Historical data were used to estimate interannual tendencies for the Sea of Oman over the past 50 years.
Declining trends were shown for the atmospheric surface level pressure in the region affected by the Siberian High
atmospheric anomaly, the zonal component of wind speed, concentration of nitrates, biomass of diatoms and sardine
landings. Changes in Zooplankton biomass showed no clear trend. These trends were associated with and accompanied by
rising atmospheric temperature, sea surface temperature, annual variability of the kinetic energy of mesoscale eddies,
frequency of fish kills (along with the death of other animals- dolphins, turtles, and sea birds) and harmful algal bloom
incidents. In terms of interannual coupling between physical and biological processes, the evaluated trends imply that the
weakening of the Siberian High atmospheric anomaly results in the decline of the zonal wind speed and a regional
increase of air temperature. This in turn increases the temperature in the mixed layer which strengthens thermo-haline
stratification of the water column. Increasing stratification prevents the penetration of nutrients into the mixed layer and
does not favor the interannual increase of biological productivity, although annual variation of biological productivity has
increased, from 1997 to 2008.