OYSTER BEDS IN THE ARABIAN GULF; ECOSYSTEM ENGINEERS UNDER THREAT
Ibrahim AL-MASLAMANI1; David SMYTH1, Mark WALTON1,2, Mohammed AL-MOHANNADI 3, Lewis LE VAY2
1Environmental Science Center, Qatar University, Doha, Qatar P.O. Box 2713
2Centre for Applied Marine Sciences, Bangor University, Menai Bridge, Wales, UK
3Department of Fisheries, Ministry of Municipality and Environment, State of Qatar
Key words: Oyster beds, ecosystem services, Arabian Gulf
Oysters of the Arabian Gulf have been fished for centuries, as a source of food and pearls, with stock declines apparent as early as the 18th and 19th centuries due to the very active pearl fishery. Large oyster beds (Pinctada radiata), found on a patchy network of limestone platforms (hairãt) in the western Gulf, have acted as bio-engineers with many of the marine habitats throughout the region formed as a result of the ecosystem services provided by these assemblages. Oysters beds have contributed to stabilisation of sediments, water filtration, the provision of hard substratum for sessile species and the subsequent reef matrix complexes for mobile fauna.
Commercially-important fish species are associated with hairãt and as a result commercial fishing with traps is focused on these areas. Recent studies have shown that incidental damage to oyster beds caused by the deployment and retrieval of static fishing gear has resulted in significant loss of oyster populations, while areas closed to fishing are in a state of conservational recovery. It is probable that a combination of the anthropogenic stressors associated with the region’s rapid coastal development and growing human population and the subsequent increase in fishing activity are responsible for the current ecological status of the offshore hairãt, with increased trap fishing intensity having a detrimental effect on primary ecosystem component species, including oysters. Recent mapping of the distribution of offshore shallow habitats, survey of the condition of oyster beds and assessment of the impacts of fishing gear are contributing to a combined approach towards spatial management of fisheries and the restoration of these key benthic habitats.