Question: can fish produce hormones like humans can

Lauren Laing answered on 10 Mar 2016:

Yes! What a great question. Fish can produce hormones. I actually spend quite a lot of my time researching how the endocrine system can be affected by chemicals in the environment. The endocrine system is a collection of glands that produce hormones that regulate metabolism, growth and development, tissue function, sexual function, reproduction, sleep, and mood, among other things.

Some chemicals, like certain plastics, and medicines such as the contraceptive pill can make it into the water systems via sewage and landfill sites. When these chemicals are in the river water, at certain concentrations they can disrupt or upset the hormones involved in reproduction. In some very polluted rivers, male fish have been reported to be feminised! This can mean they begin to produce more female hormones, they may be less fertile, or even begin to develop ovaries, which are part of the female reproductive system.

I study a particular chemical call Bisphenol A or BPA, this is a chemical used in plastics to make them form and maintain different shapes. This chemical can disrupt, or upset reproduction in fish. Reproduction is controlled by hormones, and is a really important process for species to reproduce and survive, so it is really worrying when chemicals affect hormones in fish in this way. I am interested in the way chemicals affect the genes or DNA in fish, this might help us to understand more about hormones in fish, how they work and how chemicals can affect them!