Salmon Return to the Thames
by Matthew Sparkes, London, UK on 03.28.07
Salmon used to travel up the river Thames, through London, to their breeding grounds in Berkshire. However, the industrial revolution and the pollution that accompanied it killed them all off by 1833.
The water quality slowly improved, and in 1974 a single, stray salmon was found alive. A few were also found in each of the years that followed. These discoveries led to the formation of the Thames Migratory Fish Committee, who were tasked with reintroducing salmon and sea trout to the Thames.
Now experts have finally declared the Thames clean enough for the reintroduction to begin. The BBC are reporting that 5,000 2cm long young salmon were released into the Thames tributary, Lambourne river, recently. It's estimated that in 5-10 years there should be a healthy population again.
Salmon are very sensitive to pollution, so the fact that they are now coming back to the Thames is great news. It's just odd that no matter how clean it gets, the Thames still looks filthy.
Our sewers were designed in 1880s to operate at 60% capacity and now the population is much larger. When it rains raw sewage has to be released into the river because the sewers cannot cope.
Last year there was a huge release that killed off 100,000s of fish (which then travelled down the river at 1mile per day due to the tide-lovely!)
A new sewer is planned for 2012 by which time the population will be 800,000 higher. Let's face it this project will be delayed as usual so by 2012 the river could be a real mess.
Due to rising sea levels the thames barrier is used more often to causing more tides and keeping more solids in the river.
for more info:
http://www.thamessewage.com/