Hayes2010.ppt
- 1. Emigration behavior of resident and anadromous juvenile O. mykiss: exploring the interaction among genetics, physiology and habitat Sean Hayes, Chad Hanson, Morgan Bond, Devon Pearse, Andrew Jones, Carlos Garza, Bruce MacFarlane
- 2. •Small watershed (75km2) •23km of stream accessible to anadromous fish •“native” resident fish above barriers •Small hatchery •Dynamic flow regime (28m3 s-1 to 0.1m3 s-1) •Small Estuary (closes seasonally) Scott Creek Map: Rob Schick, NMFS
- 3. Scott Creek O. mykiss life history strategies Ocean upper watershed estuary/lagoon Upstream resident Mature in estuary (never enter ocean)
- 4. x x x 3 km Adult weir Instream PIT tag readers Scott Creek X= barrier Seine, hook & line, and electrofishing Smolt trap
- 5. Resident populations “diverged” >100 yrs ago Big Creek Adults Weir Adults Lagoon Juveniles 60 Hatchery Juveniles Scott Creek Adults 76 Mill Above Big Creek, Boyer 63 92 Big Creek Above 68 Scott Creek Above Neighbor-Joining distance tree, with bootstrap values for supported nodes Do rainbow trout and steelhead differ?
- 6. x x x ? Proportion of fish assigned to Resident or Anadromous ancestry by habitat 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Above Barrier Upstream Smolt trap Estuary Anadromou Resident
- 7. Genotype distribution in upper watershed 0.00 0.10 0.20 0.30 0.40 Fork length Frequency Resident (n=128) Anadromous (n=209)
- 8. Emigration rate from above anadromy barrier • 400 fish PIT tagged above • 2.3 % over the falls • 1.8 % detected at smolt trap
- 9. Na+ K+-ATPase Physiology Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec ATPase activity 0 2 4 6 8 Smolt Trap Estuary Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec ATPase activity 0 2 4 6 8 Above Barrier Upstream ?
- 10. Upstream samples 0.00 2.00 4.00 6.00 8.00 0 2 4 6 8 10 12 Month ATPase Resident Anadromous Na+ K+-ATPase Physiology 0 2 4 6 0 2 4 6 8 10 12 14 16 ATPase Frequency Resident Anadromous
- 11. Why do wild fish migrate at such small sizes? 0 0.04 0.08 0.12 0.16 Fork Length (mm) Frequency Typical steelhead smolt size distribution
- 12. Lagoon- Sand Bar Closed (July-Dec.) Estuary- Open to Ocean (Jan.-June) Does estuary serve as nursery habitat? (Morgan Bond’s thesis)
- 13. Black lines indicate upper watershed growth Blue lines indicate migration to estuary and growth Jan Jul Jan Jul Jan Jul Jan Jul Jan Fork Length (mm) 0 50 100 150 200 250 Mean 5th % 95th % YOY 1+ 2+ 3+ Is the estuary a nursery? Ocean upper watershed estuary/lagoon 85% of returning adults use estuary pathway Size threshold for ocean survival
- 14. What happens when water quality degrades? 3 km >45% detected moving Upstream each fall (probably >90%)
- 15. Size of recaps at smolt trap in spring 0 2 4 6 8 10 12 14 16 18 20 60 80 100 120 140 160 180 200 220 240 260 280 300 Fork Length Frequency Upstream Estuary (previous summer)
- 16. A tale of two watersheds Functional estuary present No estuary available Year 1 Year 2 Year 3 Year 1 Year 2 Year 3 (in Central California…)
- 17. Acknowledgements Funding • NMFS • DFG FRGP • NURP • California Sea Grant Land Owner support •Big Creek Lumber Company •The Wilson Family •Monterey Bay Salmon and Trout Project •Cal Poly Swanton Ranch •Lockheed Martin
- 18. Implications of resident trout studies • Should residents be counted in steelhead populations for delisting criteria? • Residents may become steelhead, but this probably happens at low frequencies • Results of resident contribution to anadromous breeding pending
- 20. Influence of genotype on migration behavior To sea or not to sea? Genotype Frequencies 0 0.2 0.4 0.6 0.8 1 Upstream Smolt trap Frequency Resident Anadromous
- 21. Typical spring downstream migrant (smolt?) After 5-6 months rearing in estuary 100mm Steelhead in Scott Creek 85% of returning adults use estuary pathway
- 23. Fork Length (mm) at Trap Big smolts are less likely to stay < <150 >150 0 5 10 15 20 25
- 24. Conclusions Central Coast steelhead adapt for estuarine use Steelhead strategies without estuary • Longer upstream rearing • Fewer smolts, reduced anadromy?
- 25. Figure 5. Estimated lagoon yearly population sizes and yearly mean growth rates from 2003-2006 (left y-axis). The bar graph (right side y-axis) represents mean fork length of fish sampled in the estuary in late fall of each year, just prior to winter storm season and lagoon opening. Years match points within labeled column. All data are means ± SE, R2 =0.99. Regression P= 0.005 Estimated Lagoon Population 0 500 1000 1500 2000 2500 3000 SGR length as a % per day 0.2 0.4 0.6 0.8 1.0 2005 2004 2003 2006 Density-dependent Estuary Growth in Steelhead
- 26. Implications for Local Rivers • Larger river- may have more rearing capacity= larger smolts upstream • BUT… is there enough water? • Estuary issues – Breaching – Estuary size reduced? – Enough flow to connect with watershed?
- 27. Lagoon fish move upstream in the fall and then back down in spring Lagoon fish PIT tag reader detections 0 50 100 150 200 250 300 350 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month Frequency Upper watershed Lower watershed >45% lagoon fish detected moving upstream
- 28. Escapement ?? Early 20th century spawning population was 4-10 times larger
- 29. Why is estuary growth so good? (Jeff Harding’s diet studies) Lots of food! Diet consists of Corophium and Eogammarus sp.
- 30. But where does food come from? • Upper watershed growth poor • Insect diet • Low flow • Low light – low nutrient input into estuary
- 31. Hypothesis- Nutrient flow from marine derived nutrients (kelp) enhances productivity (Alison Collins senior thesis) Terrestrial Marine Marine 13C and 15N from Juvenile Steelhead d13 C (0/00) +/- SD -26 -24 -22 -20 -18 -16 -14 d 15 N (0/00) +/- SD 6 8 10 12 14 16 Juv. Steelhead - Lagoon Juv. Steelhead - Above Fall Adult Steelhead Coastal Marine Fish
- 32. Why don’t all fish recruit to the estuary?