On 6 November 2010, a mass stranding event (MSE) occurred on Rutland Island, Co Donegal involving 33 long-finned pilot whales (Globicephala melas). While the cause of the stranding remains unknown, the event enabled the collection of a large number of tissue samples for opportunistic quantification of Persistent Organochlorine Pollutants (POP) and from across a spectrum of age-classes, maturity, and sexes. The concentrations of 24 Polychlorinated Biphenyls (PCBs), 15 Organochlorine Compounds (OCs), 5 Brominated Flame Retardants (BFRs) and 17 Polychlorinated-dibenzo-dioxins/furans (PCDD/Fs) were investigated in blubber samples via lipid extraction and subsequent analysis by Gas Chromatography-Mass Spectrometry (GC-MS). Concentrations ranged from, 48.03 ng/g lw-46,860.76 ng/g lw for ΣPCBs, 1585.40 ng/g to 558,833.71 ng/g for ΣOCs, 3.24 ng/g lw-134.82 ng/g lw for ΣBFRs and 0.008 ng/g lw-0.0518 ng/g lw for ΣPCDD/Fs. Concentrations of POPs quantified were consistent with those reported in previous studies with the exclusion of organochlorine compounds which were found to have significantly higher total concentrations. With high levels of such legacy pollutants posing potentially severe implications for the health and reproductive abilities of this species and marine mammals, the continual monitoring of POPs concentrations in animals across multiple demographics remains vital.

The flapper skate (Dipturus intermedius) is a Critically Endangered skate distributed throughout the NE Atlantic and requiring urgent conservation measures. Existing models of the flapper skate's distribution are not detailed enough to inform management. The aim of this study was to develop more highly resolved predictions of the skate's distribution across its range, building on existing studies to provide a comprehensive baseline for flapper skate presence. Location The NE Atlantic shelf region. A Bayesian spatial binomial GAMM was used to model the distribution of flapper skate across the NE Atlantic shelf. Following an exhaustive search of fisheries-independent DATRAS catch records, skate presence was modelled as a function of environmental covariates and AIS fishing pressure data. Skate presence was highest in coastal areas approximately 40-50 km from shore, where fishing pressure and benthic productivity were low. A smoother for the bathymetry variable indicated presence was highest at depths of 100-200 m. Regions with the highest predicted probability of occurrence included the north and west coasts of Scotland, and the west coast of Ireland near Counties Clare and Galway. In contrast, very low support was given for presence in the southern and central North Sea, likely reflecting historical population collapse, as well as in deeper offshore waters beyond the shelf. This study presents the first large-scale model of flapper skate presence across the NE Atlantic shelf that integrates both environmental and fishing pressure data, providing new baseline insights into habitat use in the North Sea and around Ireland. Three core regions of presence were identified, likely reflecting natural refugia from fishing and critical habitats (EFHs). Future research should prioritise these strongholds, focusing on identifying critical habitats to support focused management strategies.

A flaperon belonging to Malaysian Airlines flight MH370 washed ashore on Réunion Island covered with the barnacle Lepas anatifera in July 2015, more than a year after the plane's disappearance. Here, we report the first high‐precision δ 18 O calcite versus temperature relationship for L . anatifera reared under laboratory conditions to unlock clues to the flaperon's drift path and origin. Using this experimental relationship and known growth rates for L . anatifera , we also demonstrate a new method for (a) converting δ 18 O data for one of the MH370 barnacles into a dated time series of sea surface temperatures (SSTs) experienced during the last part of the flaperon's drift and (b) identifying best fits between the observed flaperon SST time series and 50,000 SST histories generated from a particle‐tracking simulation. Our new method identifies a flaperon drift path far south of a previous isotope‐based reconstruction. We conclude with specific recommendations for using our method to continue the search for MH370 and other applications.

Ocean biodiversity loss is being driven by several anthropogenic threats and significant efforts are required to halt losses and promote healthy marine ecosystems. The establishment of a network of Marine Protected Areas (MPAs) can help restrict damaging activities and have been recognised as a potential solution to aid marine conservation. When managed correctly they can deliver both ecological and socio-economic benefits. In recent times, MPA designations have increased rapidly while many countries have set future MPA targets for the decades ahead. An integral element of MPA management is adequate monitoring that collects data to assess if conservation objectives are being achieved. Data acquired by monitoring can vary widely as can the techniques employed to collect such data. Ideally, non-destructive and non-invasive methods are preferred to prevent damage to habitats and species, though this may rule out a number of traditional extractive sampling approaches such as dredges and trawls. Moreover, advances in ocean observation technologies enable the collection of large amounts of data at high resolutions, while automated data processing is beginning to make analyses more logistically feasible and less time-consuming. Therefore, developments to existing marine monitoring techniques and new emerging technologies have led to a diverse array of options when choosing to implement an MPA monitoring programme. Here, we present a review of new and existing non-extractive techniques which can be applied to MPA monitoring. We summarise their capabilities, applications, advantages, limitations and possible future developments. The review is intended to aid MPA managers and researchers in determining the suitability of available monitoring techniques based on data requirements and site conditions.

Funding information Marine Institute, Grant/Award Number: CF/16/04 Abstract Dispersal of meroplankton larvae in the ocean is a key process which determines larval supply to areas of suitable habitat and enables connectivity between populations, particularly for nonmigratory species. Our objective was to use a biophysical larval transport model to create a time series (2000–2019) of larval retention, dispersal distance and connectivity estimates for the commercially important Norway lobster (Nephrops norvegicus) on mud grounds off Ireland. Where time series of population estimates were sufficiently long to conduct analysis, we also investigated if larval dispersal indices could be used to predict variations in adult density, after a lag period, hypothesising that this would only apply to grounds with consistently low larval supply. Grounds off Ireland had varying characteristics related to their ability to retain and exchange larvae which was influenced by the local hydrodynamic regime and spatial isolation from other grounds. Larval supply was consistently low on the Aran grounds to the west of Ireland, which have experienced abundance declines in the past. The time series of modelled larval dispersal indices at the Aran grounds was linked to empirical adult burrow densities with a 3-year lag. Whereas the western Irish Sea, which has consistently high larval supply, showed no such relationship. Models can provide important larval recruitment information early in the life cycle for species of commercial or conservation importance.

Aim The critically endangered common skate species complex is a large-bodied and long-lived batoid, which has experienced local extirpations and population declines over the past century mainly due to overfishing. Due to its decline, fisheries management measures were introduced to prevent further decline and fragmentation of populations. For example, in 2009, a landings prohibition was introduced in the European Union, which banned the retention of common skate onboard commercial fishing vessels with captured individuals to be discarded. We aimed to explore the spatial and temporal population dynamics of the common skate species complex, against the backdrop of changes in fisheries management measures. Location Northeast Atlantic Ocean. Methods We used publicly available fishery-independent trawl survey data from several regions of the Northeast Atlantic shelf to examine trends in incidence and abundance for the common skate species complex. We also constructed a species distribution model to identify changes in the spatio-temporal distribution of the common skate. Results A sustained increase in the common skate species complex was evident in several areas of its distribution. An increase was observed in five separate trawl surveys encompassing distinct regions of its distribution. Despite the observed increase, little evidence of recolonizing previously extirpated areas was evident. Main Conclusions The findings demonstrate the effectiveness of fisheries management measures in contributing to an increase in the common skate species complex. Such measures may also be effective if applied to numerous other batoid species currently threatened with extinction.

During the months of May, June, July and August 2019 the Red Band Difference algorithm was tested over Irish waters to assess its suitability for the Irish harmful algal bloom alert system. Over the 4 weeks of June an extensive localised surface phytoplankton bloom formed in the Celtic Sea, south of Ireland. Satellite imagery from the Sentinel-3a’s Ocean and Land Colour Instrument, processed using the Red Band Difference algorithm detected the bloom in surface shelf waters and helped monitor its movement. Daily satellite images indicated that the bloom appeared at the sea surface on the 2nd June 2019 and peaked in size and surface abundance in offshore shelf waters within 4 weeks, remnants remained at the surface into July. A particle tracking approach was used to replicate oceanic circulation patterns in the vicinity of the observed algal bloom and estimate its trajectory. The initial horizontal distribution of particles in the tracking model were based on a satellite imagery polygon of the bloom when it first appeared in surface waters. Good agreement was observed between satellite imagery of the bloom and the particle tracking model. In situ sampling efforts from a research cruise and the national inshore phytoplankton monitoring programme confirmed that Karenia mikimotoi was the causative organism of the bloom. This pilot study shows great potential to use the Red Band Difference algorithm in the existing Irish harmful algal bloom alert system. In addition, satellite ocean colour data combined with particle tracking model estimates can be a useful tool to monitor high biomass harmful algal bloom forming species, such as Karenia mikimotoi, in surface coastal waters around Ireland and elsewhere.

Because environmental temperature has an important influence on developmental rate and physiology, marine ectotherms are vulnerable to phenology changes due to ocean warming. Identifying changes to phenology, the timing of biological events, and understanding their effect on recruitment and abundance is of critical importance to establish potential population effects. We examined the larval phenology of the commercially important Norway lobster (Nephrops norvegicus) and used a larval transport model to examine its effect on simulated transport patterns. Using a model to estimate annual larval release dates based on temperature-dependent embryo incubation, an earlier shift of 17.2 d occurred between 1982-1995 and 2000-2010 in the Irish Sea, similar to an observed empirical shift in phenology of 19.1 d using historical zooplankton data sets. Despite this earlier phenology, temperature-dependent pelagic larval durations were unchanged because the water column to which larvae were released earlier had also warmed. Larval transport simulations in the western Irish Sea indicated that the phenology shift had minimal effects on larval retention and advection distance overall, because major variations were observed only at very early or late stages of the larval season, that is, times when lower proportions of larvae were present. As the western Irish Sea grounds exports small but consistent quantities of larvae to nearby populations, especially off Scotland, it may act as an important source of larvae, especially when retention of native larvae is low. Overall, larval transport tools may indicate grounds that are periodically vulnerable to recruitment failures and offer potentially valuable information in fishery management.

The vertical distribution of pelagic marine larvae can greatly influence their dispersal due to depth-varying currents, which can determine larval retention or transport away from critical habitat. Vertical distribution of commercially important lobster Nephrops norvegicus larvae was examined over fishing grounds off the west and east coasts of Ireland. Larval vertical distribution for both grounds was significantly influenced by the temperature differential between the surface and 60 m depth, zooplankton biomass and, to a lesser extent, stratification, measured using the potential energy anomaly. Fixed station sampling was conducted over 3 d in the western Irish Sea (WIS) to investigate the occurrence and extent of a diel vertical migration (DVM). Larvae performed twilight DVM with an ~10 m ascent prior to sunset and sunrise and a descent at midnight and after sunrise. Particle-tracking model simulations were used to examine the effect of DVM behaviour on larval retention over mud habitat. The presence of a DVM actually reduced the likelihood of retention on both the Aran and WIS grounds. Predicted larval retention was unusually low over the Aran grounds in 2018, which is potentially significant in the context of historic stock fluctuations in this area. These findings suggest that understanding larval dynamics could be crucial in managing N. norvegicus stocks on fishing grounds, in particular those with variable interannual oceanography and a low rate of larval donation from other grounds.

Most deep diving toothed whales rarely come into contact with humans due to their preference for deep offshore waters. In recent years many studies have connected underwater acoustic disturbances with unusual stranding events of deep diving species. Strandings can provide a valuable opportunity to learn about the ecology of stranded specimens and investigate the cause of mortality. The study determines how environmental and anthropogenic variables such as sea surface temperature, wave height, wave period, wind direction and seismic surveying can influence strandings events of deep diving odontocetes. The results of these analyses suggest that the occurrence of offshore seismic surveying operations increase the number of strandings of long-finned pilot whales, which are probably the most abundant deep diving species in the north Atlantic. The study also demonstrates the value of cetacean stranding schemes and how they can be utilised to establish the natural and anthropogenic processes that contribute to stranding events.