Maybetheyjustallocate_partitionitdifferently.ppt

《Maybetheyjustallocate_partitionitdifferently.ppt》由会员分享，可在线阅读，更多相关《Maybetheyjustallocate_partitionitdifferently.ppt（59页珍藏版）》请在淘文阁 - 分享文档赚钱的网站上搜索。

1、The Influence of Hatchery Rearing on Tucannon River Spring ChinookMichael GallinatWDFWPurpose of this talkProvide a quick background on hatchery management of Tucannon Spring Chinook.Describe the influence of hatchery rearing on selected phenotypic traits.Inform you about the latest cutting edge adv

2、ancements in fisheries phenomenon and ask really deep philosophical?s.Describe our latest attempts to improve survival of our hatchery fish&possible genetic implications.Quick BackgroundLSRCP Mitigation ProgramHatchery mitigation was for 48%loss(1,152)through the dams with the remaining 52%(1,248)ex

3、pected to be self-sustaining.Mitigation was to be accomplished by the annual release of 132,000 smolts with an assumed SAR of 0.87%.Evaluation program was established in 1985 to monitor the success of the program in achieving the mitigation goal.First smolts(derived from wild Tucannon brood)were rel

4、eased in 1987.Since 1989,the hatchery broodstock has consisted of both H&N origin fish(strive for 50:50 ratio).The stock was listed as“Threatened”under the ESA in 1992.Hatchery Mitigation Goal=1,152 Relatively stable runs from 1985-1993(mean=550 fish)Between 1994-1999 the average run declined to 196

5、 fish(range 54-351)Captive Broodstock ProgramPurpose/GoalTo artificially boost broodstock numbers over the course of one generation(5 brood years 1997-2001)and supplement the population through a bottleneck situation.Captive broodstock were selected from the hatchery supplementation program(HxW,HxH,

6、and WxW parents)with a progeny release goal of 150,000 smolts 15 fpp.With the captive brood program we can now look at three levels of hatchery influence on the same stock Captive Brood-extreme influence.Hatchery-origin-partial influence.Natural-origin-minimal influence.NatureNurtureVersusAge at Mat

7、uration(M&F Combined)Age at Maturation(M&F Combined)Age 4 Female Spawner Fork LengthEgg SizeFecundityIndex of Relative Fecundity“Normally”=Fecundity Body WeightModified Index of Relative Fecundity=Fecundity Fork LengthRelative FecundityMaybe they just allocate/partition it differently?Maybe Hatchery

8、 fish=Natural fish?Index of Reproductive Effort=Fecundity x Egg Wt.Index of Reproductive Effort Gallinats PhenomenonPhenomenon whereby hatchery-origin fish are able to divert more energy than natural-origin fish in producing larger eggs due to a readily available food supply and protected hatchery e

9、nvironment.These larger eggs result in overall lower fecundities at size compared to naturally-reared fish.What does this mean in the big picture?Productivity might be lower with a higher composition of hatchery-origin fish in the runIs this a“bad”thinghatchery fish that are less fecund?Might not be

10、“bad”if based on DNA analysis they are genetically the samemight actually be preserving genes with the hatchery program!Would just have to use natural fish equivalents in comparisons.Smolt-to-Adult Returns 0.87 SAR Smolt-to-Adult Returns0.87 SAR Yikes!Based on the current average hatchery SAR of 0.2

11、2%(well below the original goal of 0.87%)the program would need to produce over 500,000 smolts annually to meet the hatchery mitigation goal of 1,152 returning hatchery adults.How can we increase survival?(Thereby mining less broodstock from the river.)Emphasis change from quantity to quality!What a

12、re some of the methods to do this?Exercise Experiments?“Natures”Rearing?Increase Smolt Size?What have other studies found?Survival vs.Size at Release(Appleby and Keown 1995)Size at Release Study(06-08 BYs)9 fpp(“large”size)vs.15 fpp(“small”size)CWT+VIE(blue&purple)2,500 PIT tags in each groupIf ther

13、es no difference in survival then its more cost effective to rear the“small”fish.If the“large”fish have significantly higher SARs-than we may be able to collect fewer broodstock from the river in the future.What might the results tell us?Q:Isnt having a larger number of jacks/precocials a bad thing?

14、and thats exactly what will happen if we release larger hatchery smolts.Todd Pearsons(WDFW)asked“Are you experiencing what we see in the Yakima?”You have to look closer“I just see a bunch of small wild fish”“We have to capture them?”How does Todds crew catch them?Underwater angling.Pooper Scooper?I

15、DONT THINK SO!A cast net!Our current record is 11 in one cast.Wild Mature Size Range 68-127 mmDNA-based parentage assignment study from the Cle Elum spawning channel(Yakima River)Interesting StudySo Are Jacks Bad?Philosophical?sDont large numbers of jacks indicate good survival and tend to foreshado

16、w good/strong runs?Precocial males are a characteristic of spring Chinook populations if the hatchery environment just causes it to be expressed without changing the populations genetic structure-why worry about it?May actually even increase genetic diversity!Age at Maturation(M&F Combined)Our natur

17、al-origin fish arent replacing themselves for the most part so why do we want to imitate them?The environment has changed from what they adapted/evolved forDams/Global Warming/Ocean Dead Zones/Loss of Estuary Habitat/Predator Changes/Forage Changes/etc.,etc.Replacement LineIf its genetically caused

18、wouldnt we see more jacks in the natural populationsince we limit the number of jacks brought into the hatchery?Large natural-origin jack runs dont tend to follow large natural-origin jack runs.Andarent increased numbers of females what were really after anyway?Fish Management DilemmaIf we actually

19、achieve increases in our hatchery fish survival it could decrease our Proportionate Natural Influence(PNI)below 50%.Key HSRG Guidelines for(Properly)Integrated ProgramsPNI must exceed 50%.For populations of special concern natural influence should exceed 70%.Catch-22We might be able to reach the LSR

20、CP mitigation goal but at the expense of not being in the“Golden Triangle of Genetic Goodness”.We can be in the“Golden Triangle of Genetic Goodness”(as we currently are)but at the expense of not reaching the LSRCP mitigation goal.In ConclusionWhile hatchery and natural-origin Tucannon spring Chinook

21、 are derived from the same endemic stock and considered genetically the same(based on our analysis to date)hatchery-origin fish natural-origin fish!But just because its different doesnt necessarily make it bad if genetically the same.Going to take experimentation/innovation to increase hatchery fish survival.AndFish management will need to decide what level of risk it is willing to accept from the hatchery program.Hatchery Mitigation Goal=1,152