Marine science update 12th September 2011

September 12th, 2011

A couple of articles over the last few weeks do make interesting and/or disturbing reading: I think it is pretty much a given that for wild fisheries to have much chance of survival they must be managed. In this light recent gene marker studies on fish sales raise both hopes that we can now clearly identify the provenance of a fish on the fishmonger’s counter, and a warning that some existing certification schemes are not working as well as they need to. Farmed fish may be managed, but that also makes them subject to pretty unpleasant management practices, such as the practice of eye-stalk ablation, which apparently speeds maturity of black tiger shrimp…

We start, however, with one of the big stories in the popular press over the last few weeks, the latest estimate of the total number of species on the planet. To be pedantic we should perhaps say eukaryotic species, though the term ‘species’ is not very easy to apply to prokaryotes…
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Posted in Conservation, Marine science update, Science

Shore Walk Roa Island 30th August 2011

August 26th, 2011

This will be an informal event looking for and recording some of the creatures that can be found on the shore at Roa Island. Low tide is at 7:30pm and will be particularly low – at 0.5 metres it should expose more of the shore than most tides which means that many creatures that are often only seen by divers may be found. There are also some creatures that divers don’t normally see that are easier to find when the tide has gone out.

Suitable for all ages; children must be supervised by a responsible adult. Meet at the top of the Jetty next to the Lifeboat Station @6:15pm – map reference SD 232648.

What to bring?

Must haves –

  • Wellies, sandals or other shoes that you don’t mind getting wet and probably a little muddy;
  • The same applies to your clothes; also bring some warmer clothes – the shore is exposed so can feel chillier than places on shore.

Optional extras –

  • A towel and a change of clothes just in case may be a good idea;
  • Shallow trays or a bucket to put creatures in to study (but be sure to put them back carefully exactly where you find them!);
  • A net;
  • A camera – but be aware that sea water and cameras do not mix well, if you bring a camera and have a waterproof housing then please use it and in any case take extreme care on the shore not to drop (or even put) your camera into water;
  • A torch – preferrably a waterproof one, or another good option would be a head torch (sunset is @8:10pm, dusk 8:45pm).

Anything that you bring or wear will be at your own risk.

If anyone wants to car share please let me know and I will try to arrange to meet at the westbound layby on the A65 about half a mile east of junction 36 of the M6 – map ref SD 541821. But note that timing will be a little tight for some of us to get away from work and get to the meeting point in time and that I will NOT do this unless it is requested and I can arrange to leave in time to get to Roa Island.

Contact: Lewis Bambury

Tel: 01524 414318
Mob: 07798 707318

Posted in Conservation, dive trips

Marine science update 21st August 2011

August 21st, 2011

The hardest coral on the reef may well be a softie, as much of the rocky structure of these reefs is found to derive from the sclerites from soft corals! This debate over how much support environmental agencies will grow as our economic worries deepen, how high up the scale do you put the environment? Essential for our continued existence on the planet, or jobs/hospitals now (environment later – maybe)? This week DSN reports on the debate in the US in our conservation leader. Our pollution section, however, points out that one of the most damaging aquatic pollutants – nitrogen from fertilisers – can be reduced while saving money and increasing yields…
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Posted in Conservation, Marine science update, Science

Marine science update 5th August 2011

August 5th, 2011

A cracker of crazy stuff from the ocean this issue: Our contribution to shark week this year might be a shark with a hump – or the camel with very sharp teeth… Plus buzzing lobsters, binary snails and when to fix your beach defenses. Perhaps the best news this issue is the partial recovery of the Grand Banks fishing area. White fish stocks had been reduced close to extinction, and this set up feedback loops that resulted in smaller fish and squid taking over, as they ate what few young fish that were born. After over 20 years of ban, however, there are signs that the cod are coming back… Lessons? – Stop fishing before you hit stock bottom (unless you can survive 30 years without work that is)!
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Posted in Conservation, Marine science update, Science

A wall of life

August 4th, 2011

Over the last few years we have built up a species list for the Hotel beach and wall at Lochaline. Most of the work has been done by Ron Crosby, with occasional contributions from other embers of the group. This year, however, we are glad to welcome contributions from Ron Ates and Godfried van Moorsel, both based in the Netherlands. Their additions (and corrections) take our list up to 122 named species – not bad at all for 100m stretch of coastline! Mind you the coastline is very conducive to diving, with easy access over a gently sloping beach, leading to a near vertical drop down to 80+m. This makes a wide range of habitats readily accessible to the diver – and reminds us about how much there is in the seas around our coasts.

Below is a quick breakdown table of the life recorded, for a full species list see our survey page:

Group No. Species
Algae 15
Sponges 8
Cnidarians 20
Worms 13
Bryozoans 4
Crustaceans 8
Brachiopods 1
Molluscs 19
Echinoderms 8
Tunicates 9
Fish 17

Posted in Conservation, dive trips

Marine science update 12th July 2011

July 12th, 2011

The coolest story in this issue is the all seeing-eye that sea-urchins apparently have, using light sensitive detectors on the tips of each of their tube feet, which are distributed all around their body! Less good is the prediction of a global marine mass extinction event. Otherwise, a few groups are publishing genetic studies increasing our understanding of how marine organisms biomineralise carbonates. Quite imporant given the expected increase in ocean acidification.

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Posted in Conservation, Marine science update, Science

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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Marine science update 19th June 2011

June 19th, 2011

This issue we see that tides keep species apart – or at least prevent the different strains of the ubiquitous seaweed Fucus spp. from all merging into one species! We also see that iron rich waters result in changes to benthic communities and get an insight into how sponges form glass skeletons – a feat of materials engineering that has always amazed me. The tone is decidedly more serious in our Fisheries section, with a link to graphics showing just how much our fish stocks have declined over the last century. Actually ‘declined’ is not nearly a strong enough word for it. ‘Wiped out’ would be a little closer to the mark.

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Posted in Conservation, Marine science update, Science

Marine science update 24th May 2011

May 24th, 2011

It has been a while, and there is a lot to go through – so best start with some light browsing! – In Science we’ve got links to a super set of marine life photos, plus an amusing look at cnidaria from the guys at Deep Sea News. The section ends with new takes from molecular biology on the flagella and the mitochondrion – fundamental building blocks of cells.

In conservation we look at attempts to model population dynamics across a patchwork of marine reserves. This kind of understanding is essential for planning effective reserves, as if reserves are too small, or the gaps between them are too large, then they will not protect all of the species within them from over exploitation. This section ends with a look at how well displaced populations survive – as aliens in the Med or the Caribbean, or displaced benthic faunal communities.

Fisheries has an interesting couple of articles on cod fishing in the Baltic – I had full access to the PLoS 1 journal article, and that appeared to say that fisheries, seals and cod could co-habit, though there would be problems. The ScienceDaily headline is a lot more strident, in saying that seals will be the financial ruin of small fishermen. Otherwise there is a paper drawing our attention to the possibility that fisheries and climate may not be independent variables. If this is that case it will make modelling fish stock that bit more challenging…

In fact there is a second link between fisheries and climate change this issue, with news that slow growing fish in the Tasman Sea are being adversely effected by temperature rise – the Tasman Sea has increased in temperature by 2°C in the last 60 years. Thankfully the Weddel Sea has only warmed by 0.6°C, but this still represents an enormous amount of heat entering the Southern Oceans from our warming climate. To ensure there is no silver lining in this issue, we learn that bacteria are the true rain makers.

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Posted in Conservation, Marine science update, Science

Loch Creran

May 11th, 2011

Thanks to Gordon for organising an excellent dive weekend based at Tralee Bay (see map) near Oban last weekend (6th-9th May 2011). Eleven of us from the MCS and Preston Sub-Aqua Club enjoyed some spectacular dives.

Brittlestars at Loch CreranThese including a fast run through the Creran Narrows, which Jo and I followed with a linked dive into an eddy pool by the North West shore, to get some better photos of the brittle star beds there, (it never ceases to amaze me how much colour there is in these beds, which appear from a distance to be rather unpleasant grey cob-webby places) before a rather hard swim back on the surface.

We also visited the wormery – where the serpulid reefs seem more substantial than ever – less substantial reefs are also to be found in the inner basin of Loch Creran.

Thornbacked ray at Galanach.Our final dive though was at Galanach, where I wanted to visit the sea-pen beds, with the intention of getting some better photos. As a rather nice bonus, however, I saw a large thorn-backed ray, which hung about long enough for me to get his mug-shot!

We also managed a small amount of microscopy, looking at a single plankton sample from Galanach. Unfortunately the phytoplankton have now disappeared (they formed a substantial component of the samples at Lochaline last month), though there is a large amount of zoo-plankton, with copepods and barnacle larvae (cyprids) as the major component.

Posted in dive trips