Latest Otter Research

[Chiltern Chris]

Hi All, (sorry this is a bit long)

Just for info. today the Environment Agency has released their latest research on otter populations. You can download it as a pdf at Environment Agency - Catalogue search

Here's a summary of the findings if you don't want to read the 103 page report:

UK otter populations are healthy and continue to expand across England and Wales. This is the main finding of a series of studies carried out by the Environment Agency over the last fifteen years. Post mortems carried out on over 950 otters between 1992 and 2003 looked at the overall health of otters, factors affecting their survival, the levels of man-made chemicals in wild otters and the impacts these have on otter populations. The results suggest that one of the factors behind this recovery may be decreasing levels of organochlorine pesticides in the environment. Post-mortems were carried out on 341 otters found dead in south west and southern England from 1996- 2003 and on 609 dead otters found in Wales and the rest of England from 1992 to 2003. Liver samples were taken and analysed by the Environment Agency for a range of pollutants including organochlorine compounds (OCs), polychlorinatedbiphenyls (PCBs) and heavy metals.

Liver analysis revealed that otters from southwest and southern England showed a significant decline in levels of organochlorine chemicals over time; this is attributed to their progressive withdrawal from 1962 and ban by 1989. However, this decline was not mirrored in otters from elsewhere.

In otters from southwest and southern England, almost 30% of otters collected between 1996 and 1999 had retinal dysplasia, a distorted retina in the eye. This condition is linked to low Vitamin A levels during development. Concentrations of the OC dieldrin were over three times higher in otters with this abnormality than in otters with normal eyes. Dieldrin and compounds related to DDT were also correlated with a shorter baculum (penis bone) in juvenile males.

Analyses showed that most otters are killed in winter, and more males are killed on the roads than females. Most were in excellent condition, though a small number (particularly orphaned or abandoned young) were suffering from infections, ill health or starvation. Road traffic accidents are a significant cause of otter mortality, the major concern being the number of breeding females killed. Results from national surveys show that otters are expanding their range and it is unlikely that the numbers killed are having a significant impact on the population as a whole.

Any more details can be obtained from the Environment Agency web site.

Cheers, Chris

[Ann2]

Thank you for the info Chris, That's good news.

Ann

[Tursiops2]

Good news indeed. Many thanks
T2

[Billy Wobble Dagger]

As the farmer bloke said on Springwatch last night, look after the rivers and the wildlife both in and around them will thrive, it's certainly the case for the otters.
We just need to teach them the green cross code now, or maybe it would be easier for drivers to slow down. It would be interesting to know if some stretches of road have high otter/vehicle death rates. We have road hazard signs for ducks, frogs and of course deer and farm animals. Would it be worth having otter crossings!
Just a thought.

BWD

[Chiltern Chris]

The answer is yes, some roads are particularly bad . It’s normally next to particular culverts or bridges the otters don’t like to go through. Some of these sites are being looked at by the Highways Agency, County Councils and Environment Agency to see if they can be made ‘otter friendly’. Also most new roads which require bridges in areas likely to have otters are now constructed with otters in mind – this includes otter fencing to stop them getting onto the road and ensuring the culverts are large enough for the otters to feel safe when entering them.

Chris

[Charles Halliday]

Apparently localised populations in the south west have taken a sudden dive and it is being suggested by some that a foreign fluke is the cause (yes - yet another alien sp). Don't pop the champagne quite yet! A dead otter was fished out of the Bristol Avon just outside Bristol during spring this year and it was also confirmed to have died from the fluke. So far, the fish that carries the fluke has not yet been identified. Early suspicions that it was the topmouth gudgeon have so far been unfounded. Can anyone update me on this?

[MrsNibblet]

Hi all,

does anyone know of any recent research on competition between the otter and mink that could explain decline in mink?