Could spatial management of sea urchins increase fishery profits?
Sarah Teck, Nick Shears, Sarah Rathbone, Steve Gaines
Department of Ecology, Evolution, and Marine Biology, University of California Santa Barbara
Photo: CINMS Photo: J. Maassen
Santa BarbaraSan Miguel
Santa Rosa
Anacapa
Santa Cruz
Background
• red sea urchin fishery:– California
~11.2 million lbs.
~$6.1 million– N. Channel Islands
~66%– Port of Santa Barbara
~52%– 90% western end
Image: www.incabrain.com
Background• seasonal variability in gonad quality influences price
($0.39/lb vs >$1.00/lb)
• fishermen race to harvest year-round vs. waiting for optimal quality
(how much more $ would they make, if they waited?)
• delaying harvest through spatial property rights,
TURF’s (Territorial Use Rights in Fisheries)
fishermen’s profits
(also would save time, no need to survey area to fish during suboptimal conditions, just wait for optimal quality)
Background
• with fished species need to wait for individuals and population growth
with urchins also need to wait for
seasonal gonad quality
• first, we need to understand more detailed ecological information on temporal and spatial variability of gonad quality
Background
• with fished species need to wait for individuals and population growth
with urchins also need to wait for
seasonal gonad quality
• first, we need to understand more detailed ecological information on temporal and spatial variability of gonad quality
Santa BarbaraSan Miguel
Santa Rosa
Anacapa
Santa Cruz
Channel Island field sampling
Santa BarbaraSan Miguel
Santa Rosa
Anacapa
Santa Cruz
Red urchin gonad variability over space
go
nad
: so
mat
ic i
nd
ex (
GS
I)
Santa Barbara Port sampling
Red urchin gonad variability over timeg
on
ad:
som
atic
in
dex
(G
SI)
Oct‘08
Dec Feb‘09
Mar May Jul Aug Oct
Red urchin gonad variability over timeg
on
ad:
som
atic
in
dex
(G
SI)
Oct‘08
Dec Feb‘09
Mar May Jul Aug Oct
Red urchin gonad variability over timeg
on
ad:
som
atic
in
dex
(G
SI)
Oct‘08
Dec Feb‘09
Mar May Jul Aug Oct
Red urchin gonad variability over timeg
on
ad:
som
atic
in
dex
(G
SI)
Oct‘08
Dec Feb‘09
Mar May Jul Aug Oct
Red urchin gonad variability over timeg
on
ad:
som
atic
in
dex
(G
SI)
Oct‘08
Dec Feb‘09
Mar May Jul Aug Oct
Red urchin landings 1985-2005
Purple urchin abundance 2007
a)
b)
Figure 4. (a) Spatial distribution of red urchin landings from 1985 to 2005 in the CINMS (landings are assigned to 10 x 10 nautical mile blocks as reported to CA Dept. of Fish and Game), and (b) spatial variation in purple urchin abundance (the larger the circle the greater the density; Data: PISCO/SBC-LTER)
<1
1-5
6-10
11-20
20-30
% Landings
<1
1-5
6-10
11-20
20-30
% Landings
Red urchin landings 1985-2005
Purple urchin abundance 2007
33.8
34
34.2
34.4
34.6
-120.6 -120.4 -120.2 -120 -119.8 -119.6 -119.4 -119.2
33.8
34
34.2
34.4
34.6
-120.6 -120.4 -120.2 -120 -119.8 -119.6 -119.4 -119.2
Red urchin landings 1985-2005
Purple urchin abundance 2007
a)
b)
Figure 4. (a) Spatial distribution of red urchin landings from 1985 to 2005 in the CINMS (landings are assigned to 10 x 10 nautical mile blocks as reported to CA Dept. of Fish and Game), and (b) spatial variation in purple urchin abundance (the larger the circle the greater the density; Data: PISCO/SBC-LTER)
<1
1-5
6-10
11-20
20-30
% Landings
<1
1-5
6-10
11-20
20-30
% Landings
Purple urchin abundance 2007
• purples compete with reds for kelp
• not commercially harvested (smaller)
• form persistent urchin barrens (mostly in the east)
• long-term monitoring sites deforested by purples ~33% of the time—mostly in the east
purple sea urchin
• manipulate ecology of a managed area to increase profitskelp restoration
0
2
4
6
8
10
12
14D
en
sity
(m-2
)Reserve (n=2)
Fished (n=5)
0
10
20
30
40
50
60
70
80
De
nsi
ty (
m-2)
Reserve (n=2)
Fished (n=5)
0
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5
6
7
8
De
nsi
ty (
m-2)
Reserve (n=2)
Fished (n=5)
Kelp
Purple urchins
Red urchins
Long-term (1985-2007) Variation in Kelp and Urchin
NPS—KFM data (eastern SCI and Anacapa Island)
0
500
1000
1500
2000
2500
De
nsi
ty (
m-2
)
Reserve (n=2)
Fished (n=5)
Red urchin biomass
Bio
ma
ss (
g m
-2)
kelp
purple urchins
red urchins
0
500
1000
1500
2000
2500
Reserve (n=2)
Fished (n=5)
Red urchin biomass
0
2
4
6
8
10
12
14D
en
sity
(m-2
)Reserve (n=2)
Fished (n=5)
0
10
20
30
40
50
60
70
80
De
nsi
ty (
m-2)
Reserve (n=2)
Fished (n=5)
0
1
2
3
4
5
6
7
8
De
nsi
ty (
m-2)
Reserve (n=2)
Fished (n=5)
Kelp
Purple urchins
Red urchins
Long-term (1985-2007) Variation in Kelp and Urchin
NPS—KFM data (eastern SCI and Anacapa Island)
0
500
1000
1500
2000
2500
De
nsi
ty (
m-2
)
Reserve (n=2)
Fished (n=5)
Red urchin biomass
Bio
ma
ss (
g m
-2)
kelp
purple urchins
red urchins
0
500
1000
1500
2000
2500
Reserve (n=2)
Fished (n=5)
Red urchin biomass
0
2
4
6
8
10
12
14D
en
sity
(m-2
)Reserve (n=2)
Fished (n=5)
0
10
20
30
40
50
60
70
80
De
nsi
ty (
m-2)
Reserve (n=2)
Fished (n=5)
0
1
2
3
4
5
6
7
8
De
nsi
ty (
m-2)
Reserve (n=2)
Fished (n=5)
Kelp
Purple urchins
Red urchins
Long-term (1985-2007) Variation in Kelp and Urchin
NPS—KFM data (eastern SCI and Anacapa Island)
0
500
1000
1500
2000
2500
De
nsi
ty (
m-2
)
Reserve (n=2)
Fished (n=5)
Red urchin biomass
Bio
ma
ss (
g m
-2)
kelp
purple urchins
red urchins
• Red urchins have persistently higher biomass inside of the reserves.
• Reproductive output is ~4 times higher in kelp forests versus urchin barrens
0
500
1000
1500
2000
2500
Reserve (n=2)
Fished (n=5)
Red urchin biomass
Proposed restoration sites
Proposed restoration sites
ecological restoration & economic revitalization
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