Ian O'Connor

Atlantic Technological University · Marine and Freshwater Research Centre

The environmental fate of microplastics (MPs) added to agricultural soils remains poorly understood, particularly regarding their mobility in soils. Here we investigate the potential for MP export from soil to surface waters and groundwater in two agricultural settings with a 20-year history of biosolid treatment. A third site where biosolids had n...

As plastic production continues to increase, we are seeing significant quantities of microplastics (MPs), a contaminant of emerging concern, being recorded worldwide. This research project has identified key challenges and recommendations that target MP pollution, highlighting immediate measures that could manage MP debris at known sources. This wi...

The increase in the use of unmanned aerial vehicles (UAVs) in marine mammal research has raised concerns, as its potential impacts remain largely unknown. To assess the effects of disturbances on harbor seals by a DJI Phantom 4 Pro, behavioral responses were recorded before, during, and after UAV approaches at two colonies. GLMMs were applied to as...

Fin and humpback whales are the largest baleen whale species most commonly occurring in the Irish Exclusive Economic Zone (EEZ), although the drivers of their known distribution in these waters are not clear. Using presence-only data (1999-2021) from multiple sources, including citizen science, we constructed predictive Species Distribution Models...

European North Atlantic ranavirus (ENARV, Iridoviridae), is a ranavirus species recently isolated from lumpfish (Cyclopterus lumpus, L.), which are used as cleaner fish in Atlantic salmon (Salmo salar) farming in Northern Europe. This study aimed to investigate (1) the virulence of ENARV isolates from Ireland, Iceland and the Faroe Islands to lumpf...

The ubiquitous nature of microplastics in aquatic ecosystems may have serious implications for aquatic biota. While microplastic research in freshwater ecosystems is increasing, very few studies have assessed the physical presence of microplastics among top predators. The Eurasian otter (Lutra lutra), a top predator of aquatic ecosystems, is one of...

Through a long-term citizen science project, the IWDG have built an extensive humpback whale photo-identification catalogue since 1999, confirming the identification of 116 individual humpback whales to date. This unique catalogue in Ireland provides the chance to derive the first robust abundance estimates for humpback whales in Irish waters using...

Microplastics are a pervasive pollutant of aquatic ecosystems and are reported to interact with a wide range of aquatic biota. The complexities of natural food webs means that the transfer and accumulation of microplastics is difficult to assess, and only a handful of studies have attempted to quantify trophic transfer in freshwater biota. Bioaccum...

The rapid development and application of drone technology has included water sampling and collection of physiochemical data from lakes. Previous research has demonstrated the significant potential of drones to play a future pivotal role in the collection of such data from lakes that fulfil requirements of large-scale monitoring programmes. However,...

Amoebic Gill Disease (AGD) is a disease affecting cultured Atlantic salmon (Salmo salar) which is caused by Paramoeba perurans. The immunomodulatory impact of functional foods has previously been demonstrated in salmon. The aim of this study was to investigate the role of a novel fish feed in mitigating the severity and progression of AGD in Atlant...

Terns are a highly migratory group of seabirds that are found worldwide. In Ireland, there are five species of commonly breeding tern: Little Tern Sternula albifrons, Roseate Tern Sterna dougallii, Arctic Tern S. paradisaea, Common Tern S. hirundo and Sandwich Tern S. sandvicensis. Prior work has demonstrated that whilst many Irish tern species, in...

White-clawed Crayfish Austropotamobius pallipes surveys were carried out between June and September 2017 in all 15 Special Areas of Conservation (SAC)for which the species is listed as a qualifying interest. Crayfish were detected in 13 SACs; they were not detected in the two (Lough Bane and Lough Glass SAC and Lough Lene SAC) from which crayfish...

Amoebic Gill Disease (AGD), caused by the protozoan extracellular parasite Paramoeba perurans ( P. perurans ) is a disease affecting Atlantic salmon ( Salmo salar ). This study investigated the gill transcriptomic profile of pre-clinical AGD using RNA-sequencing (RNA-seq) technology. RNA-seq libraries generated at 0, 4, 7, 14 and 16 days post infec...

Seabird eggs are considered a favourable matrix for monitoring marine pollutants and are widely used as higher trophic level indicators. Concentrations of Polycyclic aromatic hydrocarbons (Σ15PAH) were determined in the eggs of four piscivorous seabirds in Ireland from multiple colonies for the first time, Common Guillemot Uria aalge, Northern Gann...

Higher levels of persistent pollutants (Σ16PCB, Σ6PBDE, ΣHCH, ΣDDT, ΣCHL) were detected in fresh eggs of Common Terns Sterna hirundo from Rockabill Island near Dublin (Ireland's industrialised capital city) compared to Common and Arctic Terns S. paradisaea from Ireland's west coast. Intra-clutch variation of pollutant levels in Common Terns was sho...

Infection with the protozoan ectoparasite Neoparamoeba perurans, the causative agent of AGD, remains a global threat to salmonid farming. This study aimed to analyse the exoproteome of both an attenuated and virulent N. perurans isolate using proteomics and cytotoxicity testing. A disproportionate presence of proteins from the co-cultured microbiot...

Guillemot eggs from multiple Irish colonies and one Welsh colony were analysed for legacy pollutants such as polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and other organochlorine compounds (OCs), as well as metals. Stable isotope ratios of carbon (δ¹³C) and nitrogen (δ¹⁵N) were measured in eggs to understand the influenc...

In aquaculture, recurrence rates of amoebic gill disease (AGD) caused by the ectoparasite Paramoeba perurans are high and no prophylactic strategies exist for disease prevention. In this study, Atlantic salmon (Salmo salar) were initially inoculated with P. perurans and following the development of amoebic gill disease were treated with freshwater...

Little is known about the humpback whales (Megaptera novaeangliae) of the East-African Coast genetic sub-unit (C1). With an estimated population size of 7000 whales, they demonstrate the resilience of the species after commercial whaling caused population numbers to decline drastically. Zavora Bay, Mozambique offers an ideal observation point of th...

Amoebic Gill Disease (AGD), caused by the ectoparasite Paramoeba perurans is characterised by hyperplasia of the gill epithelium and lamellar fusion. In this study, the initial host response of naïve Atlantic salmon (Salmo salar) inoculated with P. perurans was investigated. Using gel-free proteomic techniques and mass spectrometry gill and serum s...

The causative agent of amoebic gill disease, Neoparamoeba perurans is reported to lose virulence during prolonged in vitro maintenance. In this study, the impact of prolonged culture on N. perurans virulence and its proteome was investigated. Two isolates, attenuated and virulent, had their virulence assessed in an experimental trial using Atlantic...

Amoebic Gill Disease (AGD), caused by the protozoan extracellular parasite Paramoeba perurans , is a disease affecting Atlantic salmon ( Salmo salar ) aquaculture. Many studies to date have investigated the pathogenesis of ADG focusing on the host immune response in the gill after the appearance of clinical symptoms. This study investigated the gil...

The causative agent of amoebic gill disease, Neoparamoeba perurans is reported to lose virulence during prolonged in vitro maintenance. In this study, the impact of prolonged culture on N. perurans virulence and its proteome was investigated. Two isolates, attenuated and virulent, had their virulence assessed in an experimental trial using Atlantic...

Seabird eggs are considered a favourable matrix for monitoring marine pollutants and are widely used as higher trophic level indicators. Persistent organic pollutants such as polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and other organochlorine compounds (OCs) as well as metals have been shown to have deleterious impacts...

Rivers play an important role in the overall transport of microplastic pollution (1 μm to 5 mm), with fluvial dynamics expected to influence biotic interactions, particularly for fish. So far, there have been few assessments of microplastics in freshwater salmonids. The prevalence (i.e. percentage occurrence) and burden (i.e. abundance per fish) of...

Within the past decade, an alarm was raised about microplastics in the remote and seemingly pristine Arctic Ocean. To gain further insight about the issue, microplastic abundance, distribution and composition in sea ice cores (n = 25) and waters underlying ice floes (n = 22) were assessed in the Arctic Central Basin (ACB). Potential microplastics w...

Until recently it was not thought possible to directly and accurately age crustacean species as any calcified structure that could preserve a record of chronological age is lost at moulting. Recent research has suggested that it may be possible to directly infer age from the number of endocuticular bands present within the eyestalks of snow crab (C...

Bio-accumulation of persistent organic pollutants including polychlorinated biphenyls (PCBs), brominated flame retardants and organochlorine pesticides continue to be of major concern for marine apex predators such as killer whales. The concentrations of 16 polychlorinated biphenyls, 7 poly-brominated diphenyl ethers (PBDEs), 1 poly-brominated biph...

Many ground-nesting bird species have been observed incubating foreign objects in their nests (Mellink 2002). Pine cones, golf balls, guano, hermit crabs, mammalian bones and many more objects have all been recorded in bird nests (Knight & Erickson 1977; Mellink 2002; Langlois et al. 2012). A study by Conover (1985) showed that 10% of Ring-billed G...

Microplastic pollution is presently considered a high concern topic by scientists, policy makers, governmental bodies, non-governmental organizations and the general public. Microplastics are highly widespread in all environmental compartments (e.g. air, water, sediments and biota) and increasing empirical evidence points towards potential negative...

Deep sea sediments have emerged as a potential sink for microplastics in the marine environment. The discovery of microplastics in various environmental compartments of the Arctic Central Basin (ACB) suggested that these contaminants were potentially being transported to the deep-sea realm of this oceanic basin. For the first time, the present stud...

Advancements in drone technology have seen the development of drone-assisted water sampling payloads resulting in the ability of drones to retrieve water samples and physico-chemical data from aquatic ecosystems. The application of drones for water sampling provides the potential to fulfil many aspects of the biological and physico-chemical samplin...

Marine anthropogenic litter, of which microplastics is part of, has long been recognised as an emerging pollutant of global concern with ubiquitous distribution and direct and indirect impacts on aquatic ecosystems, marine fauna and local economies. In order to contribute to the international debate on microplastics, we hereby propose a standardis...

The poster presents our research project aims, objectives and expected outcomes

Systemic infections with predominantly Exophiala species have emerged as regular and significant pathogens of lumpfish in Ireland and abroad. Exophiala is a genus of melanised fungi in the order Chaetothyriales. They are regularly found as opportunistic pathogens of cold blooded vertebrates and several species have caused high mortalities in aquacu...

Amoebic gill disease (AGD) is one of the main diseases affecting Atlantic salmon (Salmo salar L.) mariculture. Hallmarks of AGD are hyperplasia of the lamellar epithelium and increased production of gill mucus. This study investigated the expression of genes involved in mucus secretion, cell cycle regulation, immunity and oxidative stress in gills...

Several studies have identified the potential for determining age in decapod crustaceans using apparent growth increments present within the mesocardiac, zygocardiac, and pterocardiac ossicles of their gastric mill. For a number of species, however, doubts have been raised in relation to this method, with studies indicating that these ossicles are...

Persistent organic pollutants (POPs) and polycyclic aromatic hydrocarbons (PAHs) are anthropogenic contaminants of environmental concern due to their persistence in the environment and capacity to accumulate in biota. Many of these contaminants have been found to have ill effects over wildlife and humans. Birds are known to be particularly affected...

Marine anthropogenic litter has long been recognised as an emerging pollutant of global concern. Its ubiquitous distribution and its direct and indirect impacts on aquatic ecosystems, marine fauna and local economies have been recently highlighted by several studies and international organisations around the world. Although comprised of different m...

Polar oceans, though remote in location, are not immune to the accumulation of plastic debris. The present study, investigated for the first time, the abundance, distribution and composition of microplastics in sub-surface waters of the Arctic Central Basin. Microplastic sampling was carried out using the bow water system of ice-breaker Oden (singl...

Microplastic (MP) polymers, 0.1 µm - 5 mm in size, are ubiquitous within aquatic environments. Due to their small size there is a risk that they may infiltrate and transfer within aquatic food webs. Though a limited number of laboratory studies can facilitate our understanding of species susceptibility, the lack of field data from freshwater enviro...

Mammals have been suggested as suitable monitoring species for pollution research and harmful effects from marine debris have been detected; microplastics have emerged as an additional threat. It is therefore necessary to develop protocols which are suitable for research groups with lower economic resources. Digestive tracts of cetaceans and seals...

Molecular diagnostics have made it possible to identify Neoparamoeba perurans as the causative agent involved in the earliest AGD outbreaks in Ireland. A range of other putative pathogens, associated with gill disease were also detected indicating that they have been present in Irish aquaculture for over 20 years.

Systemic infections with predominantly Exophiala species have emerged as regular and significant pathogens of lumpfish in Ireland and abroad. Exophiala is a genus of melanised fungi in the order Chaetothyriales. They are regularly found as opportunistic pathogens of cold blooded vertebrates and several species have caused high mortalities in aquacu...

This study aims to demonstrate the presence of oxidative stress in farmed Atlantic salmon (Salmo salar L.) infected with Neoparamoeba perurans and undergoing clinical amoebic gill disease (AGD). Hydrophilic antioxidant activity (HAA), activity of antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and glutathione reductase (GR),and gene...

Persistent organic pollutants (POPs) are chemical compounds of environmental concern due to their toxic, persistent nature and their ability to bio-accumulate in biological tissue. Seabirds, for often being at the top of the food web, have been used as monitors of environmental pollutants. Adverse effects caused by POPs have been reported in common...

Amoebic gill disease (AGD), caused by the protozoan parasite Neoparamoeba perurans, is one of the most significant infectious diseases for Atlantic salmon (Salmo salar L.) mariculture. The present study investigated the humoral immune response (both local in gill mucus and systemic in serum) of farmed Atlantic salmon naturally infected with N. peru...

Marine non-biodegradable debris is not uncommon in the ocean, in fact, it is regularly reported on shorelines, in the water column and in the deep sea. Interactions between marine organisms and marine debris are also reported and can include deleterious effects. Plastics as marine pollutants fall under Descriptor 10 of the MSFD. It is crucial to kn...

Seabirds can interact with marine litter, mainly by entanglement or ingestion. The ingestion of plastics can lead to starvation or physical damage to the digestive tract. For chicks, it could additionally lead to reduced growth, affecting survival and fledging. This study quantified the ingestion of plastics by seabird chicks via an opportunistic s...

Amoebic gill disease (AGD) caused by Neoparamoeba perurans, has emerged in Europe as a significant problem for the Atlantic salmon farming industry. Gross gill score is the most widely used and practical method for determining AGD severity on farms and informing management decisions on disease mitigation strategies. As molecular diagnosis of AGD re...

Plastic pollution has been the subject of much research in the last decade. Seabirds can mistake plastic fragments for prey, which can perforate or block the digestive tract and cause ulcers. Most commonly, seabirds accumulate this indigestible matter in their stomachs, obtaining no nutrition and may die from starvation. Certain species of seabirds...