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 –
http://www.zen102367.zen.co.uk/diving/farnes0806.htm

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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Gulf Oil Spill

November 18th, 2010

On November 10th at our monthly meeting Barry Kaye gave an excellent illustrated talk on the Gulf Oil Spill. He explained in the most clear and concise way the complexity not only of the problem, but also of the solutions.

It quickly became clear that the human thirst for petrol and diesel driven mobility drives the demand for oil, and that if the economics are right, it will be extracted from the most inaccessible or environmentally sensitive places. The great depth of the Gulf of Mexico site produced it’s own problems, but BP was using ‘state of the art’ technology at the time. There are clearly questions about the quality of some of the technology, but we also learned that this was far from a unique case, instead it is just the latest of a series of accidents in the gulf, involving more than just the BP company.

It would seem that any idea of the Gulf spill having been ‘cleaned up’ is just a cosmetic illusion. The shores and wetlands are a very visible indication of what has been achieved there, and dispersants have removed the oil from the surface waters, but this is just a fraction of the larger impact of the spill. The less obvious but greater impact is out of sight in the mid-depth waters of the Gulf, and on the deeper sea bed. Only time will tell what the longer term impacts are on the ecology of these waters, which in turn will have an impact on surface and inshore marine life.
Gordon Fletcher.

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New diary of events

November 15th, 2010

We’ve just added our events diary for January to May 2011 – some good talks to look forward to plus lots of things to get involved with: beach cleans, our annual photo comp., coastal walks and dive/walking/survey trips up to the West Coast of Scotland.

MCS Diary

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Lune Deeps Dive October 2010

November 8th, 2010

The Lune Deeps are not known for crystal clear visibility. To dive here you have to have the right weather, the right tides, and these have to coincide with time that you can spare to go diving. I have to admit that it would be a first for me. So I was very lucky to get a phone call from Ian at Darwen SAC inviting me on a survey dive in the Deeps. This did mean getting up at 4:00 am a couple of days later on an October Sunday morning, in order to get to Knott End in time to launch for the high tide slack water, but these opportunities don’t come up very often and I grabbed it while I could.  

Setting up gear in the car park, it had the feeling of a night dive in the dark. Boats launched, we set off for the chosen site with the sun rising above Blackpool, turning the sky over the bay shades of pink. Fantastic – as a diver what more can you ask for?  

hornwrack, starfish, and edible crab 

 
 

Well there’s the dive. The plan was to drop to the sea bed at about 10m just out of the deeps, and to swim over the edge and down the slope; each buddy pair to have a surface marker buoy visible. Things went pretty much to plan for us, we found the sea bed and managed to work down the slope to 30m. We could have gone deeper but my – borrowed – computer had run out of no-stop time and I was wary of running it into decompression. 

Greater Pipefish
A Greater Pipefish Syngnathus acus

 

So, what was it like? Where we started the sea bed had quite a few fist sized pebbles and was silty enough that any misplaced fin kick would reduce visibility to zero; this wasn’t too much of a problem as the tide was running fast enough to move us smartly along and clear the silt away. At the end of the dive we got a glimpse of a clearer, more gravelly sea bed. Throughout one of the most striking things was that the dominant species was bryzoan Hornwrack Flustra foliacea, which is quite an unusual habitat to find yourself diving. The silt covering meant that much of the benthic fauna was difficult to discern, but there was still plenty to see, with numerous Coryphella nudibranchs and even a large Triton Sea Slug Tritonia hombergi. As well as some butterfish and a greater pipefish we did find an area with quite a few goldsinny wrasse, which was a bit of a surprise; several people reported seeing large dogfish.  

Sponge and hydroids
A sponge (Dysidea fragilis I think) and Oaten pipe hydroids Tubularia indivisia.

 

An interesting dive, but considering the size of the area that we covered there is still plenty of the deeps undived and waiting to be explored. Would I do it again – certainly.

 

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Beachwatch, Heysham, 2010

September 20th, 2010

Members of the Group joined forces with members of the Morecambe & Heysham Soroptomists organisation on Saturday 18th. September to conduct a beach clean and litter survey at Half Moon Bay, Heysham. The survey was part of  a National survey of beach litter organised by the Marine Conservation Society over the weekend 18/19th.  Sept. This annual event attracts thousands of volunteers to clean and record the litter on hundreds of beaches all around the UK coast.  Litter on Britain’s  beaches has more than doubled since the surveys began in the early 1990’s. Most items of  litter recorded , in excess of 60%  are made from plastic and in the region of 40%  of the litter is left by visitors who come to enjoy the beach. We hold quarterly litter surveys at Half Moon Bay, Heysham,  the next one will be on Sunday 19th. December 2010 at11.30am. Why not come along and help?

Group with collected litter.

recording

Photo. images by kind permission of Christine Fletcher.

The weigh in

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