AQUATIC birds usually display a tremendous ability to cope with the habitat and migrate from one place to another in search of food, shelter, mating, and for spawning purposes. Habitat characteristics play an important role in attracting birds and provide amenities to such guests and permit them to wander around.

However, some birds permanently switch from one place to another owing to pollution, rampant trapping or other disturbances in their respective areas of origin. For instance, reef heron, a bird that fundamentally inhabits rock pools and coral reefs, is now settled on the mudflats and shallow waters, indicating that either the habitat was disturbed or the increasing pollution in reef areas influenced it to alter its original habitat.

Reef heron is now flying abundantly around mudflats of Shah Bunder area for the last two decades. The bird has completely adopted the habitat and established nesting in rhizophora (red-mangroves) that is massively planted in the area. The old forests there are also fascinating, attaining a height of over a dozen feet.

The dense plantation is now home to various coastal birds permanently residing, hatching and growing there. The stay of birds near the coasts is not only a symbol of mercy, but it ultimately supports fish production and benthic communities, the organisms that live in or on mud, because their faeces mal(e nitrogenous surfaces and enhance phytoplankton productivity, which is ultimately utilised by the grazers, like fish and shellfish, in an ecosystem.

Nevertheless, fisheries production in creeks is very high due to mangrove forest, but rampant use of destructive gears would lessen biodiversity and would also thin fishproduction in the decades ahead.

To assess the impact of using such gears, I took a shrimp sample of 800gm and it comprised 259 individuals measuring3-5cm, while normally only 10-15 shrimps can add up to the same weight. This indicates thatthe use ofsuchgears does not allow the organisms to reach marketable size or to spawn and increase their population. Stringent actions are needed to prevent the use of destructive gears for the sake of fish for tomorrow.

Dr Sher Khan Panhwar Centre of Excellence in Marine Biology Karachi