At the moment, zooplankton samples are being collected both by multi-nets (which can sample at different depths) and by Bongo (which collects larger amounts of zooplankton, but from the whole water column). Samples are being used to determine community composition, the geographical and depth distribution of different species as well as for stable isotope studies that investigate the importance of different zooplankton taxa as a food source for fish and squid.

In addition to being an important food source, zooplankton also harbor the juvenile stages of many commercially and ecologically important fish species. These are called the ichthyoplankton. During the life-cycle of most fish, it is the early juvenile stages that are most at risk from their environment. Due to their small size, the ichthyoplankton are at the mercy of the currents and individual larvae cannot protect themselves against predators. This is why the majority of fish die when they are very young (often >99%). It is frequently the success or failure of this planktonic life-stage that determines the potential success of adult fish stocks.

(left: fish larvae; center: fish larva; right: cephalopod larva)


text and images by: Sven Kaehler

The search for new chemical entities with exploitable medicinal properties is the cornerstone of modern drug discovery. Traditionally, these new chemical entities have been procured from several sources including the vast natural product reservoirs characteristic of terrestrial and marine ecosystems. Many marine organisms (invertebrates e.g. sponges; algae and micro-organisms) produce natural products (biomolecules) as chemical defence agents against predation or in a chemically mediated response to, inter alia, inter-species competition for limited resources (e.g. space on a reef or nutrients) and intra-species communication (e.g. larval settling cues). Surprisingly, many of these marine natural products also possess medicinal properties and internationally several marine derived chemical compounds are currently in development as new anti-cancer and anti-inflammatory drugs.

A tropical depression has been evolving in the vicinity of Diego Garcia over the past week. The non-frontal synoptic scale low-pressure system definitely has some indications of cyclonic wind circulation as can be seen in the adjacent synoptic chart and satellite image courtesy of the Mauritius Meteorological Service. Winds circulate clockwise around low-pressure and cyclonic systems in the southern hemisphere. Gusts associated with tropical depressions are generally less than 90 km per hour whereas in a true tropical cyclone winds can range from 150 to over 300 km per hour. The red cross in the satellite image indicates our approximate position and we expect to receive the full force of the storm tomorrow evening followed by two days of strong winds and heavy showers. We will spend some time tomorrow battening down the hatches and ensuring that all the equipment in the labs is securely fastened! If physically possible I will add some photos of the cyclone and the Dr Fridtjof Nansen weathering the storm!

From 14-15 October we were sampling stations in the vicinity of the Cargados Carajos Shoals (see adjacent Google Earth Image). The shoals consist of 16 small islands (and some 34 cays) and are classified as a dependency of Mauritius. The shoals used to be a volcanic island that over time eroded until it became submerged and a coral atoll was left behind. The length of the Mascarene Plateau cruise and the lack of any port calls over the five week period will place strain on both scientists and crew. It was therefore decided at the start of the cruise that we will have two barbeque (braai) parties at locations where we could safely anchor the ship to rest and recuperate. The Cargados Carajos Shoals presented just such an opportunity and it was decided, after completing the last station, to anchor off Coco Island (île aux Cocos at 16°50'S, 59°30'E).

The demersal trawling programme is producing some very colourful fishes of fascinating variety. We caught 38 species in our first half-hour trawl and the total is now up to nearly 130 species. Five of our bottom trawls so far have been in about 20-30 m depth and the species found at this depth are now becoming very familiar to us, so sorting is becoming quicker and easier. I was able to name all of the fish in this morning’s sample in a very short time. Smith’s Sea Fishes is proving an excellent guide to identify these fishes even though we are well away from the sea area covered by this famous book. This illustrates the role of the Agulhas current in spreading these species down the south east African coast.

Before I left Grahamstown, Eric Anderson, SAIAB’s expert on deeper water fishes, told me that the deeper waters around the Mascarene Plateau were very poorly explored and that many species caught in waters around 300 m deep are likely to be new. I’m not sure how true that comment will prove to be, but I’m certainly having difficulty identifying some apparently common large species from deeper water trawls in 200 m and 300 m. I’m still searching the literature and thus won’t put pictures of these on the web yet to ask for help, but may do so before the end of the cruise.

Among the more interesting species landed was a black snoek, Thyrsitoides marleyi, not far short of 2 m long, held up in the photo by Jackie Hill, and also a sawshark, Pliotrema warreni, whose toothy snout became so entangled in the netting that it had to be cut free. Other common fishes are a variety of trigger fishes, fusiliers, butterfly fishes and other tropical reef fishes. The opening of the codend at the end of each trawl continues to be eagerly anticipated, to see what new species spill out on to the deck

Image captions (top to bottom): A collection of fishes from the trawl awaiting sampling of muscle tissue for genetic analysis; Balistoides conspicillum; Lactoria fornasini; Apolemichthys trimaculatus; Sargocentron spiniferum; A very colourful mantis shrimp trawled from 50 m depth; (bottom left): Jackie holding a large black snoek trawled at 300 m depth; and (bottom middle): A sawshark, Pliotrema warreni, caught at 200 m depth.

Text and images by Denis Tweddle & Oddgeir Alvheim

The second cruise of the 2008 ASCLME expedition started with a bang on 4 October 2008 following the successful local launch of the ASCLME Project in Port Louis the previous evening. James took some good photos of the event and these will soon be added to the blog. The Mauritian Cruise was largely an oceanographic survey (physical, chemical and biological) along 8 transects perpendicular to Mauritius (see adjacent completed survey track). Due to time constraints the first transect was sampled on the way in from Madagascar and the last two lines to the north (7 & 8) were sampled during the first two days of the Mascarene Plateau Cruise. Due to limited survey time and almost no visible acoustic registrations only one pelagic blind trawl haul was carried out. The only fish species caught were some lantern fishes (Myctophidae) and a few juvenile barracudas (Sphyraenidae), tobies (Lagocephalus) and flounders (Bothidae). Overall, a total of 47 stations were sampled in little more than 5 days, which is more environmental stations than will be sampled during the current 43 day Mascarene Plateau Cruise!! The short survey period and two crew changes in between placed severe strain on the few scientists that had already found their sea-legs or were not prone to sea-sickness. Despite a lack of sleep and the loss of the bongo early on in the cruise, the Mauritian Survey was succesfully completed as planned and the scientists and crew of the Nansen should be congratulated on a job very well done!

This morning, I received an SMS from Tommy Bornman who is currently on the Nansen (I left the ship last night after the function; the ship sailed to start the second part of the cruise, a survey around Mauritius, early this morning) to say that the wire that was connected to the Bongo nets snapped whilst the vessel was in around about 1,000m of water off Mauritius. I believe it was accidentally lifted up too high on the winch, which caused the break EDIT: I have been corrected - the SMS correspondence I had with someone aboard was evidently incorrect - apparently it was corroded winch cable which caused the loss of the bongo. There is another bongo net frame on board, but I'm not sure there are spare flowmeters for it; there was a third one in the bongo supply box but it didn't really spin very well. I guess we'll have to expedite some spares from somewhere! There are codends on the vessel which could be adapted too. Whether there are spare nets of the right mesh size though, I'm not sure. There were several in the box, so hopefully, things will be OK. Bongos seem to be quite fragile, or maybe it's just this expedition being overly harsh on them.

I hope Tommy will keep you all informed about what is going on aboard the Nansen and continue updating this blog. If anyone else aboard the vessel would like to contribute to the Blog, please send me an email (Tommy has the address) and I will add you to the system.

I am currently using a hotel PC as the hotel's wireless internet seems to be down. I've also apparently left my flash stick on the vessel, so can't carry across the images from the big function last night. I will make a retro-active post as soon as I can.

We just had a quick group photograph with many of the delegates from the meeting I mentioned in the last post. Unfortunately, not everyone is in the group photo.

David Vousden, the Project Director of the ASCLME Project and Magnus Ngoile, the Policy and Governance Coordinator for the ASCLME Project had to go and meet with one of the Ministers of Mauritius for a in-depth briefing on the project, which is a fantastic opportunity for us. I, of course, am behind the camera!

This is a full-resolution image, so it is around a 1.87 megabyte download to get the whole image if you click on it. This may take some time if you are on a slow connection; once the picture loads in your browser, right click on it and save it to your computer. If anyone has a problem getting this image, I can provide a resized, lower resolution image - let me know.

I'm currently sitting in a large gathering of projects involved in the marine environment from all around the region, not only the three partner projects in the ASCLME Programme (ASCLME, SWIOFP and WIO-LaB), but also a diverse range of other projects.

A large problem with managing transboundary resources is that there are not only many countries involved - itself a major challenge - but also many projects involved. All of them are doing excellent work within the region, but sometimes the communication and cooperation between the projects isn't all it could be. Essentially, what we'd all like to do is work together, so that we don't end up duplicating our efforts and so that we can effectively share our knowledge and results, and perhaps work more closely together where particular focus areas overlap. People have been talking about this for years, but we've never quite managed to get this level of collaboration really going.

For these reasons, we are hosting a pioneering 3 day Regional Project Coordination Forum here in Mauritius, at the Hotel La Plantation, a few minutes north of Port Louis. A dedicated meeting to really introduce the projects to each other and then, perhaps more importantly, spend time talking about joint aims, coordination and how to work together, is exactly what we need - and has, as far as we know, not been done in the region previously.

For the last three days, the ASCLME Project has been discussing coordination with its closest partners, with a particular emphasis on cruise coordination, data and information, capacity building and communication; I haven't had a chance to discuss with my colleagues yet how those meetings went, but I think they probably went very well.

The present meeting, however, has a broader vision. Today's meeting is designed to allow projects to briefly introduce themselves and outline their aims and activities. I don't have a full list, but some of the projects either present or represented include the IRD from France, ACEP, WIOMSA, AMESD, FAO and their projects SWIOFC and EAF-Nansen, GOOS-Africa and CLIVAR/TRIO, Indian Ocean Commission, ReCoMaP, RAMP-COI, GEF-WIO Marine Highway Development and Coastal and Marine Contamination Prevention Project, International Knowledge Management, and several other projects whose names I unfortunately do not have in front of me.

I'll go around with a camera later and post some pictures. (Edit: I have added a few pictures).

Well, we're finally en route to the last station, just outside Port St. Louis Harbour, we're getting a lovely view of the mountains of Mauritius from here. After that, it's straight into the harbour, then time to clear the customs and immigration formalities. And after that, well, we're getting off the ship and going out! Sigbjørn has declared this evening a "welfare dinner", where everyone goes and eats together on shore.

I think everyone is pretty keen to get off and stand somewhere where you don't get thrown off balance every few minutes, where things stay put where you put them, and you don't have to think every moment "Hmm, if I leave this here, will it break?". Not to mention seeing something other than endless blue ocean, that whilst lovely for a while, does eventually get trying - but it makes you realise how badly named this planet is. We call it "Earth", yet over 2/3rd of it is ocean - and a much bigger fraction of the total biosphere. It's strange to note that humans have seen more of the dark side of the moon than the deep oceans. More of even Mars or some of the more distant planets. We still have a lot to learn out here!