By Emma Theobald – Research assistant on Lobster Grower 2
As the Lobster Grower 2 (LG2) project draws to a close, we thought we’d share with you some of the wonderful species we’ve seen along the way (besides the European Lobster of course). While waking up at 4.30am to drive to the dock on a freezing morning might not be that appealing, the thought that you might encounter dolphins or see a beautiful sunrise during the boat trip to the site definitely helps to get me out of bed in the mornings! So far in 2019 we’ve been lucky enough to come across common dolphins, harbour porpoise and barrel jellyfish. Over the last three years we’ve also spotted seals, bottlenose dolphins and much rarer migrants such as tuna and a fin whale, plus a huge variety of birds including gannets, guillemots, razorbills, shags, herons, kingfishers and oystercatchers!
After a 20 minute boat ride we reach the Westcountry Mussels of Fowey site, and it’s time to haul up our containers to monitor the growth and survival of the juvenile lobsters. Unlike most aquaculture projects which require a continued feed input, our sea-based containers are designed to be self-sufficient, allowing planktonic organisms to enter the cells and provide a food source for the lobsters. To our surprise, a vast array of pelagic and benthic species have settled on the outer and inner walls of the containers, covering every surface and effectively acting as an artificial reef. It has been interesting to observe the changes in these communities with the seasons, and has demonstrated the incredible biodiversity of marine life within St Austell bay.
The settling fauna includes commercially valuable species such as the edible crab, spider crab, king and queen scallops and common mussels. Echinoderms such as spiny starfish, feather stars, urchins and brittle star are commonplace, as are other crustaceans including the velvet swimming crab, harbour crab, common prawns, skeleton shrimp and amphipods. Rocklings are the most abundant fish species, but blennies, wrasse, lump sucker and even a trigger fish have been observed! Sea squirts, anemones, nudibranchs and cowrie are present in a huge variety of colours, as well as kelp, sponges, bryozoans and worms. Among the highlights for me have been the adorable juvenile spiny squat lobsters with their bright blue and orange coloration, and numerous occurrences of one of Britain’s most threatened molluscs the fan mussel (Atrina fragilis) which normally lives embedded in sediment.
In addition to observing the biodiversity occurring within the containers it is also crucial to understand any potential effects that the Lobster Grower 2 pilot site may be having on the surrounding environment. In order to assess this we conducted a voluntary environmental assessment which consisted of obtaining grab samples, seabed imagery and baited video. Monitoring was conducted at various locations within the Lobster Grower site, the wider mussel farm and control locations 1km outside of the mussel farm area. The initial surveys were completed in 2016 and early 2017 to establish the baseline conditions, and then compared to subsequent surveys conducted in 2018 to understand potential impacts. We were glad to discover that sea based container culture at Lobster Grower site has not had an impact on the local benthic ecology and habitat condition. These surveys also revealed an insight into the distribution of maerl (Phymatolithon calcareum) within the survey area; a species of coralline algae of considerable conservation value because it supports a rich associated fauna. Further, we were able to obtain some interesting video footage, showing the foraging behaviour and interactions between mobile species such as spider crab, angular crab, dogfish and whiting!
It’s safe to say that there are not many jobs which offer the chance to see such a wide range of incredible animals, and the team feel very lucky to have been a part of this pioneering mariculture project!