Cork Harbour Research Articles

New Discoveries of <em>Diplocraterion</em> and Tidal Rhythmites in the Upper Devonian Rocks of Grab-all Bay, Cork Harbour: Palaeoenvironmental Implications

New Discoveries of <em>Diplocraterion</em> and Tidal Rhythmites in the Upper Devonian Rocks of Grab-all Bay, Cork Harbour: Palaeoenvironmental Implications

Thirty-year history of Irish (Rossmore) Ostrea edulis selectively bred for disease resistance to Bonamia ostreae.

The protistan pathogen Bonamia ostreae was first detected in Ostrea edulis at Rossmore, Cork Harbour, on the south coast of Ireland in 1987. A selective breeding programme commenced in 1988 by Atlantic Shellfish Ltd. to produce B. ostreae-resistant oysters using 3 to 4 yr old survivors as broodstock for controlled spawning in land-based spatting ponds. On-growing of oyster spat settled on mussel cultch was carried out on designated beds within Cork Harbour. Oyster production subsequently increased successfully, resulting in 3 yr old Rossmore O. edulis being marketed from 1993 onwards and a record tonnage of 4 yr old oysters being produced in 1995 and 1996. O. edulis production, B. ostreae prevalence and oyster mortalities have been monitored and recorded at Rossmore for over 30 yr. The collation and analysis of this data from 52 samples and 3190 oysters demonstrate the introduction and progression of bonamiosis and subsequent interventions to ameliorate disease effects during this period at Rossmore. Results suggest that O. edulis mortalities are now negligible during the first 4 yr of growth, prevalence of B. ostreae infection is low, and no correlation exists between prevalence of infection and oyster mortalities. This study, when compared to other studies of bonamiosis-infected oyster populations, suggests that an intervention in the form of a selective breeding programme is required to reduce the impact of the disease.

Monitoring a toxic bloom of Alexandrium minutum using novel microarray and multiplex surface plasmon resonance biosensor technology

Blooms of Alexandrium occur annually during the summer months in the North Channel of Cork Harbour on the south coast of Ireland. This study monitored an extensive bloom of the toxin producing Alexandrium minutum during the summer of 2011 with the use of the MIDTAL (Microarrays for the Detection of Toxic Algae) microarray and a prototype multiplex surface plasmon resonance (multi SPR) biosensor. Microarray signal intensities and toxin results from three testing platforms of the prototype multi SPR biosensor, commercial (CER) enzyme-linked immunosorbent assay (ELISA) and high performance liquid chromatography (HPLC) were compared against light microscopy counts. The main aim was to demonstrate the use of these methodologies to support national monitoring agencies by providing a faster and more accurate means of identifying and quantifying the harmful phytoplankton community and their toxins in natural water samples. Both the microarray signals and multi SPR biosensor results followed a significant trend with light microscopy results and both techniques indicated detection limits of <4000 cells of A. minutum in natural seawater samples.

Field Testing of an Optical in Situ Nitrate Sensor in Three Irish Estuaries

In situ measurements of nitrate (NO3) were made using a submersible ultraviolet nitrate sensor (SUNA) in three Irish estuaries (Bandon, Blackwater and Lee) in January and February 2012. Measurements were compared against discrete water samples analysed in the laboratory. There was excellent agreement between the SUNA and laboratory measurements, with the variation in in-situ nitrate measurements explaining nearly 100% of the variation in laboratory measurements (r 2 � 0.99, with a negative bias of � 10%). In each estuary there was a conservative mixing relationship between salinity and nitrate, indicating that the main source of nitrate to these estuaries in winter is from the main inflowing river. The highest nitrate concentration of 235.2mM at salinity 0.7 was found in the Lee Estuary and the lowest concentration of 7.5mM at salinity 34.6 was found in Cork Harbour. The successful demonstration of this technology in Irish estuaries provides a powerful example of how future developments in this field will allow the real-time assessment of environmental conditions in these environments.

Field Testing of an Optical in Situ Nitrate Sensor in Three Irish Estuaries

In situ measurements of nitrate (NO3) were made using a submersible ultraviolet nitrate sensor (SUNA) in three Irish estuaries (Bandon, Blackwater and Lee) in January and February 2012. Measurements were compared against discrete water samples analysed in the laboratory. There was excellent agreement between the SUNA and laboratory measurements, with the variation in in-situ nitrate measurements explaining nearly 100% of the variation in laboratory measurements (r2 = 0.99, with a negative bias of ∼10%). In each estuary there was a conservative mixing relationship between salinity and nitrate, indicating that the main source of nitrate to these estuaries in winter is from the main inflowing river. The highest nitrate concentration of 235.2µM at salinity 0.7 was found in the Lee Estuary and the lowest concentration of 7.5µM at salinity 34.6 was found in Cork Harbour. The successful demonstration of this technology in Irish estuaries provides a powerful example of how future developments in this field will allow the real-time assessment of environmental conditions in these environments.

Protein thiols as novel biomarkers in ecotoxicology: A case study of oxidative stress in Mytilus edulis sampled near a former industrial site in Cork Harbour, Ireland

Oxidative stress produces reactive oxygen species which can modify proteins and thiols of cysteines are especially susceptible. Mytilus edulis was sampled from three stations in Cork Harbour, Ireland and from an out-harbour control site in Bantry Bay, Ireland. A variety of traditional biomarkers were benchmarked against thiol oxidation. Lysosomal membrane stability diminished in haemocytes from the three Cork harbour sites, although a stronger effect was observed in two in-harbour stations of environmental concern (Douglas and Haulbowline Island). Catalase and glutathione transferase (GST) activities were decreased in digestive gland extracts of animals from in-harbour sites especially the in-harbour control (Ringaskiddy) showed lower GST than Bantry. Mussels collected at Haulbowline Island showed elevated lipid peroxidation (p

Low Cost Navigation for Unmanned Underwater Vehicles Using Line of Soundings

This paper focuses on localization and navigation as a critical skill for mobile robotics in general and underwater vehicles in particular. The main objective is to explore the possibility of the incorporation of historical navigation techniques into Autonomous Underwater Vehicle (AUV) localization and navigation algorithms, using low cost sensors and good quality bathymetry. The Line of Soundings (LOS) localization approach, used extensively by mariners in the past, includes several sources of errors. This paper explores these errors and their effects on localization precision in specific application areas. Selected preliminary results from field trials with ROV LATIS in Cork Harbour and Bantry Bay are presented in this paper.

An integrated approach to trophic assessment of coastal waters incorporating measurement, modelling and water quality classification

Various protocols have been developed for trophic assessment of coastal waters but most incorporate single value compliance criteria for water quality parameters which, in reality, exhibit significant spatial variation. Application of these protocols generally requires the averaging of data recorded at discrete locations to obtain single values for comparison with compliance criteria; however, there is no guarantee that the averaged values are truly representative of overall water quality. The present approach to trophic assessment integrates measurement, remote sensing, flushing analysis and water quality modelling with the aim of identifying sub-regions in coastal waterbodies that demonstrate homogeneity. Averaged water quality data for these homogenous sub-regions should be more representative of the water quality in the sub-region as a whole making the assessment process more accurate. The integrated approach incorporates water quality classification criteria developed by the Irish Environmental Protection Agency but it can incorporate any suitable classification criteria. The approach was validated for a sub-region of Cork Harbour, Ireland and the trophic assessments agreed with previous assessments by the Irish Environmental Protection Agency (EPA). The approach has significant applications in the implementation of the EU Water Framework Directive and was adopted by the Irish EPA in convincing the EU to provide the Irish government with structural funds for water quality management within Cork Harbour.

Seasonality in the excystment of Alexandrium minutum and Alexandrium tamarense in Irish coastal waters

Excystment experiments were carried out on cysts of Alexandrium minutum and A. tamarense (Group III) taken from Cork Harbour, Ireland. Freshly sampled cysts were isolated into well plates and their excystment was monitored over a 30 day period. A pronounced seasonality was observed in the excystment behaviour in both species when measurements were carried out seasonally. Between 80 and 100% of the isolated cysts excysted within 30 days when samples were taken between March and June. However, between only 0 and 15% excysted in samples taken between August and early February. This seasonal characteristic was observed repeatedly over a 3 year period (2004–2007). The effect was observed in cysts which had been sampled from both inter-tidal and sub-tidal locations. No endogenous clock was evident in the germination of A. tamarense and A. minutum cysts taken from Cork Harbour which had been stored cool and in the dark under anoxic conditions for up to 18 months. The seasonal effect observed was independent of water temperature, although temperature did affect the rate of excystment. Temperature also affected the maturation of cysts which had been freshly formed in the laboratory. The significance of incorporating seasonality in excystment of Alexandrium into models describing its growth is also discussed.

The use of polar organic compounds to estimate the contribution of domestic solid fuel combustion and biogenic sources to ambient levels of organic carbon and PM 2.5 in Cork Harbour, Ireland

PM 2.5 samples collected at Cork Harbour, Ireland during summer, autumn, late autumn and winter, 2008–2009 were analyzed for polar organic compounds that are useful markers for aerosol source characterization. The determined compounds include tracers for biomass burning primary particles, fungal spores, markers for secondary organic aerosol (SOA) from isoprene, α-/ β-pinene, and d-limonene. Seasonal and temporal variations and other characteristic features of the detected tracers are discussed in terms of aerosol sources and processes. The biogenic species were detected only during the summer period where the contributions of isoprene SOA and fungal spores to the PM 2.5 organic carbon (OC) were estimated to be 1.6% and 1% respectively. The biomass burning markers, and in particular levoglucosan, were present in all samples and attributed to the combustion of cellulose-containing fuels including wood, peat, bituminous and smokeless coal. The contribution of domestic solid fuel (DSF) burning to the measured OC mass concentration was estimated at 10.8, 50, 66.4 and 74.9% for summer, autumn, late autumn and winter periods, respectively, based on factors derived from a series of burning experiments on locally available fuels. Application of an alternative approach, namely principal component analysis–multiple linear regression (PCA–MLR), to the measured concentrations of the polar organic marker compounds used in conjunction with real-time air quality data provided similar trends and estimates for DSF combustion during all seasons except summer. This study clearly demonstrates that, despite the ban on the sale of bituminous coal in Cork and other large urban areas in Ireland, DSF combustion is still the major source of OC during autumn and winter periods and also makes a significant contribution to PM 2.5 levels. The developed marker approach for estimating the contribution of DSF combustion to ambient OC concentrations can, in principle, also be applied to other locations.

Summer dynamics of Alexandrium ostenfeldii (Dinophyceae) and spirolide toxins in Cork Harbour, Ireland

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 425:21-33 (2011) - DOI: https://doi.org/10.3354/meps08983 Summer dynamics of Alexandrium ostenfeldii (Dinophyceae) and spirolide toxins in Cork Harbour, Ireland N. Touzet1,*, J. P. Lacaze2, M. Maher3, E. Turrell2, R. Raine1 1The Martin Ryan Institute, School of Natural Sciences, National University of Ireland, Galway, Ireland 2Marine Scotland, Marine Laboratory, 375 Victoria Road, Aberdeen AB11 9DB, UK 3Molecular Diagnostics Research Group, National Centre for Biomedical Engineering Science, National University of Ireland, Galway, Ireland *Email: nicolas.touzet@nuigalway.ie ABSTRACT: Proliferations of toxic Alexandrium spp. have adversely affected the shellfish aquaculture industry worldwide. A. ostenfeldii can produce several biotoxins, including the recently characterised fast-acting toxins spirolides (SPX). A dual labelling fluorescent in situ hybridisation (FISH) assay was developed for discriminating simultaneously between the closely related taxa A. ostenfeldii and A. peruvianum. Surveys were undertaken throughout the summers of 2006, 2007 and 2008 in Cork Harbour, Ireland, where a mixed community of Alexandrium spp. develops annually. A. peruvianum was not detected but the presence of A. ostenfeldii was confirmed by FISH and morphological analysis. The species never reached high concentrations (max. ~200 cells l–1) and contributed on average to only 0.4% of the Alexandrium community, usually dominated by A. minutum and A. tamarense (Group III). Although cell concentrations were several orders of magnitude lower, the dynamics of A. ostenfeldii were similar to those of other Alexandrium spp. during the 3 consecutive summers, suggesting a common response to environmental forcing. Analytical chemistry performed on extracts from passive solid-phase adsorption samplers identified lipophilic toxins dominated by okadaic acid, but also 13-desmethyl SPX C and 20-methyl SPX G, with dynamics generally congruent with those of A. ostenfeldii. The passive samplers enabled the quantification of background toxin levels at very low A. ostenfeldii concentrations, showing potential for forecasting of toxic events. The ability to quantify toxic A. ostenfeldii cells within high density microalgal populations of morphologically similar species makes the dual FISH assay valuable for phytoplankton monitoring programs and future biogeographical and population dynamics studies. KEY WORDS: Harmful algal bloom · HAB · Alexandrium · Solid-phase adsorption toxin tracking · SPATT · Spirolides · Fluorescent in situ hybridisation · FISH · Cork Harbour Full text in pdf format PreviousNextCite this article as: Touzet N, Lacaze JP, Maher M, Turrell E, Raine R (2011) Summer dynamics of Alexandrium ostenfeldii (Dinophyceae) and spirolide toxins in Cork Harbour, Ireland. Mar Ecol Prog Ser 425:21-33. https://doi.org/10.3354/meps08983 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 425. Online publication date: March 14, 2011 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2011 Inter-Research.

Fine‐scale population genetic structuring of bottlenose dolphins in Irish coastal waters

AbstractThe identification of localized discrete populations is particularly important to the management and conservation of animal species, especially in the marine environment, where potential for dispersal is high but barriers to gene flow are often not clear. We investigated population genetic structuring of bottlenose dolphinsTursiops truncatusfound along the west coast of Ireland, with particular attention to the Shannon Estuary, which is the only candidate Special Area of Conservation designated for this species in Irish waters. A genetic structure analysis using 62 biopsy samples from free ranging dolphins and 23 necropsies from stranded dolphins revealed fine‐scale population structure among three distinct populations. The Shannon Estuary population appears to be genetically isolated from adjacent coastal areas, with the exception of four animals sampled from a small group of six dolphins that are now resident in Cork Harbour (south coast) indicating ongoing gene flow or recent dispersal between these two areas. A second genetically distinct aggregation was identified in the Connemara–Mayo region, where recent photo‐identification studies have suggested that dolphins found in this area show a degree of site fidelity. We found moderate nuclear (15 microsatellites) and low mitochondrial (544 bp of the control region) gene diversity in dolphins using the Shannon Estuary and the Connemara–Mayo region, while dolphins that stranded along the coast showed markedly higher levels of gene diversity at both classes of markers. Specifically, these stranded dolphins formed a third genetically distinct cluster, which may be part of a larger pelagic population, as also suggested by the high levels of gene diversity. These results provide new insights into population structure of bottlenose dolphins in Irish waters and will aid future management and conservation of the species in the eastern North Atlantic.

Modelling phytoplankton dynamics in a complex estuarine system

The primary objective of this research was to develop a generic methodology for numerical modelling of the water quality within estuarine systems; in particular, this research focused on modelling nutrient dynamics and phytoplankton growth. This paper presents details of the developed modelling methodology and its application to Cork Harbour, an Irish waterbody that regularly experiences algal blooms. Input data requirements and, in particular, an innovative method for the determination of spatially varying initial conditions are presented. Phytoplankton dynamics are highly dependent on light intensity; a novel formulation for the light intensity component of the phytoplankton growth module was therefore developed and implemented in the model. The formula, which relates light intensity to turbidity and chlorophyll-a concentrations based on field data, is shown to achieve good results. Phytoplankton predictions were validated in an unusual but very effective manner using remote sensing techniques. A flushing module was included in the model to provide insights into transport processes. The paper demonstrates how simple flushing models may be used as a more cost-effective alternative to full water quality models for identification of potential eutrophic waters. Results from the Cork Harbour model are used throughout to demonstrate the effectiveness of the modelling methodology.

Source apportionment of PM&amp;lt;sub&amp;gt;2.5&amp;lt;/sub&amp;gt; in Cork Harbour, Ireland using a combination of single particle mass spectrometry and quantitative semi-continuous measurements

Abstract. An aerosol time-of-flight mass spectrometer (ATOFMS) was deployed for the measurement of the size resolved chemical composition of single particles at a site in Cork Harbour, Ireland for three weeks in August 2008. The ATOFMS was co-located with a suite of semi-continuous instrumentation for the measurement of particle number, elemental carbon (EC), organic carbon (OC), sulfate and particulate matter smaller than 2.5 μm in diameter (PM2.5). The temporality of the ambient ATOFMS particle classes was subsequently used in conjunction with the semi-continuous measurements to apportion PM2.5 mass using positive matrix factorisation. The synergy of the single particle classification procedure and positive matrix factorisation allowed for the identification of six factors, corresponding to vehicular traffic, marine, long-range transport, various combustion, domestic solid fuel combustion and shipping traffic with estimated contributions to the measured PM2.5 mass of 23%, 14%, 13%, 11%, 5% and 1.5% respectively. Shipping traffic was found to contribute 18% of the measured particle number (20–600 nm mobility diameter), and thus may have important implications for human health considering the size and composition of ship exhaust particles. The positive matrix factorisation procedure enabled a more refined interpretation of the single particle results by providing source contributions to PM2.5 mass, while the single particle data enabled the identification of additional factors not possible with typical semi-continuous measurements, including local shipping traffic.

Nested circulation modelling of inter-tidal zones: details of a nesting approach incorporating moving boundaries

Nested circulation models developed to date either exclude the flooding and drying process or prohibit flooding and drying of nested boundaries; they are therefore ill-suited to the accurate modelling of inter-tidal areas. The authors have developed a nested model with moving boundaries which permits flooding and drying of both the interior domain and the nested boundaries. The model uses a novel approach to boundary formulation; ghost cells are incorporated adjacent to the nested boundary cells so that the nested boundaries operate as internal boundaries. When combined with a tailored adaptive interpolation technique, the approach facilitates a dynamic internal boundary. Details of model development are presented with particular emphasis on the treatment of the nested boundary. Results are presented for Cork Harbour, a natural coastal system with an extensive inter-tidal zone and a complex flow regime which provided a rigorous test of model performance. The nested model was found to achieve the accuracy of a high resolution single grid model for a much lower computational cost.

Sources of ambient concentrations and chemical composition of PM 2.5–0.1 in Cork Harbour, Ireland

Particulate matter (PM 10–2.5 and PM 2.5–0.1) has been collected over a period of one year in Cork Harbour, Ireland, using a high-volume cascade impactor and polyurethane foam collection substrate. Collected PM 2.5–0.1 was analysed for water-soluble inorganic ions and metal content using ion chromatography and inductively coupled plasma-optical emission spectroscopy. On average approximately 50% by mass of the chemical content of PM was identified. The motivation for the study was to assess the potential impact of shipping emissions on air quality in Cork Harbour and City, with a view to informing public health impacts. The average ambient concentration of PM 10 between May 2007 and April 2008 was 4.6 µgm − 3 and the maximum concentration measured in one sample, representing a 4 day collection period, was 16 µgm − 3 . The major inorganic constituents identified in PM collected in Haulbowline Island in Cork Harbour were sulfate, ammonium, nitrate, chloride and sodium ions, which were mainly attributable to sea salt and secondary inorganic aerosols from regional sources. The results were analysed by principal component analysis for the purpose of source apportionment. Four factors were identified explaining over 80% of the data set variance. The factors were: shipping, sea salt, crustal material and secondary inorganic aerosols (SIA). The smaller size fraction was frequently observed to dominate, as the average concentration was 2.77 µgm − 3 for PM 2.5–0.1 compared to 1.9 µgm − 3 for PM 10–2.5. Fresh ship plumes were not found to make a significant contribution to primary PM 2.5–0.1 concentrations adjacent to the shipping channel. However, this was partially attributed to the ultrafine nature of ship emissions and the majority of the toxic metal content was attributed to emissions associated with heavy oil combustion sources, which include ship engines.

Dynamics of co-occurring Alexandrium minutum (Global Clade) and A. tamarense (West European) (Dinophyceae) during a summer bloom in Cork Harbour, Ireland (2006)

The dinoflagellate genus Alexandrium contains neurotoxin-producing species, which have adversely affected the aquaculture industry and fisheries worldwide. Seasonal toxic blooms of Alexandrium spp. occur on an annual basis in the North Channel area of Cork Harbour, Ireland, where resident populations of non-toxic A. tamarense (West European ribotype) and PSP toxin-producing A. minutum (Global Clade) co-occur. Field surveys were carried out throughout a bloom of Alexandrium spp. in the summer of 2006. Taxa-specific fluorescently labelled probes were used in a dual whole-cell fluorescent in situ hybridization (WC-FISH) assay for the simultaneous discrimination and quantification of A. minutum and A. tamarense in the water column. The bloom occurred following a weak spring tide in early June and Alexandrium cell concentrations exceeded 3×104 cells L−1. A. minutum dominated numerically over A. tamarense throughout the sampling period (74% on average). The maximum cell concentration was ∼3.3×105 cells L−1 at the peak of the bloom and was localized at the eastern end of the North Channel. The bloom collapse coincided with increasing tidal flushing and significantly changing meteorological conditions (wind speed increase, lesser irradiance), which led to a water temperature drop of ∼3 °C within a period of 7 days. GTX3 was the dominant PSP toxin variant and C-toxins were at times observed in samples. Assuming that A. minutum was the only microorganism synthesising PSP toxins, the internal toxin quota was on average 13.4 fmol cell−1, a value similar to that observed in laboratory experiments. Monitoring of toxic Alexandrium species in Ireland will require the use of molecular methods for reliable discrimination and quantification.

Assessment of recreation activity and its application to integrated management and spatial planning for Cork Harbour, Ireland

Abstract The coastal environment is commonly the location for multiple human activities, of which recreation is just one. The coastal and marine sector has experienced nascent growth and this trend is likely to continue into the foreseeable future; the projected growth of the sector will impact coastal and marine resources, whilst also placing demands on those tasked with planning and managing the coastal environment. In Ireland, this presents particular challenges for coastal local authorities, as the principal planning consent body. In order to address these emerging challenges an innovative working partnership was developed between the research community and local authority to examine marine recreation in Cork Harbour, situated on the southern coast of Ireland. A programme of work was devised to identify data gaps in terms of: baseline information; user attitudes and perceptions towards existing management framework and facilities for recreation; interactions between different user groups; and, spatial distribution of recreational activities. The results of the assessment provided an improved understanding of the current coastal recreational situation, have value as input to spatial planning and contribute to the development of an integrated management plan for Cork Harbour.

Evaluation of taxa-specific real-time PCR, whole-cell FISH and morphotaxonomy analyses for the detection and quantification of the toxic microalgae Alexandrium minutum (Dinophyceae), Global Clade ribotype

The dinoflagellate genus Alexandrium contains neurotoxin-producing species that have adversely affected the aquaculture industry in many countries. The morphological similarity between Alexandrium species has led to the development of molecular methods for the discrimination, enumeration and monitoring of toxic and nontoxic species. A quantitative real-time PCR assay (qRT-PCR) targeting the internal transcribed spacer 1-5.8S rRNA gene using hybridization probe technology was developed for the potentially toxic species Alexandrium minutum (Global Clade) (GC). The assay was specific with a detection limit of less than one cell equivalent. The assay was used to detect and quantify A. minutum (GC) in seawater samples collected during summer 2007 in Cork Harbour, Ireland. The results were compared with those obtained using whole-cell FISH (WC-FISH) and morphotaxonomy analyses. Alexandrium minutum did not reach high bloom concentrations over the sampling period (maximum of c. 6 x 10(4) cells L(-1)), and the average concentrations determined using qRT-PCR, WC-FISH and morphotaxonomy did not significantly differ in eight of nine comparisons. Regression curves showed positive relationships between the methods; WC-FISH and qRT-PCR slightly under- and overestimated, respectively, the A. minutum concentrations compared with the morphotaxonomy method. The qRT-PCR assay for A. minutum (GC) offers high-throughput sample analysis and may prove suitable for implementation in microalgae monitoring programmes and assist in population dynamics studies of the species.

Effects of contaminated sediment from Cork Harbour, Ireland on the cytochrome P450 system of turbot

Hatchery-reared juvenile turbot ( Scophthalmus maximus L.) were exposed for 3 weeks, under laboratory conditions, to inter-tidal sediments collected from polluted sites in Cork Harbour (Whitegate and Agahda) and a reference site at Ballymacoda Co., Cork, Ireland. The potential of the sediment exposure to induce cytochrome P450 activities and CYP1A1 in the fish was assessed. Chemical analysis revealed that the sediments originating from the reference and harbour sites were contaminated principally with PAHs—the harbour sites having double the levels of those at the reference site. Following 3 weeks exposure to the sediments western blotting demonstrated a strong immunogenic response for CYP1A1 in the liver, but not for gill or intestine. P450 activities were generally significantly higher than those exposed to reference site sediment. Liver was the most responsive tissue with significantly greater P450 activities compared with gill and intestinal tissues.