Piel Channel dive

April 2nd, 2012

Weather conditions for the site had been perfect for more than a week, so we travelled to Roa Island on Sunday 1st. April with high expectations of having a good interesting dive. Looking down on the water from the lifeboat gantry the conditions looked OK, so we kitted up and took the plunge.  Much to our surprise after we had covered only a few metres from the shore  the underwater visibility was no more than half a metre. It was quite light but there was very fine silt suspended in the water. As we progressed deeper it became more and more gloomy. At the deepest point (10.7m) in the middle of the channel it was completely dark and impossible to see anything. We swam slowly back up the slope to into shallower water, about (5m deep). here the bright sun penetrated the silty water a little more and the diverse marine life that we are used to seeing in the channel came into view. In the very small field of vision there were numerous species of crab, tiny anemones, sponges, common whelks, mussels and a small number of the  beautiful hydroid, Tubularia indivisa with tentacles extended. On returning to shore we  discovered that dredging operations were being carried out in the Channel and had been for a number of days.  This was the reason for the poor visibility and our far less than perfect dive. It was though the first of April !

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Oban area weekend

July 5th, 2011

Seven members of the group spent an interesting long weekend at the end of June in the very popular area around Oban. Weather conditions were quite mixed, but we did manage to avoid the showers.  A number of dives took place including one on a rocky reef in the inner basin of Loch Creran, then north to the spectacular submarine wall in Loch Linnhe near Kentallon.  We also made a visit to the littledived Loch Feochan just a few miles few miles south of Oban. The chart indicated that we could expect to see a lot of mud.   The mud was part of the attraction, would we find sea pens and large anemones.  From the easy access point, a lay-by right alongside the loch we swam over stones and pebbles covered with various green and brown seaweeds, then onto the gently sloping mud. There were occasional boulders covered with mussels, then at about four metres deep were dozens of the sea slug Philine aperta and the small almost transparent sacks of their eggs.  Continuing down the slope to about six and a half metres below the surface where hundreds of sea pens Virgularia mirabilis covered the sea bed.  This was only a quick look at a loch that I feel has much more to offer.  Many thanks to Jo and Barry Kaye for organising a very enjoyable weekend.

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Lochaline, April 2011

April 22nd, 2011

A very successful trip to Lochaline on the West coast of Scotland was enjoyed by ten members of our group. General weather and sea conditions over the four days was on the whole very good.  Based at the Old Post Office in Lochaline we were only a couple of  hundred yards from the access point to a spectacular dive location, the  Hotel Beach Wall. The dive starts off swimming down a very gentle slope of mainly white silica sand with occasional large boulders covered with kelp and sheltering shore crabs and sea stars etc. as the slope gets steeper tube anemones, Cerianthus lloydii  in a variety of colours are very common.  The sandy slope ends quite abruptly as we reach the top of the almost vertical wall which plunges down to a depth of more than one hundred metres.  Just a few of the very common inhabitants on the wall are Tubularia with numerous nudibranchs,  football sea squirts, squat lobsters, feather stars and sponges etc. We  are also able to add a further two animals to our Group’s list of recordings for this dive site, a lumpsucker, Cyclopterus lumpus spotted on a couple of dives and a number of Brachiopods, (lamp shells)  Terebratulina retusa.  Dives also took place at Fiunary Rocks, a typical sea loch slope  further West along the Sound of Mull and on the sea grass beds at Rubha-nan-So’rnagon  in Loch Linnhe. 

Most members of the party spent some time walking in the area, on the shores of Lochaline, to see the carved stones at Kiel and to the East side of the loch to the fossil burn where we were very lucky to see otters.

Many thanks to Jo and Barry for such a well organised trip.

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Summer events with the MCS

April 19th, 2011

Our diary has just been updated with events for this summer. This includes a series of talks on common marine ecosystems around the UK coastline, plus dive trips and walks.

Lancashire MCS summer diary

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Monthly Meeting – March

March 13th, 2011

Sea Cucumbers in the Indian Ocean – Mandy Knott

March’s meeting was a talk by Mandy based on her work with Shoals Rodrigues (http://www.shoalsrodrigues.net/), surveying sea cucumbers in the lagoon of the island of Rodrigues.

Rodrigues is the furthest east of the three Islands of Mauritius and, from a marine biology view, is interesting because it is effectively isolated from lands to the west by the trade winds and ocean currents that sweep in from the south east, from which direction the nearest landfall is Australia. Politcally it is an autonomous region of Mauritius. Much of the land is mountainous and many people turn to the sea to provide their living. To this end Rodrigues does possess the largest coral lagoon in the world.

There’s always a ‘but’ and for Rodrigues there are several when it comes to taking advantage of this resource. What all the ‘buts’ come back to is overfishing; the large predatory fish have all gone from the lagoon, the fishermen have no boats capable of fishing beyond the safety of the lagoon, and the sea cucumber has become the main stay of the fishery.

Sea cucumbers are not vegetables, or even plants, but animals – Echinoderms – closely related to urchins and starfish. Their basic form is a sausage shaped animal with a mouth at one end that has tentacles that pass food to the mouth. Food for these animals usually being detritus or some other microscopic source or protein. Reproduction can be sexual or asexual – either male and female animals communicate by and respond to chemical signals in the water to synchronise the release of sperm and eggs into the water, or some species can also multiply by splitting into two parts. Overfishing therefore can be a big problem for sexual reproduction in these animals – as they need to be close enough to one another in order to be able to use their chemical communications effectively; the population could drop to a point where the animals are present but unable to breed.

That they could be thought of as food may seem an unlikely direction, as to western eyes they don’t appear all that apetising and the processing they go through after being caught doesn’t improve this viewpoint at all. However sea cucumbers are valued in China and South East Asia for both cuisine and traditional medicine – the general rule being the uglier the better.

Signs that the sea cucumbers were following the fish have been there for some years, and four reserves were set up around the lagoon to give areas where there was no fishing. Unfortunately it seems these are not being managed or enforced. An earlier Shoals Rodrigues survey had estimated the sea cucumber population of the lagoon at @48 million. The 2010 survey looked at many of the same sites and used the same statistical model to estimate the population again – and found a significant reduction in the overall population.

Prior to restrictions of fishing being imposed a official study found that 55000 animals were taken in 15 days (these were just the fishermen they knew about – there were probably more people fishing unregistered).

One glimmer of light on the horizon is the possibility of ‘ranching’ sea cucmbers. This would be a bit like farming them. Even this has its problems though; the Rodrigues government is understandably very keen to to get it going and wants use a species – Holothuria Scabra – that is native to Mauritius and has been successfully ranched elsewhere. One of the key criteria is that the species used should be one that is native to the Rodrigues lagoon and Holothuria Scabra has only ever been recorded on one survey there – one commissioned by the government; it has never been recorded by any of the other surveys, which have taken many days and many sites into account. Naturally there is some scepticism about that one survey and some concern of the effects the introduction of a non-native species could have on the endemic species resident in the lagoon.

Another glimmer is that a fisherman’s cooperative has been set up and is in the process of obtaining and fitting out boats fishing beyond the reef, which would hopefully reduce pressure on the lagoon species. To what degree that is successful remains to be seen.

See also –

http://www.sos.bangor.ac.uk/research/php/theme.php?project=445 for some information on Bangor University’s work in Rodrigues

http://www.sempa-rodrigues.com/images/3rd%20Ecology%20and%20GIS%20Interim%20Report.pdf – a report on SEMPA (the South East Marine Protected Area) including survey data

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February Meeting – Marine Mammals – Janet Preece

February 15th, 2011

Janet took us through a range of mammals that can be classed as ‘marine’, from polar bears to whales via sirenians, otters, dolphins and – her particular favourite – seals.

Mammals have problems adapting to life in the marine environment, not least of them insulating themselves against the chilling effect of the water on their warm blooded bodies. While most marine mammals rely on a layer of fat to help keep them warm, we learnt that not only is the sea otter the smallest marine mammal, it is the only one that relies solely on its fur for insulation, having the densest fur in the animal kingdom. It’s probably the only tool user too: they often use a rock to break open shellfish, lying on their backs in the water with the shellfish on their chests and pounding down with the rock.

As well as the problems of keeping warm marine mammals have all the problems of being air breathing animals in a watery environment, tied to maintaining contact with the surface, and with a range of breeding strategies to cope with this. They have also reached differing levels of adaption to moving through water; some being fully aquatic, and others needing to return to land.

We skimmed on past whales, dolphins, and porpoise to concentrate on Janet’s favourite animals – seals.

Both species of seals we have in this country are true seals, as opposed to the sea lions and fur seals, and the walruses. True seals are more adapted to the water than the other two groups but are still tied to the land.

Our two species are the harbour (or common) seal Phoca vitulina, and the grey seal Halchoerus grypus. We have significant proportions of the world populations of both species in our seas, which makes them globally significant.

Janet covered some of the threats to seals and other marine life in general. One of the most shocking was the ‘corkscrew killer’, where animals have been found with deep wounds spiralling along their bodies; the most likely explanation for this being that the animals have been caught in a ‘ducted’ propellor. Other threats included all the usual suspects – pollution, plastic bags and ballons, discarded fishing gear, hunting, and the effects of overfishing on the food chain.

Some great pictures and stories of seal encounters around the Farnes reminded me of some of my own seal encounters around the Farne Islands and others. I haven’t got any Janet’s pictures but some of my pictures are at –

A selection of interesting facts that I picked up on the way –
If you find a dolphin or porpoise stranded on the shore it can be difficult to tell the difference; but if you look at the teeth, dolphins have conical shaped teeth and porpoise have spade-like teeth.
Walruses use the “squirt and suck” method of feeding (I can’t remember exactly how it works but I just love the way it sounds!).
Whales make footprints. Their skin is oily and the tail will leave an oily ‘print’ on the surface of the water as they dive.

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Monthly Meetings

February 11th, 2011

The first two meetings of 2011 were very well attended. They both had quite different themes and each provided all present with a most enjoyable evening.

The January meeting started off with a quick AGM followed by the annual photo. competition. the competition had three categories , Underwater, Above water and Humorous images. Entrants were allowed to submit a total of  four images across the three categories. We had 32 images from 8 entrants, and the winners were:-

Above water, Lewis Bambury. –    Underwater, Mark Piotrowski. – Humorous, Christine Fletcher.

Congratulations to all the winners. (Images can be seen on a previous post).

Janet Preece from Blackpool & Fylde Coll. was the speaker at the February  meeting, the subject of her presentation was marine mammals.  Janet briefly covered the whole range of marine mammals from the small sea otters to the giant blue whales.  Many interesting facts emerged, we heard about the extremely dense fur sea otters have in place of a fatty layer which protects them from the cold and the oily footprint  left on the surface by a sperm whale when it submerges.  Much of the presentation focused on the  sea lions, walrus and seals with the emphasis on the two species of seal, the common or harbour seal and the much more common grey or Atlantic seal  that inhabit our UK coastal waters.  Features to look out for when attempting to identify the different species of the various groups and the many threats to the survival of these animals were explained in some detail.  The whole presentation was both educational and entertaining and fully enjoyed by the whole audience.  Thank you Janet.

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Photo competition winners

February 9th, 2011

Here are the winners from the 2011 Lancashire MCS photo competition. Winners are divided into three sections – above water, below water, and humour. Winning photos were by popular acclaim at the January AGM:

Click any picture for a larger version, images are copyright as indicated.

Above water winner: Shanny by Lewis Bambury
Shanny by Lewis Bambury

Underwater winner: Ribbon fish by Mark Piotrowski
Ribbon fish by Mark Piotrowski
Humour winner: Christmas on Crosby Beach by Christine Ryan.
Christmas on Crosby Beach by Christine Ryan.

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Seaweed guide

January 11th, 2011
Cover of the 'Guide to Seaweeds of Britain and Ireland'
The Seasearch 'Guide to Seaweeds of Britain and Ireland'

Seasearch has recently released a guide to the seaweeds of Britain and Ireland. This excellent ID guide fills a space in the market. It has full colour photographs, size and location guides for over 200 seaweeds found around our coasts. Armed with this you will never need to attend a basic seaweed ID course again – so I’ll have to think of other ways of getting algae into our annual lecture series!

Best of all, there are copies available at a cut down price of (I think) £14.50 (c.f. the normal retail price of £16.95). Numbers are limited, please contact Mandy at one of our meetings to reserve yours!

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Sea Mice

November 24th, 2010

I was in Cleveleys this Sunday (21/11) and a on short diversion down to the beach I counted 20 dead sea mice Aphrodita aculeata on a 2 or 3 metre stretch of the hight tide strand.  The tide was in so there wasn’t much beach to look at and I couldn’t tell if this was a localised collection or if it was typical of the whole shore. Got to admit that there was a bit too much dog muck on the beach for me to want to look much further!

Dead sea mice on Cleveleys beach 21/11/10
Sea mice washed up on Cleveleys beach

miceThis was striking to me as a diver because sea mice are creatures that we rarely see.  I would guess that I’ve done something of the order of 300 dives in British seas and in that time I’ve seen 3 sea mice.  That’s a 1 in 100 dive ratio of sightings.  So 20 – admittedly dead – in one smal area is unusual.  It also has some interesting similarites to a sighting of a large number of sea mice made by Lancashire MCS members on a dive in Loch Fyne in November.  Follow up dives were arranged in subsequent years to see if this was a regular occurence (I saw 2 of my total count on one of these dives) but nothing conclusive was found again.  Maybe we should have been looking a bit closer to home?  

What else was there on the beach?  You can see a mermaid’s purse – probably a dogfish’s – in the debris behind the sea mice.  I was also quite surprised to find jellyfish stranded. It’s not a time of year that I would have thought of for strandings. Didn’t see any leatherbacks though. 

Stranded jelly fish, Cleveleys 21/11/10
Stranded jelly fish, Cleveleys 21/11/10

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