting is that you could raise fewer, but smarter fish, and you will still have higher survivability once you release them."
The researchers released their findings on July 31, 2013 in the Proceedings of the Royal Society B, placed pebbles and rocks at the bottom of the tank and added plastic plants weighted down so they would float vertically in the water. Braithwaite said the objects created a more natural, three-dimensional ecosystem.
"In the hatchery the world is homogenous, life is boring and monotonous," Braithwaite said. "The water flow is the same, you don't have to find your food and you don't have to avoid predators."
The researchers also moved the objects around about once a week during the eight-week study, which took place in Norway.
When the researchers placed the salmon in a maze, the fish raised in the enriched tanks made fewer mistakes when trying to escape the maze, Braithwaite said. The performance of the salmon from the enriched tank continued to improve with each trial, and they learned to solve the maze much faster than fish reared the standard way.
The brains of the fish from the enriched tank were also different from the fish raised in the standard hatchery tanks, according to the researchers.
They noted increased expressions of a gene in a region of the fish's brain that is associated with learning and memory, an indication of increased brain function and growth. The fish raised in standard tanks did not show this sign of increased brain development.
Interacting with the environment can influence gene expression in the brain, Braithwaite said.
"The brain is a very plastic organ, it's a dynamic structure," said Braithwaite. “The enriched tanks created significant improvement in the intelligence and adaptability of the fish, but were relatively inexpensive and easy to implement. Owners of fish hatcheries should be able to afford the creation of enhanced tanks,” Braithwaite said.
Source: ScienceDaily. Retrieved July 31, 2013, from http://www.sciencedaily.com/releases/2013/07/130730193532.htm
Steelhead Sex Ratio and Verification of Some Fall Spawners
Evermann, B.W. and S.E. Meek. 1898. A report upon salmon investigations in the Columbia River basin and elsewhere on the Pacific Coast in 1896. Extracted from U.S. Fish Commission Bulletin for 1897. Article 2, pages 15 to 84, plates 1 and 2, and 6 text figures. U.S. Commission of Fish and Fisheries.
Fall Spawning Steelhead
“On September 18 the wheel at Celilo took 160 steelheads, 28 chinook, and 6 silver salmon, and 75 steelheads were taken by Indians with spears and dip nets. Of the steelheads, 111 were males and 124 females; 10 males and 15 females were in an advanced stage of development, and would have been ripe in a comparatively short time; the rest of the catch would not have been ripe until late in the season. Of the chinooks, 19 were males and 9 females; 10 males and all of the females would have been ripe by about the first week in October.
“During the five days spent at Celilo 1,512 steelheads, 119 chinook, and 55 silver salmon were examined. Of the steelheads, 991 were females and 521 males; 299 females and 120 males showed considerable signs of development, and would have been fully ripe by the first week in October.
“The eggs and milt of the salmon caught during October were somewhat further advanced than that of those examined in September at Celilo. A large part of the eggs of the chinook on being taken from the fish would immediately separate; this was also true of many of the silver salmon and steelheads. A number of the latter showed no signs of development, but many were well advanced and some about ready to spawn. It would seem that the spawning season of the. steelhead extends over a greater period of time than that of other species.”
“While at The Dalles during the last week in September and the first half of October Mr. Alexander examined 4,179 steelheads, of these, 1,531 were males and 2,648 females; 1,376 (476 males, and 900 females were well developed, and would probably have spawned in four to six weeks. The remaining 2,803, he thinks, would not have spawned until some time in the spring.”