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Demographics of kelp bass in the Santa Barbara Channel

Demographics of kelp bass in the Santa Barbara Channel. J. Wilson White Jennifer E. Caselle. Dept. of EEMB Marine Science Institute UC Santa Barbara. Study Sites. Cojo. Naples. Harris Pt. Hazards. Scorpion. Forney. Pelican. East. Crook Pt. Middle. Yellow- banks. Valley. Gull

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Demographics of kelp bass in the Santa Barbara Channel

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  1. Demographics of kelp bass in the Santa Barbara Channel J. Wilson White Jennifer E. Caselle Dept. of EEMB Marine Science Institute UC Santa Barbara

  2. Study Sites Cojo Naples Harris Pt. Hazards Scorpion Forney Pelican East Crook Pt. Middle Yellow- banks Valley Gull Isle Years of Data 2 3 6 PISCO

  3. Fish transects Algae transects Annual survey Within-site sampling design Algae/invertebrate transect distribution Coastline 5 m 15 m

  4. 2 m 2 m 30 m Fish Surveys: Kelp Surveys: 1. Count # kelp stipes • Count fish • Estimate sizes- total length (to nearest cm) • Three levels in water column (where canopy present)- bottom- midwater- surface canopy

  5. Estimating Larval Supply: SMURFs Standardized Monitoring Unit for Recruitment of Fishes Giant Tuffy

  6. Sampling Schedule SMURFs (biweekly per site) settlers M S O J J A N D J Community Surveys (once per site) recruits + all adult fish kelp abundance

  7. SMURF-YOY relationship SMURFs (biweekly per site) M S O J J A N D J Community Surveys (once per site) Only used SMURF data up to date of benthic survey

  8. Larval supply - recruitment relationship: dependent on kelp abundance ln(recruits) = 0 + 1ln(larval supply) + 2kelp + 3kelpln(larval supply)

  9. Estimating Post-settlement Survivorship year t year t+1 YOY juvenile survival 1 yr old adult survival 1+ yr old YOY = Young-of-the-year = ‘recruits’ (fish that have settled recently and are counted in benthic surveys)

  10. Estimating Young-of-Year (YOY) survivorship SMURFs (biweekly per site) M S O J J A N D J Community Surveys (once per site) Entire YOY cohort not sampled by benthic surveys

  11. Juvenile Survivorship settlers (from SMURF) 1 yr olds (from surveys) YOYs on transect (predicted from recruitment regression) ln(1 year olds) = 0 + 1ln(YOY density) + 2kelp

  12. Juvenile Survivorship settlers (from SMURF) 1 yr olds (from surveys) YOYs on transect (predicted) fit parameters for both transitions Recruits = 1(SMURF settler densitykelp) 1 yr olds = Recruits/(1+Recruits/2)

  13. Adult Survivorship 1+ yr olds (from surveys) 1 yr olds & 1+ yr olds (from surveys) Nt+1 = Nte-( +adults + adults kelp)

  14. Large-scale patterns: • Adult kelp bass density is • positively correlated with larval supply • negatively correlated with kelp

  15. Large-scale patterns of larval supply & kelp density

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