F is for Fish
They are not what you’d think of immediately, if someone mentions endangered animals. And of course, keeping track of the fish and sea creature populations is very hard. But sometimes it’s easy to know that a species is endangered – cod for instance, when fishermen catch fewer and fewer and smaller and smaller specimens.
Nevertheless, many sea creatures are suffering because of us – over-fishing, the type of fishing (trawlers scape up the sea bottom and indiscriminately kill all species in that area), nets that catch porpoise and dolphins as well as the tuna that they live on and we also relish…
Plastic is a major polluter and is a big threat. Some plastic breaks down in the sea quite quickly into nasty chemicals like bisphenol A, PCBs and derivatives of polystyrene. Other plastics in the ocean break down slowly into smaller and smaller polymers. They do not biodegrade. The tiny polymers are there forever – in the air, on our land – and in the sea. In the sea, they absorb chemicals like the PCBs and DDT that are in the water.
These tiny polymers, which have absorbed poison, in some places exist in greater quantities than zooplankton. Small creatures take it in as food. Bigger creatures eat those creatures, and eventually, we eat creatures higher up the food chain that have these chemicals, concentrated, stored in them.
And, thought by some scientists to be the greatest threat to all living creatures – CO2 absorption is causing the sea to become more and more acidic. This threatens many creatures that have a higher magnesium level than others – echinoderms, like starfish, but also corals which will just dissolve (corals may all have gone in 10 years due to many other threats).
Our fish are indeed endangered, as are we by our pollution of the sea.
So, after all that worrying stuff, I am going to post a poem about a little freshwater fish, that is not, as far as we know, endangered. Except that it lives in many South American rivers, like the Amazon, that are subject to problems from forest clearing, over-fishing, pollution from mining…
Anyhow, these small 8cm fish live near the banks in these large slow-moving rivers. When it is time to breed, the male and female swim side by side at the surface, leap high out of the water and cling together underneath an overhanging leaf.
The eggs are laid by the female and fertilised by the male before the fish fall back into the water after a few seconds or so. They carry on jumping out until about 50 eggs are on the leaf. Then the male chases away the female but stays himself for 3 days to splash the eggs with his tail fins to keep them wet.
The fry hatch and return to the water with the falling drops of their father’s splashes. Although their endangered status is unknown, they are increasingly collected for aquaria.
If you’d like to read more about the plastic danger to our oceans some info is here: Great Pacific Garbage Patch. If you’d like to read more about the Splashing Tetra, Copella arnoldi click here: Splashing Tetra.
If you’d like to ‘blog hop’ to another blog doing the A-Z challenge, click here: A-Z Challenge.
Poem © Liz Brownlee
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