Signs of the times: Summer #23

More comparisons between the British countryside of today and that from 1959-1961 in the paintings of Charles Tunnicliffe in the Ladybird "What to look for..." series of books.

“Kali frae Bali in classroom three,

 Swallaes her chippataes wi a cup o tea.
Dod Jean an Donna sit doon tae dine,

On a parten an a labster frae the ocean brine.”


From: "Doric Food Rap" by Sheena Blackhall

 

(Copyright: Ladybird Books)

Summer Picture 23
Here we are again, still at the shore and in a rock pool AGAIN! I’m not really sure what the purpose of this picture is in the set of Summer pictures as we’ve looked at rock pools already on a couple of occasions. These later pictures are meant to be taking the reader towards Autumn (and the next book in the series), when the rock pooling summer holidays season is long gone…

My, this is a busy rock pool full of crustaceans, with a large lobster, an edible crab, a hermit crab inhabiting an old common whelk shell, a large prawn and a smaller shrimp (in the bottom right). I can’t tell what species the little shrimps/prawns belong to, so, other than to note that there are unlikely to have been significant declines in these species in the last 50 years (just my professional opinion!), I don’t intend to say more about them here.

The lobster shown here is a member of the famous, gastronomically-popular “common” lobster species(Homarus gammarus), for which Scotland’s rocky coastline supports a small but, given the high commercial value of individual lobsters, significant commercial fishery. The Scottish Government publishes annual fishery statistics, including a report of the total tonnage of lobster landed. In 2009, 1100 tonnes of lobsters were landed at Scottish fishing ports, little changed from the previous few years. For comparison, the 1960 fishery statistics reveal that 889 tonnes of lobsters were landed in Scotland by British and foreign vessels, more or less the same as in 2007, so perhaps lobsters are fished at a level that their population and productivity can tolerate, there apparently being little change in the last 50 years in the weight removed by the fishery in Scottish coastal waters. In its deep, lower shore rock pool, this particular lobster may well be safe from such fisheries but not necessarily from hand-collecting by divers. Lobsters in UK waters may be found down to about 60 metres depth.

The edible crab (Cancer pagurus), the one that has a shell that looks not unlike a pie crust (!), is also a widespread species around Scotland’s coast, which also supports a significant commercial fishery. In Scotland, the edible crab is also traditionally known as a "parten" or a "parten crab" - I only just found out that the word "Parten" in Scots Gaelic means "crab"!

The most recent fishery statistics published by the Scottish Government show that 9500 tonnes of edible crabs were landed in Scotland by UK vessels. By comparison, 1960 fishery statistics for Scotland indicated that 32,556 British hundredweight, or 1654 tonnes, of crabs were landed. Now, unlike lobster, the modern edible crab catch is much larger (nearly six times higher) than the 1960 figure. This may indicate that the fishery was underexploited in 1960, compared to the level of fishing it could tolerate. It might also indicate that the fishery has become more efficient (most of them have – I once read that there is an estimated 2% per year improvement in fishing efficiency as a result of “technological creep”). Without contradicting that previous statement, it might also mean that the edible crab fishery is taking more crabs out of the system than is sustainable in the long-term, although the figures from 2005 – 2009 are relatively stable, so who knows? I really don’t know very much about how we regulate shellfish fisheries in Scotland – there may or may be a quota for edible crabs.

Hermit crabs, of which there are several species in British coastal waters, are well-known for their habit of protecting their soft bodies within the old shells of dead gastropod molluscs (“snails”) such as, here, the common whelk Buccinum undatum. As they grow they have to move into increasingly larger shells and as a result they have been used in many choice and competition experiments by ecological researchers. I think hermit crabs might just be one of the most popular elements of rock pool fauna for young children when they go rock pooling (I speak from distant personal experience). There’s something very entrancing about their lifestyle, with its recurring need to keep finding a new home.