You can read this article written by the youngest fish researcher of India

Fish has the largest number of species amongst vertebrates (over 55000 species ), highest in abundance, whose zoogeological features ranges from freshwater, marine to estuarines. Larger species number are found in the marine environment. Fish has been found to inhabit the ice polar legion with suitable adaptive features.

thanks dr Stanley for input

According to the data reported in 2017, there are some 30,000 recorded species of fish out of which about 10% species can be taken as food fish. These food fishes with the help of further research can be established for the production enhancement however some species have proved their production enhancement in the form of carrying capacity.

thanks dr Rakesh

fish diversity has been affected by the environmental factors . for example the freshwater fish diversity affected by the changes in the salinity

Thanks Dr noori and Dr gopikrishna for valuable input

All fish species known to science are documented and curated by an international consortiumscientific that produces www.fishbase.org and ensures its data quality through extensive scientific literature (>45,000 publications used so far). The number of currently known fish species is 33,600 almost equally split between freshwater and marine. More than 7,000 species are being used by humans in one way or another and thus in need of active management.

FishBase is freely accessible. The database format allows for easier pursuit and testing of very diverse research questions directly avoiding the high effort at individual level of standardising metrics in the literature to test one's hypothesis. This standardisation is done by the FishBase Group for the benefit of all users. Collaboration welcome. Check out the site to see where the information is most robust and where gaps need filling. More than 2,000 voluntary collaborators are acknowledged to keep the global system updated and developing. Collaboration always welcome.

You can read this article written by the youngest fish researcher of India

thanks dr mitra

Water covers about three quarters of the globe and there are about 28,000 species of described fish of which 40 percent are freshwater species.

High seas fishing fleets of industrialized countries contribute significantly to catches in waters of less developed countries: for example, at 45 percent of catches off West Africa.

In addition to the resulting impacts on fish stocks and the marine environment, local artisanal coastal fishing is in conflict with this high seas fishing fleets of developed countries.

Salinity changes, variation in water temperature, Overexploitation, flow modification, destruction of habitats, invasion by exotic species, pollution including the worldwide phenomena of eutrophication and sedimentation are the main factors affect the fish diversity

Check Adaka, et al., (2016). in advances in life science and technology. 46:25-32

thank u all for useful answers to my question.

Protected areas work as a important factor in preventing habitat and biodiversity loss

thanks dr Noori

fish nursery area should be protected to support fish diversity

There is an industrial plundering of marine bioresources in developing countries.

Thus, each year, West Africa loses, according to Sophie Mignon in our Afrik No. 48, October 2014, "up to 1.6 billion dollars" .

This shortfall is caused by the illegal fishing of Western industrial vessels.

Thanks dr OUM for input