#92 Sea Hare by Caroline Pindar
Meet Caroline Pindar, marine biologist, volunteer, and recorder!
Caroline Pindar is a marine biologist specialising in intertidal ecology along the Yorkshire coast. An active volunteer recording with Yorkshire Wildlife Trust, Scarborough Field Naturalists and Shoresearch on land, she is also a North Sea scuba-diver and Seasearcher, photographing and identifying the fabulous underwater marine life our coast has to offer. Promoting the biodiversity of our intertidal habitats through creating digital content on ‘Scarborough Rockpooling’, Caroline also highlights the impact of plastic pollution on our coastline.
Caroline’s chosen species, the Sea Hare Aplysia punctata, is present all around the Yorkshire coast and is the most wonderful find when you spot one in a rockpool.
Sea Hare by Caroline Pindar
Sea Hares are soft marine gastropods (snails), within the family Aplysiidae. Whilst they might look more like a slug, the Sea Hare does have a shell. Instead of being on its back, which has instead been reduced to a flat plate or ridge, its actual shell is around 4cm, almost transparent, and internal rather than external. They also have tentacles on their heads, considered not unlike hares' ears, giving them their common name. They generally range in size from 7-20cm in length but tend towards the smaller end of this scale. They come in a variety of colours, favouring weedy coastal waters all around the UK.
Although they are well camouflaged, as they take on the colour of the seaweed they choose to graze on, when you see one you are instantly engaged by its deliberate, slow progress, endearing appearance, and its pair of rather penetrating, beady eyes.
A tiny juvenile Sea Hare, blending in with the rockpool environment!
You may also come across them left behind by the tide amongst the seaweed, looking like wavy lined gelatinous blobs. Individually they can easily be mistaken for sea anemones, but between May and October they can be found stranded in great numbers on coasts around the UK. Sea hares are hermaphroditic, having both male and female organs, and form reproductive chains, often entwined with the eggs they have just laid that look like threads of pink spaghetti deposited on seaweeds. After the eggs hatch, the larvae join the plankton before maturing and settling out of the plankton after a few months.
Being soft bodied and a good source of protein, camouflage is not enough protection in the marine savannah that is the rockpool. The tentacles, or rhinophores, and the oral tentacles closer to the mouth host an array of sensory organs, detecting chemicals in the water similar to taste and smell. However, when faced with a predator, the Sea Hare has an impressive defence mechanism. Under threat, they not only expel a purple ink from a gland above their gills to scare off hungry crabs but also give off an opaque secretion from the opaline gland beneath their gills, which when combined with sea water and the ink, forms a glutinous substance which acts as a decoy, confusing the would-be predator.
The greatest joy when finding a sea hare though is not to prod it with a stick and stimulate its defence mechanism, but to admire its beauty and your good fortune at spotting such a fabulous creature!
Whilst rockpooling is a fantastic activity, especially around the Yorkshire coast with its miles of rocky shores, it is important to rockpool responsibly.
· If you turn a rock over to look what is underneath, always turn it back over gently, and replace it where you found it
· Avoid handling the creatures and if you do move them, and replace them back in the rockpool you took them from
· Crab legs are fragile and losing a leg makes the crab more vulnerable to predation when you tip it out of your bucket – make sure to treat creatures gently and avoid harming them
· Leave fish in the water - many fish gills quickly fuse out of water, and they easily lose their scales when touched, again reducing their chances of survival when they are returned to the water
Recording and monitoring
Anterior image of a Sea Hare
Records of Sea Hare and other marine species can be submitted to your local LERC or via Yorkshire Naturalists’ Union’s Marine and Coastal section recorder (details here). If you would like to get involved with marine and coastal recording in Yorkshire, Yorkshire Wildlife Trust runs Shoresearch, a citizen science shore survey where volunteers are trained to record across walkover, box corer, quadrat, and timed species search surveys on the coastline. You can find out more about opportunities to get involved here.
Further information and acknowledgements
NEYEDC would like to thank Caroline for her time and expertise in helping to create this blog.