Over the last few years there has been a lot in the media about otters “flooding back” and
being present in nearly all rivers in the UK. And yet, as we have mentioned time and time again, this is confirmed only by otter spraints (droppings), which bears no relation to actual otter numbers.
Otter surveys are almost always based on secondary signs in the form of spraint, but this really only gives information on the distribution of otter spraint and can give no idea of otter numbers, or even if the animal is resident. The otter could merely have been passing through trying to establish a home range and it could pass through several 10km squares on its way, leaving spraint as it goes.
Otters have vast home ranges and in freshwater systems a male can have a home range of about 50km of waterway. In a radio-tracking exercise in Perthshire in the 1980s a male otter travelled a distance of 41km in a single night. So it is perfectly feasible that he may actually have sprainted in four 10km grid squares giving four positive records. This would therefore suggest that there were four otters rather than one.
In spite of this difficulty of assessing numbers, it has been estimated that the total number of otters in England Scotland and Wales is around 10,000. Let us put this into context by looking at three other species listed in the UK Biodiversity Action Plan. There are estimated to be 1.2million water voles, 800,000-1,250,000 brown hares and 160,000 red squirrels. And yet all three of these species are causing concern because of declining populations.
We can therefore see how rare our otter, the Eurasian otter, actually is. The reason for this is that they need a large quantity of clean water to provide food and Eurasian otters do not live in groups, just single animals or a female with cubs. They are therefore very vulnerable – for example, if a female is killed on the road it may take a long time for her to be replaced.
The otter came close to extinction in the UK after dramatic population declines from the mid 1950s-60s. These declines were largely linked to the use of organochlorine pesticides, including dieldrin, in agricultural and in sheep dips. When they leached into waterways, these chemicals had a serious impact on top predators, including the otter, as the chemicals become more and more concentrated in animals higher up the food chain. Although the chemicals were eventually withdrawn from use it took a long time for the levels of pollution in waterways to decline and the otter population started to recover.
However, in August 2019 a report was published following an investigation by The Times into the state of our waterways. This stated that many of the rivers in England are so polluted that they are dangerous for people to swim in. If it is so dangerous that people cannot take the occasional swim then they can hardly be healthy for the fish and otters either.
In fact, 86% of the rivers in England fall short of the EU’s ecological standard – just ten years ago this figure was 75%, which is bad enough. Yes, there are clearly debates about the rights and wrongs of control within Europe, but do we really want to accept such poor water quality?
According to the report almost half of the rivers monitored by the Environment Agency (EA) exceeded limits for at least one harmful pollutant, including heavy metals and dangerous industrial and agricultural chemicals. Cadmium is a carcinogen used in batteries and it is leaching out in landfill sites so safe levels have been breached more than 1,200 times in the past two years!
Raw sewage is also ending up in the rivers – sometimes accidentally and sometimes deliberately. Southern Water were fined £127 million in July 2019 after the dumping of an unknown quantity of sewage but this fine was not so much for the pollution incident but for “deliberate misreporting” data. Of course sewage carries the health hazard of disease to bathers but it also contains various household chemicals. And there is the added risk that no-one knows the cocktail effect of all these chemicals on the environment.
According to EA, “Water quality is now better than at any time since the Industrial Revolution, largely due to the £25 billion of investment that the Environment Agency has required water companies to make.” And yet according to The Times report “Dangerous pollutants in England’s waterways have reached their highest levels since modern testing began, with no river in the country now certified as safe for swimmers.” Clearly both of these statements cannot be true.
The budget of EA has been drastically cut and this obviously has serious implications. There is less testing and less enforcement and so in many cases the water companies are suggesting their own penalties, which are often contributions to charity! Have you ever heard of a person or organisation who breaks a law and then decides on their own penalty! As Kerry McCarthy, MP, a member of the environmental select committee, put it: “the companies are treating fines as the cost of doing business, rather than seeing them as a serious deterrent.”
Under EU rules, our waterways should be of a good ecological standard by 2027 but we are clearly a long way off that. One of the reasons for the poor quality according to EA is the extreme weather – it is always a safe bet to blame the weather!
Even the Angling Trust are concerned about this and Stuart Singleton-White of the Trust said “We’re going backwards — our rivers are getting worse.”
So is this why fish stocks are dwindling and otters are not necessarily the villains they are made out to be? Clearly if fish are still at such risk from pollution, any predators, including birds and otters will not help. However, it is the root cause which must be tackled i.e. the waterways authorities must take responsibility and not make our native wildlife scapegoats.
To us it is simple. We continue to pollute our waterways with sewage and dangerous chemicals. We change the habitat so that fish find it more difficult to find suitable spawning grounds. And man-made structures such as weirs and dams, are making it harder for eels, a popular prey item of otters, to reach the areas where they mature after their long trip from the Sargasso Sea.
As a result the fish population in general is at risk, not because of the otter, but because of the careless actions of people, yet again. Otters and fish have clearly co-existed for millennia – it is the basic ecological principal of the relationship between predators and prey. It is only once man upsets this balance that we have a problem – and in this case the otter is being the scapegoat.
So all this begs the very serious question – “Are we heading for the same dangerous conditions for wildlife that started in the 1950s?”
To read the Times report go to :https://www.thetimes.co.uk/article/pollution-no-river-in-england-is-safe-for-swimming-q8thdx678?wgu=270525_54264_15663127520327_f62cdb679e&wgexpiry=1574088752&utm_source=planit&utm_medium=affiliate&utm_content=22278