Wracks - Do you know your eggs from your bladders?
Serrated - Foot size or more, flat tips no swellings, edge has saw like teeth.
Bladder - Foot size or more, Flat blades, swollen tips (forked or other shapes), pairs of bladders on blades but see notes.
Egg - Arm size straggly, flattened firm oval blades, single bladders along stipe, often has wiry weed attached in bunches, tennis bat like growths on stipe.
Spiral - As bladder but swellings on tips have a rim as if 2 parts stuck together (no bladders)
Channeled - Hand size at biggest, wiry, in-curved narrow blades
Estuary - As bladder but swollen blades as if inflated up (no bladders).
Note; bladders do not always have bladders, they can look like wiry twigs. If mid shore 90% certain of bladder wrack. If high shore might be Spiral or Estuary. Not all wracks can be positively identified they have variable growth forms.
Try your skills on the images below. Hover over image for answers.
Top shell or not top shell that is the question.
The snails are difficult, luckily they give us some clues though, you just need to know where to look. We will avoid the penis check recommended for flat periwinkles though.
Colour – this can help but remember, age and weathering on a sandblasted beach aren’t conducive to maintaining your looks. Look at more than one individual.
Size- Again different generations might be around at the same time so be careful with size unless a significant number of them are the same.
Location – This helps, but they can become dislodged and thrown around by waves so use location in combination with other clues.
High tide zone on rocks – rough/small periwinkle.
Mid tide in pools or on rocks – Toothed/ purple topshells. Mostly in pools – edible periwinkle. Mostly on weed- flat periwinkle
Low tide in pools and on rocks – grey and painted topshells. Mostly on weed - flat periwinkle
Start with the easy bit is it a topshell or periwinkle?
Pick it up and turn it over, when the animals retreat into the shell it uses a small hard plate to seal the shell (operculum). In periwinkles, this is ear-shaped in top shells it is round. If it is too small to pick up leave it.
Topshell; again turn it over (sorry snail) does it have the tooth (toothed) or umbilicus (purple) or neither (see images). Now place it on a rock and look from the side. Is it a distinct pyramid/triangle - with a very pointed top (painted) or is it more like an iced gem (grey)? If there is any confusion at this stage turn it over again (apologize once more) narrow lines on shell makes it grey. Painted are generally very pretty.
Periwinkle; Are they tiny look like grape pips, uniform dull colour and need superpowers to see hidden in cracks in rocks or inside dead barnacles? Small periwinkle.
Are they ridged so when you run a fingernail across them the ridges are easy to feel and living alongside the small periwinkles? Rough periwinkle (see notes below).
Are they mostly on seaweed, a mixture of colours from yellow to green/brown perhaps a few striped, The shells very strong fingernail size, at largest. If you turn them over do they wiggle their tentacles at you and try to come out fully. Look like hard boiled sweets (don’t eat them). Flat periwinkles. (see note below).
Are they often together in large numbers in pools or in corners under rocks, dull brown large marble size, none stripped or heavily patterned certainly never yellow or anything bold. Resemble garden snails in size and lack any interesting activity. Edible periwinkle.
Note; there are 2 types of flat periwinkle, you need to look at the penis (honestly some scientists need a life). 3 or more types of rough periwinkles not all are ridged but they live in the same location. Some look more like small edibles but these are further down the beach. Whelks always have a tube in the shell at one end, it might be enclosed but it is there.
Try these pictures - hover over for answers