Restoration of the Coconut Crab Birgus latro (L.) in Green Island: Artificial Cultivation of Larvae, Investigation of Juvenile Habitat and Community Education

1
Restoration of the Coconut Crab Birgus latro (L.)
in Green Island Artificial Cultivation of
Larvae, Investigation of Juvenile Habitat and
Community Education
Chang-Po Chen, Fang-Lin Wang Research Center for
Biodiversity, Academia Sinica, Taipei, Taiwan115,
Republic of China.
Introduction
The coconut crab Birgus latro (L.), a
monospecific genus Birgus within the family
Coenobitidae, is found throughout many of the
islands of the Indo-Pacific, including, the Green
Island in Taiwan . Females release their larvae
into the sea in the new moon phase, and the
larvae live with the planktonic community for
about a month. Then as postlarvae, or
glaucothoes, settle to the bottom, and carry a
small snail shell, and then emerge onto the
shoreline as a part of hermit crab communities
(Reese, 1968). When they reach a size of roughly
1 cm across the carapace, coconut crabs give up
the shell-carrying habit of their hermit crab
ancestors. With intensified harvesting
and habitat deterioration, a rapid decline has
happened in the number of Birgus latro. It has
been on the Red list of the IUCN since 1983
(Wells et al., 1983), and is the only protected
crustacean species designated by the Wildlife
Conservation Law in Taiwan since 1995.
Successfully conserving the habitat of coconut
crabs will not only protect the coastal zones and
nearby waters, but also land areas. It is an
umbrella species of Green Island, and the best
indicator for monitoring the quality of this
island's ecosystems. In order to restore and
manage the vitality of this threatened species,
we have implemented three comprehensive lines of
works, including artificial culture, habitat
protection, and community education.
Three actions for coconut crab conservation
3. Local community empowerment through education
The goal of restoration of coconut crab
local residents
government organizations
local educational institutions
Effective conservation strategies
Increasing the number of the coconut crab
population
Making the conservation of species and ecology
sustainable

• Environmental education

• Collecting the culture and
• history of coconut crabs
• and local residents

?Let local residents practice the work of
conservation
?releasing the reared juveniles to natural
environment. ?providing a basis of habitat
preservation

• Habitat preservation

Coconut crab conservation team work

• Development the eco-tourism
• subject to coconut crabs

• Seizure of illegal harvest

• Artificial cultivation

3.Community Education
1.Larval cultivation
2.Investigation of Juvenile Habitat
1. Larval culture of coconut crabs
Fig.1 Larval sampling of Birgus latro. (a) gravid
female in the vessel with sea water to
make eggs hatching. (b) the first stage
zoea.
Future works
Fig. 4 The mean survival rates of enriched
Atemia (EA) groups were significantly
higher than unenriched Atemia (UA)
those in the forth and fifth zoeal
stages (t-test, Plt0.05).

1. Ecological corridors for crabs will be built to
   separate the crabs migration routes from the
   road encircling Green Island through
   community-based works including the study of the
   distribution of population, migrating behavior of
   crabs and environmental education of local
   residents.
2. Environmental education and local communication
   will be promoted effective through the coconut
   crab conservation team work.
3. The research on larval mass cultivation will be
   continued in 2006.
4. The study of genetics of Birgus latro in the
   Indo-Pacific region will apply to plan the
   appropriate conservation strategies for coconut
   crab.

Reference
Fig.5 There were 20 Zoeae metamorphosed
to glaucothoes on the 27th to 34th day
and 6 carrying the shell on the 37h to
43rd days of its zoeal life in our study.
This picture shows a glaucothoe of
coconut crab hiding in a snail shell.
Fig.2 Larval culture devices of Birgus latro
under the condition of 24-25? and 34-35
(a) zoeal-reared aquarium (b)
glaucothoel-reared glass container (c)
aquarium simulating intertidal environments for
rearing glaucothoes. Zoeae were fed
with hatched Artemia nauplii.
Reese, E.S. R.A. Kinsie 1968 The larval
development of the coconut or robber crab Burgus
Latro (L.). in the laboratory
(Anomura, Paguridae) Crustaceana Suppl. 2,
117-144. Wells, S.M., Pyle, N.M. and Collins,
R.M. 1983. Coconut or robber crab. In IUCN
Invertebrate Red Data Book. International
Union for Conservation of Nature and Natural
Resources, Gland, Switzerland.