There was a CMFRI ( Central Marine Fisheries Research Institute of India ) report that Global Warming affects fish production.
Co2 emissions are more. The Carbon Dioxide combines with ocean water and forms Carbolic Acid. This increases the acidity levels of the ocean water and affects fish.
The Sea Surface Temperature (SST) goes up due to GW and this affects fish. Fish tend to go to colder areas.
The SST has gone up. In 1962, the SST was 28.3 and in 2007, it is 28.94 !
In fact, the quanity of fish has not come down. It is because of the burgeoning population - 1.2 billion in India and more consumption, that it seems to be so. Some species of fish disappeared. Some moved away to other areas.
In Kerala, from 1960 to 1984, fish production increased threefold due to technology, more education and good nets. But then after 1990, it has not gone up. After 1992, there was not much tuna catch. Mackerels catch also declined significantly. Sardines catch only increased marginally.
Catfish production also declined. Catfish has moved from Trichur but is available in Calicut District. Sharks also have disappered from the Trichur coast.
The heat above the surface of the ocean will be more before the South West Monsoon and will come down during the SW Monsoon. For the last 41 years, a different phenomenon has been observed. The temperature during the Monsoon season was 27.16 and now it is 28. 46!
Sardines are available on the Kerala coast after the Monsoons. Mackerel is available during the monsoons. The difference in temperature is responsible for this.
The difference in temperature is the cause for the change in habitat for fish. Ghee sardines and macekerels, which are found in less deep waters, move towards colder areas when they experience heat. There are also fish which move towards deeper waters. Mackerels which were never caught in deep waters before. are now available in deep waters. Different types of fish survive in different temperatures and GW changes the fish production equation !
The food which is eaten by the fish is also affected by the rise in temperature. Phytoplankton is the main food of fish. The Co2 is absorbed by Phytoplankton and food is prepared. The rising temperature destroys the Phytoplankton thus affecting the food of the fish ! Fish cannot survive due to the destruction of the Phytoplankton ! Some small plants grow rapidly due to the increasing heat, which cannot be eaten by fish ! During some seasons, phytoplanktons grow rapidy and gets destroyed. This also affects fish !
That the ocean becomes orange and red has been reported. This is due to certain phytoplanktons spreading. Some species of fish become more and some less. Poisionous plants become more and this adversely affects fish !
Let us hope GW will not devastate furthur !
G W has also affected astro meteorological patterns. Kerala received 56% more rains during this Monsoon season. Intense rains destroys crops and agri lands were indundated.