Supplementation using steelhead fry: performance, interactions with natural steelhead, & effect of enriched hatchery environments Christopher P. Tatara NOAA Fisheries, Northwest Fisheries Science Center Stephen C. Riley USGS, Great Lakes Science Center Julie A. Scheurer NOAA Fisheries, Sustainable Fisheries Division Barry A. Berejikian NOAA Fisheries, Northwest Fisheries Science Center

Overview  Current status of steelhead under ESA  Role of hatcheries in steelhead management  2 potential pre-release techniques for steelhead conservation hatcheries  Environmental enrichment  Stocking fry  Field evaluation of these two conservation hatchery techniques

ESA Status of Steelhead DPSESA Status 1Puget SoundThreatened 2Olympic PeninsulaNot Warranted 3Southwest WashingtonNot Warranted 4Lower Columbia RiverThreatened 5Upper Willamette RiverThreatened 6Oregon CoastSpecies of Concern 7Klamath Mountain ProvinceNot Warranted 8Northern CaliforniaThreatened 9Central California CoastThreatened 10South Central CA CoastThreatened 11Southern CaliforniaEndangered 12Central ValleyThreatened 13Middle Columbia RiverThreatened 14Upper Columbia RiverEndangered 15Snake River BasinThreatened

Hatcheries in steelhead management Historic and current - Stock Enhancement –Provide fish for harvest and recreational angling More recent – Restocking and Conservation –Restore spawning biomass/population to sustainable/stable level Controversy over the use of hatchery fish for rebuilding imperiled natural populations –Changes to minimize genetic and environmental influences of hatcheries

Photo: NWPCC Photo: DIPAC Conservation hatchery techniques 190 mm 90 mm ConventionalHatchery EnrichmentStream Smolt release – 1 yearFry release – 4-5 months

Rearing Environments Enriched Photo: Scotty Corp. Photo: USFWS Natural Conventional

Upstream Downstream 11 Creek 12 Creek Upstream Downstream E + N C + N Stocked: 31 July 2003 Final sampling: September 2003 Observed: 5 occasions between 6 August and 11 Sept 2003 Evaluating conservation hatchery techniques: Experimental Design

Evaluating conservation hatchery techniques: Responses and Hypotheses Upstream Downstream 11 Creek 12 Creek Upstream Downstream E + N C + N Response Variables: Behavior, Territory size, Habitat use, Spatial distribution, Growth, and Survival H1: How do conventional and enriched hatchery fry compare to natural fry? C = E = N H2: Are natural fry differentially affected by type of hatchery fry stocked? N CON = N ENR

Results: Foraging and aggressive behavior – natural fry Hatchery type x Week interaction (F 3,79 = 3.97, p = 0.011) Hatchery type (F 1,79 = 5.01, p = 0.028) Week (F 3,79 = 4.34, p = 0.007)

Results: Territory size H1: C = E = N –(F 2,135 = 0.043, p = 0.653) H2: N CON = N ENR –(F 1,45 = 0.45, p = 0.504) Additional analyses –Fork length (F 1, 132 = 9.40, p = 0.003) –Spatial use (T-value = 4.37, p < 0.001) C = E = N (F 2,133 = 0.66, p = 0.520) –Local density (p = 0.129)

Results: habitat use Pool Use Index = (# fry pool /# fry encl )/(Area pool /Area encl ) Stream x type interaction F 2,74 = 11.68, p<0.001 Stream x hatchery type stocked interaction F 1,36 = 14.40, p = 0.001

Results: spatial distribution Standardized Morisita Index = 0 indicates randomness > 0 indicates clumping (+) < 0 indicates uniformity (-) Hatchery type, F 1,33 = 3.51, p = 0.07Stream x fish type, F 2,76 = 6.42, p = 0.04

Results: Growth (ANOVA, F 1,18 = 7.23, p = 0.02) n=6 for natural n=3 for hatchery Mann-Whitney, n=6

Results: Survival after 6 weeks (ANOVA, F 2,18 = 27.57, p < 0.001) n=12 for natural n=6 for hatchery Paired t-test, n=16Mann-Whitney, n=6

Results: Estimated survival over the course of the experiment Sheirer-Ray-Hare, F 1,95 = 45.2, p < Proportion of initial population observed

Effectiveness of steelhead fry supplementation

Supporting research evaluating effectiveness of fry stocking Hatchery program established 2002 –Featured fry stocking (after complete yolk absorbance) –Extensive genetic monitoring & adult & outmigrant traps Used genetic monitoring to compare # age-2 smolts produced by female steelhead –Spawning naturally in the river –Spawned artificially in hatchery with their offspring released as fry Year Class ComparisonRelative smolt production 2002H2:NS6.2 ** 2003H1:NS2.1 ** 2003H2:NS1.3 * Carrofino et al Can J Fish Aquat Sci : 65:

Conclusions Fry from conventional and enriched hatchery environments develop natural social behaviors shortly after release Individual hatchery fry establish and use territories like natural fry Hatchery fry use pools like natural fry, but have a more clumped spatial distribution Stocking enriched hatchery fry altered the foraging and aggressive behavior of natural fry –No effect on growth or survival of natural fry

Conclusions Conventional and enriched hatchery fry grow as well as natural fry Natural fry have higher survival than hatchery fry –most mortality of hatchery fry occurred within 2 weeks of stocking Growth and survival of natural fry was similar when stocked with conventional or enriched hatchery fry Supplementation with hatchery fry increased steelhead populations over the short-term (density increase of 2.9X) –no differences using conventional or enriched fry –Fry supplementation increases relative production of age-2 smolts Longer studies of fry supplementation are needed to fully evaluate effectiveness

Acknowledgements Rob Endicott Jeff Atkins Skip Tezak Eric Kummerow Rudy Wynn Brandon Nickerson Weyerhaeuser Corporation WDFW, Bingham Creek Hatchery