The best gauge to protect the oceans is to stop the industrial waste right away. And then take measures to ensure the part of food. The industry can be grown by exporting the fish to different regions and all over the country.
From ISFAQ.com
What measures could be taken to protect and develop the fishing industry in Pakistan?
Development? With a good coastline along the Arabian Sea it shouldn't be a problem. As Rooster pointed out, keeping an eye to pollution would make the waters close to shore more fishable. Such warm waters should produce great harvests of fish.
But protection? Again it comes down to proximity to your own waters. Trawlers can sail far in their search for fish and you would run the risk of Somalian and other marauders if you travel too far west. Perhaps safer fishing would be found to the south.