: Natural History

In my previous blog I explained what rafting bivalve shells are and how Caribbean bivalves are ending up on British and Irish shores attached to plastics. There are numerous records of non-native bivalves on plastics in the southwest of Ireland and England but nothing has yet been reported in Wales, which is something that I’m trying to rectify. To encourage recording I’m enlisting citizen scientists – volunteers from the general public – who can help to spot and identify these rafting species in Wales. But first of all, I want to check to see if there are rafting species turning up on our shores so I began talking to groups who already go out on the shores to survey, beach clean or educate.

 

Presenting the rafting project at the annual Porcupine Marine Natural History Society Conference at SAMS (Scottish Association for Marine Science).

In December 2019 I met with a fantastic group of people at PLANED in Narbeth. PLANED have excellent coastal community links and everyone I spoke to was enthusiastic and willing to incorporate the rafting bivalves project into their usual activities of beach cleans, foraging, outdoor activities or education.  They were keen to help record any rafting species that they discover and we talked about how to identify any bivalves found. Since then I have been working on an identification guide that I plan to develop with the help of these community groups.

 

Pembrokeshire National Parks staff and volunteers looking for plastics at Freshwater West beach

In February 2020 I met up with 35 people at the Pembrokeshire Coast National Parks offices in Pembroke Dock. They were eager to learn more about non-native bivalves on plastics. After lunch, those daring enough braved the freezing temperatures and gales to carry out a mini beach clean at Freshwater West beach. We found a lot of large plastic items in less than half an hour which we brought back to the car park for a closer look. Even though there were a lot of pelagic goose barnacles (stalked crustaceans related to crabs and lobsters that attach to flotsam) on some items, proving that the items had been floating in the ocean for a long time, no non-native bivalves were found.

Plastics found at Freshwater West beach - no bivalves attached, though!

In early March two colleagues and I attended the annual Porcupine Marine Natural History Society’s

Presenting the rafting project at the annual Porcupine Marine Natural History Society Conference at SAMS (Scottish Association for Marine Science).

conference where I presented the project and had several more offers of eyes on the ground to record and test the identification guide, which is great news.  I’ve also set up a Facebook page where volunteers can post images of any suspected non-native bivalves for me to identify. I’m hoping to meet up with several more groups later in the year to ask them to look for these pesky hitchikers so we can find out if and where they are attempting a Welsh invasion!

If you would like to help record non-native bivalves on plastics on Welsh beaches then do contact me at Anna.Holmes@museumwales.ac.uk

 

For our avid blog readers, you might recall previous articles about a group of worms which certainly dig! They are the shovel head worms, or to give them their scientific name, magelonids. Shovel head worms are a small group of marine bristle worms (polychaetes), which are sea worms related to earthworms and leeches, with bristles along their bodies. Shovel head worms get their name from their spade-shaped heads, which they use to dig in soft sediments such as sands as muds. They are pretty small and delicate, so although we have them around our coasts, they are often tricky to find. Therefore, they are not as well-known as other marine bristleworms such as lugworms and ragworms, often used by fisherman as bait! Their size also means that they can be pretty difficult to collect, ever tried looking for a worm less than 1 mm wide on a beach? We have! Despite their size they are quite beautiful worms (although, I may be slightly biased!) and like other marine bristleworms they are an important food source for many other sea creatures, and also are the gardeners of the ocean, re-working the sediments like earthworms do on land.

Shovel head worm, Magelona filiformis, first described off Plymouth in 1959

Although, I wear many different hats in the museum, one of my principle jobs is being a taxonomist. Taxonomy is the science of naming, describing and classifying life on earth. That may be finding new species, or re-describing species which were discovered many moons ago. When we find a new species, we draw it, take photographs of it (sometimes using Scanning Electron Microscopes enabling us to Zoom in really closely!), describe it and then pick a name for it in Latin. To give you an example here is a species that I described with colleagues in China.

Shovel head worm, Magelona equilamellae, first described off Southern France in 1964

So, what have we been up to recently? We have been reviewing the shovel head worms of Europe, of which there are currently nine species known. Four of which were first described from the UK, three off France, one off Portugal and one off Sweden. Although, these are worms we know, back when the species were first described we didn’t know all of the features/characters that we needed to know in order to correctly identify and seperate them. Unfortunately, this means that the worms get mis-identified, causing problems for people who monitor the health of our seabeds! This is where we step in, re-describing the species and producing identification keys and guides to help people in the future. Over the last year we have been busy reviewing the species, a paper on which has just been published. Now scientists all around the world will be able to correctly identify their European shovel head worms.

Eight species of shovel head worm found in Europe

We have been doing this with a Professional Training Year Student from Cardiff University, and colleagues from Spain and Portugal. 

 

Find out more about our work on ‘Worms that Dig!’

West African Worms that Dig 

More on West African shovel head worms

Species new to science, Shovel head Worms from around the world

 

 

Chama sarda from the Caribbean, found in western Ireland

In the previous blog (What are Non-native (or alien) Species?) I talked about non-native species and how they are transported around the planet. In this blog I’ll tell you a bit more more about rafting bivalves that can cross the Atlantic on plastics and about some of the UK hotspots for these non-native (alien) hitchikers.

 

What is rafting?

Rafting has occurred throughout geological time, and it is how many terrestrial (land-dwelling) species colonised islands and other regions across the seas. A good example of this is the lemurs of Madagascar. 60 million years ago there were no lemurs on the island of Madagascar, but their ancestors were on the mainland of the African continent. So how did they actually get to Madagascar? Palaeontologists tell us that rafting is the answer. Back then, Madagascar was closer to the mainland and currents in the Mozambique Channel were much stronger towards the island than they are now. The lemurs’ ancestors must have found their way onto mats of vegetation or branches and by chance rafted to Madagascar. A completely fluke event! 

 

Violent storms assist the dispersal of non-native species on plastics

Today, our litter ends up in the oceans and provides unnatural vehicles for marine non-native species. Over the last decade more than 20 species of Caribbean bivalve shells have ended up on British and Irish beaches attached to plastic buoys, bait buckets, ropes and others items – even a piece of a car running board! The latter had three different types of Caribbean bivalves attached, one of which, the Bicolor Purse Purse Oyster, is an invasive species in Brazil. Violent storms help to throw the plastic objects high onto our shores and they are then found by beach cleaners, beachcombers and others on the strandline at the top of the beach. Many of the shells or photographs are sent to Amgueddfa Genedlaethol Caerdydd - National Museum Cardiff to be identified and hence to work out where they came from.

 

Conveyor belts and hotspots

General locations of rafting bivalve records in the southwest of Britain and Ireland

The rafting species that we are studying start off attaching to plastics in the Caribbean. These plastics eventually float into the warm ocean currents of the Gulf Stream, which originates in the Gulf of Mexico, and provides a conveyor belt to transport non-native species across the Atlantic Ocean to the British Isles. Once here, violent storms then deposit the plastics, with their hitchhikers still attached, onto our shores. 

The hotspots for non-native species records are in the southwest of England and western Ireland, but there are also records for western Scotland. Strangely enough there are no records for Wales, even though some of the beaches are prime, exposed shores similar to those in Ireland and England. 

I want to discover if there are any welsh hotspots for rafting bivalves, find out which beaches to search and to encourage people to go out to those locations to try and get some records for Wales. 

 

Why should we monitor these species?

It is important to establish points of entry for any non-native species, which is why we need to map where the rafting species are arriving so that we can monitor numbers of any species arriving alive that could possibly pose a threat. When a species moves to a new location, the species that already live there have to adapt to cope with the newcomer. This can put a strain on populations that use the same food source or habitat as the invading species, which is why we want to know where these rafting species are washing ashore. All the rafting species that we’ve encountered so far cannot reproduce in our waters as they need warmer sea temperatures of 20°C or more to breed. However, if sea temperatures continue to rise, climate change could aid more rafting species to create self-sustaining populations here which could become a real problem

 

The Bicolor Purse Oyster – an invasive species in Brazil

Byssus threads of Bicolor Purse Oyster from the Caribbean

Of the non-native rafting species found so far in the UK, the Bicolor Purse Oyster (Isognomon bicolor) is the one that has shown up in the greatest numbers. It was first described as a species in 1846 by C.B. Adams who collected it in Jamaica. It has been spotted around the coasts of Florida, Texas and Bermuda and several of the Caribbean islands all of which are considered its natural range. However, in 1970 it was recorded outside its natural range in the eastern state of Rio Grande do Norte in Brazil. It has since moved further southwards and is considered an invasive species in Brazil as it is competing with native oysters and mussels for space and is spreading quickly. 

The Bicolor Purse Oyster in Britain and Ireland

The Bicolor Purse Oyster has been found in Cornwall, Dorset and western Ireland by eagle-eyed beachcombers. They noted locations, objects that the oysters were attached to, and they collected the shells. The beachcombers are great photographers so we have a record of the variety of sizes, shapes and colours of the shells found here. The Bicolor Purse Oyster is small (up to 28mm), flattened and elongated. The outside is beige and white, sometimes with purple blotches and is smooth apart from being a bit flaky-looking. The front of the shell has byssus threads of pale to dark brown that protrude ready to attach to hard surfaces. In its natural range this species attaches to rocks and is commonly found in the Florida Keys. 

 

What next?

Although there are lots of records of rafting species in Ireland and England, there are none for Wales. Does that mean that they do not wash ashore in Wales? Doubtful! This is why I’ve set up a project to get people out onto beaches looking for any plastics that could be likely rafts. The project involves citizen scientists – volunteers from the general public – who can help to spot these rafting species in Wales.

To find out more about this part of the project see next week's blog entitled Rafting Bivalves - the Citizen Science project.

As humans transport goods all over the planet we also unintentionally transport animals and plants to places that they do not belong. We call these animals and plants non-native or alien species. If conditions are right for the non-native species they can become established and outcompete our own native species for food and habitat. This is when they are called invasive species and could have a negative impact on our native species sharing the same habitat. This is bad news considering all the other pressures on our wildlife.

 

How do they travel such great distances?

Mytilopsis leucophaeta, native to Gulf of Mexico, found in Roath Docks, Cardiff in 1997

One of the major transporters of marine non-native species are the large goods ships that travel from one side of the planet to the other, taking on ballast water in various ports and ejecting the water at their destination. Ballast water aids the huge ships to balance. At ports, as containers are removed from the ship, ballast water is taken on to keep the whole vessel evenly balanced. The problem is that the water in ports often contains tiny floating animals that are the offspring (or larvae) of mussels, crabs, clams and other invertebrates. These larvae get sucked into the ballast tanks and survive onboard until ejected at the destination port, which is sometimes on the other side of the planet. These animals would not normally have reached these far off destinations naturally. 

 

The Manila Clam originally from the western Pacific Ocean  

Aquariums and aquaculture, or the farming of aquatic plants and animals, are another two major contributors towards the invasive non-native species spread. Shellfish farms import juveniles to grow and breed from but these can often escape captivity or have other species attached to them. The Manila clam (Tapes philippinarum) from the Indo-Pacific region was introduced for farming in the south of England in 1989, but has since escaped! Of all mollusc farming in the world, the Manila clam makes up an astounding 25% and this is because the species can grow quickly and reproduce in great numbers. It is also very hardy and has started to spread in the south of England and is breeding with one of our own native species. To learn more about Invasive Non-Native Species (INNS) in Wales check out the Wales Biodiversity Partnership INNS pages.

Caribbean Chama sarda - the Cherry Jewelbox - attached to ropes washed ashore in Ireland

A third, less well-known method of transportation of non-native species is by rafting – or attaching to floating items. Numerous bivalves (eg. mussels, cockles, oysters) have crossed the Atlantic Ocean attached to bait buckets, buoys, crates and other sturdy plastic items. They wash ashore usually after particularly violent storms and are then stranded with the rest of the marine litter.  We call these bivalves ‘rafting bivalves’. They attach to their ‘raft’ using byssus threads or cement, depending on the kind of bivalve. Byssus threads are produced by a special gland in the foot of the animal to allow the shell to anchor onto hard surfaces such as rocks. You may have seen this with mussels on our rocky shores. Oysters and other similar bivalves use a special cement to glue themselves onto hard surfaces and so they are also able to attach to the plastic rafts. I am especially interested in learning more about marine bivalve shells that attach to ocean plastics and then wash ashore on our beaches and have started to add them to our Marine Bivalve Shells of the British Isles website.

To find out more about Rafting Bivalves check out next week's blog.

What is Ming?

Ocean Quahog shells - scientific name Arctica islandica

Ming is an Ocean Quahog clam with the scientific name of Arctica islandica. It was nicknamed Ming when scientists discovered that it would have been born in 1499 during the Ming Dynasty of China. Ocean Quahogs grow up to 13 cm long and the oldest one fished off the coast of Iceland was 507 years old, making it the oldest non-colonial animal known to science.

Where do Ocean Quahogs live?

These are the siphons of the Ocean Quahog - the shell is buried in the sand. It uses the siphons to suck in water and feed off tiny particles in the water

Ocean Quahogs belong to a big group of shells called ‘bivalves’. Most bivalves are filter feeders and suck in water through their tube-like siphons (you can see in the photo, the two holes surrounded by darker pink). While lying on the seabed or buried in the sand or mud bivalves can safely take food particles and oxygen from the water.

Ming was collected from the deep waters around Iceland but we get this species in British and Irish waters too, although it does not live to such a great age here. The waters surrounding our islands are warmer than those surrounding Iceland, which is just south of the Arctic Circle. Warm waters hold less dissolved oxygen than cold water and so around the UK the Ocean Quahog needs to work harder to get oxygen and so has a faster metabolism. A faster metabolism means that it grows quicker but when animals have a fast metabolism they do not live as long. In the colder waters surrounding Iceland the Ocean Quahog has a slower metabolism and so grows slowly and may even live for longer than 507 – scientists just haven’t found an older one yet!

 

How long do animals live?

Geoduck lives in the coastal waters of western Canada and USA and can live to 168 years

Some other bivalve molluscs can live for a long time as well. Giant clams can grow to 4 feet long (1.2 m) and live for around 100 years. They have tiny plant cells in their tissue that photosynthesize producing energy from the sun to give to the clam. This is why they reach such a large size – talk about plant power!

The Geoduck, which lives in the coastal waters of western Canada and USA, can live for 164 years. It is known as Gooey duck and has large meaty siphons that are a popular food for humans!

Come to our Insight gallery at Amgueddfa Genedlaethol Caerdydd - National Museum Cardiff to to find out more about how long animals can live for and much more...

Giant clams live in the tropics and can reach over 4 feet long (1.2 m) and live for 100 years

 

An introduction to Ming the clam can be found here:

https://museum.wales/blog/2020-02-11/Meet-Ming-the-clam---the-oldest-animal-in-the-world/