Shetland Porpoises in the Spotlight: volunteers and drone footage give new insight into porpoise behaviour

Our brilliant volunteers have now been completing surveys for Harbour Porpoises (Phocoena phocoena) since September 2021 at dedicated survey sites in Quendale Bay, Mousa Sound and South Nesting Bay as well as reporting sightings from all areas of Shetland. The Shetland Porpoise survey is led by UHI Shetland through the Shetland Community Wildlife Group in collaboration with WDC Shorewatch and NatureScot.

Site Focus- South Nesting Bay

  • Volunteers have undertaken over 50 watches
  • Out of those watches porpoises were seen on 41 occasions
  • They were seen every month from October to March
  • with groups of over 50 individuals being recorded on occasions.

An amazing effort considering the weather and short daylight hours we have over the winter here in Shetland.

During the surveys we have seen and managed to capture on film, some really interesting behaviour which has not been documented in Shetland before, and very rarely elsewhere in the world!

From the shore we had often been seeing individuals ‘rushing’ at other porpoises creating a fair bit of motion and splashing. Thanks to Richard Shucksmith and Nick McCaffrey, who managed to capture drone footage of porpoise groups, we have been able to see this behaviour more clearly and can see that the porpoises are performing behaviours linked to mating – males rush towards females in mating attempts and flash their undersides to the females as a form of display.

Rachel Shucksmith from UHI Shetland says;

“porpoises around Shetland can often be overlooked, but at locations like South Nesting Bay, Mousa Sound and Quendale Bay we are seeing large aggregations. The effort-based shore observations and drone footage can provide important insights into porpoise behaviour. Observations from outside of our watch sites are also important and we encourage reporting of sightings across Shetland. We are also really keen to get further drone footage, particularly at South Nesting Bay and at our site overlooking Mousa Sound, so if you are a drone pilot and have experience filming wildlife we would love to hear from you!”

The work being undertaken by our volunteers at our porpoise survey sites will help us gain a better understanding of porpoises around Shetland and how they use different areas during different times of the year.

It will be used as a preliminary dataset for PhD student Sophie Smith, who will be starting in October 2022. Sophie will be based at UHI Shetland, supervised by Rachel Shucksmith, Prof Ben Wilson (SAMS UHI), Dr Lauren McWhinnie (Heriot Watt University), as well as benefiting from the expertise of the UHI team behind the Shetland Community Wildlife Group, Emma Steel and the team at Whale and Dolphin Conservation (WDC), Marine Scotland Science, and from Shetland based marine mammal expert at NatureScot, Karen Hall. The studentship is funded via the SUPER Doctoral Training Programme.

The Shetland Community Wildlife Group along with Whale and Dolphin Conservation will be supporting the project by continuing to undertake surveys, reporting one-off sightings and helping to capture drone footage and images of porpoise behaviour.

The studentship will then explore the use of these data collection techniques to further investigate porpoise behaviour, and spatial and temporal use relevant to their conservation and management.

If you are interested in getting involved in undertaking porpoise surveys or have one-off sightings records to submit please get in touch via email at Shetlandcommunitywildlife@outlook.com or take a look at our Porpoise Survey page for more details


A Plaice for Skate at the Ness

By Rhiannon Jehu

A friend and I went to the Discover Shetland’s Sharks and Skates event at the Ness Boating Club a few weeks ago. We both enjoy nature, but I don’t know that much about individual marine species lifestyles, so this felt like a great opportunity to learn more.

Before I went I decided to swat up on flatfish since they are superficially so similar to skate but are really very different. They are a great example of convergent evolution – being flat and living close to the seabed is a good niche and has been selected as a strategy by many species through deep time. So, here is some of what I learned before and during the event.


Bony fish (Osteichthyes) & Bony flatties:

The bony fish ‘standard’ model has bilateral symmetry and use their whole bodies as one big muscle to drive through the water in a streamlined way – fast, efficient and sort of rocket shaped. They move up and down in the water column through the use of a swim bladder which is essentially a built in buoyancy aid.

Plaice (Pleuronectes platessa) are a good example of a bony flatfish. They start life with the standard symmetrical body shape, but then gradually their left eye migrates round their head, and the fish lies on its side and flattens out so it has 2 eye’s on the top (right side) of its body. This means that when a flattie beats their tail they are beating up and down, rather than the more usual side to side. Plaice have white undersides that are hidden from the world, but the topside becomes the colour of the seabed. This camouflage varies a lot in colour, usually a grey/brown base with a range of stars and spots – white, yellow, orange.

Atlantic Cod- Richie rocket CC-ND 2.0
Plaice- Gentiane CC-BY-2.0

So what are skate?

Skate are cartilaginous fish (chondrichthyans) and are related to rays and sharks. Cartilage is resilient, rigid, flexible, and light weight. Chondrichthyans don’t have swim bladders but their pectoral fins are rigid enough and large enough to allow the fish to move around the water column as easily as bony fish do. Bony fish have an active pump system for pushing water through their gills however most (pelagic) chondrichthyans need to keep swimming to keep breathing. Bottom living (demersal) species (generally) have a small hole found behind each eye (a spiracle) where they take in water before pushing it out through their gills. This better suits their lifestyles, and, their mouths are on their undersides, unlike flatties whose mouth is at the front.

Skate are flat like plaice but instead of their body providing the power to swim, they flap their large, pectoral fins (wings). They then use their long thin tails for direction and balance (bony fish use their fins to steer). Essentially skate have strong arm muscles and use their tail as a rudder while plaice have strong tail muscles and use their arms to steer.

Bony flattieSkate
Mouthat front, sideways openingunderside
Propulsiontail musclespectoral fins (rigid)
Guidance systempectoral fins (flexible and fan like)tail (flexible with fins on top)
Breathing stylein from the front, out from the top and undersidein from the top out from the underside

Types of skates

We have a range of batoides (skate and ray) in Scottish waters. Including the common skate which is one of the largest species in the world – it has a wingspan that can reach almost 3m. In recent years this species has been divided into 2 separate ones – flapper and blue, with the flappers being more common in our northern waters.

Flapper Skate caught and released as part of the Skatespotter project
Flapper skate eggcase (c) Sally Huband

These giants of the marine world produce egg cases ‘mermaid’s purses’ up 28cm in length that are tethered to the seafloor. The young take around 18 months to hatch and then take a long time to reach sexual maturity – on average, females mature at 21 years of age, while males mature at around age 14. Marine Scotland Critically endangered flapper skate study – Marine Scotland (blogs.gov.scot) These factors and the skate body shape make them very vulnerable to disturbance and over fishing.  Ultimately, this has resulted in the once common skate being one of our rarest sea creatures.

Though flapper skate were overfished throughout the 19th and 20th centuries they are now protected and there are ways that fishermen can avoid accidentally capturing them, for example, some fishing vessels use nets fitted with skate panels which allow juvenile flappers to escape without the fisherfolk having to release their entire catch Home – Orkney Skate Trust

In 2021 our neighbours in the Western Isles got a site within the Inner Sound of Skye temporarily listed as a ‘Marine Protected Area’ (Red Rocks and Longay MPA). The aim was to protect the largest flapper nursery found in Scottish waters by prohibiting some marine activities (fishing, diving and construction). This temporary designation was under review earlier this year – do people want the site to become a permanently protected? RIFG


The event

The skate event was great fun. There was a 5-6 foot paper skate for people to leave their mark on – ‘skate art’. It’s only when I think about it now, that I realise that the model skate was a realistic size. To imagine something so big gliding through the water – it’s spectacular.

There were interesting and fun videos showing some of the chondrichthyans that visit or live in our waters and also showing how skate embryos develop in the safety of mermaids purses. We then saw a range of egg cases that we tried to identify from shape, size and features – including a flapper ‘purse’ that was bigger than my hand.

The event had 2 microscopes that we could play with; a small digital one and a traditional laboratory type.  We spent quite some time chasing and identifying different micro beasties in a few drops of sea water.

I had one question – What is the difference between a skate and a ray? They are all lumped together as chondrichthyans. Sharks look very different to skate and ray, but these last 2 have very similar body shapes. It turns out that skate lay eggs while ray’s lay live young. But that is for another time.


Conclusion

We know very little about our local marine species and their lifestyles. It’s only in recent years that we have come to identify 2 separate (un)’common skate’. And learning about their slow development suggests to me that we need to take special care to protect them as a species. By protecting the flappers, other species are given respite too. Experimenting with new fishing technology to allow fisherfolks to harvest the seas, whilst at the same time reducing bycatch seems so important for us to find ways of living with nature, supporting it as it supports us.

Links

Surveying for flapper skate eggs | Scotland’s Nature (scotlandsnature.blog)

Become a Skatespotter

Eggcase hunting in Shetland


Calling all swimmers, divers and snorkellers!

We are looking for records of rare and important marine life. In Shetland we are very fortunate to have a long and varied coastline, home to a wide variety of marine life. Compared to other parts of the UK, the Shetland coastline is relatively well studied thanks to survey work undertaken to support the building of Sullom Voe, work UHI Shetland to map important marine habitats and continued government agency survey work. But there are still large amounts of coastline yet to be surveyed.

All the species in the guide have been included as they are either rare, provide a vital habitat for other marine species or provide an important function such as storing carbon, stabilising sediments or maintaining water quality.

To be able to monitor and record these species we need to have accurate and up-to-date information on their distribution around Shetland. This information is used by the marine spatial planning team at UHI Shetland to create maps which are then used by developers, policy makers and local decision makers.

That’s where we need your help, we are asking wild swimmers, divers and snorkellers to report sightings of these key species. If you think you may have spotted one of the species in this guide please send us thew following information:

  • WHAT species you found
  • HOW many or how large
  • WHEN you found it
  • WHERE you found it (including coordinates if you have them) and at what depth.
  • Any PHOTOGRAPHS you may have

To download your copy CLICK HERE

We would also welcome records of any unusual species or invasive species (Shetland’s Marine Non-native Species), or shark and skate eggcases you might spot when diving (Shetland Shark and Skate Eggcase Hunt).


Mousa Biosecurity Trail

Guest blog from Holly Paget-Brown, Biosecurity for LIFE

At Biosecurity for LIFE we are working hard to raise awareness of the threat of invasive predators and put in place systems to prevent their accidental introduction to islands. In particular we are focusing our efforts on 42 specially protected islands that are designated for breeding seabirds, including 7 in Shetland. Biosecurity is the practice of protecting places from the threats to wildlife posed by introducing new diseases or types of plants or animals that do not naturally occur there. Seabirds often choose to nest on islands with no land predators and are particularly vulnerable to introduction of predators such as rats, stoats, mink, and feral cats. Biosecurity for LIFE will work to ensure that the UKs important island seabird populations are provided with safe places to breed and build long-term resilience considering the other significant threats. It will also aim to ensure that island communities are engaged and central to the implementation of successful biosecurity measures.

What better way to learn about the environment and island biosecurity than being a warden for the day?

On Mousa in Shetland we now have our ‘Be a Warden’ trail set up and open. Here children (and of course adults!) can have fun learning about biosecurity and getting hands on with an RSPB warden’s duties for a day.

When you arrive on the island you can pick up a backpack with tools you’ll need and a map for your walk around the island.

As you go around you can look out for the native seabird and plant species present on the island that it’s important to protect from invasive species. Mousa is special as it is home to thousands of European storm-petrels as well as many other seabirds such as great skuas and Arctic terns.

The warden’s pack you can take around Mousa with you. Photo by Holly Paget-Brown

One of the key reasons European storm-petrel flock to Mousa is because it has no mammal predators living on it! This makes it a safe place to breed. Storm petrels nest in the Broch on Mousa and in other areas such as on the stony beach (photo at top of page by Holly Paget-Brown). It is important to keep Mousa free from invasive mammalian predators  so our special native species can continue to thrive.

Keep an eye out for the surveillance that’s out on the island and see if you can spot any rodent teeth marks on the wax block in the ‘warden’s box’. This is a useful tool used on many islands to help monitor whether there are any rodent species present. The smell of the chocolate wax attracts them and they leave distinctive gnaw marks which can help to identify if they’ve reached an island.

You’ll learn about some key things to remember when you’re on Mousa and other seabird islands:

  • Don’t disturb the wildlife
  • Stay on the path
  • Take your rubbish home with you
  • Rats and mice like to hide in bags and boxes: check your bags for stowaways before getting on the boat
  • If you see an animal that shouldn’t be there, report it!
  • Don’t climb on the stone walls, there may be storm petrels nesting in there
  • Inspire others to do the same

So if you’re on Shetland why not take a trip to Mousa and find out more about biosecurity and our incredible native species!

As well as when on Mousa, keep an eye out on other seabird SPA islands in Shetland for invasive predators and follow the other key biosecurity guidelines you’ve learnt on your visits.

The map to follow around Mousa with a few things to look out for along the way. Photo by Holly Paget-Brown

Mammalian predators aren’t the only non-native species in Shetland, there are many in the marine environment as well. As you walk around Mousa or if you’re ever close to the seashore or out for a swim, why not keep an eye out for some of our non-native and indicator marine species. Take a look at the Shetland Community Wildlife Group’s guide to species of interest here: Identification Guides | Shetland Community Wildlife Group.


Introduced animals in Shetland

Guest blog by Paul Harvey, Shetland Amenity Trust

Yesterday we considered a few invasive plants that have the potential to wreak havoc among our native plants, today it’s the turn of animals. Let’s start with land mammals. There was no land bridge between Shetland and the British mainland or continental Europe after the last ice age some 10-12,000 years ago. It is therefore highly likely that all of Shetland’s resident land mammals, yes even the Otter, were introduced to the islands by humans. Some of these were unintended consequences of human activity but some were by design. Bats do of course occur naturally, albeit rarely, as they can fly but alas it seems that we have insufficient volumes of flying insects in our short, cold summers to enable them to colonise the islands. They could yet do though on the back of global warming, and currently breed as close as Orkney.

Potentially the most serious of these introduced land mammals for our native wildlife is one of the most recent and was indeed deliberate. In the 1980s, a few folk thought it was a good idea to introduce ferrets to control rabbit numbers. Well, that turned out well. The ferrets flourished, bred, started to revert back to animals that look much more like their polecat ancestors and seem to have had little impact on the rabbit population. They almost certainly have, however, contributed to the declines observed in some of our ground-nesting native birds and also help themselves to domestic ducks and poultry when the opportunity arises. If you are in any doubt as to how successful this introduction was then just look at the number of polecat x ferret road kills in autumn when the animals are starting to struggle to find food. It is unlikely that this species could ever be eradicated from the Isles now even if someone was to throw a six or seven figure sum at the task.

Stoats were also introduced deliberately, or so the story goes. Some time before the 17th century they were apparently brought in and released by the King’s falconer to spite some local folk who had refused to give their levy of hens demanded as food for his young falcons. They too will feed primarily on rabbits but I’m sure are not averse to a clutch of birds’ eggs or a brood of young birds if they happen across them. They, though, seem to have reached an equilibrium in Shetland, are rarely seen in comparison to the burgeoning population of ferret x polecats and seem to present less of a threat to our native birds.

Stoats (photo at top of page by Jim Nicholson) were supposedly introduced over 300 years ago but their population has not increased as markedly as the polecat x ferret which was introduced just over 30 years ago.

Another guilty party is our much-loved Hedgehog. I love hedgehogs too but only where they belong and that does not extend to Scottish Islands! Here they do untold damage as they stumble around munching any eggs that they come across. They have been known to devour practically the entire contents of an Arctic Tern colony here in Shetland. The problem is our ground-nesting terns and waders have just not evolved to co-exist with these alien mammals.

Hedgehogs (right) although cute can cause havoc for ground-nesting birds when they are introduced to offshore islands like Shetland.

Photo by Jim Nicholson

Most of the mammals I have mentioned to date have not been introduced (or at least successfully introduced) to our outer islands, which is a blessing for their native birds. One alien mammal has, though, been introduced to every island with human inhabitants and perhaps leads to more controversy than any other. The good old domestic cat. The problem is some of these cats become feral and then breed with other domestic, or feral, cats and before you know it there is a significant population of ‘wild’ feral cats. Seabirds really have no defences against those feral cats that choose to make their homes on the slopes of our seabird colonies. Why wouldn’t you move onto a cliff with an endless supply of cheap food. Radio-tracking has shown that even our beloved pet moggies – go far, far further from home than we realise after the hours of darkness. Who knows what dastardly deeds they get up to? The impact of cats is well illustrated by the story of Noss National Nature Reserve. Cats once roamed the island under the auspices of bringing the local rabbit population under control. Scottish Natural Heritage came to an agreement with the owner to remove cats from the island and since then Storm Petrels have started to breed there.

Pink-barred Sallow moth – Photo by Jim Nicholson

Some moths like this Pink-barred Sallow (above) have probably arrived in Shetland as eggs or larvae on introduced plants but they do not appear to have an impact on native species and add a nice splash of colour to the islands.

What of other animals? There is no doubt that a whole variety of invertebrates have colonised the islands after being brought here as eggs or larvae among plants. Many of these may well be harmless and some e.g. moths add extra colour to the scene but others are more sinister. The boom in horticulture in Shetland has certainly made the island a prettier place to live but it is also responsible for introducing the New Zealand Flatworm the length and breadth of the isles. This species was first introduced to the UK in the 1960s. It lives on earthworms covering them in its digestive juices to dissolve them before sucking them up. Earthworms are a vital part of a healthy soil and the fear was that the flatworms would destroy earthworm populations and therefore soil fertility. Although the flatworms do reduce earthworm numbers it seems that without human interference they are not good at getting around so remain largely restricted to human-altered habitats. Thus far they have not had quite as disastrous an impact as first feared.

The New Zealand flatworm – Photo from FERA, courtesy of GB NNSS

Humans have an unenviable reputation for casing untold damage to natural habitats through a variety of processes – but the introduction of alien plants and animals is near the top of the list. The ecology of some island groups has been fundamentally altered through such introductions – only 17 of the 50 or so honeycreepers that once lived on the Hawaiian islands remain, the others are extinct; habitat destruction, introduced mammalian predators and diseases associated with introduced mosquitos have all taken their toll. And of course, the loss of these honeycreepers, some of which were key pollinators of endemic plants, has led to the loss of some plants too. Here in Shetland we have been spared the worst of these excesses but we should remain cautious about the impacts of introduced animals on our native fauna.


Introduced Plants in Shetland

Guest blog by Paul Harvey, Shetland Amenity Trust

Around a third of the species of flowering plants that one might come across in the Shetland countryside are not native to the islands. That’s a staggering 300 or so species that were deliberately, or accidentally, brought into Shetland by humans! The majority of these were brought here to brighten up gardens, or their seeds arrived as contaminants of agricultural crops.

Most have not moved far – maybe they’ve jumped (not literally) over a garden dyke or fence, or rely on the ground being ploughed for more crops. Some may provide an additional nectar source for insects – very welcome in areas where native flowers are beheaded by sheep before getting a chance to flower, but others contribute very little to wildlife and some may even be detrimental. Native wild plants and animals have adapted together, so can be useful to each other for example through pollination, or are in a continuous battle where the insect consumes the plant and the plant tries to evolve defences to keep the insects at bay. And of course their flowers, leaves and seeds, and the insects attracted to them, provide food for birds. These complex relationships simply don’t exist with many non-native species.

A good number of these non-natives have, however, found the Shetland environment very much to their liking and have spread through the islands to the extent that they look perfectly natural here. And indeed some of these co-exist with the native flora and fauna without causing any issues. A few, though, are more problematic. Here we consider three such species.

Japanese Knotweed

Japanese Knotweed is native to eastern Asia and was brought to the UK in 1850 by botanist Philip von Siebold. We don’t know when it was brought to Shetland but it was first noted at Kergord in 1952 and now occurs at quite a few places in the islands. It is most easily seen at the Dale of Walls where it occurs along the burn either side of the bridge across the road.

Down south this really is the archetypal triffid –  it spreads very quickly suppressing any other plants in its vicinity. It dies back in winter and then new stems arise from rhizomes that are deep underground. Even though it rarely sets seed in the UK new plants can arise from even a tiny bit of a rhizome – hence it is classed as controlled waste under the Environmental Protection Act needing to be disposed of at licensed landfill sites. Eradication is problematic and often involves calling in professional help. Indeed, if you’re trying to buy a house and Japanese Knotweed is known to be present then it’s unlikely you’ll get a mortgage until it’s eradicated – more expense!

Fortunately, here in Shetland it doesn’t appear to spread so quickly and at most of the sites I have seen it, its distribution hasn’t changed that much. I have had to give one potential house buyer in Lerwick the bad news on one occasion though, so beware!

Photo by Paul Harvey

Japanese Knotweed at the Dale of Walls (above). Here it dominates part of an old croft garden and appears to be slowly spreading along the burn. Fortunately, in Shetland this invasive plant only spreads slowly unlike its counterparts down south where it can soon spread and take over large areas.

Ground Elder

Ground Elder is a member of the carrot family that was introduced to the UK by the Romans as a medicinal and culinary herb. Its leaves are quite tasty – a kind of lemon come celery taste – and presumably that is what encouraged folk to bring it to the islands and plant it in their gardens. Don’t eat too much though as I have read that after flowering it can have a mild laxative effect. And therein lies the problem. Once established it takes over – forming a carpet of green, outcompeting and shading out all other flowers; that’s an awful lot of salads… and potentially toilet roll. Although not being subject to the same legislative issues as Japanese Knotweed, eradicating Ground Elder is a real challenge, as like the knotweed, it seems to be able to regrow from just the tiniest piece of white root that you might accidentally leave behind when attempting to remove it.

Ground Elder (right and in banner) grows quickly in spring and can soon dominate roadside verges, waste areas and gardens.

Picture by Jim Nicholson

Monkeyflower

The final plant I want to consider is Monkeyflower and its various hybrids and forms. This one is much more controversial as it has become much-loved by many Shetlanders. It actually originates from North America, is undoubtedly attractive and seems to thrive in Shetland in wet places; ditches, loch margins and marshy ground. It was brought to the UK in the mid-1700s and found growing wild by 1830. Beeby was the first to note it in Shetland in 1886 at the Loch of Clickimin, although it was restricted to just two or three sites until at least the 1920s. Since then, it has expanded markedly and despite its pretty appearance it might be having a negative effect on some plants and animals. The jury is still out but it certainly has a tendency to form extensive mats and dominate some damp areas and ditches at the expense of our native flora.

Monkeyflower (right) comes in several colours from yellow through to a burnt orange. This is the most common colour. Although attractive, the plant can soon clog-up and dominate ditches and wet, marshy areas.

Photo by Jim Nicholson

In their native ranges these plants are kept in check by insects, fungi and other predators but once introduced into a new environment where these natural predators are absent they can explode and replace our native plants. Whether we have learnt the lessons from such introductions is something of a moot point. Folk should be particularly careful when dumping garden waste away from their gardens. As well as being illegal fly-tipping, this can also lead to the spread of invasive plants including those outlined here.

This feature is also available at the Shetland Amenity Trust website.


Monitoring marine non-natives at UHI Shetland

Today we’re exploring the species that get moved around across oceans and continents to be introduced to our coastal seas. As the world becomes increasingly connected by trade, there are more opportunities for species to hitch-hike attached to boats or within ballast water, or be accidentally transported for aquaculture, released from aquariums or as part of live food imports.

The species we find in the UK which are commonly introduced are those which are good at living or growing in man-made environments – i.e. they can be found attached to hard structures like boats, piers or pontoons.

Free-swimming species such as fish and jellyfish have caused big impacts in other parts of the world, introduced when canals like the Suez Canal connect two previously isolated water bodies. Hundreds of species have moved from the Red Sea to the Mediterranean along this pathway.

Marine species can be transported vast distances and no place is remote enough to escape the impact – there is increasing worry about the potential introduction of novel species to the Arctic and Antarctica on visiting boats. These environments could be especially vulnerable to novel species due to their isolation and unique habitats.

Becky (left) monitoring non-native species on a research trip to Svalbard in the arctic with colleagues from Wageningen University & Research (photo by Hans Verdaat).

Monitoring in Shetland

Rachel and Kate at UHI Shetland look at the fouling species in a Shetland marina

At UHI Shetland, we monitor key sites to detect the arrival of new species and track the spread of marine non-natives already present in Shetland. We do this every year by setting out monitoring panels in marinas and harbours as these environments are most at risk. Native and non-native fouling species that like to grow on hard structures settle on these plates. We remove the plates after 3 months or so and identify the different species. This gives us an easy way to look at what’s living under the surface without having to go for a swim.

We have been carrying out this monitoring over the last decade. There are records of 12 marine non-native species in Shetland which is far fewer than are found in the south of the UK, or in mainland Scotland, potentially as a result of the colder waters around Shetland.

However, we still have had a few introductions which have the potential to cause problems. For example, the orange ripple bryozoan, a type of animal where lots of individuals housed in box-like outer skeletons (zooids) which form a larger colony. It was originally from the northwest Pacific but has been found in Scotland since 2010. It is used to cold-waters and can come to dominate fouling communities that grow on hard structures, taking over space from native species.

Causing problems

The reason why we’re so keen to detect species quickly once they arrive is that it’s much harder to control the impact they have once they have become established and started to spread. And while many non-natives don’t cause any problems, others can harm both the environment and people.

Invasive species can cause problems for marine industries, for instance by growing on structures such as piers or slipways, by getting tangled in boat propellors, or by spreading disease or growing on aquaculture species. They can also change how we interact with the sea. The introduction of a jellyfish species Rhopilema nomadica to the Mediterranean meant more people were being stung on beaches, resulting in millions lost in reduced visitor numbers for the tourism industry.

Some changes might not have such big economic consequences, but can still change how people interact with the environment. The invasive wireweed Sargassum muticum has become the dominant species in rockpools in some areas of the south of England and on the Isle of Man, and because it floats and is very stringy and tough it means people are more likely to trip and fall over when exploring rockpools as it gets tangled around your legs.

The invasive wireweed Sargassum muticum dominating a rock pool by cutting out light for other species in the Isle of Man. This is one of the species we’re on the lookout for in Shetland.

Keeping an eye out

It’s important that we detect new arrivals quickly and it is challenging to monitor species over the long coastline so we also rely on members of the public looking out for key species or noticing unusual species while they are out and about. Species we are most concerned about include wireweed, Sargassum muticum, and the Carpet seasquirt, Didemnum vexillum. We have an identification guide that sets out key species we’re interested in hearing about if you find them on Shetland. Any records can be sent via the shetlandcommunitywildlife@outlook.org email address, with a note of where exactly you found something, a description and a photo.

Preventing the spread of invasive plants and animals is something we can all help with. If you are moving equipment or boats, paddleboards or snorkel gear between water bodies, and especially on/off Shetland you should follow “Check, Clean, Dry”. The GB Non-native Species Secretariat website has a lot of information on biosecurity in the UK, including information specific to the marine environment for industry and individuals.

Download our INNS guide here

Anyone interested in learning more about non-native species is welcome to come and see what we do at one of our events in Scalloway or Burravoe this week, and we’ll be running further training in the summer for anyone who wants to get more actively involved in monitoring. Let us know if you’d be interested in this by dropping us an email!

You can find out more information about the work we do on marine non-natives on the UHI Shetland website – click here


Welcome to INNS Week!

This week is the UK’s Invasive Species Week which aims to raise awareness of the issues that invasive species can cause and of the work being done to prevent their spread and reduce impacts.

So what is an invasive non-native species and why do we worry about them? Non-native species (which can also be called alien or introduced species!) are animals and plants which have been moved to new locations outside their native range. The majority of these don’t cause any problems but a few can have drastic consequences in their new environments, harming other wildlife or causing problems for the people that live and work there – these are known as invasive non-native species (or INNS).

Non-native species are moved by humans – either intentionally such as for food or as pets, or accidentally as hitchhikers on boats, equipment or with other organisms. For instance, people think the invasive wireweed Sargassum muticum (header photo) was introduced to Europe when it was used as packing material for oysters being moved from the USA to France in the 1960s. It’s now widespread across a lot of the coasts in the south of the UK, and a species we’re keen for folks to keep an eye out for on Shetland’s coasts.

Non-native species can be introduced into any type of habitats – on land, into rivers, or into seas. And species that are part of our native wildlife here cause problems in other parts of the world. For instance our native green shore crab (Carcinus maenas) which is a normal shoreline species in the UK has competed with native crabs after its introduction to the USA and is considered a pest. It’s always fun chatting to other non-native species researchers from across the world, as we’re often studying the same species but consider each other’s native species the problem – it gets a bit confusing!

Image by Sara Redstone, GBNNSS – Oak processionary moth caterpillars devouring an oak tree.

The environmental problems caused by invasive species can range from impacting individual native species to completely changing the structure of habitats. Where invasive species can cause the most environmental damage is to places where the native species do not have any natural defenses. One example of this is the introduction of predators such as rats or mink to islands with nesting birds which naturally have no land predators. The lack of familiarity with novel species can also cause problems for people as well. For instance, caterpillars of the oak processionary moth which was introduced to England in 2005 can cause rashes and breathing problems due to tiny toxic hairs if people disturb them.

Invasive species can also cause costly problems for people by affecting industries, for example the introduction of sea-squirts Styela clava and Didemnum vexillum have caused problems for aquaculture by fouling gear and increasing cleaning costs. In the Black Sea, the introduction of the invasive ctenophore Mnemiopsis leidyi (a small jellyfish-type animal) contributed to the decline of commercial fish stocks in the 1990s by competing with fish for food and eating small fish larvae. It’s hard to predict which species will cause problems so it’s best to take a precautionary approach and try not to move species around.

The invasive sea-squirt Styela clava fouling aquaculture gear in Canada.

Biosecurity

It can be very hard to control a species once it has arrived and begun to spread. The best idea is to stop new species from ever arriving, and to be especially cautious when we want to protect vulnerable habitats or where people’s livelihoods might be affected. We use the term Biosecurity for actions taken to protect places from the introduction of new non-native diseases, plants or animals. This encompasses a wide range of activities and behaviours we can take personally or which are built into how businesses operate.

As individuals we can do things like make sure our boots are clean of mud and seeds before travelling away and back from holiday, cleaning the gear we use to paddleboard, swim or kayak, or stowing food securely and checking for rats or mice when travelling on boats to smaller islands.

Coming up this week

This week we’ll be sharing some information about what non-natives are found in Shetland, and some of the research and work going on to prevent spread into and around the Shetland Islands. We’ll be posting a blog a day and sharing information and resources on social media, so follow along!

Tuesday – Marine non-native species monitoring at UHI Shetland

Wednesday – Introduced plants in Shetland – Guest blog by Paul Harvey, Shetland Amenity Trust

Thursday – Non-native mammals in Shetland, and a flatworm all the way from New Zealand – Guest blog by Paul Harvey, Shetland Amenity Trust

Friday – Keeping an eye out for rodents on Mousa – Guest blog by Holly Paget-Brown, Biosecurity for LIFE

If you want more information on invasive species in the rest of the UK, have a look at the GB Non-native Species Secretariat website!


Doing Less for Nature

By Rhiannon Jehu

I think that this year I’m going to commit myself to doing less for nature. No Mow May is a campaign started by Plantlife and is linked to their wild verges campaign that I mentioned in a blog last year and also to their Citizen Science project called #everyflowercounts Every Flower Counts | Plantlife.

The thinking goes like this:

  • People depend on plants and their products. Many of the plants we depend on, depend on insects to pollinate them.
  • We need to care for our insects so we can care for our plants, so we can care for ourselves and those we love.

However, as the UK population has increased, and agriculture has industrialised to try to feed us all, the number of meadows has reduced and the use of pesticides has increased. This means that people’s gardens are becoming more and more important as refuges for wildlife.

(c) Rhiannon Jehu

In the past it was popular to have a flat, green, single species, manicured lawn. There was stigma against not mowing, but councils and individuals are beginning to understand the benefits of an unmown lawn. If you spend 1 hour a week cutting your lawn your CO2 footprint will be around 293kg per year. Indeed, less mowing and allowing species to arise naturally gives your lawn the opportunity to sequester carbon – to become a better carbon store. Also, a manicured lawn takes a lot of effort to maintain – mowing, raking, weeding (or using weedkillers).

Gardens are often multi-purpose and vary in size. Some people grow vegetables, others flowers, some use them as children’s play areas, and all these different functions need to be taken into account. Plantlife and the RSPB both offer advice on managing your garden to make the most of it and share it with nature at the same time.

Cuckoo Flower
(c) Kate Allan
Heath spotted orchid
(c) Kate Allan

Plantlife suggest giving gardens a ‘Mowhican’ style cut – as with the hair style, cut some grass short and leave other areas long. Allowing two lengths of grass to grow maximises the diversity and quantity of flowers that will arise and this will increase the quantity of nectar your lawn produces and the length of time it is productive. ‘Short-grass’ plants like daisies and clover start flowering again soon after being cut, while areas of longer, unmown grass welcome a different range of flowers, in Shetland this could include yellow rattle, dead nettles (don’t worry, they don’t sting!), selfheal, cuckoo flower and even heath-spotted or northern marsh orchid!

The ideal is to cut the short grass once every month or so to a height of 1 or 2 inches (2.5 to 5 cm) then strim all the grass in August or September and remove the clippings. Mow it a couple more times if needed and then let your lawn rest over winter.

Other ideas include rotating patches of long and short grass within your garden so there are always some areas in flower. Or leaving areas long and then cutting strips to areas like the washing line that you want to keep clear for easy and ‘dry footed’ access.

The RSPB describe more detailed ways of creating wildlife habitats in your garden Stop mowing your lawn for nature (rspb.org.uk) and have a range of gardening ideas for all the family Wildlife garden ideas (rspb.org.uk)

(c) Rhiannon Jehu

Dr Trevor Dines a Botanical Specialist at Plantlife said:

“Put simply, the less you mow the more bees and butterflies there will be in your garden.” And that works for me.


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A Celebration of Birds and Bogs

By Rhiannon Jehu

I find birds amazing, they can seem so small, so light weight, so vulnerable looking, and yet they survive in what to us feels like harsh extremes. The RSPB suggest that birds are probably the most researched and recorded wildlife on the planet. At the opposite end of the spectrum, wetlands have often been viewed by people as wastelands. However, they are essential not just for the survival of many of our much loved bird species, but also for our survival as a species. This month I thought that I’d write about 2 different events that have happened almost together this year –RSPB’s Big Garden Birdwatch that has been running since 1979 and World Wetlands Day which has been celebrated since 1997 and has just become an official UN event.


The Big Garden Birdwatch

The Big Garden Birdwatch is a very popular citizen science project – in 2021 over one million people took part across the UK with 78,000 people counting a total of 1.5 million birds in Scotland. The BGB data was combined with information gathered by 70 other organisations and used in the ‘State of Nature 2019 report’ which in turn is being used to advise and campaign for improvements in nature care. The BGB count is especially important because it has been taking place for so long that it allows trends and changes to be identified. Sadly, this means that we know that over the last 50 years, 40 million birds have vanished from the UK’s skies.

For me, doing the birdwatch is a social experience since we compare notes with neighbours and friends as to what we’ve seen and not seen. This year we saw sparrows, starlings and pigeons. The RSPB ask us to record the maximum number of each species we see with their ‘feet on the ground’ at any one time. This means no counting the flock of geese flying over-head, which can be very frustrating – a case of the ones that got away.

Sparrow looking handsome on a hawthorn. (C) Rhiannon Jehu
Starlings are amazing generalists – I see them at the table, on the beach and amongst the bogs and heather. (C) Rhiannon Jehu

The stats from 2021 show that house sparrows were our most common garden visitor across the UK. In Scotland this was followed by starlings but in England, blue tits came number two. Nationally, sparrow populations have dropped by 58% and starling numbers by 83%, since 1979.


Wetlands

So, where do wetlands come into the equation? The name wetland describes a wide range of habitats, saltwater or fresh, inland or coastal, natural or human-made. In Shetland, this includes our peatlands, blanket bogs, marshes, lochs and lagoons.

Blanket bogs (a type of peatland), form where soils are water-logged and acidic. Conditions are too harsh for many non-specialised species but mosses, especially sphagnums thrive. They can hold up to 20 times their dry weight in water meaning they reduce runoff (and therefore flooding) and hold water during dry periods, reducing the risk of droughts.

Sphagnums and other bog plants break down very slowly and thus build up (at a speed of about 1mm a year) to form layers of peat which can be over 8m deep (Blanket bog | NatureScot). However, though healthy peats store carbon, when they are degraded they release it back into the atmosphere. This means that caring for our bogs is massively important if we are to limit climate change.

(C) Rhiannon Jehu

There are over 30 species of sphagnum moss in the UK, but they are very difficult to tell apart.

(C) Rhiannon Jehu

The Shetland Amenity Trust, with funding from the Peatland ACTION project have so far helped to restore about 400 ha. of Shetlands degraded peatlands as part of a wider national target to restore 250,000 ha. of degraded peatlands by 2030. In Shetland, they are hoping to reach the point where we are restoring 1000 ha. a year. The RSPB in Shetland are also working hard to protect peatlands, employing a dedicated Peatland Officer who works to restore and protect peatland habitats for the benefit of Shetland’s bird species.  

Scotland’s location at the edge of the Atlantic means that it catches a lot of rain which the hard rocks stop from draining away quickly. This combined with agricultural practices has allowed bogs and thus peat to cover almost a quarter of Scotland’s landscape (1.8 million hectares). This is a significant amount of our planet’s blanket bogs which in turn support some of our rarest wildlife. So, whilst some people may view wetlands as not being very productive because we can’t grow many crops in them, globally, they are home to 40% of the world’s known plant and animal species and 30% of known fish species, with, for example, many birds using wetlands as rest & refueling stops during migrations.

In Shetland, the vast extent of peatlands is an important breeding area for wetland birds such as dunlin, golden plover and curlew, giving islanders plenty of opportunity to spot these birds while out and about.

Curlews breed on a range of habitats including moorland and bogs. For me, their song suggests the start of spring (almost)

(C) Rhiannon Jehu

I love watching for the birds that visit our islands and our gardens – even when they hide. Monitoring the wellbeing of individual species, as happens with the Big Garden Birdwatch, helps us to see and understand the long-term situation and can inspire action. However, individual birds trying to survive and reproduce need a wide range of resources and wetlands are incredibly valuable. Caring for them here and around the world is important if we want to give other species and ourselves the opportunity to survive and live well.

If anyone is interested in learning more about carrying out peatland restoration on their hill or apportionment then Sue White from Shetland Amenity Trust would love to hear from you. There are also some ‘how to’ You-tube guides to peat restoration by NatureScot: Peatland Restoration Techniques.