Kittiwake-sandeel paper!

I should have also mentioned in my previous post that we now have a publication out on our sandeel-kittiwake work. This showed that sandeels aggregated close to the surface during maximum ebb tidal currents, and this was associated with maximum kittiwake feeding.  However this only occurred in limited locations, especially those locations with high sub-surface chlorophyll levels, thus creating localised foraging 'hotspots'. 

Embling et al (2012) Investigating fine-scale spatio-temporal predator-prey patterns in dynamic marine ecosystems: a functional data analysis approach. Journal of Applied Ecology

This is a nice follow on from another paper from the same survey also showing the very patchy nature of these foraging hotspots:

Scott et al (2010) Sub-surface hotspots in shallow seas: fine scale limited locations of top predator foraging habitat indicated by tidal mixing and sub-surface chlorophyll. Marine Ecology Progress Series.

Happy reading!

...still in progress but soon!

It won't be long now before all the cruise results are published in a special issue of Progress in Oceanography - we are just making the final changes to the papers.  It should be in press early next year.  So keep watching this space - a summary of all the papers findings will be posted here once the papers are in press.

End of project - update coming soon!

Well, sadly we're coming to the end of the project now - we're all writing up our results & analysis & hoping to publish all the different aspects in a Special Issue of Progress in Oceanography. The final project reports are due in March. So we're busy writing everything up. I'll be back soon to update you on all the findings - I'm curious to find out how it all fits together - already the fish behaviour and seabird foraging behaviour are showing some similar preferences for tidal currents... but as we bring all the different strands of research together it'll be interesting to find out what the overall big picture looks like :o) This is the most exciting part of the project (well apart from the fieldwork!)... so watch this space for exciting results to come!

Work continues!

Just a short note - the work continues on the project despite the quietness of the blog! I'm currently on maternity leave (see photo), but meanwhile the project rumbles on without me. We recently had a project workshop in Glasgow, so I'll get a summary & post it on here soon. However, we're aiming for publishing our findings from the James Cook cruise in a special issue of Progress in Oceanography... so watch this space...

In the news!

We're in print! Check out this link to an article on our project in the EU Projects magazine.

This gives a great update on some of our progress to date. We had a great project meeting in the Lakes at the end of January revealing some interesting insights already...

Birds (Andy Webb, JNCC): the two main species were gannets & storm petrels (see earlier posts for photos): the gannets showing particularly interesting behaviour, diving at the location of the large internal waves at the bank edge at the first spring tide, but generally found in larger numbers at neap tides than spring tides.

Fish-wise, there were clear on-off bank differences in species of fish, with scad (horse mackerel), haddock & whiting more common on the bank (left photo), and blue whiting and nephrops off the bank (right photo).

Photos credited to Jim Roberts (MRAG)

The benthos critters (Nicholas Owen, Trinity College Dublin) also showed a distinct on-off bank change in species. With higher abundance and diversity of bivalves on the bank, and lowest on the bank slope.

These differences between bank & off-bank are likely, at least in part, to be related to the exciting dye tracking results (Mark Inall, SAMS) that showed that any new nutrients or productivity over the bank is likely to be dispersed to the south-east over our off-bank flat site.

Lower down the food chain (a whole host of researchers!), the results were less clear, the strongest influence over changes in nutrients, productivity & phytoplankton was due to the first spring tide or perhaps the associated stormy weather, both helping to thoroughly mix the water column.

How these all link together is the story we're still working on piecing together as the analysis continues...

Analysis underway...

Well I've been a bit silent since the end of the trip - our heads are down analysing the data collected during the survey. Two tasks underway at the moment (1) writing a paper from the analysis of the IMPRESS* North Sea data looking at changes in the feeding behaviour of sandeels (picture shown above) and kittiwakes (picture shown on right) over tidal and diurnal (i.e. changes over day-night) cycles**, and (2) analysing the fish data collected in July firstly to determine species composition, and then to look at changes in species schooling behaviour with time of day, tides (high/low tides as well as spring-neaps). We're hoping to have the paper submitted by Christmas, and the preliminary James Cook data processing done by January. At the end of January we have a James Cook workshop in the lake district where we will present all our findings to date and hopefully find out how all the different bits (turbulence, dye dispersion, plankton, benthos, fish, seabirds) link together & tell us a more complete story of what's going on down in the Celtic Sea.

* IMPRESS = Interactions between the Marine environment, PREdators and prey: implications for Sustainable Sandeel fisheries: a project Beth Scott was previously involved in & from which sandeel data was available to analyse

** This work was presented in September at the ICES (International Council for the Exploration of the Seas) conference in Halifax, Nova Scotia.

Figure 3 - Typical echogram of sendeel schools - so recall we're travelling from left to right, the bottom green line shows the seabed, and the top red line is the echo from the surface. The sound is bouncing back off these sandeel schools. The photo on the right shows a feeding aggregation of kittiwakes (and a few other seabird species) that occur when the sandeels are found at the surface.

So we're busy beavering away...

At the end of October we had a meeting with NERC and DEFRA to meet the other 5 projects funded under the sustainable marine bioresources program. It's a really interesting and diverse array of projects:

(i) modelling interactions between top predators and fishing vessels - looking at the overlap between seal foraging and fishermen using satellite tags both on the top of the heads of seals and on the fishing vessels.

(ii) new production in the North Sea deep chlorophyll maximum - similar to our study they have been analysing the sub-surface chlorophyll levels that exist at the thermocline but throughout the whole of the North Sea. They are then linking this to the rest of the North Sea ecosystem from zooplankton to fish.

(iii) a spatially resolved ecosystem model for the assessment of fisheries - by linking our understanding of how oceanography influences the growth and migrations of fish, these models are able to model the dispersion and age-structured distribution of fish stocks.

(iv) population structuring of cod around the UK - by taking DNA samples of lots of different cod from around the UK it is possible to determine how much genetic mixing there is between populations, by then comparing this to tag data on cod (they can tag fish!!!) they can see how this compares to the actual movement patterns of the cod (they make quite big migrations!).

(v) climate change and macroecological patterns in an exploited marine fish assemblage - a topical subject modelling benthic fish communities with environmental variables over time to see what effect climate change may be having on fish communities.

So, it's a really interesting group of projects & very exciting work! So I better get back to my paper writing & analysis... deadlines to make! Watch this space for progress...

Bonanza day(s)

Wowee! What a day! The shelf edge was as exciting as I was hoping, and it felt a bit like the last day of school, the way everyone was grinning all day.

I, Beth & the birders managed to force ourselves up for dawn (around 5:30am) – this was unusual for me, but not for Beth (with her dawn bongo nets), nor for the birders (who are up nearly every day at dawn looking for birds). Apart from getting up ridiculously early (yawn) it's a lovely time of day to be awake - we had a lovely sunrrise (see picture to right) - it dawned a glorious sunny day with calm blue seas… perfect for whale-spotting. As we approached the shelf edge, lines of surface slicks (one indication at the surface of internal waves beneath the sea surface) appeared on the horizon, and soon we were in amongst the slicks and on cue lots of storm petrels appeared, picking food from the surface (a couple are pictured below).

We stopped close to the shelf edge for a few CTD stations, bongo net deployments to see how different the shelf edge is from the area on and around Jones Bank, and some sediment grabs (Nick happily found lots of worms in the sandy substrate). Meanwhile, the birders threw over ‘chum’ made with the soggy remainder of the mackerel Inigo had left over as bait for his camera, mixed in with sunflower oil & cornflakes. They wanted to make sure that they got some interesting birdy sightings at the shelf edge. As I popped out onto the back deck, all three birders turned and beckoned, grins on their faces and gleams in their eyes like little schoolboys… ‘it’s a Wilson’s storm petrel!’ they exclaimed. I grabbed Andy’s soggy mackerel encrusted binoculars, but there were so many European storm petrels surrounding the ship, dip feeding on the chum, that I couldn’t pick it out. But I did spot some feeding common dolphins again! Everyone who wasn’t working was on the deck enjoying the sunshine, the dolphins and the storm petrels (see picture on right).

For the next station we were going over the edge… into water 3000m deep – it dropped off so quickly – an odd feeling to know that you’re essentially going over the edge of an underwater cliff, and hovering up above. En route, many of us were busy with polystyrene cups writing messages & drawing silly pictures, and tying them onto the outside of the CTD. What on earth is this silly ritual? Well, the CTD was going to be sent into the abyss… to be lowered on the wire down to nearly 2000m to measure the temperature & salinity through the water column, and to collect water samples for ‘muf’ Clare to analyse. At such depths, anything with air in it is squished small by the huge pressure of the water sitting above it – so hey presto – our large polystyrene cups are turned into miniature souvenirs of the trip (see before and after pictures below).
But the main excitement of going over the edge was the whales… it wasn’t long before the first blow of a whale was spotted – this looks like a big tall plume of steam – which it is more-or-less, but it’s actually very smelly fishy watery breath of the whale that it spurts out of its blow hole on the top of its head when it comes up to breath after a long dive under the sea to feed. You can see these blows for miles – right up to the horizon. And if you’re lucky (we were), after the blow, you’ll see the long black back, and finally the dorsal fin (the sharp fin on its back) – this was a fin whale. And the first of many – for the whole 5 hours that we were over the abyss, we were surrounded by the blows of fin whales. Inigo and I stood up at the birders boxes for hours marvelling at the magnificence of these beasts. And as the sun began to set, the birders (Andy, Mark & Adam) & Beth also came up with some cans of beer, and we sat in the opera boxes and toasted a great day (see photos below)… and were rewarded with the green flash!!!

Adam, Andy, Mark, Beth & Inigo toasting the green flash over the abyss

The green flash, for any of you lucky enough to see it, occurs as the sun is just sinking over the horizon, and fills with a bright bursts of green colour as it disappears… this is the green flash – and it’s spectacular to see. The scientific explanation of the green flash can be found at the Wikipedia here.

...and I was going to end the blog today on that note, but just as I was going to press the birders spotted a pod of killer whales on the starboard bow!!!! Now, I've never seen a killer whale in the wild in my life, despite many hours at sea, so I was OVER THE MOON!!!! I was so absorbed watching the 3 female adults, 2 wee calves and nice hefty male with a nice tall dorsal fin, that I didn't take any photos - sorry! But I do have a nice sunset photo to end on:

the Aberdeen crowd celebrating the end of a magnificent day

So we're now steaming for Falmouth to offload - so the last blog of the cruise might be a bit delayed in all the kerfuffle... but so far it's been a fantastic finale to the trip :o)