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Seagrasses are considered to be globally important for carbon sequestration and they provide a range of ecosystem services. However, they are also known to be vulnerable to various anthropogenic activities, not least bottom contacting fishing gears such as dredging and potting. We set out to test the effects of dredge fishing, in early spring and potting in late summer, in a historically fished but considered "pristine" seagrass meadow on the west coast of Ireland. We found that despite dredging and potting pressures, growth of seagrasses was driven by seasonal changes in light and temperature and that neither fishing activity had any effect on rhizome weight or shoot or blade densities during the growing season. We hypothesize that it is possible for fishing to co‐occur with seagrass if fishing activities are restricted to winter or early spring, before the main seagrass growing season, and/or if particular types of gear, such as the traditional gears described here are used. High levels of dredging and potting had positive increases in the count of both sessile and mobile epifauna suggesting that for mobile species at least, they may take advantage of post‐fishing scavenging opportunities. [ABSTRACT FROM AUTHOR]

Bycatch of protected species in static net fisheries is a global conservation concern and is currently considered the dominant anthropogenic threat facing many marine mammal species. Effective bycatch mitigation remains challenging, contingent on an understanding of the underlying mechanisms that cause individuals to become entangled.We combined data collected by scientific observers and fishers to identify predictors of seal bycatch in static net fisheries along the west, southwest and south coasts of Ireland. We first analysed the broad regional and seasonal trends in seal bycatch before identifying environmental variables that could explain these patterns.Based on negative binomial generalized linear mixed effects models, seal bycatch significantly varied with season and decreased with greater distance to major seal colonies and in clearer, less turbid water.Synthesis and applications. Our results suggest that distance to major seal colonies was a significant driver of spatial variation in seal bycatch, and water turbidity a major driver of seasonal trends. These findings will enable us to identify future bycatch risk and target mitigation measures effectively. This is the first study to identify the effect of water turbidity on bycatch of a protected marine species. Increasing net visibility in turbid waters may provide a novel approach to mitigating against protected species bycatch in static net fisheries. [ABSTRACT FROM AUTHOR]

In this article, we undertake the first broad-scale, cross-institutional collaboration to collect data on the size at maturity and reproductive strategy of the commercially fished decapod crab species, Cancer pagurus. Using identical methodology and temporal sampling, morphometric and physiological estimates of size at maturity were undertaken using 1806 crabs sampled from populations in the seas off Ireland, the Isle of Man, Scotland, Wales, England, and Norway. Additionally body condition, prevalence of external parasites, black spot disease, and the hepatosomatic index (HSI, hepatopancreas weight as a percentage of total tissue weight), and gonadosomatic index (GSI, gonad weight as a percentage of total tissue weight) were estimated for some populations. C. pagurus appears to use a "capitalist" reproductive strategy, relying on previously accumulated energy to use through the reproductive season. Crabs displaying black spot disease had significantly lower HSI values, taking into account that HSI decreases with each progressive reproductive stage. Male crabs with poor body condition and black spot disease displayed greater GSI values. Though this pattern was regionally variable, it indicates that, in some cases, physical stress may induce greater investment into reproductive resources. Based on the carapace width (CW) at which 50% of the sampled population was physiologically mature (CW50), estimates of size at first maturity varied between sampled populations in the range 97-117mm CW in females and 59-106mm CW in males. The CW50 estimates reported here are smaller than previously reported values for C. pagurus populations. However, the variety of laboratory and statistical methodologies used in published studies prevent absolute comparisons with our results. We discuss the benefits of developing a standardized methodology for size at maturity research and the need for greater collaboration in fisheries research to achieve goals set under the European Union's Data Collection Framework for this species. [ABSTRACT FROM AUTHOR]

Atlantic herring, Clupea harengus, is an imporant commercial and forage species in Irish waters. Spawning takes place in coastal waters mostly between September and February in high energy environments, usually at the mouths of bays and estuaries. Herring are benthic spawners and require specific substrate, normally gravel and/or rock, on which to lay their eggs. Because of this reliance, spawning herring can be vulnerable to various anthropogenic activities. It is important to have information pertaining to these sensitive spawning grounds available in the public domain. This is the first study to document all known locations in Irish waters. Available information from previous larval surveys was analysed and a comprehensive fishing industry survey was conducted. A detailed inventory of individual herring spawning beds, grounds and areas around the coasts of the Republic of Ireland was produced. Seabed classification data were consulted to compare the locations of known herring spawning beds with areas consisting of the necessary substrate. There was close agreement in most areas. A larval transport model (LTRANS) was then used to study the predicted dispersal of herring larvae from those areas identified. Preliminary results predict a broadly clockwise dispersal around the coast and that Celtic Sea sites potentially contribute larvae through four ICES management boxes with important implications for fisheries management. This study could be used to assist in future marine spatial planning to ensure that these vulnerable areas are afforded maximum protection. [ABSTRACT FROM AUTHOR]

The combined effects of temperature and salinity on the survival and development of larval and juvenile Palaemon serratus from the west coast of Ireland were investigated. Survival over time was measured at thirty combinations of temperature and salinity ranging from 10–19°C and 9–34‰ in a fully factorial design. Salinity had a stronger influence than temperature on survival at all larval stages except stage V. For juveniles the main effect changed from temperature between 100 and 200 degree days to salinity between 200 and 600 degree days and temperature between 600 and 800 degree days. Estimates of time taken to 50% mortality showed that juveniles tolerated lower salinities for longer periods and exhibited optimal salinity values which were 3‰ lower than larvae, at temperatures between 10 and 15°C. Larval stage durations were found to be influenced by temperature but not salinity. Comparison with published data suggests that populations of P. serratus have adapted to local conditions of temperature and salinity. The results presented here have practical implications for fisheries assessment and management, as the incorporation of environmental effects into stock–recruitment models can improve their predictive capacity. [ABSTRACT FROM PUBLISHER]

The aim in this paper is to put forward an approach to the issue of access rights that is suitable to Ireland''s crustacean and molluscan fisheries. We begin by reviewing proceedings of a recent international conference on the issue of property rights in fisheries. We then pose objectives for fisheries management to be met by our approach. Following this, we outline the present limited entry initiative regarding crustacean and molluscan fisheries in Ireland. We conclude that—for fishers to operate with, but not exchange licences like, owners—a licence should be returned to the issuing authority once it is no longer being fished by its holder. [Copyright &y& Elsevier]

The velvet swimming crab Necora puber has been fished in Ireland since the early 1980s and contributes significant income to smaller fishing vessels. From 2016 onwards, reduced landings have been reported. We undertook a full pathological investigation of crabs from fishing grounds at 3 sites on the west (Galway), southwest (Castletownbere) and east (Howth) coasts of Ireland. Histopathology, transmission electron microscopy and molecular taxonomic and phylogenetic analyses showed high prevalence and infection level of Paramarteilia canceri, previously only reported from the edible crab Cancer pagurus. This study provides the first molecular data for P. canceri, and shows its phylogenetic position in the order Paramyxida (Rhizaria). Other parasites and symbionts detected in the crabs were also noted, including widespread but low co-infection with Hematodinium sp. and a microsporidian consistent with the Ameson and Nadelspora genera. This is the first histological record of Hematodinium sp. in velvet crabs from Ireland. Four N. puber individuals across 2 sites were co-infected by P. canceri and Hematodinium sp. At one site, 3 velvet crabs infected with P. canceri were co-infected with the first microsporidian recorded from this host; the microsporidian 18S sequence was almost identical to Ameson pulvis, known to infect European shore crabs Carcinus maenas. The study provides a comprehensive phylogenetic analysis of this and all other available Ameson and Nadelspora 18S sequences. Together, these findings provide a baseline for further investigations of N. puber populations along the coast of Ireland.