Demographics of kelp bass in the Santa Barbara Channel
J. Wilson WhiteJennifer E. Caselle
Dept. of EEMB Marine Science InstituteUC Santa Barbara
Naples
Scorpion
Middle
Gull Isle
Yellow-banks
ForneyPelican
Hazards
Cojo
Valley
Harris Pt.
Crook Pt.
Years of Data
36
2
Study Sites
East
PISCO
Algae/invertebrate transect distribution
Coastline
5 m
15 m
Annual surveyWithin-site sampling design
Fish transects
Algae transects
2 m
2 m
30 m
1. Count fish2. Estimate sizes
- total length (to nearest cm) 3. Three levels in water column
(where canopy present)- bottom- midwater- surface canopy
Fish Surveys: Kelp Surveys:1. Count # kelp stipes
Estimating Larval Supply: SMURFsStandardized Monitoring Unit for Recruitment of Fishes
Giant Tuffy
Sampling Schedule
J A S O N D JJ
SMURFs(biweekly per site)
Community Surveys(once per site)
settlers
recruits + all adult fish
kelp abundance
M
SMURF-YOY relationship
J A S O N D JJ
SMURFs(biweekly per site)
Community Surveys(once per site)
M
Only used SMURF data up to date of benthic survey
Larval supply - recruitment relationship:dependent on kelp abundance
ln(recruits) = 0 + 1ln(larval supply) + 2kelp + 3kelpln(larval supply)
Estimating Post-settlement Survivorship
YOY
1 yr old
1+ yr old
juvenile survival
adultsurvival
year t year t+1
YOY = Young-of-the-year = ‘recruits’(fish that have settled recently and are counted in benthic surveys)
Estimating Young-of-Year (YOY) survivorship
J A S O N D JJ
SMURFs(biweekly per site)
Community Surveys(once per site)
M
Entire YOY cohort not sampled by benthic surveys
settlers (from SMURF)
1 yr olds(from surveys)
Juvenile Survivorship
YOYs on transect (predicted from
recruitment regression)
ln(1 year olds) = 0 + 1ln(YOY density) + 2kelp
settlers (from SMURF)
1 yr olds(from surveys)
Juvenile Survivorship
YOYs on transect(predicted)
Recruits = 1(SMURF settler densitykelp)1 yr olds = Recruits/(1+Recruits/2)
fit parameters for both transitions
1+ yr olds(from surveys)
Adult Survivorship
1 yr olds & 1+ yr olds(from surveys)
Nt+1 = Nte-( +
adults +
adults kelp)
Large-scale patterns:
Adult kelp bass density is
-positively correlated with larval supply
-negatively correlated with kelp
Large-scale patterns of larval supply & kelp density
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