Dear respected Researcher R Singh,

I think you may find some good peaces of help from Bay of Bengal Programme (BOBP) documents. As you know the Bay of Bengal is a directly connected with the Indian Ocean, Therefore many dynamics and limiting factors may be in line (may be not). However I here put some Dynamics and regulating factors of Fishing Ground that controlling the fish abundance in the Ocean

- Temperature variation

- Sunlight: Sunlight is the main source of energy and regulates the biological production of the ocean.sunlight reaches up to the ocean floor may be a good indicator.

- Dissolved oxygen concentration: D.O. concentration is very important for respiration as well as metabolic activities of marine organisms.

- Nutrient content: Different micro or macro nutrient (elements) are essential for the growth of phytoplankton (primary production), which ultimately regulates the secondary production (production of zooplankton, fish, etc.).

- Salinity

- Water depth: Less depth facilitates much more soil water interaction

-Turbidity-

pH of water 

-Water Pressure at Different Depth

- Earthquake: Earthquake into the sea also influence the diversification of fishing ground .By the actives of earthquake into the deep sea sediment floor also destroy or affect the plate tectonics into the sea floor. So that the areas of available fish abundance are destroy by the activity of earthquake into the sea floor.

- Biological characteristics the occurrence of marine species - both plants and animals - has largely been controlled by the physico-chemical properties of ocean water.

-Upwelling and mixing, Organic sediment load, Rate of photosynthesis, Presence of sea birds also you may taken in to account.

Sorry for any inconvenience.

This question is not clear. If you mean the zone of an existing fishery, then you will need a set of fishing data from the fishery. If you want to determine the fishing zone of a new fishery, then you may have to conduct a survey to determene the zone