The
Indonesian Sea Large Marine Ecosystem (LME) is a tropical LME of about
400,000 square kilometers (km2) situated at the confluence of the
Pacific and Indian Oceans. It has a composite structure of environmental
conditions, with local areas of upwelling, strong wind-driven and tidal
currents, and nutrient inputs from rivers or human activities. The LME
is influenced by a monsoonal system, with a pattern of surface currents
varying during the southeast and northwest monsoon. It experiences
annual and interannual variations in surface temperature. The warm ocean
and its links to the atmosphere create the El Niño Southern
Oscillation (ENSO) phenomenon. LME book chapters and articles include
Morgan, 1989, Zijlstra and Baars, 1990, and Kadri et al, 1999.The
Indonesian Sea LME extends in an east/west direction across a distance
of 5,000 km. Geologically, it lies at the confluence of three tectonic
plates: the Eurasian Plate, the Indo-Australian Plate and the Pacific
Plate. There are numerous islands, active volcanoes and earthquake
occurrences. For a map of the eastern Banda Sea and the northern Arafura
Sea, indicating geomorphology and isobaths, see Zijlstra and Baars,
1990, page 55. The LME has complex ocean-atmospheric dynamics. For a map
of surface current patterns during the southeast and northwest monsoon
and for the locations of areas of upwelling and downwelling during both
periods, see Wyrtki (1958), and Zijlstra and Baars, 1990, p. 56. The
influence of El Niño, La Niña and the Australian and Asian monsoons
contribute to the unique climate conditions in this region, an object of
global climatology research. For more information on Borneo’s Marine
Ecosystem and the Greenhouse Risk Factor, see Kadri et al, 1999. The
Indonesian Sea LME is considered a Class II, moderately high (150-300
grams of carbon per square meter per year) productivity ecosystem based
on SeaWiFS global primary productivity estimates. The Banda Sea, and the
Aru Basin in particular, are areas of extensive upwelling. For
locations of upwelling during both monsoons, see Zijlstra and Baars,
1990. Nutrient concentrations are influenced by ocean mixing and sea
surface temperatures. The sea water exchange between the Pacific and
Indian Oceans impacts seasonal cycles of primary and secondary marine
productivity. For more information on the plankton system, see Zijlstra
and Baars, 1990. Pelagic fish resources appear to be significantly
higher during periods of seasonal upwelling. Fish species harvested in
this LME are giant gouramy, common carp, milk fish, tilapia, tuna,
skipjack tuna, barramundi, anchovy, travelly, mackerel, garfish, shrimp,
thumb nail (parrotfish), octopus, squid, crab, and lobster. Black
marlin is a highly mobile species, fished recreation ally. The coral
reef environment harbors all kinds of reef fish. Ornamental fish species
are harvested and exported to the United States, Japan and Germany.
These include the clownfish (Amphiprion), damselfish (Dascyllus), and
wrasse (Coris gaimardi). Pearl oysters, tortoises and turtles, as well
as exotic species of crabs and mollusks living both in salt and fresh
water, are found in this LME. There are marked changes in the abundance,
activity and composition of almost all components of the pelagic system
of the Banda Sea, related to the monsoon-induced alternation between
periods of upwelling and downwelling (see Zijlstra and Baars, 1990).
However, the Food and Agriculture Organization (FAO) 10-year trend shows
a steady increase of the total catch (see FAO, 2003), from 1.1 million
tons in 1990, to 1.6 million tons in 1999. There is a high catch
percentage for clupeoids (herrings, sardines and anchovies) (23%),
coastal fishes, crustaceans, molluscs and demersal fishes. For more
information on micronekton and fish, see Zijlstra and Baars, 1990. The
Central Research Institute for Fisheries (CRIFI) is under the Indonesian
Ministry of Agriculture. The University of British Columbia Fisheries
Center has detailed fish catch statistics for this LME. For a portrayal
of the data, see the graph above.The fishing practices for commercial
shrimp harvesting are harmful to endangered sea turtles that are
vulnerable to retention in shrimp trawls as bycatch. Artisanal fishing
and aquaculture appear to have less harmful effects. Not much is known
about the status of the ecosystem in regards to pollution or coastal
habitat alteration. Apart from fisheries, a major ecosystem issue is
urban expansion and industrialization along the thousands of miles of
coastline of the Philippines archipelago. This has resulted in water
pollution from industrial wastes, sewage problems, and air pollution.
Oil spills, slowly degrading toxic wastes from chemical and
non-chemical industries, agricultural runoff and the dumping of
materials such as metals threaten inland and coastal waters. Toxic
materials settle into sea-floor sediments where they accumulate as
hazards to living organisms that feed on bottom mud. Long-lasting
chemicals may enter the food web and contaminate fish and shellfish.
There are threats to the reefs and mangroves. For information on ozone
depletion and the greenhouse risk, see Kadri et al, 1999.