For some time there has been a growing worry about the numbers of jellyfish, with massive swarms being reported in Hawaii and the Gulf of Mexico in late 2008 (Science Daily article).

Jellyfish swarming is a natural event, but evidence is mounting that human activities are favouring these occurrences. Nutrients entering seawater from land run-off increases phytoplankton numbers, and over-fishing reduces the competition for this food. The consequence? – a Jellyfish swarm that can be several kilometres across!

NASA’s Earth Observatory has just published a set of images showing average global primary production fro the period 1999 to 2008. The images show the most highly productive areas of land and ocean by colour (demonstrating again how productive the seas are off the UK). You can see how transient events – like an unusually wet year, can dramatically increase the vegetation levels over desert areas. As the covering notes say, however, it is not so clear why oceanic productivity varies so greatly from one year to the next. For more details and all of the images from this super gallery:

Global biosphere

Barry

I too have to thank Gordon for doing most of the real work in organising the weekend.  The drift through the narrows was one of those dives that gets imprinted in your memory, and I couldn’t believe the numbers of sea lemons on the stanchion when we dived on slack.  The life and colours were brilliant.  I hope those doing the photography ‘course’ found it useful and enjoyable, and that you’ve looked at your pictures and filled in that matrix 🙂

If anyone’s interested I’ve put some of my pictures from the weekend on the web at

http://www.zen102367.zen.co.uk/diving/lochcrerran09/crerran09.html

Lewis Bambury

We’re just back from a very welcome long dive weekend near Oban, combined with an informal underwater photography course given by Lewis Bambury. On the 23rd we had two dives starting from the old Creagan Ferry slipway. This is situated on the North bank of Loch Creran, and about 100m after the new bridge, with a good sized layby to kit up in.

The weather was very wet, and the underwater visibility, at between 2 and 4m was unusually poor for the area – adding to the challenge of getting good photos (good photos were taken by others on the course, unfortunately you’ll have to make do with mine!). The morning dive was a low water bimble around the slipway itself, Loch Creran is home to numbers of sea cucumbers, of which the most commonly encountered is Psolus phantapus (see photo), which is bright orange, and these were the photographic high-spot of this dive, though there were also plenty of crabs, dead-mens fingers and squat-lobsters!

In the afternoon we drifted with the flood tide into the inner basin of Loch Creran – being at springs, there was with strong current. Or at least it was after we found it! – We’d taken a direct bearing to the bridge, and so ended up too close to the North side of the channel to get into the main current until we were pretty much under the bridge itself. Our route did take us through a deep basin immediately North West of the bridge, however (see charts). This contains an extensive brittle-star bed, which looks rather grey and unappealing at any distance, but go in close, and the grey hairyness resolves into myriads of brightly coloured brittle-stars (see photo). These are interspersed with the occasional giant starfish (typically 0.5m from arm-tip to arm-tip).

The final drift through under the bridge was very exhilarating, though with the stronger spring tide it was not possible to stop where we had intended, necessitating a 100m walk in full kit back to the car.

All in all, an excellent weekend, so thanks to Lewis and Gordon (who organised 5* accommodation and dive details).

Barry Kaye

Cod fisheries off the American coast have now largely collapsed, and recent research, by the University of Iceland and Marine Research Institute in Reykjavik, indicates that the remaining commercailly viable fisheries around Iceland are also teetering on the brink.

For a long time we have known that fishing exerts a strong pressure on the size and age at which cod mature. The scientists report that this has resulted in a reduction in the length at which a fish becomes mature by nearly one centimeter per year. The loss in size at maturity has a corresponding loss in fitness, with shallow water fish (the most heavily hunted) having only 8% of the fitness of their deep water counterparts. These changes are almost certainly hereditary, the fish responding to the dead-end that modern fisheries management has forced them into.

The authors speculate that the immediate establishment of large no-take reserves might relieve selection pressures on the fish, and avert a population collapse.

Full article Árnason et al. Intense Habitat-Specific Fisheries-Induced Selection at the Molecular Pan I Locus Predicts Imminent Collapse of a Major Cod Fishery. PLoS ONE, 2009; 4 (5):

This article via Science Daily Headlines

An expedition, led by Dr Anthony Grehan, has discovered extensive deep water corals, standing up to 2m high, off the Irish Coast. Possible sites for investigation were identified from the high resolution bathymetry collected by the Irish National Seabed Survey, and then identified by deep-sea Remote Operated Vehicle (ROV).

Via Science Daily Headlines

The depth that the corals were recorded at is not recorded in the article, or the main page on the NUI dsite. The Porcupine Bank, close to where the corals were dicovered, is between 80 and 100 fathoms* deep (140-180m), however, so we will not be arranging a dive trip(!). As an aside, the Porcupine bank is named after the Naval research vessel HMS Porcupine, from which the Porcupine Natural History Society also derives its name – small world…

Porcupine Marine Natural History Society

*From Haddock on the Porcupine Bank, September 1944 by C.F. Hickling MA

Basking sharks are welcome visitors to the British coastline during the summer months, when they swim close to the surface straining the sea water through modified gills to collect plankton. The species is listed as endangered and the MCS promotes and collects public sightings, through the Basking Shark Watch (BSW) project to try to help us understand more about this enigmatic animal.

Until recently, while summer sightings were quite common, nothing was known about the animals distribution during the winter months. Recently (May 14 2009), however, researchers have filled in the blanks. Satellite based tracking systems have followed basking sharks as they overwinter at depths between 200m and 1km, while migrating through the tropical waters of the Atlantic. The sharks were observed to stay at these depths for weeks or months at a time, effectively vanishing from sight!

For more information:

Science News Report

To report a sighting, or for more information on basking sharks in UK waters:

MCS basking sharks reportings

An article in The Times newspaper by Frank Pope ( Ocean correspondent of The Times) brings home the immense value of the treasure trove of nature in the Chagos Archipelago, a British Indian Ocean Territory.  The vast tropical, marine area belongs to Britain and is directly administered by the British Government, yet few British people know anything about it.

This is by far Britain’s richest area of marine biodiversity.  It has the world’s largest coral atoll, its cleanest seas and its healthiest coral reefs.

As Frank pope says, the Chagos is indeed comparable to the Galapagos and the Great Barrier Reef, and provides the British people with an extraordinary opportunity to protect a precious natural piece of the planet.

Proposals for a Chagos Archipelago Conservation Area are being discussed within the Chagos Environment Network by the Chagos Conservation Trust, the RSPB, The Royal Society, Pew Environment Group, The Linnean Society and the Zoological Society of London.

Drawing on best practice in other great sites, the aim would be to: protect nature, including fish stocks (benifiting neighbouring countries); benifit science and support action against damaging climate change; be compatable with security; be financially sustainable; and provide some good employment opportunities for Chagossian and other people.

To read full article visit:  A Jewel in the Indian Ocean’s Crown.

From the Telegraph newspaper, comes this story about an octopus at a German aquarium, who’s bored and angry because it’s shut for Winter and there are no visitors. Apparently, he likes to juggle hermit crabs, rearranged the aquarium, and figured out how to short the lights with carefully aimed jets of water. A warning tale to aquarium owners everywhere- give your octopi plenty to keep them amused!  

Here’s another census/catalogue/portal of marine life. OBIS is the Ocean Biographic Information System and claims to be “a spatially and temporally interactive online archive for marine mammals, sea turtles and seabirds data”. It takes contributions from researchers all over the world and is based at Duke University in the US.  

The Encyclopedia of Life  is a fantastic, and very ambitious new website, which aims “to organize and make available via the Internet virtually all information about life present on Earth”. You can get involved by adding photos to their flickr group, or become a curator or contributor. I’d like to see more UK and marine-related partners contributing data (like the MCS for example), but it’s a great start!