Climate Change: Struggle of fishes

How do fishes breathe?

Fishes breath by taking water through their mouths and ‘breathing’ it out through their gills. The gills are similar to our lungs; they contain numerous blood vessels with very thin walls i.e. capillaries. When the water passes over the thin walls of the gills, dissolved oxygen travels to the blood stream and carbon dioxide is released out into the water.

Moreover, different fishes use different methods to obtain oxygen from water. For instance, sharks use a method of breathing called ‘ram ventilation’. In this process the sharks do not take the water into their mouths and breathe it out through their gills but the water passes through the gills as the shark swims through the water. Which means that they have to constantly keep moving otherwise they’ll suffocate.

What is climate change?

Climate change is an alteration in global weather patterns. These changes are largely attributes to the increased levels of atmospheric carbon dioxide produced by the use of fossil fuels and mainly human induced changes. For the few decades’ climate change has emerged as the leading global concern. Some of these changes includes increasing temperatures, more frequent extreme weather conditions and rising sea levels amongst other things.

These changes are directly linked to our economies, lifestyles, activities, practices and operational cycles and are negatively impacting all sectors of our society not only the climate system. 

Climate change affects every aspect of our community such as agriculture, fisheries, health, tourism, water availability, recreation, and energy usage. But how is it affecting fishes and fisheries?

How is climate change connected to fishes?

Across the world, fisheries are a key source of food and they support livelihoods but recently, they are under great pressure due to poor management and overfishing. Climate change is now adding to this pressure as it is affecting fishes, by reducing the amount of oxygen available in the water.

Climate change has been making the oceans warmer, when this occurs, it depletes the amount oxygen present in the water.

Fishes are cold blooded and as a result they cannot regulate their own body temperatures, to get oxygen they obtain it from the water through their gills. When their environments, the waters they dwell in becomes much warmer than usual, their metabolism accelerates, hence they will require more oxygen to sustain their body functions.

Therefore, if the changes in the climate are reducing the oxygen available in the waters, it is becoming more and more difficult for fishes to breathe, as a result the issue of climate change becomes much more serious as it is now affecting fishes, which are fighting daily for their survival.

Furthermore, some scientist believes that when the fish reaches to the stage where it is difficult to breathe, meaning its gills cannot supply oxygen to its larger body, since its gills does not grow at the same rate as the rest of the body, that the fish will eventually stop growing larger. Some even argue that fishes are shrinking in size as they as they make efforts to cope with the lack of air.

What is happening in Guyana?

© Guyana Times: Dead fishes floating in the canal

About a week ago hundreds of fishes were found dead and floating in the Essequibo Coast canal, between the Richmond Housing Scheme and the La Belle Alliance Housing Scheme in Pomeroon/ Supenaam (Region Two).

The residents became very concerned and started to complain about the stench coming from the canal, saying that it was unbearable and unhealthy. Upon discovery of the of the dead fishes, an investigation was immediately launched.  Residents became very disturbed as well as many other Guyanese and especially the Agriculture Minister, Noel Holder. It was later discovered that the fishes died from a lack of oxygen.

“The water where they lived is relatively low, resulting in limited oxygen for their survival.” Minister Holder explained.

And he further stated that the Ministry is doing its best by trying to prevent this situation from occurring again, firstly by clearing the overgrown weeds in the canal, since they too need oxygen and also by assigning the National Drainage and Irrigation Authority (NDIA) to pump additional water into the canals in Region Two.

Climate change is affecting almost everything on planet Earth, that includes fishes, that are finding it harder and harder to take a breath, as the days goes by.