Sea Balls, an unwise choice for egg laying

Among the various odd things found on beaches recently have been numbers of balls of compressed plant fragments. The typical size of the near spherical things is about 8 – 12 cm across. They appear to be composed of interwoven bits of marram grass or fragments of rushes. During the storm surges of last winter the fronts of sand dunes were washed away along with the roots of the grasses and much debris was also mobilised from inundated salt marshes. A likely explanation is that some of this debris became waterlogged and was washed out onto the sea floor. Over time, some was rolled into dense balls by the oscillation of swell waves. 

Yesterday we came across at least a dozen such balls on a stretch of the west coast of Anglesey. Another surprise was that a few of the balls were so dense and waterlogged that they must have stayed put on the seabed long enough for Nursehounds (Scyliorhinus stellaris), otherwise known as Bull Huss, to attach their egg cases to them. A rather unwise choice for a dogfish whose eggs are said to take about 9 months to develop before hatching. 

Blogpost by Ivor Rees, a regular contributor to Natur Cymru.

Razorbills in the 2014 Seabird Wreck

In a post here on 19th February attention was drawn to the major Seabird Wreck happening on the Welsh coast due to the persistent series of winter storms. The annual RSPB Beached Bird monitoring survey seemed likely to record numbers of bird bodies in orders of magnitude greater than typically found in recent decades. Also noted were early indications that disproportionate numbers of Razorbills were among the casualties in Wales. This indeed has turned out to be the case in North Wales with many more Razorbills being found than Guillemots, in spite of  having a breeding population only a fifth the size. Just a few Puffins were found here in contrast to the thousands found on the French coast, an event which inevitably attracted most of the news headlines about this seabird wreck.

Razorbill showing bill with white line and two grooves
beyond it of an adult

The enlarged and colourful beak of the Puffin in the breeding season will be familiar to all. Razorbills also have beaks that change to a lesser extent seasonally and grooves develop on the sides of the bill as the birds mature. Much of the work to clarify the sequence of bill development in Razorbills was done in the 1980s by eminent Welsh ornithologist, Peter Hope Jones. Careful examination of ringed birds of known age or breeding status as well as post-mortems on large numbers of birds killed in some major oil pollution incidents, enabled Peter to show that the characteristic vertical white line on the bill did not form until the bird’s second summer. In Britain Razorbills have only one white line, but a very small proportion of mature birds at some Norwegian colonies, as well as a few of those examined from fishery by-catches off Newfoundland had double white lines. Like many long-lived seabirds, Razorbills take several years to reach sexual maturity. Normally this is age 4, by which time most have the obvious white line and two other bill grooves beyond it. For simplicity this is referred to as W + 2, but some birds seen at the breeding colonies are W +1. The change in bill size and ornament occurs in late winter, so some February casualties may be expected with partly formed second grooves (W + 1.5).

During the seabird wreck of February 2014 I looked sufficiently closely at over 50 of the Razorbills washed up in Anglesey to have seen if they had white lines on their bills. As all did, none would have been first or second winter birds. This fits with ringing recovery data from British and Irish colonies, showing the young birds mainly disperse further to the south than the adults. Moreover, on fine winter mornings adult Guillemots and Razorbills sometimes come ashore at the breeding colonies for just a few hours. To do this it must be assumed that they would have been at sea within a few hours flying time of the colonies.

Peter Hope Jones surveying for Razorbills
and Guillemots accompanied by dependant
young in the Irish Sea, August 1981

As information on bill grooves might be of further interest in determining which segments of the Razorbill population succumbed off different parts of NE Atlantic coasts, photos were taken showing the bills of 25 birds on Anglesey beaches. Of these, 14 had the white line plus two grooves (W+2). Five more would be classified as W + 1.5 and five had W + 1. Only one bird was W + 0.5 and was thus probably over age 2 but still immature.

Whether In a few weeks time it may or may not be possible to detect if there are fewer Razorbills ashore in any of the South Irish Sea colonies remains to be seen. Guillemots stand on open ledges where sample sections of whole colonies can be monitored to determine breeding success.  This is somewhat more difficult with Razorbills as most lay in crevices or partly hidden under boulders, so estimates of productivity variability are less reliable in this species. Individual long-lived seabirds are known to sometimes skip a year in attempting to breed. Whether more Razorbills will enter this breeding season in poor condition and skip a year is possible and worth looking out for. The proportion of adult Razorbills accompanied by chicks at sea during the immediate post-breeding period in July-August might be an alternative indicator of productivity. The chicks leave the cliffs when half grown and are looked after at sea for about another 6+ weeks by one parent. At sea each small juvenile stays close to the parent, while making frequent high pitched contact calls. Experience from seabird at sea surveys in the 1980s showed that Ad+juv couples are relatively easy to distinguish. They were not scattered thinly all over the whole Irish Sea, but the young had been shepherded to a few favourable areas. Would this be another way to gather supporting evidence for relative breeding success?

This blogpost was written by Ivor Rees, a regular contributor to the Natur Cymru magazine.

Swept clean?

As well as the coastal erosion and damage to infrastructure caused by the succession of storms and tidal surges this winter, there have been other noteworthy consequences. Anyone who has been to Welsh beaches in the last few weeks will have been struck by the huge amount of litter cast up by the sea. This isn’t just big items like plastic drums and broken fish boxes, but also huge quantities of tiny fragments of expanded polystyrene and other plastics.

In the aftermath of major oil pollution incidents years ago, work was done to model the drift of oil and other things on the sea surface. In general, figures of around 2-3% of the near surface wind speed provided a good approximation for both forecasting drift and hindcasting origins. So, while a waterlogged pallet might drift at about 3% of the wind speed, things with more windage, such as empty drinks bottles with lids, would be expected to travel rather faster. Sometimes, where the origins of objects are known, the speed of travel to reach our shores from distant places can seem quite surprising. An example of this from a few years ago was when identifiable parts of a catamaran, which broke up in a storm off Cape Finisterre in NW Spain, reached an Anglesey beach in 110 days.

Seeing the amounts of debris and particularly the fine fragments of broken up plastic on some Welsh beaches facing the SW wind or where the tidal surges have swept debris up inlets, one is reminded of the poetic musings of the Walrus and the Carpenter, as they walked along a beach before over-exploiting the local stock of oysters. Verses 4 & 5 of the poem as told to Alice in Lewis Carroll’s Through the Looking Glass were as follows:-

The Walrus and the Carpenter

Were walking close at hand

They wept like anything to see

Such quantities of sand:

‘If this were only cleared away,’

They said, ‘it would be grand?

‘If seven maids with seven mops

Swept it for half a year,

Do you suppose’ the Walrus said,

‘That they could get it clear?’

‘I doubt it' said the Carpenter,

And shed a bitter tear.

It only requires a slight substitution of junk for sand in verse 4, to express the nigh on impossibility of removing the smaller fragments of plastic even by armies of volunteers. Seaborne litter should be getting a higher profile and is now included in the EU Marine Strategy Framework Directive. Thought is currently being given to how best to develop monitoring programmes for the various components of marine litter. Actually collecting and disposing of it is quite another matter.

One consequence of the prolonged sequence of depressions swept across the Atlantic by the jet stream may have been a reduction in the “standing stock” of litter actually washing to and fro out at sea with more of it landing up on the shore. Back of envelope calculations would suggest that 40 days or so, with winds as they have been, might have swept ashore most of the litter from about 700 – 1000 nautical miles out in the ocean. Looking at the organisms growing on the litter, it was noticeable that while the lost whelk pots and other items thrown up from the near-shore seabed by the early storms had the usual range of barnacles and saddle oysters on them, the floating litter coming up then had few attached organisms. Debris floating in the open ocean for long enough usually gets colonised by things like stalked or goose barnacles (Lepas spp.). The occurrence of such organisms can give clues as to whether a proportion of the litter has come from out in the open ocean or from more local sources in and around the Irish Sea. It was interesting to see that photographs showed Lepas on the bottom of the boat on which the Mexican fisherman apparently survived, drifting across the Pacific for many months.

Lepas anatifera

Five species of goose barnacle turn up on debris washing up on Welsh shores. Of these the most familiar is Lepas anatifera. Unusually, at least in Llŷn and Anglesey, L. anatifera has been less common this winter than a smaller species, L. pectinata, which can be distinguished by the obvious radial ribbing on the shell plates. Another species, which can be found sometimes is L. hilli. This one has an obvious pale and often bright orange band where the stalk reaches the shelled part. The fourth species, L. anserifera, which seems to be rare, perhaps partly because it is less easy to identify, grows to be similar in size to L. anatifera but has ribbed shell plates. Finally there are a few records of the buoy barnacle Dosima fascicularis which starts off by attaching to small things like feathers but then goes on to secrete a float of its own.

Lepas pectinata, which can be distinguished by
the obvious radial ribbing on the shell plates

The author of this blogpost is Ivor Rees.

Worm Takeover

The long awaited fine warm weather was bound to attract people to bathe or paddle on the north Wales beaches. At the Llanddona end of Red Wharf Bay, walking down to the sea at low tide a couple of evenings ago, we met conditions that caused some to hesitate before proceeding. The topography and texture of this normally flat sandy beach had changed with a series of hummocks and softer muddy black sediment between.

Closer inspection showed that there were astronomical numbers of small sandy tubes so packed together that the sediment was building up into hummocks. The irregular topography had encouraged fine and organic deposits, probably originating from a plankton bloom, to settle. Under a very thin surface the rate of decay was such that the soft sediment was anoxic and black.

Looking a little more closely, the worm so dominating the Llanddona beach now is the Sand Mason Worm – Lanice conchilega. These worms glue sand and shell grains together to create the long tubes in which they live. On top of the tubes they construct a characteristic fringe and feed by grasping particles from the water with tentacles. Normally you see these scattered fringe tops just protruding from the sand, but when there has been a mass recruitment there can be so many that they modify the topography of the beach or nearshore seabed. I did not have time to explore the full extent of the area covered by the unusual density of tubes, but the feature must have spread over 1.5 Km along the shore by 300 to 400 metres wide.

The muddy sand offshore area in Red Wharf Bay has been sampled on an almost annual basis for over 25 years. Experience shows that it is particularly liable to substantial changes in the species that dominate the fauna and are capable of modifying the conditions for others. Having visited Llanddona beach for many years, I do not recall seeing quite such a mass takeover of the lower shore by quite such a hugely successful recruitment of Sand Mason Worms.

Red Wharf Bay with worms - lots!

This post was written by Ivor Rees, a director of Natur Cymru amongst many other things!

Sorry but no, it is not ambergris

Not Ambergris but Palm Oil

Walking an Anglesey beach after recent gales and noticing a few lumps of a waxy substance reminded me of the several occasions in the past when similar lumps were brought in to the Bangor University marine lab in Menai Bridge by people suspecting they had found ambergris. Used as an ingredient for some expensive perfumes, ambergris is highly prized. Sometimes it sells for over £250 a gram. It always seems rather bizarre that a constituent of cosmetics applied to high maintenance human females should originate in the intestines of a sperm whale. It is secreted by the whales as a waxy substance to limit injury to the lining of the gut by the beaks of the squid they eat. When freshly ejected it is said to have a faecal smell but, after months or years of floating on the sea, microbial and photo degradation in the presence of salt-water results in lumps that are usually grey and have a musky aroma. Currents, wind and waves disperse the lumps so they may wash up far from the regions of the ocean where the sperm whales were feeding.

On the west coast of Anglesey this autumn, and quite frequently in the past, lumps of a waxy substance have washed up. A bit like ambergris these lumps are greyish white on the outside, but they are bright yellow inside. Some lumps may be quite large so they would be worth a small fortune if they really had come from a whale. Their origin, though seeming mysterious to beach walkers, has a much more mundane explanation.

As well as ships carrying the crude oil, refined fuels and chemicals passing Welsh coasts, there are others carrying various vegetable oils in bulk. These go into a range of products including processed foods, biofuels and soap. Among the vegetable oils imported to the Mersey ports are derivatives of palm oil. Following initial separation, one fraction of palm oil becomes solid and waxy at the ambient temperatures of our seas. It therefore needs to be warmed before it can be pumped from the stainless steel tanks in the specialised ships. To expedite this, heating starts while the ships are still on passage. With thermal expansion and in rough weather some of the cargo may ooze out of access hatches or vents. This then may get washed overboard becoming the waxy lumps that wash up on beaches. The lumps get pecked by birds and other shoreline scavengers but even so they may take months to disappear.

As with mineral oils, it is probably microbes that are ultimately responsible for breaking down such materials man spills into the marine environment. While not having the charisma of sperm whales and the mystic of ambergris, marine microbes, with their huge biodiversity and capacity for providing ecosystem services, should not be overlooked.   

This post was written by Ivor Rees.

When the tide goes out - zostera!

Zostera marina

An equinoctial spring tide is a great time for exploring Porth Dinllaen and Ivor Rees had agreed to meet me there to explain the zostera beds for Country Focus (broadcast on 25th March). Lying flat on the sands were thin green blades about 30cm long which in summer will be between 100cm and possibly 200cm. This is Zostera marina, a flowering seagrass, the larger of three species. 

It’s neither threatened nor rare but this is the only (unless anyone knows differently?) place in Wales where you can see it without diving. The beds at Porth Dinllaen cover an area of about twelve hectares and it spreads either by rhizome or by seed. If I return in September I will find seeds stuck in the stems of the zostera.

On a nearby outcrop of rock there was a profusion of all sorts of seaweeds and I naïvely asked Ivor how these differed from zostera – they’re algae whilst zostera is a plant with a totally different reproductive system. 

Zostera beds are important fish nurseries for many species and off the south coast of England this is where sea horses will be found; but for the moment our waters are too cool for them.

We were not the only explorers on the beach, Chris Richardson, head of Bangor University’s School of Ocean Sciences, was there with a group of students. As well as looking at the zostera beds, and identifying goodness knows how many species and organisms, they were hunting razorfish. First identify a likely looking entrance to a razorfish burrow then pour on some salt and a few minutes later out pops a razorfish.  

As we walked over the normally sea covered sands other tasty fruits of the sea were wondering where the water had gone. King scallops were perfectly camouflaged, the bright shell buried on the underside and a plantation of seaweeds on top – then they would blow their cover by squirting water if you came too close. A sad looking lobster was trapped in a pot, other lobsters were seen lurking in puddles beneath rocks. Plaice, wrasse and prawns briefly marooned in puddles until the turn of the tide.   

What a beautiful beach. I must return with snorkel.