FISH KILL

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Context

• On various beaches of southeast Texas in USA, dead fish numbering tens of thousands were washed up.
• This accentuated the risk of being exposed to bacteria and sharp fins and hence public was asked to stay away from these beaches.

Other Details

• The main type of fish found in these dead fishes was mostly menhaden.
• However other fishes like catfish, bass, sharks, trout, bass, and stingrays were also found dead.

Fish Kill

• The phenomenon when there is sudden and unexpected death of acquatic animals, including fish, due to variety of reasons is referred to as fish kill.
• This phenomenon is usual in Texas during summers.

Reasons for fish kill

• Fish may be suffocated due to reduced and low level of dissolved oxygen in water.

Rise in sea temperature

• It makes ocean water, especially shallow water, warmer and reduce the oxygen holding capacity of water.
• Hence it is difficult for Aquatic animal to breathe.
• This leads to the unexpected and erratic activities of fish which further depletes oxygen in water.
• Hence these deaths are attributed to these extremely low levels of dissolved oxygen.

Calm seas

• There is no mixing of waves and winds.
• It may reduce the dissolved oxygen and leads to the low levels of oxygen.

Cloudy sky

• It prohibits/hampers the process of photosynthesis by phytoplankton.
• Oxygen is generated as the by-product of this process.
• As there is reduced or no sunlight due to presence of clouds, oxygen generation impacted.
• It leads to the low levels of dissolved oxygen available to aquatic animals.

Must read Article:

Warming of Oceans

https://www.iasgyan.in/daily-current-affairs/state-of-the-global-climate-2022-report

PRACTICE QUESTION Explain the phenomenon of fish kill. Highlight the possible reasons contributing to this phenomenon. Also suggest measure which can be adopted to minimize the instances of fish kill. (250 words)

https://indianexpress.com/article/explained/everyday-explainers/thousands-of-dead-fish-wash-up-on-texas-coast-what-is-fish-kill-and-why-it-happens-8667424/