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PhD Research

Assessment of demersal fishery in Brunei Darussalam

Overview, context and setting

Within the last decade, the marine ecosystem of Brunei Darussalam is suspected to undergo significant changes, particularly with the rapid shift in the state of the demersal (i.e. sea bottom) stocks from being ‘lightly fished’ in the 1990s to being ‘overexploited’ in the 2000s. Despite its relatively small landings and fishing area covered, Brunei marine ecosystem is considered a valuable reference point – a lightly harvested system within a region known to be chronically overexploited. Brunei’s stable economy which is largely based on oil and gas, small population, and low reliance on coastal resources placed Brunei on a unique position in terms of fishery developments and management challenges. Yet, fisheries research progress in Brunei is relatively slow compared to the neighbouring countries, and the impact of fisheries in Brunei waters remains poorly understood.

Brunei Darussalam: Environmental setting

Brunei Darussalam is a coastal state with a land area of 5765 km2, located in the north-western part of Borneo Island (Figure 1). The country has a 130 km long coastline fronting the South China Sea and is bordered by the east Malaysian state of Sarawak. The total marine territory covers an area of 38600 km2, within the 200 nautical mile (nm) limit of Exclusive Economic Zone (EEZ). The territorial waters of Brunei are characterized by a narrow continental shelf of about 8600 km2, and an offshore area of about 30000 km2 within which depths reach ≥ 2000 m depth. Brunei waters is also included in the Sulu-Sulawesi Marine Ecoregion which ranks among the most diverse and productive ecosystems in the world.

Authors from the Reef At Risk in Southeast Asia (RRSEA) project estimated the coral reef and coralline areas in Brunei waters to cover roughly 200 km2, including fringing reefs, patch reefs, and one atoll. There are also several artificial reefs made up of tyres, galvanised pipes, concrete piles and redundant oil platforms which have been placed at several sites parallel to the coastline. At present, there are seven offshore oil and gas fields in operation, with connecting pipelines between the fields. Over 50% of Brunei’s gross domestic product (GDP) is contributed by the oil and gas industry, so any fisheries and environmental development program must ensure safety and unhampered operation of the sector’s offshore installations.

Location of Brunei Darussalam and the fishing zones used for management purposes

FIG 1. Location of Brunei Darussalam and the fishing zones used for management purposes.


Fisheries management in Brunei and research to date

The Department of Fisheries (DOF), under the Ministry of Industry and Primary Resources, is the authoritative body in charge of the Brunei waters, responsible for fisheries research, extension, enforcement, marketing, conservation, development and management. For the purpose of fisheries management, the fishing area in Brunei is divided into four zones (Figure 1).

Routine trawl survey and hydroacoustic survey are the two main techniques employed by the DOF in their stock assessments, in addition to a regular catch and effort data analysis. Although reports of some of these analyses were used in DOF’s management processes, too much of the data being collected remains unpublished. Furthermore, relatively limited technical capacity and scientific knowledge in the country meant that Brunei is constantly seeking help from international organizations in executing comprehensive assessments and monitoring programs. To date, most of the fisheries research carried out in Brunei waters were executed by international organizations investigating on South China Sea on a whole. These researches, however, tend to generalise and apply the results of low density sampling to large areas.