Changing Coastal Commons in a Sub-Tropical Island Ecosystem, Yaeyama Islands, Japan - Island Futures: Conservation and Development Across the Asia-Pacific Region - page 128

and climate is sub-tropical, although the surrounding sea is tropical, with an annual
mean surface temperature of 24.7°C around Ishigaki, the largest island of the
Yaeyama group. Most of the islands are fringed by coral reefs. The Sekisei Lagoon,
located between the two largest islands (Ishigaki and Iriomote), contains coral reefs
extending over an area of about 13,000 ha, the outer margin of which is barrier reef.
The lagoon is a rich coral habitat supporting considerable species diversity; it con-
sists of numerous patch reefs, coral rocks, passages, sandy grounds and other coral
formations that provide the principal fishing grounds for local small-scale fisheries.
Mangroves develop along the lower reaches of rivers, some of which reach over
10 km in length, especially on Ishigaki and Iriomote. Mudflats and beds of sea
grasses are also to be found. Reef-sustaining nutrients flow into the sea through
these rivers and artificial waterways.
With the great biodiversity of coral reef environments, fishing activities
undertaken in them tend to be highly specialized and therefore relatively small in
scale. They may take place at day- or night-time, and employ diurnal and nocturnal
fishing strategies, depending on the species sought or whether one is fishing for
individual specimens or aggregations.
Ethnographic and historical documents show that fishing methods can vary
considerably, according to the place and time of fishing, and according to
age-groups (Kuchikura 1977 ). More than 30 fishing methods can be identified,
including fish drive, basketry trapping using bamboo or wire-made cylindrical
traps, underwater shell-collecting and spearing, turtle hunting, the use of tidal
stone weirs, coastal gleaning, use of gill-, stake-, set-, and lift-nets, or line fishing
by bottom line, trolling, long-line, drop line, or pole line. Each fishing method
can be further subdivided depending on target species and fishing gear employed.
Some methods have persisted over a long period of time while others date to the
past decade or so. Methods are always changing as technologies evolve and
economic demands fluctuate: for example, more recently, the use of payao
(underwater buoys used to aggregate fish) to catch large surface swimmers such
as tuna, wahoo and marlin has become common in deep waters (Kakuma 2002 ).
Coastal aquaculture operations for seaweed, pearl shell, giant clam, and grouper
have been launched.
Certain fishing techniques have been banned due to their destructive nature.
Once Okinawa prefecture was restored to mainland Japan in 1972, following
various decades of administration by the United States, Japanese laws were
brought into force. These included the Japanese Fisheries Cooperative Association
Law, which, amongst other things, prohibited indiscriminate blasting and cyanide
fishing, which had been earlier employed by some fishers (Ruddle and Akimichi
1984, 1989 ).
Moreover, various customary practices and rules that had existed prior to adoption
of the Japanese fisheries laws fell into disuse and were no longer recognized after
1972. One of the most prevalent local practices facing total disappearance was the
use of tidal stone weirs to catch fish.