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

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: so

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Santa Barbara Port sampling

Red urchin gonad variability over timeg

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ad:

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dex

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SI)

Oct‘08

Dec Feb‘09

Mar May Jul Aug Oct

Red urchin gonad variability over timeg

on

ad:

som

atic

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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

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% Landings

<1

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Red urchin landings 1985-2005

Purple urchin abundance 2007

33.8

34

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34.4

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-120.6 -120.4 -120.2 -120 -119.8 -119.6 -119.4 -119.2

33.8

34

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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

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11-20

20-30

% Landings

<1

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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

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Long-term (1985-2007) Variation in Kelp and Urchin

NPS—KFM data (eastern SCI and Anacapa Island)

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Long-term (1985-2007) Variation in Kelp and Urchin

NPS—KFM data (eastern SCI and Anacapa Island)

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Long-term (1985-2007) Variation in Kelp and Urchin

NPS—KFM data (eastern SCI and Anacapa Island)

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kelp

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red urchins

• Red urchins have persistently higher biomass inside of the reserves.

• Reproductive output is ~4 times higher in kelp forests versus urchin barrens

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Red urchin biomass

Proposed restoration sites

Proposed restoration sites

ecological restoration & economic revitalization