Life in Liverpool docks

April 7th, 2018

Review of ‘What’s up Dock?’, a talk presented by Wendy Northway (MCS North West England Seasearch Coordinator) on 14th March 2018.

While Liverpool’s pre-eminence as a maritime centre in the North West is undisputed today, it was only in 1751, with the construction of the world’s first commercial wet dock that she cemented her call to that title. Previously the most important port in the area was Chester, a position the city had held since Roman times.

The first wet docks allowed ships to be unloaded in a day and a half, significantly undercutting the older practice of unloading cargo to smaller boats at sea for transfer to shore – a process that could take two weeks on good weather. This gave the port a massive commercial advantage, and soon the docks were over-subscribed, leading to the rapid construction of new, larger facilities, which were also required as the expansion of trade with the industrial revolution lead to ever larger vessels…

Liverpool's Albert Dock with the Liver Building in the background. Photo B Kaye
Above: Liverpool’s Albert Dock (with the Liver Building in the background) has been cleaned up and is now a major tourist destination, housing Tate Liverpool and a number of museums. Diving in the docks is now strictly controlled. Photo B. Kaye

As each new dock was built, unseen and rather unheralded, we also built a new marine habitat, and it is these that were the subject of the talk What’s up Dock? by Wendy Northway (MCS North West England Seasearch Coordinator) to the group on 14th March 2018. The docks are no longer used commercially (having closed in 1972), but are actively managed leisure spaces. Water from the river Mersey is not used, as it is too polluted, instead the docks are topped up from the Irish sea on high water springs, giving a salinity in the range 24‰ to 28‰. The exchange of water with the Irish Sea allows for migration of marine wildlife between the Irish Sea and the docks, which have as a consequence become colonised by a fairly select group of organisms.

Mussels and algae colonising a discarded bicycle. Photo (c) BrokenDiver
Above: An old bicycle thrown into the dock has been colonised by mussels and algae. Photo © BrokenDiver.

In 1988 the docks were colonised by up to 1000 mussel spat per square meter. The absence of common starfish in the docks have allowed very large population densities of mussels to be established, and larger individuals have grown too big to have any natural predators. The mussels have been calculated to filter the entire of the docks water every four days, and are probably vital to maintaining water quality. Other filter feeders include bryozoans, sponges and tunicates, while cockles have colonised the soft, muddy bottom of the docks.

Black goby amidst mussels, bryozoans and sea squirts in Liverpool docks. Photo (c) Catherine Gras
Black goby amidst mussels, colonial hydroids and sea squirts (Ciona and Ascidiella) in Liverpool docks. © Catherine Gras

The modern docks are home to a thriving marine community, including a number of fish and crustaceans. I was, however, particularly interested to hear that the seasearch divers had confirmed the presence of an introduction from the southern hemisphere, the worm Ficopomatus enigmaticus in the Collingwood Dock. This species may have been introduced on the bottoms of ships or as larvae in bilge water. Unfortunately we do not know if this is a relatively modern introduction on pleasure craft, or a relict from the Liverpool port’s trading days.

Ficopomatus enigmaticus, an Austrolian introduction. Photo Wendy Northway (c) PhoebeSparke
Above: The characteristic pagoda shape of the tubes created by the worm Ficopomatus enigmaticus, an Australian introduction. Photo Wendy Northway © PhoebeSparke

NOTES: Ficopomatus has become a nuicance in many areas it has colonised, producing dense aggregations that can interfere with dock gates and other marine/estuarine structures, though at high densities in docks may help clear the water of particulates, and improve bottom biodiversity (JNCC report linked below). In some places it forms large reef structures in shallow brackish water. Needing a temperature above 18°C to breed, it may not be as invasive in our local open waters, but has been recorded in the docks at Barrow, so we should be looking out for it in the Bay! More information on Ficopomatus enigmaticus at ‘The Exotics Guide‘ and JNCC.

Posted in Marine science update, MCS talks

World Ocean Day at Freeport Fleetwood

June 24th, 2016

Thanks to everybody who made the recent World Oceans day at Freeport Fleetwood such a success. Trawls in Fleetwood harbour resulted in us finding and identifying nearly 50 species, many of which were available for visitors to Freeport to see, and touch – before being returned safe and unharmed on the Saturday evening! Stars of the event included a European eel, a lobster, a greater pipefish and several species of flatfish.

More from this event on That’s Lancashire TV (via YouTube):

Posted in Conservation, Events, Marine science update, Shore walks

Wanderers of the sand

December 12th, 2015

Bernard the hermit crab

At our December meeting we looked at some of the birds and fish that use the Bay – waders feeding on the rich pickings in the mud while the tide is out, replaced by flatfish swimming in with the tide to feed while the mud banks are immersed. The Bay is ranked second most important area for migratory birds in the UK, offering a vital stop-over point on the East Atlantic Flyway, connecting wintering grounds in South Africa with feeding and breeding grounds in Norther Canada, USA and Russia. Rather less is known about the fish population, but both birds and fish are free to move in three dimensions, and have the freedom to exploit the Bay. Our next talk looks at groups of animals that have more limited movement, and must stick to channels, or suffer being flooded and dried out twice a day…

Hunters and hunted – those that crawl the sands of the Bay are an alien band of creatures, armoured, multi-armed, poisonous; whatever it takes to survive… Bernard the hermit crab (above) has sharp eyes, but he is too slow to escape the fish that might snack on him, so he retreats into an old whelk shell, guarding the entrance with his impressive claws.

On Wednesday the 13th January we will have three short talks on starfish, crustaceans, slugs and snails:

‘Wanderers of the Sand’ 19:30hrs Wednesday 13th January at the Gregson Community Centre, Moore Lane, Lancaster LA1 3PY
All welcome – admission £2, proceeds to Lancashire Marine Conservation Society.

Posted in Marine science update, MCS talks

MCS Marine Life ID course at Leighton Moss Nature Reserve

May 28th, 2015

Saturday 18th July 10:00-17:00: Members of the Lancashire MCS will be presenting an introduction to marine life, with a particular focus on life in the Bay area and the North West Coast of the UK. This course is suitable for beginners, and introduces many of the important groups of marine life, from shore plants to fish. Price £10 per person.

Booking is essential for this event, please contact us to confirm your place.

Download our poster for more details (PDF 446kB).

Posted in Marine science update, MCS talks

Algae spring surprises

January 6th, 2014

Any of you who have attended one of our marine plants ID courses will recall that we are a bit hazy about identifying the coralline, pink encrusting species. It looks as though our reticence (or ineptitude!) on this topic is more than justified, with recent genetic studies from Mexico indicating that their most common coralline alga is actually a community of five species.

Science Daily – coralline algae species

(New ID courses are planned for 2014 – see our diary for more information)

Posted in Marine science update

Estimating diving conditions in Morecambe Bay

October 14th, 2013

By Barry Kaye, Local MCS, 9th October 2013

The talk reviewed a web project that brings together physical information about the Bay from a range of sources, including weather, sea state and river inputs. This data informs our current understanding of physical processes in the Bay. Data are interpreted in a map that shows sea states, wind directions and the levels of principle rivers over the last five days. In addition, graphical displays review sea-sate (wave height and period) and river levels over the last fifteen days.

Graph showing river levels into Morecambe Bay
Graph showing river levels into Morecambe Bay over the last fifteen days (archival data)

The talk went on to look at how physical conditions might interact with the geography of the Bay to influence diving conditions. There is no formal model of the Bay’s ‘underwater weather’, but a number of approaches to developing such a model were proposed.

A link to the observatory is given below, users are advised, however, that this is a ‘work in progress’, there are a few rough edges, and information is provided without warranty of any kind:

Diving Roa Island: Estimating diving conditions in Morecambe Bay

Posted in dive trips, Marine science update, MCS talks

Images from the Roa Island shore walk (August 14th 2013)

August 15th, 2013

Presented by Lewis Bambury at Capernwray Dive Centre, this talk reviewed some of the photographs taken on the shore walk at Roa Island in July, and put this into the broader context of our previous surveys of this area.

Parasite Lernaeenicus sprattae shown on a juvenile spratt, and after removal
The parasite Lernaeenicus sprattae shown on a juvenile spratt, and after removal

One of our mystery organisms (pictured) was a parasite on one of the juvenile spratts caught in the rock pools. Lewis had narrowed it down to probably being a copepod, and this was confirmed by David Fenwick and Mike Moon, who identified the species as Lernaeenicus sprattae. Commonly seen on Spratts in UK waters, it gets its name from its preferred feeding mode, attached to the eye of the unfortunate fish. Extensive parasitism is possible, and this can result in considerable deterioration in the health of individual fish. The two green appendages are egg sacks.

Some of the other organisms featured in the talk are shown int he gallery below, alongside some photos taken underwater on the same site:

Posted in Marine science update, MCS talks, Shore walks

The Piel Channel Recording & Survey Project

March 19th, 2012

Work by the Lancashire MCS group recording the Piel Channel is now available online. The work dates from the late 1980’s to the present day.

Thanks to Ron for bringing the data together for this; the full report is available through the link below:

Piel Channel survey

Posted in dive trips, Marine science update

Marine science update 12th September 2011

September 12th, 2011

A couple of articles over the last few weeks do make interesting and/or disturbing reading: I think it is pretty much a given that for wild fisheries to have much chance of survival they must be managed. In this light recent gene marker studies on fish sales raise both hopes that we can now clearly identify the provenance of a fish on the fishmonger’s counter, and a warning that some existing certification schemes are not working as well as they need to. Farmed fish may be managed, but that also makes them subject to pretty unpleasant management practices, such as the practice of eye-stalk ablation, which apparently speeds maturity of black tiger shrimp…

We start, however, with one of the big stories in the popular press over the last few weeks, the latest estimate of the total number of species on the planet. To be pedantic we should perhaps say eukaryotic species, though the term ‘species’ is not very easy to apply to prokaryotes…
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Posted in Conservation, Marine science update, Science

Marine science update 21st August 2011

August 21st, 2011

The hardest coral on the reef may well be a softie, as much of the rocky structure of these reefs is found to derive from the sclerites from soft corals! This debate over how much support environmental agencies will grow as our economic worries deepen, how high up the scale do you put the environment? Essential for our continued existence on the planet, or jobs/hospitals now (environment later – maybe)? This week DSN reports on the debate in the US in our conservation leader. Our pollution section, however, points out that one of the most damaging aquatic pollutants – nitrogen from fertilisers – can be reduced while saving money and increasing yields…
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Posted in Conservation, Marine science update, Science