(Above) Blue Rayed Limpet © Phil Abraham (below) Lacey Sea Mat © DWT
Mermaid's purse is another name for the eggcases of skates, rays and sharks. They are often found washed up on our beaches left behind on the strandline hidden amongst the seaweed as the tide retreats.
Although many of these eggcases look very similar, they may be from different species and are a great clue to helping us understand what animals are living and breeding off our coasts. To help you tell the difference, click on this link to download your free id guide from The Shark Trust: http://www.sharktrust.org/shared/downloads/display_materials/great_eggcase_hunt_leaflet.pdf. Once you have identified the eggcases, you can also report your findings to the Shark Trust, which is useful for their research.
The eggcases that are found on the beach have usually already hatched and would have contained one embryo which feeds from a yolk inside the eggcase. Depending on the species they can take up to 10 months to hatch; the eggcase then becomes lighter and rises to the surface from where it washes in to the shore for us to find.
Find your own mermaid's purses...
Want to know more? Come along and help us with our eggcase hunt at Kimmeridge on 26th October from 12.30pm to 2pm. More information about this event can be found on our events page.
Animals living on Kelp
This month have a look at some of the seaweed that forms the strandline as there are some interesting things to be found. Kelp is a type of seaweed commonly washed up onto our beaches. It is a large seaweed and needs to be firmly anchored to the seabed, which it does with a root-like structure called a ‘holdfast’. In rough sea conditions, this holdfast can become detached from the seabed and the seaweed ends up on our beaches. There are many other species that live or feed on the kelp, that are consequently washed up too.
Blue-rayed limpets are one of the species to look out for. Much smaller than common limpets, they are quite striking in appearance, with iridescent blue lines running along their shells. They feed on kelp fronds and can sometimes be found still clinging to the seaweed blade or even hidden inside the holdfast where they migrate for the winter.
You might also come across kelp that has a grey/white, cloth-like, textured coating. Take a closer look and you will see a mesh-like structure. This is lacy sea mat and is actually a bryozoan - a colony of tiny animals. Each of the individual holes or chambers making up the mat contains a microscopic animal which feeds by filtering out any drifting particles or plankton in the seawater.