How many Otters live in Clew Bay?

Coastal Otter spraints on rock after emerging from fishing session at Dorinish Island, Clew Bay 07032019

This is a question no one can answer. Why you may ask? No one has tried to count the otters because to do an otter survey of Clew Bay you need lots of time to search and you need to be able to access 140 small islands. In Shetland a female coastal otter have been found to have a territory for every two kilometers of suitable coastline. To discover how many female otter territories are in Clew Bay a person would need to walk the coast looking for otter activity. Low tide is the best time to detect otters. That is when they are most active, foraging in the seaweed looking for fish, their main diet. After otters eat when they come ashore they often leave a spraint (otter poop). Researchers can tell what an otter has eaten by examining spraints. As otters are only seen by accident or by very persistent observers researchers have used surveys of otter spraints to estimate otter numbers. A sighting of an otter is a better indication of otter numbers than otter poop. Otters poop many times a day. Genetic material retrieved from a fresh spraint can be used to identify a single otter. The analysis costs 60 euro per spraint.

So doing an otter survey in Clew Bay’s Special Area of Conservation is not a simple undertaking. When I hear people say, Oh otters are doing well in Clew Bay. I think yes, where is the evidence? There is none. Why is it important to know?

In Shetland if there is lots of fish for otters to eat they found that females would rear two or three cubs. In years when the fish population was reduced they found a female otter may only have one cub surviving. Female otters look after cubs for eighteen months.

In Clew Bay human activity effects otters. They are vulnerable to drowning in lobster pots. The fish otters eat live in the seaweed fringe of islands. Removing the seaweed reduces the fish population. Reducing the fish population reduces the number of otters.

Curlews are easier to see than otters. They are nearly extinct as a breeding bird in Ireland due to human activity. Otters are harder to see and will disappear as we continue to destroy our environment. We live in a country that does not value nature. This Government spend more taxpayers money on greyhound and horse racing than protecting nature.

How many otters live in Clew Bay?

Published by shayfennelly

Marine scientist and photographer. Interested in all marine ecology, exploration, science and technology.

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