Monday, 9 January 2012

Inside and out of the otters

Chances are you may have seen the excellent feature on otters at Tophill Low and the River Hull this evening.

So by means as a bit of background to the story:

Otters in the river Hull

Otters have always been indigenous to the River Hull and Holderness area. Like most populations in England during the 50’s to 80’s they suffered from the widespread use of industrial and agricultural pollution in the form of dieldrin, PCB’s and the like. Canalisation and drainage schemes did not help their cause and the animals became extinct in many river catchments.

At their low ebb the otters in the river Hull had dwindled to handful in the upper reaches – but even in the bad times spraints were still found around Wansford and Brigham. This carries great significance as the Hull otters are genuine East Yorkshire otters. In some areas – such as over the Wolds on the Derwent the population was deemed to be so small that captive reared individuals were released to bolster the population. This has never happened on the river Hull (contrary to some beliefs)and as such they are gentically very valuable.

Gradually the otters have made a return and there are now estimated to be a dozen or so in the Holderness area. Again we have had mutterings that the population is rocketing leading to fears over fish stocks – however otters are extremely territorial animals. A dog will require around ten miles of prime river, and a female around six of lesser habitat. They will not tolerate other individuals or even their own mature young and will fight viciously to protect their territory – often targeting their opponents genitalia to render them ‘useless’. This has been reflected in heavy scarring in some road casualties. According to Jon Traill of the Yorkshire Wildlife Trust casualties have been recovered from Fraisthorpe on the coast and individuals have now been seen on Hull foreshore; reflecting a population expanding outwards.

Meanwhile the hazards of modern life unfortunately claim many otters both on the roads and in illegal eel nets – such as those that claimed what could well have been two of Tophill’s otters at High Eske two years ago.

All in this makes for a stable population – the otters have been well attuned to their environment for thousands of years and will not eat themselves out of their environment – but inevitably there will be occasional conflict when an otter finds an easy and captive meal – like koi ponds and intensive fisheries. There is much information available on how these can be protected. Ultimately it is telling that the winning peg on the EA all River Hull fishing match this summer was won at Hempholme – next to one of the rivers best otter habitats.

Seeing the otters

Those who have put in hours of time have sometimes managed to glimpse these animals at Tophill Low and other reserves like High Eske. Sometimes people are lucky – like those on two of our roost walks this autumn when an otter ran in front of us twice running. But generally it requires a long wait in the hides – North Marsh, South Marsh West / East and Watton have all returned sightings in the last year. But for example the footage in the Youtube video below was the culmination of approximately 40 hours or more of observation!

Much of our understanding has been obtained through the use of a trail camera – these have come down in price massively in the last few years. We have been using a Wildgame IR4 – but there are many others as good or better out there.

One of the interesting notes is the one family of an adult and three cubs in the video have been observed from as far north as Hempholme to as far south as half way along Leven Canal – a huge area.

Some of our quiet and patient photographers have managed pictures – like these outstanding pictures by Andy Marshall:

Tony McLean:

and Rory Selvey to name a few:

Remember – the reserve closes at 6pm nightly – to observe outside these times you need to be a member – details above. If you don’t have a members permit (or have a valid day ticket in the accompaniment of one of our members) you will be asked to leave.

Again please be respectful when viewing – make noise and the otters will simply not show or pass the hides underwater. And they usually only pass once – so if you are noisy the chances are those next to you whom have waited for 5 hours may not be pleased…

In addition to the BBC InsideOut team we would also like to thank the volunteers at Tophill who work both on and off screen to better the habitats. Credit is also due to Jon and Gareth and their team from the Yorkshire Wildlife Trust who helped us with the piece and Andy Walker for his infra-red binos!