Mapping Environmental Indicators for Potential Fishing zones Using Earth Observation Satellites

Sea and ocean significantly contribute to the fish stock worldwide. Sustainable use of marine resources requires effective monitoring and management of the world's fish stocks. Some insights from NARSS.

Mediterranean Sea is one of the marine sources of fish to northern African countries. Naturally, fish tend to aggregate in ocean areas that exhibit conditions favored by specific fish species. Sea color varies according to concentration of chlorophyll and other aquatic pigments. 

Remote sensing techniques are now used to help managing marine fisheries at sustainable levels. It also gives guiding to locate fish schools more efficiently. This need to monitor and assess some relevant oceanographic conditions including sea surface temperature, ocean color and oceanic fronts, which strongly influence natural fluctuations of fish stocks. 

These conditions can be observed and measured by remote sensors on satellites, aircraft and ships. Satellite sensors could capture images that able to observe the color of the light reflected from the shallow depths of the water as well as estimate the amount of phytoplankton is growing in marine water mass. High levels of chlorophyll should indicate of color, nutrient rich water, at the other side lower levels of chlorophyll should indicate cleaner water, and the very low levels will indicate clean blue water. 

Satellite thermal sensors are also capable to estimate the sea surface temperatures that influence the availability of phytoplankton. These kinds of sensors estimate the temperature of the top millimeter layer of the sea water surface. When surface waters are cold, it is easier for deeper water to vertically rise to the surface, bringing nutrients to sunlit areas where phytoplankton can use and flourish. When surface water is warm, cooler, nutrient-rich water is trapped below. 

So, the best combination for offshore fishing would be to find where the clean blue water (assuming the temp is good) meets an area with a higher level of plankton. This study explored the potential of developing robust routine service from satellite data to estimate the sea surface temperature and its effect on chlorophyll concentration as an indicator for phytoplankton Productivity to be a guide for potential fishing zones. 

This research shows how the remotely sensed data are helpful providing near-real time data and information to help fishermen save fuel and ship time during their search for fish, to modelers who produce fisheries forecasts, and to scientists who help develop strategies for sustainable fisheries management.

Example of SDP2- Estimated Potential Fishing Zone for October, 2018

Keywords:
Satellite data, sea surface temperature, chlorophyll a, fishing, Mediterranean Sea, potential fishing zone, fish aggregation.


More information

• Prof. Islam Abou El-Magd, imagd[at]narss.sci.eg
• Dr. Omar ELBADAWY elbadawy@cedare.int