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Isle of Man Marine Monitoring

Sunrise Buoy


The Isle of Man’s territorial waters make up 87% of Manx territory and the Manx population are reliant on the sea for transport of food and other goods, fishing, tourism revenue, transportation and recreation, as well as marine ecosystem services. For our seas to continue to play this important role in our lives and livelihoods, a healthy marine environment is vital. In 2016 the Isle of Man was designated as a UNESCO Biosphere and is currently the only entire-nation Biosphere; thus monitoring and protecting its waters is of great importance and environmental interest.

Marine monitoring in Manx waters, dates back to 1904 and is one of the longest and most respected time-series of various marine parameters in Europe. Isle of Man marine monitoring data has been used in numerous research studies on the Irish and Celtic Seas, including studies assessing eutrophication, salinity, and ocean surface warming. Marine monitoring not only provides crucial information about Manx waters and its status within the wider Irish Sea, but also provides global insights on the impacts of climate change due to the long-term datasets.

Marine monitoring was conducted by the Port Erin Marine Laboratory (Liverpool Marine Biology Committee and University of Liverpool) from 1904 to 2006. Following the closure of the Marine Laboratory, the Government Laboratory took responsibility for the routine collection and analysis of marine data from 2006 to 2017. As of 2021, the responsibility for marine monitoring moved to the Environmental Protection Unit, with the aim of continuing and expanding upon the historic monitoring of Manx waters to provide crucial data to support the protection, productivity and resilience of the Isle of Man’s territorial sea.

Marine monitoring timeline

  1904: Temperature monitoring began in Port Erin Bay

 1954: Cypris monitoring site was established. Monitoring for: temperature, salinity, DO and phosphate levels

1958: Monitoring for silicates began at Cypris

1960: Monitoring for nitrates/nitrites began at Cypris

1992: Monitoring for chlorophyll and ammonia began at Cypris

1995: Phytoplankton monitoring began at Cypris

2022: Monitoring began for OSPAR CEMP hazardous substances

2023: Monitoring buoy at Cypris deployed

2023: Physical water sampling at Cypris for phytoplankton, zooplankton and nutrients

2023: Monitoring device fitted in Port Erin Bay

Port Erin Bay Marine Monitoring Time Series

Port Erin sonde in the seaMarine monitoring in Port Erin bay dates back to 1904 and the Environmental Protection Unit are continuing this time series. Stainless steel tubing has been fitted at then end of the jetty in Port Erin to house our monitoring device.

The monitoring device measures for:

  • Temperature
  • Salinity
  • Conductivity
  • Turbidity
  • pH
  • Total Algae
  • Dissolved Oxygen

Cypris Marine Monitoring Station

Cypris buoy in the seaThe Cypris Monitoring Station dates back to 1954 and is located at 54°05’ 50” and 004°50’ 00”, roughly two nautical miles off the coast of Bradda Head. A 1.9 m marine monitoring fulmar buoy has been deployed at this location. For safety measures, the buoy has been equipped with Type 1 AIS, a radar reflector, GSM antenna, a St. Andrews cross and a light. Real time data from the buoy is automatically uploaded to a server that is publicly available online.

The parameters the buoy monitors are:

  • Temperature
  • Conductivity
  • Salinity
  • Turbidity
  • Dissolved Oxygen
  • pH
  • Partial pressure of Carbon Dioxide (pCO2)
  • Chlorophyll
  • Wave height and direction

The Cypris site is accessed bi-weekly (weather permitting) to collect water samples and ensure the sensors on the monitoring buoy are accurate and in calibration. Water samples are collected for nutrient, phytoplankton, and zooplankton analysis. Phytoplankton data can be downloaded from the excel spreadshseet within the 'data' dropdown on this page.

OSPAR CEMP Monitoring

The Isle of Man is a signatory, via the UK, to the Oslo-Paris Convention for the Protection of the Marine Environment for the North East Atlantic (OSPAR) and has recently begun participating in the Coordinated Environmental Monitoring Programme (CEMP), which aims to deliver comparable data across the OSPAR maritime area. The monitoring data and information generated by OSPAR CEMP will assess and address global changes in the marine environment. The co-ordinated data collected and analysis can be used to inform and guide efforts to protect and preserve the North East Atlantic marine environment.

OSPAR CEMP is divided into six themes reflecting different issues that OSPAR is aiming to address. The Isle of Man has started monitoring for Theme H, Hazardous Substances, which monitors and assesses contaminants and their biological effects.

The OSPAR Commission’s strategic objective with regard to hazardous substances is to prevent pollution in the North East Atlantic maritime area by continuously reducing discharges, emissions and losses of hazardous substances. The ultimate aim is to achieve close to zero concentrations of man-made synthetic substances and to maintain safe levels of naturally occurring substances.

In accordance with OSPAR CEMP guidelines, the Environmental Protection Unit collects sediment and biota samples yearly for analysis. These samples are sent to Cefas for the analysis of heavy metals, polychlorinated biphenyls (PCB's), poly-aromatic hydrocarbons (PAH's), and polybrominated diphenyl ethers (PBDE's). Cefas uploads the data to the International Council of Exploration of the Sea (ICES) database in accordance with OSPAR CEMP Theme H. Annual reports on the results will be uploaded to this webpage.

Monitoring of Ocean Processes


Temperature controls the rate of fundamental biochemical processes in organisms, and consequently changes in temperature can influence population, species, and community level processes. In the marine environment, temperature can alter the number and diversity of adult species in a region by changing larval development time. Fluctuations in sea temperature are critically important in governing the species ranges of organisms in the marine environment.

There is evidence to suggest that increasing ocean temperatures are resulting in pole-ward migration of warmer water species of plankton, fish, benthic and intertidal organisms. This shift will likely have wide scale impacts upon commercially sensitive fish stocks such molluscs, crustaceans, and finfish, whose distributions have shifted northwards to cooler waters over recent decades.

Additionally, increasing sea surface temperatures have been linked with the increased occurrence of harmful algal blooms. When examining long term data sets, there is a correlation between rising sea temperatures and increased frequency and timing of harmful algal bloom outbreaks. Monitoring sea surface temperatures and their correlation to algal blooms could provide important information on ocean dynamics and shifting phytoplankton assemblages.

Sea surface temperature has been recorded in Port Erin Bay from 1904 to 2017 and has been gradually increasing with the highest rate of increase in the last 30 years. This data is consistent with global trends of rising sea temperatures. Sea temperature is a major driver of marine ecosystems and one of the key factors affecting the distribution, physiology and ecology of marine species and habitats. Knowledge of how sea surface temperatures are changing is important for how the marine environment is managed and protected. Temperature measurements also benefit a wide spectrum of operational applications, including climate and seasonal monitoring and forecasting.


Salinity is a key factor determining the density of sea water. Determining how salinity is changing is essential for understanding its impact on ocean circulation, the Earth's water cycle, marine ecosystems, and climate change. Long-term alterations affecting the balance of high salinity water (e.g. the Atlantic Ocean) and low salinity water (e.g. river discharges) are likely to have implications for variables such as nutrient concentrations, and thus exert a potentially substantial impact in the Irish Sea. Some marine species are sensitive to salinity and their survival and long-term distributions may be affected by change.

The Atlantic Ocean has a salinity of approximately 35 on the Practical Salinity Scale (PSS) and when it enters the Irish Sea the salinity is altered by freshwater inputs from the land (MCCIP Report Card, 2020). The Irish Sea experiences a strong salinity gradient due to the variations in the quantity of freshwater entering the sea from riverine discharge, and is typically lower in the eastern Irish Sea (closer to river inputs from NW England) compared to off the island’s west coast. Climate change is leading to changes in the strength and frequency of storms, which can lead to increased riverine discharge. In addition, the melting of the polar ice caps can decrease salinity and impact ocean currents (MCCIP Report Card, 2020). By the close of the 21 century the coastal waters around the British Isles have been predicted to be around 0.2 fresher, depending on location (MCCIP Report Card, 2020). This predicted change in salinity is particularly dependent on the projected changes in storm tracks and effects on precipitation and river flows.

Ocean acidification

Ocean acidification has many severe consequences, especially for marine organisms that build shells from calcium carbonate, such as shellfish, corals, and planktonic organisms (MMEA, 2018). Anthropogenic carbon dioxide (CO2) is an important greenhouse gas that is linked with increasing global atmospheric and oceanic temperatures. The world’s oceans are believed to remove approximately a quarter of atmospheric CO2 emissions derived from human activity.

Increased levels of CO2 dissolved in seawater leads to the increased acidification of marine waters. As CO2 production increases as it is anticipated to, the overall amount of CO2 absorbed in the ocean will continue to increase until it reaches levels close to saturation, this will decrease the oceans pH, causing it to become more acidic. The North Atlantic Ocean contains more CO2 than any other ocean basin and from 1995 to 2013 has demonstrated a pH decline of 0.0013 units per year (MCCIP Report Card, 2020). High emission scenario models are predicting that by 2100 ocean pH could drop by 0.366 units and the rate of ocean acidification will be highest in coastal areas (MCCIP Report Card, 2020).

Monitoring partial pressure of carbon dioxide (pCO2), pH, dissolved inorganic carbon (DIC) and total alkalinity (TA), provides long-term ocean acidification (OA) data which is essential to assess variability and trends in the ocean’s carbon system. By monitoring these variables it allows for an assessment of ocean acidification and the risk this possess on marine ecosystem and services so that appropriate measures can be taken and early warning signs highlighted.


Turbidity is a measure of relative water clarity due to the presence of suspended material, and therefore has both physical effects, such as smothering or clogging, and also influences photosynthesis and visual activities, affected by the amount of light that is able be transmitted through the water column. Increased particles and molecules within the water column lead to light being scattered and absorbed and thus less light reaches deeper layers of the water column. Waters that have high-turbidity are less transparent. An increase in ocean turbidity can be the result of increased total suspended matter, increased phytoplankton biomass, and an increase in dissolved organic matter.

The amount of suspended particulate matter, and therefore light, in the marine environment can influence the following marine functions:

  • primary production (the amount of carbon fixed via photosynthesis)
  • air-sea heat transfer
  • sedimentation rates
  • biogeochemical transfers (including pollutants) through the water column and to the seabed
  • productivity of the benthos
  • dissolved oxygen levels (via increased biological oxygen demand) 

It is therefore important for the Isle of Man to monitor the turbidity of our waters to collect information on potential terrestrial sources (such a building developments and catchment management) and the impact that is having on marine ecosystems.

Wave height and direction

Knowledge of the wave regime and how it is changing is important in developing shoreline defence schemes, large infrastructure projects, transportation and for flood and coastal management.

Sea level

Operational monitoring of sea level and tides helps underpin coastal flood forecasting and risk modelling. Changing mean sea levels have implications for coastal erosion and coastal regions.

Monitoring of Eutrophication

Eutrophication is one of the major threats to the health of marine ecosystems around the world. It occurs when waters are enriched by nutrients, especially compounds of nitrogen and/or phosphorus, causing an accelerated growth of algae and higher forms of plant life to produce an undesirable disturbance to the balance of organisms present in the water and to the quality of the water concerned. Anthropogenic eutrophication can occur in certain conditions when inputs of nitrogen and phosphorus (nutrients) from point sources (e.g. sewage effluents and industrial processes) and diffuse sources (e.g. agricultural run-off and transport emissions) enter the coastal and marine environment. A nutrient-induced increase in phytoplankton productivity can result in undesirable and harmful effects on the marine ecosystem and significantly impact water quality. Severe cases of eutrophication and the conclusion of the bloom, can lead to the death of many marine organisms. Indicators for eutrophication in Manx waters can be to examine nutrient concentrations, dissolved oxygen levels, chlorophyll concentrations and phytoplankton assemblages.

Monitoring of Biodiversity - Pelagic Habitats

Plankton within the marine water column (pelagic habitat) are the fundamental building block on which all life in our seas and oceans depend. Phytoplankton comprise the basis of the marine food web and produce approximately 50% of the world's oxygen. These microbes are key drivers of marine carbon and nutrient cycles and represent an important carbon sink.

In 2019, the Marine Strategy Part One assessment concluded that plankton communities are changing and that human activities could not be ruled out as a cause of that negative change. The assessment outcomes also concluded that some fish communities are not recovering, breeding seabirds are in decline and trends in cetaceans are unclear. All the aforementioned ecosystem components are wholly dependent upon a healthy planktonic ecosystem.

Marine Scotland has noted significant changes in plankton community structures over the last three decades. This is of significant concern as phytoplankton and zooplankton make up the basis of the marine food web and produce fifty percent of the oxygen we breathe. Changes in phytoplankton and zooplankton distribution and abundance act as 'a canary in the coal mine', giving an early indication of potential impacts to higher trophic levels, such as declines or distributional changes in fish, crustaceans, molluscs and marine mammal populations. Impacts to phytoplankton and zooplankton species as a result of climate change, have been noted across the UK and linked, for example, to decreasing seabird populations with notable decreases in puffin colonies due to the consequent effects on their primary food sources. In addition, changes in plankton community structure has been associated with shifts in the geographical distribution of marine mammals and has been linked to the crash of right whale populations in the North Atlantic.

The Isle of Man began monitoring phytoplankton community assemblages in 1995. As of May 2023, the Isle of Man has begun marine monitoring again, with a marine monitoring buoy being deployed 2nm off the coast of Port Erin bay, at the Cypris monitoring station. Monitoring at this site has been conducted since 1954. Physical water samples are collected every two weeks for the analysis of phytoplankton, zooplankton, and nutrients. Phytoplankton data and real time data from the buoy can be accessed and downloaded from the 'data' dropdown on this page.

Monitoring of Contaminants

It is important to monitor and detect human-induced changes in marine ecosystems to be able to identify the reasons for these changes. Marine organisms are exposed to a range of anthropogenic hazardous substances from riverine discharges and direct inputs. These substances can result in metabolic disorders, an increase in disease prevalence and can potentially affect entire marine populations through changes in growth, reproduction, or survival. It is only through monitoring and understanding these changes that measures can be put in place to improve the management of the marine environment.

The OSPAR Commission’s strategic objective with regard to hazardous substances is to prevent pollution in the Northeast Atlantic maritime area by continuously reducing discharges, emissions and losses of hazardous substances (CEMP, 2016). The ultimate aim is to achieve close to zero concentrations of man-made synthetic substances and to maintain safe levels of naturally occurring substances.

OSPAR Theme H, Hazardous Substances, are focused on monitoring the concentrations and effects of selected contaminants in the marine environment as follows:

  • Heavy metals (cadmium, mercury and lead etc.) in sediment and biota
  • Poly-aromatic hydrocarbons (PAH) in biota and sediment
  • Poly-chlorinated biphenyls (PCB) in biota and sediment
  • Poly-brominated diphenyl ethers (PBDEs) in biota and sediment

To protect the marine environment, monitoring must be conducted to limit and assure chemicals derived from land based sources are not causing harm to the marine environment, based on accepted low-risk concentrations. Heavy metals and toxic chemicals related to industrial, anthropogenic, and natural sources are monitored to ensure the safety of the environment.

Heavy metals

Heavy metals can be deposited in the marine environment from both natural and anthropogenic sources. The principle man-made sources of heavy metals into the marine environment come from industrial point sources, such as mines, smelters and other manufacturing industries, as well as from diffuse sources, such as traffic and combustion by-products. The Isle of Man has a history of mining, with the last mines on the island closing during the 1920s. Ore-bearing strata in specific river catchments across the island will naturally contribute heavy metals and mining activities would have enhanced this effect. Even after mining activities have ceased run off from spoil heaps and mine workings can flow via freshwater systems to the marine environment, and these are the primary sources of such metals today in Laxey, Neb/Foxdale and Glen Maye catchments. Previous Isle of Man marine monitoring reports have identified that heavy metal concentrations in King and Queen Scallops were generally highest in waters to the west of the island (Bradda & Targets), although also off Laxey, and are thought to reflect contamination through natural run-off,  harbour dredging disposal,  and via run-off from catchments with historic mine sites.

Once in the marine environment, heavy metals can accumulate in sediment and biota through a process called bioaccumulation. Heavy metals can bind to particles in marine sediment, where they are either buried and remain for long periods of time or are suspended and redistributed through disturbance to the sea bed. Heavy metals can be redistributed through both natural and anthropogenic practices, such as ocean currents or dredging activities. In biota, heavy metals can accumulate in the tissues of organisms over time, which has the potential to be a human health risk if seafood with high levels of contamination are consumed. Heavy metals can have numerous impact on marine organisms, potentially affecting growth, metabolism, reproductive success and overall changes of survival.


Polycyclic aromatic hydrocarbon (PAHs) are natural components of coal and oil, and are also formed through the incomplete combustion of fossil fuels, wood, and other organic materials. PAHs enter the marine environment through atmospheric deposition, urban run-off, industrial discharges and as a result of oil spills. PAHs can be found in marine sediment and biota due to their high persistence, low solubility and their tendency to bind to particles in the water column.

PAHs accumulate in sediment where they remain trapped unless the sediment is disturbed. PAHs can also accumulate in fish and shellfish as they are poorly metabolised, which can result in increasing PAH concentrations accumulating in the fatty tissues of marine organism as they pass through the food web to higher trophic levels. This process is known as biomagnification.

The impacts resulting from PAH contamination in the marine environment vary considerably, from tainting the taste of fish and shellfish to being potentially carcinogenic to humans and animals. PAHs in marine biota may also result in developmental abnormalities, reduced growth rates, and decreased reproductive success in marine organisms.  Monitoring and reducing the release of PAHs into the marine environment is important both for the protection of marine ecosystems but also humans who consume seafood. 


Polychlorinated biphenyl concentrations (PCBs) are a group of man-made synthetic organic chemicals that were largely used in industrial applications such as electrical equipment, coolants, and lubricants. The production of PCBs was widely banned in many countries in the 1980s, however, despite this ban, PCBs are still present in marine biota and sediment due to their persistence and ability to accumulate in the fatty tissue of marine organisms. PCBs can still enter the marine environment through the destruction and disposal of industrial plants and equipment or from emissions from construction materials and old electrical equipment (for example from landfill sites). 

PCBs are hydrophobic and insoluble in water, which makes them prone to absorb onto suspended particles and settle in sediment. They often accumulate in sediment where they are trapped until they are disturbed either through natural processes, such as storm events or through dredging activities. PCBs also enter the food chain when marine organisms ingest contaminated particles or consume contaminated organisms. As with PAHs, PCBs can bioaccumulate and biomagnify, as marine mammals occupying the upper trophic levels with larger lipid reserves can accumulate high concentrations of PCBs. PCBs are extremely toxic to animals and humans, causing reproductive and developmental problems, damage to the immune system, interference with hormone function, and can also cause cancer.


Polybrominated diphenyl ethers (PBDEs) are a class of synthetic chemicals that have been manufactured as flame retardants. These chemicals can be found in furniture, rugs, draperies, clothing, upholstery, electronics and appliances. PBDEs are persistent, bioaccumulative and toxic pollutants that can be found in marine sediment and biota due to the high stability and tendency to accumulate in fatty tissues. PBDEs were banned in Europe in 2004 and since their ban the main sources are from the disposal of PBDE products.

PBDEs are not easily dissolved in water and tend to settle in sediment and can also bioaccumulate in aquatic species. PBDEs are often found in lower layers of marine sediment where they remain unless the sediment is disturbed. PBDEs can also accumulate in shellfish and fish, where they are taken in either directly from the marine environment or indirectly through food consumption.

The presence of PBDEs in the marine sediment and biota is of concern as these chemicals can have harmful effects on marine organisms, such as developmental abnormalities, reproductive problems, and endocrine disruption. PBDEs have also been found to be toxic to humans and have been linked to thyroid problems, developmental and cognitive problems in children, and other health effects.


Environmental concentrations of monitored hazardous substances in the sea have generally fallen, but are still above levels where there is a risk of pollution effects in many coastal areas, especially where there have been historical discharges, emissions and losses from high population densities or industry. Levels of persistent organic pollutants found in marine species have declined following the regulation of the substances concerned, but additional manmade chemicals are still being found in marine samples and there is a need to keep gathering data to assess their potential impacts and the need for further controls.

Phytoplankton Monitoring & Marine Biotixins

Plankton within the marine water column (pelagic habitat) are the fundamental building block on which all life in our seas and oceans depend. Phytoplankton comprise the basis of the marine food web and produce approximately 50% of the world’s oxygen. These microbes are key drivers of marine carbon and nutrient cycles and represent an important carbon sink.

Marine biotoxins are poisons that are produced by certain kinds of phytoplankton, which are naturally present in marine waters, often in quantities that are too small to be harmful. However, a combination of warm temperatures, sunlight, and nutrient-rich waters can cause plankton to rapidly reproduce causing 'blooms'. These blooms are commonly referred to as harmful algal blooms or 'HABs' because of their potential to cause illness.

Bivalve shellfish (scallops, mussels, oysters, clams etc) are filter feeders and ingest particles in the surrounding water column. Phytoplankton are a food source for bivalves and when toxin-producing species are ingested in high quantities they can bioaccumulate, becoming concentrated within the organism. These toxins can lead to illness if contaminated shellfish is then eaten by humans. The more toxin producing phytoplankton species the shellfish eat, the more biotoxins they accumulate. Biotoxins are not harmful to shellfish, so they will continue to eat toxin producing species until the bloom subsides. When the levels of phytoplankton return to normal, the shellfish will eventually flush the toxins from their bodies. The time it takes for shellfish to flush these toxins can vary and depends on how dense the phytoplankton bloom was.

Shellfish biotoxins are broken down into three categories based on the toxin producing phytoplankton that have the potential to bioaccumulate in shellfish,Amnesic Shellfish Poison (ASP), Diarrhetic Shellfish Poison (DSP), and Paralytic Shellfish Poison (PSP).

Amnesic Shellfish Poison (ASP)

Domoic acid is a marine biotoxin and the causative agent for Amnesic Shellfish Poison (ASP). Domoic acid is produced by the diatom Pseudo-nitzschia species, which is a naturally occurring phytoplankton species. When shellfish ingest this algae they can retain the toxin, which in high quantities can become harmful to humans. People can become ill from eating shellfish contaminated with ASP and in very severe cases can result in permanent short-term memory loss.

Diarrhetic Shellfish Poison (DSP)

Diarrhetic Shellfish Poison (DSP) is produced by the dinoflagellate Dinophysis species and Procentrum lima, which are both naturally occurring phytoplankton species. People can become ill from eating shellfish contaminated with DSP.

Paralytic Shellfish Poison (PSP)

Paralytic Shellfish Poison (PSP) can be produced by Alexandrium species, which is a naturally occurring species of phytoplankton that produces saxitoxins, the causative agent for PSP. This biotoxin affects the nervous system and paralyzes muscles, which in severe cases has resulted in respiratory paralysis and death.

EPU Phytoplankton Data

The Environmental Protection Unit (EPU) collect physical water samples every two weeks (weather dependent) for phytoplankton, zooplankton, and nutrients. Samples are collected from the historic Cypris marine monitoring station, located at 54°05’50” and 04°50’00”, roughly two nautical miles off the coast of Bradda Head.

The phytoplankton data can be downloaded from the data drop down menu on our website.

The data is primarily being collected to monitor for climate change, as monitoring nutrients, phytoplankton, and zooplankton trends are extremely important to assess the cascading impacts that changes in pelagic habitats can have on the marine food web. 

Identifying marine biotoxins is a secondary driver for our phytoplankton monitoring, as our data can be useful in identifying potentially toxic strains that can cause ASP, DSP and PSP. In addition to having a full community analysis, we highlight these potentially toxic species in our data, as they can act as an early indicator for the potential bioaccumulation of toxins in shellfish on the west coast of the Island.

According to Food Standards Scotland – Managing Shellfish Toxin Risks, there are cell count trigger levels for wild shellfisheries where it is suggested that processors increase end of product testing due to the risk these potentially harmful species have on the bioaccumulation of toxins in shellfish. These levels are as follows: 

Shellfish Poisoning

Phytoplankton species

Consider increased end of product testing if levels are equal to or greater than the following:

Amnesic Shellfish Poisoning (ASP)

Pseudo-nitzschia species

50,000 cells/litre

Diarrhetic Shellfish Poisoning (DSP)

 Dinophysis species and Prorocentrum lima

100 cells/litre

Paralytic Shellfish Poisoning (PSP)

Alexandrium species


Our most up to date data can be downloaded as an excel document located in the 'Data' dropdown tab on our website. For any inquires on the data please email the Environmental Protection Unit at

For guidance documents on shellfish biotoxins, as well as historic data on ASP, DSP and PSP levels in shellfish, please visit Environmental Health’s website.

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