Embed Size (px)
Citation preview
Studies on oceanic turtles
Introduction Objectives Methods Results & Discussion
Oceanic isoscapes and the feeding ecology of sea turtles in the southeastern Pacific Ocean:
a stable isotopic analysis
Shaleyla Kelez, Jeffrey A. Seminoff & Larry B. Crowder
1
n o i t u b i r t n o C y r e k o o R d e t a
m i t s E
GNC OST SIN GRO OAX CHIS BCS GOR EV
ROOKERY
Fisheries related research
Genetic analysis, X Velez-Zuazo
GNC OST SIN GRO OAX CHIS BCS GOR EV
ROOKERY
Introduction Objectives Methods Results & Discussion
Introduction Objectives Methods Results & Discussion
Objectives D Study the foraging
ecology of sea turtles in southeastern Pacific
D Compare trophic status of 3 species in oceanic areas
D Explore spatial patterns in stable isotope signatures
Est
imat
ed R
ooke
ry C
ontr
ibut
ion
2
Introduction Objectives Methods Results & Discussion
Stable isotope analysis
1144NN 1155NN 1122CC 1133CC ((77pp ++ 77nn)) ((77pp ++ 88nn)) ((66pp ++ 66nn)) ((66pp ++ 77nn))
Introduction Objectives Methods Results & Discussion
Stable isotope analysis Food webs and trophic level Migratory patterns
3
Fishing trips
377 sets 2003-2009
Introduction Objectives Methods Results & Discussion
Study area: Southeast Pacific
Introduction Objectives Methods Results & Discussion
4
Introduction Objectives Methods Results & Discussion
Results: δ15N and δ13C values Greens
n = 76
Loggerheads
n = 36
Olive ridleys
n = 27
139 δ
Introduction Objectives Methods Results & Discussion
δ15N and δ13C values
(-16.53, 13.69)
Loggerhead (-15.80, 11.71)
Olive ridley
Green (-16.12, 11.58)
δ
δ
δ
5
Introduction Objectives Methods Results & Discussion
δ13C distributions per species
Introduction Objectives Methods Results & Discussion
δ15 N distributions per species
6
Trophic niche comparisons
δ 15 Nitrogen δ 13 Carbon
Green
δ
Olive ridley
** Loggerhead
Green
Loggerhead
δ
Olive ridley
Introduction Objectives Methods Results & Discussion
Introduction Objectives Methods Results & Discussion
Capture sites
Large area Denitrification Upwelling OMZ ENSO
7
Spatial patterns in δ15N values
Loggerhead Green Olive ridley
Introduction Objectives Methods Results & Discussion
Spatial patterns of δ13C values
Olive ridley Green Loggerhead
Introduction Objectives Methods Results & Discussion
8
Introduction Objectives Methods Results & Discussion
Focal area analysis
39 greens
19 loggerheads
10 olive ridleys
Introduction Objectives Methods Results & Discussion
Correlations with latitude Loggerhead - δ15N Green - δ15N Olive ridley - δ13C
9
Trophic niche comparisons
δ 15 Nitrogen δ 13 Carbon
Green
δ
Olive ridley
Loggerhead
Green
Loggerhead
δ
Olive ridley
Introduction Objectives Methods Results & Discussion
Conclusions
D Spatial patterns are evident not only for Carbon but also for Nitrogen.
D The values of δ15N could be wrongly interpreted if spatial patterns are not considered.
D Loggerheads, greens and olive ridleys apparently forage at the same trophic level.
10
Thank you !!
11
