Marine Conservation Society: Lancashire area group

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

No limit to growth? – This is the surprising conclusion from studies on reef ecosystems, where it is found that total productivity continues increasing as the biological diversity on the reef increases. The broader implication for marine conservation management is that it is important to maintain balance across the widest possible diversity of life in the ecosystem.

Otherwise in this issue we see reasons not to be popular – if your a Weddell seal, and your popularity is as a snack for orcas. Also we get a glimpse of the slow lives of deep corals – which have led blameless, if rather uneventful, lives since the times of the Roman emperors, only to be killed by the recent oil spill in the Gulf of Mexico. There are no places left on the planet that can claim to being untouched by human activity. We must understand our impact better, and take responsibility for our actions – our ancestors will be able to read the records of our crimes in the sediments of the deep seas…
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This issue’s worrying news is of an oil spill that has devastated two islands in the Tristan da Cunha archipelago. Otherwise we have cutbacks, and separated populations, watching sharks get spruced up, and an indication that water fleas do have a history…

In our final article you are warned to slap on sun block now if you live in the Northern Hemisphere, due to a hole in the ozone layer. This problem is set to disappear by the end of the century, however, so it is one climatic problem we won’t be handing over to our grandchildren to solve.
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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

In marine science this issue, most of our articles relate to how phisico-chemical environment influences the distribution of species. I particularly liked the way the bio-geographical history of the North Atlantic has been revealed through the mDNA of the rough periwinkle. Conservation issues cover cetaceans, coral and cod. Our first article in fisheries raises some questions about the sustainability of invertebrate fisheries. Finally, new estimates suggest that ocean currents (rather than biological activity) are more important in removing carbon from surface waters in the North Atlantic.

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We start this issue with a look at a new species of archaea – where we learn how difficult it is to find out anything specific about these organisms. We put phytoplankton on ice, and in ice, use them to make pretty patterns and find them hard to kill; unlike blue sharks, which just wind up dead by accident.

Our conservation section starts with a look at alien species and threat networks, and has news of a new marine protected area off Costa Rica, before links to some personal accounts of manatees and the sex life of groupers (amongst other subjects).

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We have the usual crop of articles involving DNA sequencing this issue – but I can offer you a link to Deep Sea News promising to demistify some of this – so that is where we start. DNA sequencing of a brown-tide algae helps to show how it can form these potentially harmful algal blooms. Our article on cryptic dolphins, however, uses isotope analysis to show that two sub-species are feeding on very different prey that they are finding in different locations. We pick up on isotope analysis again in pollution, where ⁷Be is used to track global pollution and rainfall – but no formal climate change section on this occasion…

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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.

In this week’s science section the life history of the Nautilus is being revealed. It proves to be an animal with a long life span, and low fecundity, so in severe danger of becoming the once and future fossil, if it is placed under much pressure. On a more aggressive note, female squid select their males by proxy – encouraging them to fight it out amongst themselves for the privilege of passing on their genes.

A couple of videos this week in the fisheries and exploitation section. These come from the HMAP (History of Marine Animal Populations) project, which endeavours to quantify what the ocean food web looked like before we had such a dominant, and apparently disastrous, impact.

Finally in climate change we have a couple of reports showing how plankton can be used to monitor ocean circulation patterns – past and present.
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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.