Just as dives can be shallow, middling or deep, our knowledge of the wonderful marine life we meet in UK waters can be basic, good or extensive.
Which is not to imply for one moment that shallow dives are in any way basic, I hasten to add - in fact they are among my favourites, because you get to see so much more, in better light and for longer.
Anyway, use this quiz to establish the depth of your marine-life knowledge. Note that Latin names arent expected even in the deep questions (with one worthwhile exception),but are included in some answers for completeness and clarity.

a = Shallow, b = Middling, c = Deep
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1a) What are these spectacular animals
1b) Why has the one on the right got such bold stripes
1c) What are their eggs often known as
2a) What is a very familiar name for this animal
2b) Where does it usually live
2c) What are its three other common names
3a) What are these colourful creatures
3b) What do they feed on
3c) Roughly how many have been recorded per square metre in their dense aggregations
4a) What type of animal does this close-up show
4b) Which species is it
4c) What is the function of the groups of bumps around the spines
5a) Which species is this, often found on wrecks
5b) What other colours does it come in
5c) Why does it look as if something has been nibbling its base
6a) What type of animal is this
6b) Is it male or female
6c) Which species is it
7a) Is this seaweed
7b) What group does it belong to
7c) What is said to be its characteristic smell
8a) What type of animal makes the yellow bumpy structure
8b) How does it feed
8c) What makes this species unusual
9a) What would happen if you trod on this fish in the shallows
9b) What is it
9c) What is the best way to reduce the effect
10a) What is this animal
10b) What does it eat
10c) How can tiny amounts of pollution from anti-fouling paint affect it
11a) To what group does this colourful fish belong
11b) Why is it so colourful
11c) Whats it doing here
12a) Is this animal more closely related to a sea cucumber, fan worm or coral
12b) What is it
12c) Whats special about this species
13a) Why is this starfish such a peculiar shape
13b) Which species is it
13c) What is the obvious white spot on its body
14a) What is this fish
14b) Which close relative is virtually extinct around most of the UK
14c) Why doesnt it clog up its gills when it lies in the sand
15a) Is this pair of velvet swimming crabs mating
15b) When is a female crab ready to mate
15c) Is this crab a herbivore, carnivore or omnivore
16a) What type of animal is this
16b) What is its delightful name
16c) What are its less-than-delightful land-based relatives
17a) Is this a blenny or a goby
17b) Which species, and where is it found
17c) What colour does the male turn when guarding eggs
18a) What sort of animals are these
18b) Which species
18c) What is so special about their larvae
19a) Is this a jellyfish to steer clear of
19b) What type is it
19c) What are the little fish often found living among its tentacles
20a) What animal is this
20b) What is its Latin name
20c) Where does it breed

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