Tuesday 16 August 2011

Beneath the waves

A beautiful nudibranch or "sea-slug"

A sand mason worm sits inside its grainy shelter

Brittlestars can be found aplenty on the shores

Sunday 14th August comments: Continuing the theme of having a look at the sometimes overlooked aspects of the Farnes, today’s blog looks at the islands’ non mammalian sea and shorelife.

The seas around the Farne Islands are incredibly rich in nutrients, which allow the water to support a vast number and diversity of animals (and plants!) The most obvious and numerous of these is the sand-eel, the plankton-eating fish which supports an entire population of breeding seabirds and seals, but there are many more critters to be found in Farnes waters. In the summer months, huge swarms of common or “moon” jellyfish come to the warming seas, accompanied by the purple Cyanea lamarkii and red lion’s mane jellyfish, the only stinging locally British jelly.

Amongst the rocks and boulders of the shoreline, swimming, shore and edible crabs await their next meals alongside the plentiful lobster and smaller squat lobsters. There are however many more weird, and wonderful small creatures here. Tiny but beautiful nudibranchs or sea-slugs (not a very attractive name for something so nice!) can be found amongst the rocks, sand mason worms build peculiar tubular homes from the ground around them and young fish hide in crevices from any would-be predators.

The Farnes wardens, along with a team from Natural England, perform surveys on the islands’ rocky shores to keep an eye on the sea’s general state. Much like the butterflies and moths, as well as being incredibly interesting to look at, the small shoreline creatures with their fast reproduction and short lifespans provide a very up-to-date view on the water’s health. A change in the populations of these shoreline beasts could be a warning of changes to come in the much longer-lived breeding seabirds, allowing the wardens to take action on a problem before it is too late.

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