Fish deaths ' linked to climate conditions'
August 30 2015 09:39 PM

The marine research in progress aboard QU's research vessel Janan.

An expert research team has confirmed that the mass mortality of around 18 types of fish in Qatari waters is closely linked to climate conditions, especially high sea temperature and a low level of dissolved oxygen in the water, the Ministry of Environment (MoE) said on Sunday.
The conclusion came after a hydrographic survey on Wednesday aboard Qatar University’s (QU) research vessel ‘Janan’.
The team consisted of specialists and stakeholders from the MoE’s Fisheries Department and the Management of Environmental Monitoring, QU’s Environmental Studies Centre (ESC) and the Ministry of Interior’s Coasts and Borders Security Department.
The research, which relied on the environmental data currently monitored for the region as well as data gathered by the US space agency National Aeronautics and Space Administration, concluded that the mass fish mortality in the region is linked to several inter-related factors including sea temperature, marine plankton, wind, ocean currents and dissolved oxygen levels.
The survey included monitoring the physical characteristics of sea water, monitoring and studying samples of dead fish, in addition to the study of the physical and chemical characteristics of marine waters at the depth of 7, 14 and 29m.
Special tools and equipment on board ‘Janan’ was used to measure a number of metrics related to the characteristics of sea water, such as temperature, dissolved oxygen, density, ionisation, salinity, transparency and others. Water samples were also collected to complete some laboratory tests on the quality and safety of sea water.
According to the survey, sea surface temperature recorded in the survey area was relatively high, ranging between 35.65 and 36.20C. Sea bed temperature ranged between 35.76 and 35.92C. Dissolved oxygen levels were low, ranging between 2.99 and 3.86 milligram per litre.
MoE’s Fisheries Department director Mohamed Saeed Shukairy al-Mohannadi said the results of the survey confirm that the current phenomenon of fish mortality is a direct result of climatic conditions in terms of high sea temperature and the subsequent low dissolved oxygen levels.
He commended the prompt response of the authorities concerned and their efforts in helping put together a team of specialists and stakeholders to participate in such an important survey.
QU's Professor Dr Ibrahim Mohamed al-Ansari pointed out that the university has been monitoring fish mortality since 1996, and that the phenomenon reoccurs nearly every one or two years, especially during the last week of August and the first week of September.
QU’s Marine Biology Professor Dr Ibrahim al-Maslamani noted that while Pelagic (sea surface) fish are usually agile swimmers capable of sustained cruising through the water column, benthic (sea bed) fish are limited in movement and therefore more vulnerable to any changes in the sea water.
“Such characteristics are the reason behind why benthic fish are usually the ones subjected to death in the case of high water temperature,” he added.

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