Non-native (or alien) invasive species are seen as one of the greatest threats facing coastal fisheries in the UK. Marine invasive species are estimated to have a direct cost of approximately £40 million per year to marine industries in the UK (Williams et al. 2010). These costs include the money spent on controlling invasive species by preventing them from entering coastal and marine ecosystems or removing them once they have entered. There are additional opportunity costs incurred by local fishers when removing or disposing of invasive species from fish catches. These are not accounted for in the direct costs and may be even higher than £40 million per year. For an industry that overwhelmingly consists of small-scale fishers this constitutes a massive burden.

Great Britain Non-Native Species Secretariat is actively involved in assessing the risk of invasive species to marine industries, educating the fishing communities about these species, and putting in place measures to prevent, control or eradicate them. Despite these measures, invasive species continue to threaten biodiversity including that of marine ecosystems (Roy et al. 2014). Of the top 30 most invasive species in Great Britain, eight are marine. These include: Asian shore crab (Hemigrapsus sanguineus), brush-clawed shore crab (Hemigrapsus takanoi), American lobster (Homarus americanus - pictured above at the top of the page), American comb jelly (Mnemiopsis leidyi - pictured below), veined rapa whelk (Rapana venosa), cauliflower sponge (Celtodoryx ciocalyptoides), Japanese sting winkle (Ocenebra inornata), and rough agar weed (Gracilaria vermiculophylla).

Image by Smithsonian Environmental Research Center on Wikimedia under Creative-Commons license American comb jelly (Mnemiopsis leidyi)

These species have a range of negative impacts on the marine environments and on the fishing industry which is highly dependent on these environments. Asian shore crab and brush-clawed shore crab both out-compete and displace native crab species such as the shore crab, Carcinus maenas (Dauvin et al., 2009, Dauvin & Delhay, 2010). American lobsters are often released into the coastal waters following purchase from restaurants. They can carry a bacterial disease, gaffkaemia, lethal to other lobsters. Parts of the North American lobster fishery have had to be closed as a result of this disease and its impact on European lobster populations and fisheries could be equally severe (Stebbing et al., 2012).

American comb jelly is a voracious predator of zooplankton including fish larvae and eggs (Faasse & Bayha, 2006). This species has been responsible for serious impacts in the Black Sea including a sharp reduction in Dolphin numbers because of a rapidly declining fish. The decline in abundance of zooplankton and fish is also known to have led to the near collapse of commercial fisheries in the Caspian Sea (Finenko et al., 2006). American comb jelly could have similar effects in the coastal waters of the UK. Veined Rapa Whelk is a large predatory gastropod and consumes a range of ecologically and commercially important invertebrates (ICES, 2004).

Cauliflower sponge is a suspension feeder growing into very extensive patches. It often grows on Eunicella verrucosa (a slow growing, fragile, habitat forming species) posing threat to coastal and marine habitats (Henkel & Janussen, 2011). Japanese sting winkle is a predator of bivalves. It is considered a serious threat to oysters in France and could pose a similar threat to oysters in the UK (Lützen et al., 2011). Rough agar weed can have a negative impact on Fucus vesiculosus (a key intertidal algal species) populations and other native algae. This species is able to grow rapidly, colonises large areas, and is highly salt tolerant (Nejrup et al., 2012).

Some invasive species have already ben adopted in new
cuisines in countries where they have invaded. Slipper limpet
(Crepidule fornicata), a native of Atlantic Coast in North
America, is considered an invasive species in Europe.But could some of these species be useful to the fishing industry? Many of these species commonly appear in the bycatch and simply have to be discarded. However, there are innovative examples where some species have been used for food. Bun Lai, owner of Miya’s Sushi in New Haven, Connecticut, USA is one of the few chefs in the world who only serve invasive species. He has come up with some new recipes made from Asian shore crab, a species that is considered invasive on the East coast of the US. The recipes include ‘Asian Crab Popcorn’, ‘Sawagani on Grilled Pineapple Salsa with Tabasco’ and ‘Asian Shore Crabs in Coconut Milk, Filipino style’.

American lobster is a delicacy in North America and is prepared in a variety of different ways to serve as food. It is even considered a “crown jewel” of the seafood industry on Prince Edward Island Province on the East coast of Canada. Veined Rapa Whelk is a species that has culinary uses along the Black Sea coast where it is considered invasive. Although these whelks are not easy to cook, they can be prepared in different ways. Romanian recipes of this species include ‘Rapane in Butter and Wine Sauce’ or ‘Rapane with vegetables’.

Many other species that are considered invasive in the UK waters, and are commonly found in the bycatch by small-scale fishers (Gray 2018), have culinary value that can be exploited. In particular, those species already popular in local cuisines in their homeland have the potential for stimulating a new culinary culture. Wakame seaweed or Japanese kelp (Undaria pinnatifida) is commonly used in Japanese cuisine. Similarly, American oyster drill (Urosalpinx cinera) is a delicacy along the gulf coast of Texas. Chinese mitten crab (Eriocheir sinensis) is a delicacy in China while Kuruma prawn (Marsupenaeus japonicas - pictured below) is a delicacy in Japanese Edo-style sushi. All these invasive species in UK waters can potentially be consumed as food.

Image by Daderot on Wikipedia under Creative-Commons license Kuruma prawn (Marsupenaeus japonicas)

Some invasive species have already been adopted in new cuisines in countries where they have invaded. Slipper limpet (Crepidula fornicata), a native of Atlantic Coast in North America, is considered an invasive species in Europe. It is commonly observed along the shore and often taken in shellfish dredges. In Cancale, France, Pierrick Clément, a local entrepreneur is turning them into culinary pleasure. American jackknife clams or razor clams (Ensis americanus) are used by British chefs as a delicacy. Mediterranean mussel (Mytilus galloprovincialis), on the other hand, a European export to North America, is used in new cuisine along the US Pacific Coast. These new cuisines are a positive sign that people are adapting to their changing marine and coastal environments by changing their diets.

Could the UK fishing industry benefit from the promotion of such new cuisines? With investment from the government, it may be possible to develop culinary tourism around invasive species, reviving coastal communities in the UK. If invasive species that routinely turn up in bycatch can be supplied to restaurants specialising in invasive species cuisine, this will generate additional streams of revenue for coastal communities. This could be a lifeline to small-scale fishers who often struggle to make ends meet in the overfished coastal waters around the UK. These new cuisines could potentially improve the marine environments by keeping invasive species under control whilst also improving the economic conditions for small-scale fishers. Fishing the aliens could be a promising solution for environmental, social and economic sustainability of UK fisheries.

The TV series that inspired this article