Hamana Lake

Osaka Bay

Okayama Prefecture

Chesapeake Bay

Gear
(% landings)

Set nets (100%)

Small trawls (70%)
Set nets (14%)
Large trawls (14%)
others (2%)

Small trawls (97%)
Set nets (3%)

Pots (76%)
trot-line (19%)
small trawls (scrapes) (0.5%)
winter dredge (4%)

Mean landings
crabs yr^-1

14 tons ('90-98)
~ 67,000 crabs
(4.8 crabs/kg for crabs
> 120 mm CW;
Ariyama 2000)

57 t ('90-98)
~ 353,000 crabs
(6.2 crabs/kg for crabs
>100 mm CW;
Ariyama 2000)

145 t ('90-97)
~ 696,000 crabs
(4.8 crabs/kg for crabs
> 130 mm CW;
Ariyama 2000)

36,000 t ('90-'99)
~ 190,000,000 crabs
(5.5 crabs/kg; CBSAC
statistics)

Value yr^-1

$171,000
($2.40/crab; pers. obs)

$1,425,000
($25/kg - Ariyama 2000)

$1,775,000
($2.40/crab; pers. obs.)

$43,000,000 (hardshell -
NOAA 2000 statistics)

Number of
fishers

400

200

-

>1000

Size limits
(2001)

Size limit=120 mm CW

None; recommended
size limit=120 mm CW

Size limit=130 mm CW
No ripe females

Size limit=127 mm CW
(hard)
Size limit=76 mm CW
(soft)
No size limit for winter dredge fishery (VA)

Season limits

None

None

None

May - November

Weekly/daily
limits

Limited Entry (Fishing Cooperatives)
3 pm - 3 am soaks

Limited Entry (Fishing
Cooperatives)

Limited Entry (Fishing
Cooperatives)

Quasi-limited Entry
(licenses), pot number
and soak limits

Fishing
Mortality Rate

-

4.39 yr-1 (~ 99% yr-1)

-

0.9 yr-1 (~ 60% yr-1)

Age at entry
(wild)

0.4-1.0 yrs

0.4 - 1.0 yrs (120 mm CW)

0.4 - 1.0 yrs

1 - 1.5 yrs (hard)
<0.5 - 1.5 yrs (soft)

Age at entry
(hatchery)

0.4 - 0.5 yrs (120 mm CW)

0.3 - 0.4 yrs (~ 100 mm CW)

0.4 - 0.5 yrs (130 mm CW)

Product value
(retail)

Softshell ea <$1.00
(not desired)
120-150 mm CW; ea ~ $3.40
160-200 mm CW; ea ~ $5.10
>200 mm CW; ea ~ $8.50

softshell ea < $1
(not desired)
<120 mm CW; doz ~ $23.00
120-150 mm CW; ea ~ $3.40
160-200 mm CW; ea ~ $8.00
>200 mm CW; ea ~ $14.00

softshell ea < $1
(not desired)
120-150 mm CW; ea ~ $3.40
160-200 mm CW; ea ~ $5.10
>200 mm CW; ea ~ $8.50

softshell ea ~ $3
120-130 mm CW; doz ~ $8
females (<150 mm CW;
doz ~$8
140-160 mm CW; doz ~ $14
>160 mm CW: doz ~ $20

Hatchery
releases yr^-1

1.4 x 106 C3-C4 ('90-98)

0.7 x 106 C3-C4 ('92-98)

1.1 x 106 C3-C4 ('91-93)

Method of
2° rearing

Tanks

Tanks with structure

Coastal impoundments

Method of
release

Single site, single release
time, Zostera beds

multiple sites, multiple
months, sandy intertidal
beaches, macroalgal Gracilaria beds

multiple sites, multiple months, Zostera beds

Harvest
Recapture
Rate (Harvest-R
/Release No.)

1.2% (mark-
recapture - '98)
0.85% (cohort '92-98)

31.3% (modeling
approach '90)

5.7%
(hatchery anomaly of chelae)

Contribution
rate (yr^-1)
(Harvest-R
/Harvest-T)

18% (cohort analysis
'92-98)

59% (modeling
approach '90)

9% (cohort analysis '98)

Method(s) for
determining
contribution
rates

Mark-recapture ('98)
Cohort analysis
('92-'98)

Post-release and
harvest model ('90)

Cohort analysis (every yr)
hatchery anomaly of chelae
('98)

Estimated
value to fishery (contribution x harvest value)

$31,000

$910,000

$160,000