Marine stock enhancement programs in Japan

1
Marine stock enhancement programs in Japan

• Katsuyuki Hamasaki
• Department of Marine Biosciences,
• Tokyo University of Marine Science and Technology

2
Lecture topics

• World fisheries production, world population
  growth, measures to sustain and/or augment the
  fisheries production
• Japanese marine stock enhancement programs
• Red sea bream Pagrus major
• Japanese flounder Paralichthys olivaceus
• Kuruma prawn Penaeus japonicus
• Mud crab Scylla paramamosain

3
World fisheries production

• World fisheries productions showed about 30
  million tons in the 1950s then linearly
  increased to about 130 million tons in the
  mid-1980s and reach the limit.

4
World population growth

• In 2000, the world had 6.1 billion human
  inhabitants.
• This number could rise to more than 9 billion in
  the next 50 years.
• To sustain the population growth, we have to
  augment the food production from agriculture and
  fisheries.

5
Measures to sustain and/or augment the fisheries
production

• Marine aquaculture
• 15.1 million tons in 2001
• 15.5 of world marine fisheries production
• Stock management
• Fishing regulation
• Marine protected area
• Marine stock enhancement (sea ranching)
• Artificial propagation to augment natural
  production by releasing cultured juveniles

6
Marine stock enhancement programs in the world
7
Hatcheries for marine stock enhancement in Japan
76 million 37 Fish 221 million 12
Crustaceans 3213 million 26 Mollusks 78
million 8 Invertebrates
8
Evaluation of stocking effectiveness of marine
finfish in Japan

• Recapture rate (return rate)
• Number of recaptured/number of released
• Yield/release
• Unit production weight from release
• Amount of catch (g) gained from one released
  juvenile
• Economic efficiency
• Net income/release cost
• gt1 profitable

9
Evaluation of stocking effectiveness of marine
finfish in Japan
Kitada, S. and Kishino, H., 2006. Lessons learned
from Japanese marine fin fish stock enhancement
programs. Fish. Res., in press
10
Catch and release statistics for red sea bream
and Japanese flounder
Kitada and Kishino (2006)
11
Relationship between landings of hatchery and
wild fish
Kitada and Kishino (2006)
12
Relationship between number released and return
rate
Kitada and Kishino (2006)
13
Macro analysis red sea bream
Kitada and Kishino (2006)
Hatchery/Total mean 9.5
14
Macro analysis Japanese flounder
Kitada and Kishino (2006)
Hatchery/Total mean 11.7
15
Changes in fishing effort
Kitada and Kishino (2006)
16
Conclusion of marine finfish stock enhancement
programs

• MFSE can augment wild production.
• There should be limits depending on the carrying
  capacity.
• For large stocks, effect of stocking is
  inevitably buried in the stochasticity of its
  intrinsic dynamic system.
• MFSE should be targeted on local populations with
  restricted recruitment and high commercial value.
• Successful MFSE should be accompanied with
  monitoring and fishing regulations.

Kitada and Kishino (2006)
17
Evaluation of stocking effectiveness of Kuruma
prawn
Hamasaki, K. and Kitada, S., 2006. A review of
kuruma prawn Penaeus japonicus stock enhancement
program in Japan. Fish. Res., in press.
18
Evaluation of stocking effectiveness of kuruma
prawn

• Marking surveys for estimating recapture rates of
  released juveniles have been conducted since 1995.

Coded wire tag
19
Evaluation of stocking effectiveness of kuruma
prawn
Tango Sea
Kafuri and Imari Bays
Eastern SIS
Ariake Sea

• 40 case studies (1995-2002)
• 17000-870000 juveniles/year
• 30-71 mm Body length

20
Recapture rate and economic efficiency
Hamasaki and Kitada (2006)
21
Evaluation of stocking effectiveness of Kuruma
prawn
Hamasaki and Kitada (2006)
22
Hamasaki and Kitada (2006)
23
Conclusion from marking surveys of kuruma prawn
juveniles

• The summary of 40 marking surveys highlights the
  variability in recapture rates.
• High recapture rates were obtained in several
  case studies.
• KPSE should be targeted on local populations in
  regions where enhancement may have more chance of
  success than in other regions.
• Rehabilitation of nursery grounds should be
  indispensable for successful KPSE.

24
Stock enhancement program of mud crabs in Urado
Bay
Scylla paramamosain
Obata, Imai, Kitakado, Hamasaki and Kitada, 2006.
The contribution of stocked mud crabs Scylla
paramamosain to commercial catches, estimated
using a genetic stock identification technique in
Japan. Fish. Res., in press.
25
Catch and release statistics for mud crabs in
Urado Bay
Obata et al., 2006
26
Evaluation of stocking effectiveness of mud crabs
using mtDNA tags

• Collection of 98 to 149 female crabs from Urado
  Bay in December 1996-2000
• Analysis of haplotypes of mtDNA D-loop region
• Amplification of mtDNA D-loop region by PCR and
  digestion by three restriction enzymes (Hinf ?,
  PshB? and Pac?)
• Visualization of RFLP (restriction fragment
  length polymorphism) profiles by agarose gel
  electrophoresis

27
Evaluation of stocking effectiveness of mud crabs
using mtDNA tags

• Selection of female crabs with specific
  haplotypes
• Seed production using selected female crabs in
  April 1997-2001
• Juvenile rearing to ca. 10 mm CW and release

28
Release of juveniles
Obata et al., 2006
29
Release of juveniles
Urado Bay
30
Collection of crab samples
Main fishing season
Jan.
June
Dec.
Aug.
Previous year
Baseline population
Release
Recruit
1st year
Mixed population
2nd year
End of life
3rd year
31
Estimation of mixing rates
The log likelihood function for the samples
the mixing rate of stocked crabs
the frequency of haplotype i in baseline
population j
the number of individuals that haplotype i in
the sample drawn from the mixed population
the number of individuals that haplotype i in
the samples drawn from baseline population j
the estimates of haplotype frequency
32
Estimates of mixing rate from Oct. to Dec. in
release year
Obata et al., 2006
33
Evaluation of stocking effectiveness
Obata et al., 2006
34
Conclusions from the marking surveys of mud crab

• Stocked crabs could account for certain
  percentages of the commercial catch of mud crabs
  in Urado Bay.
• Stock enhancement program of Scylla paramamosain
  would be profitable by avoiding the release
  mortality due to poor seed quality.

35
General conclusions from MSE in Japan

• MSE have a potential to augment fisheries
  production.
• MSE should be targeted on local populations with
  restricted recruitment and high commercial value
  in regions where enhancement may have more chance
  of success than in other regions.
• MSE should not succeed without monitoring and
  fishing regulations and rehabilitation of
  habitats.

36
Advanced Topics for Fisheries and Marine Science
Supported by SOI Asia Project 20/2/2006
REPORT FOR ASSIGNMENT Answer all of following
questions. Please send all reports on Q-1 to Q-3
back to each lecturer. Q-1 -2 are common
through eight lectures (1- 8), and Q-3 is
raised by individual lecturer. Q-1 Summarize all
of eight lectures on Food Technology and
Aquaculture by using less than 400 words for
each. Q-2 Indicate problem(s) remaining
unresolved in fisheries of your country.  Then,
propose your idea to improve the problem(s) by
your knowledge established in a series of SOI
lectures (describe by less than 500 words in
total). Q-3 Introduce the present status of
aquaculture and/or stock enhancement activities
in your country.