Expert topic: Lobster
As reported by Dr Jamie Luxmoore, Research Fellow, University of Exeter
Led by the National Lobster Hatchery, based in Padstow, and including partners from the Westcountry Mussels of Fowey,
The Centre for Environment, Fisheries and Aquaculture Science(CEFAS) and, Falmouth University, the three-year project,
known as Lobster Grower 2, focuses on the European lobster by developing the technology and science for growing lobsters at sea.
It is thought that long term an industry will develop, providing a new product, with a separate market from that supplied by
the fishery and therefore creating market diversification andgenerating additional jobs and wealth in coastal communities.
Professor Lars Johanning, Associate Professor in Ocean Energyand academic lead of the University of Exeter"s Renewable Energy Department, based at the Penryn Campus in Cornwallexplained, "This pivotal project unlocks the potential for industryspecialists and scientists to work together to address global foodsecurity in a sustainable and environmentally-friendly way.
He continued, "Crucially, it could pave the way not just to providing nutritious food to many millions more people worldwide, but also bring new and exciting employment opportunities as well. The University of Exeter is implementingfield studies to study the well-being of the lobsters, potentialenvironmental impacts and leads on engineering developments."
Lead researcher for the National Lobster Hatchery, Dr CarlyDaniels developed, "This is the biggest lobster aquacultureresearch project taking place in Europe at the moment and it"s fantastic that it"s happening here in Cornwall, where it willgenerate scientific jobs and intellectual capital."
"Europe is rapidly falling behind the rest of the world when it comes to growing its own seafood and this project is vital in addressing that imbalance. A key component is that lobsters willbe grown in systems with no artificial feed inputs. This means thatsome of the broader sustainability issues sometimes associatedwith aquaculture (i.e. feeding farmed fish on wild caught fish) donot apply. In a nutshell we are assessing whether it is possible to grow one of the most valuable species (by weight) of seafood in the UK, using similar approaches to those used to grow low value species (such as mussels), in passive, environmentally friendly systems."
The project will use a sea-based container culture approach (SBCC) specifically developed for the species, in an early stageproject, to assess performance and develop holistic application of the systems. The project will run a pilot scale lobster culture site to gather practical, operational, environmental, biological, engineering and economic data, that can be used to develop an essential tool to encourage and inform future investment. Interms of environmental credentials, farmed fish and seafood has received its fair share of bad press. This project specifically seeksto address these issues from the outset, undertaking a thorough environmental evaluation of operations.
Keith Jeffery, Programme Director in Food Security and Aquaculture with CEFAS, remarked, "This project is an excellentexample of what can be achieved when industry, government agencies, engineers and the research sector pull together toaddress the needs of a specific aquaculture sector. CEFAS will bring its depth of experience in aquatic animal health andpathology and will help to clarify regulatory aspects - therebycontributing to the development of a roadmap for this exciting and high value aquaculture sector."
Talking about the field monitoring on our LobsterGrower 2 project
A brief introduction into the project itself and then an overviewof the whole field monitoring programme. Then I"m going
to dive into the deep end of what we"re monitoring: Site and Environment Monitoring including; Wave buoys, AcousticDoppler current profilers, Bio-chemical water quality arrays, Spot-point sampling for bio-chemical water quality and micro-constituents. Finally, we will discuss Container BasedMonitoring; Internal environment monitoring and Container motion monitoring.
Lobster Grower 2 is a three-year project funded by Innovate UKand BBSCRC to establish a pilot scale lobster farm. The lobstergrower 1 study developed a no-feed input system for rearingEuropean Lobster (Homarus gammarus) at sea. The techniques developed should be suitable for either stock enhancement or for aquaculture.
At the moment, lobster farming isn"t really something that happens, certainly not on any scale, for a number of reasons. They take a long to grow for one and they tend to eat each other so they need to be kept in separate containers. But theLobster Grower 1 study developed a no-feed input system forrearing European Lobster (Homarus gammarus) at sea. We"re looking to continue that project and prove it can happen at a bigger scale, as the techniques developed should be suitable for either stock enhancement or for aquaculture (if we can get around some of the regulatory problems).
Aims of the project:
- Field test the sea-basedcontainer culture systems previously developed;
- Develop novel anchoring/ mooring systems for the containers;
- Develop an aqua-economic model and roadmap to de-risk futurefarming operations.
We"re about a year and a half in to the project and so far over 25,000 lobsters have been deployed into St Austell Bay, Cornwall on the south coast, to mid-year two. Survival rate is variable, the main die-offis very soon after you put them out at sea, survival also depends on how old they are when you put them out at sea, whether they"re in post larval stage or malting stage. The idea is to get them to stage 6 where the survival rates are a lot better.
Three main methods of holding the containers in place have been trialled – hangingfrom mussel lines, floatingabove a weighted ground lineand a novel integrated seabed-based system, with the aim to be a bit more stable than therope-based system to see if
that makes any difference. The project is being managed from an already existing mussel farm and using mussel farm boats for the servicing.
Field monitoring programme overview
Basically, we"re looking at the oceanographic conditions, we"re looking at the motion of containers and looking at the water quality. For the water quality we"re looking and continuous quality and spot point sampling.
In terms of the wave environment we"ve got two wave buoys which have been deployed throughout the project, one to the south west of the site in the bay and one in the entrance of St Austall Bay. They"ve been monitoring fairly continuously throughout the project.
We"ve also got some ADCP"s (Teledyne RDI Workhouse Sentinel Acoustic Doppler Current Profilers) which as well aswave data are also giving us some current data. The static ADCP is deployed at the southeast corner of the site and the roamingADCP moves around the bay every 1-2 months, the roaming one is to give an idea of how the currents are flowing around the bay. Samples at 1 Hz or averaged over 10 minutes at 1m bins up the water column. (Slide 7)
In terms of the analysis of the data of those we"ve developed a SWAN model of the waves across the site by using the wave buoy data as the input conditions, and the ADCP"s as validation. We"ve also got a PhD student working on developing a DELFT3D model of the currents around the bay also using the ADCP data.
The picture on the right (Slide 8) give you an idea on theconditions around the site, it is relatively sheltered, certainly sheltered from the prevailing South West at least. Waves areusually from the "south south west" to the south east, averaging atabout 2.6 metres, although I expect we may have exceeded that in the last few weeks.
In terms of the currents, they are fairly low in the bay except at the surface where there is wave and wind inputs affecting the currents.
Water quality (Slide 9)
We"ve got four water quality streams through the middle of the site. One of them is at three different depths. They"re monitoring;
• Dissolved Oxygen
Looking at the slide, they"re not actually recording at those frequencies that are on there because they"re out there continuously. We"re also doing spot point sampling for the waterquality. This involves spot point sampling for bio-chemical water quality and micro-constituents, this is held at two locations inAustell Bay at three depths each, monthly in summer and every two months in winter (weather dependent).
There is analysis for temperature, conductivity/salinity, dissolvedoxygen, salt-adjusted DO and Alkalinity (pH). Samples are alsoanalysed for Ammonia (NH3), Nitrate (NO3, Orthophosphate(PO4) and turbidity. And finally, for offshore analysis for micro-constituents – metals and organics (trace legacy pollutants).
We"re also doing CTD profiles (Conductivity TemperatureDepth), which have been collected at the same locations as thespot-point water quality samples. (Slide 11)
Looking at the graphs you can see that in June there is some temperature stratification, which is fairly consistent, by autumn
it looks like the temperature has mixed out a fair bit and again the salinity is relatively constant. In winter it"s slightly colder at surface but salinity is slightly lower, presumably due to fresh water or rain input, which means that the temperature would be fairly consistent across the depth I would have thought.
We"re also monitoring inside the containers (the internal environment). We"re looking at here;
Measurements of temperature (T), light intensity (LI), dissolvedoxygen (DO) and G-force/motion(G);
Using onset HOBO sensor arrays;
• Positioned inside the uppermost, centremost and lowermost tiers of the rearing containers;
• Measuring every 30 minutes.
Looking at the graph (Slide 12 Graph), the green line is one ofthe water quality strings outside the containers, the blue line is for internal monitoring, the results show that there is a reduction of oxygen within the containers which can be expected at this time of year. But it is something we continue monitoring throughout the projects because the lobsters get bigger and the containers get more fouled and of course this may change. The unadjusted levels of environment dissolved oxygen, compared to DO levels recorded within the lobster rearing compartments through Autumn and Winter.
Next, we"re looking at the motion of the containers this involves (Slide 13 images);
• Two pulse INTEGRIpod-S accelerometers measure translational acceleration in three axes;
• The accelerometers are set up to measure at 10 Hz for 10 minutes in every 30 minutes;
Four custom made Inertial Monitoring Units use an Aduino-compatible SparkFun Razor IMU board with three axis sensors – an accelerometer, a gyroscope and a magnetometer; finally, the IMUs are set up to measure continuously at 10 Hz.
Looking at the slide which is a very simplified model, (Slide 14) we"re using the data on those to build up an idea of how the containers are moving. You can see on the right that as wave increases the motion of the contained increases.