Mai Po Wildlife

Mammals

Species of Interest - Eurasian Otter Lutra lutra

© WWF-Canon, SANCHEZ & LOPE

Physical Description

The Eurasian Otter has a streamlined body and tail covered in strong and glossy brown fur, with lighter fur at the chin and throat, and short webbed limbs enabling them to swim smooth and fast in water. Typically an adult weighs between 3-7 kg with a body length of 100-120 cm.

Global Status and Distribution

The Eurasian Otter is distributed across all of Europe, extending down to North Africa and most parts of Asia (SE Asia, Japan, China and Taiwan). Despite its extensive global distribution, the Eurasian Otter is listed as "Near Threatened" in the IUCN Redlist. This is in part due to numerous local extinctions and a declining population particularly in many European countries since the early 1960s. There is a lack of population and distribution information from China and SE Asia, but a similar situation may well exist.

Habitat destruction to make way for dams, alteration of wetlands for agriculture or aquaculture, and water pollution has greatly reduced the range of otter. Otters are still hunted in some countries for their fur or because they are regarded as a pest, particularly to fisheries.

Otter populations in several European countries are now starting to recover thanks to protective legislation to ban hunting and impose penalties for harming them. Other conservation measures like habitat restoration, setting up sanctuaries, captive breeding and reintroduction are also helping.

Local Status

The Eurasian Otter is native to Hong Kong and protected under the Wild Animals Protection Ordinance (Cap. 170). It has only been found in and around the Deep Bay area including Mai Po Nature Reserve, Lok Ma Chau and San Tin. Several artificial dens have been constructed inside bunds between the Mai Po gei wai/ponds as a conservation measure to help encourage breeding.

Basic Ecology

The Eurasian Otter is a semi-aquatic mammal, which rests on land but hunts for food in water. They can be found in both freshwater (river, stream, lake and pond) and saltwater coastal wetlands (such as estuarine and gei wai).

Otter feed mainly on fish and aquatic invertebrates such as crabs, insects and worms, but will also capture frogs, rats and even waterbirds. The whiskers on their chin act as sensors underwater to detect the movement of their prey.

During the day otters rest in a "holt" (underground burrow on river bank), coming out to hunt at dusk and during the night. They are solitary except during the breeding period when they pair up temporarily, or when the mother is rearing her young. Otter breed all year round with 2 or 3 cubs in each litter. They can live up to 10 years.

Recently studies using infra red camera studies are helping to improve our knowledge about the species and its use of the wetland environments.