Sounds like an antenna, if you'll accept electromagnetic noise then there are some fish that could pass for your shrew, e.g. https://en.wikipedia.org/wiki/Gymno

Sounds like an antenna, if you'll accept electromagnetic noise then there are some fish that could pass for your shrew, e.g. https://en.wikipedia.org/wiki/Gymnotus https://en.wikipedia.org/wiki/Gymnotus