Edition accompagnee de planches gravees, representant les types de tous les genres, les caracteres distinctifs des divers groupes et les modifications de structure sur lesquelles repose cette classification

Le Règne animal distribué d'après son organisation, pour servir de base à l'histoire naturelle des animaux et d'introduction à l'anatomie comparée. Les arachnides. Atlas

Human populations have been concentrated along and exploiting the coastal zones for millennia. Of regions with the highest human impacts on the oceans (Halpern et al. 2008), 6 of the top 10 have recently experienced blooms or problems with jellies. I review the time lines of human population growth and their effects on the coastal environment. I explore evidence suggesting that human activities—specifically, seafood harvest, eutrophication, hard substrate additions, transport of nonindigenous species, aquaculture, and climate change—may benefit jelly populations. Direct evidence is lacking for most of these factors; however, numerous correlations show abundant jellies in areas with warm temperatures and low forage fish populations. Jelly populations fluctuate in ∼10- and ∼20-year cycles in concert with solar and climate cycles. Global warming will provide a rising baseline against which climate cycles will cause fluctuations in jelly populations. The probable acceleration of anthropogenic effects may lead...

Jellyfish and Ctenophore Blooms Coincide with Human Proliferations and Environmental Perturbations

Although there are various indications and claims that jellyfish (ie, scyphozoans, cubozoans, most hydrozoans, ctenophores, and salps) have been increasing at a global scale in recent decades, a rigorous demonstration of this has never been presented Because this is mainly due to scarcity of quantitative time series of jellyfish abundance from scientific surveys, we attempt to complement such data with non-conventional information from other sources This was accomplished using the analytical framework of fuzzy logic, which allows the combination of information with variable degrees of cardinality, reliability, and temporal and spatial coverage Data were aggregated and analyzed at the scale of Large Marine Ecosystem (LME) Of the 66 LMEs defined thus far that cover the world’s coastal waters and seas, trends of jellyfish abundance after 1950 (increasing, decreasing, or stable/variable) were identified for 45, with variable degrees of confidence Of those 45 LMEs, the majority (28 or 62%) showed increasing trends These changes are discussed in the context of possible sources of bias and uncertainty, along with previously proposed hypotheses to explain increases in jellyfish

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Increasing jellyfish populations: trends in Large Marine Ecosystems

Marine aquaculture relies on coastal habitats that will be affected by climate change. This review assesses current knowledge of the threats and opportunities of climate change for aquaculture in the UK and Ireland, focusing on the most commonly farmed species, blue mussels (Mytilus edulis) and Atlantic salmon (Salmo salar). There is sparse evidence to indicate that climate change is affecting aquaculture in the UK and Ireland. Impacts to date have been difficult to discern from natural environmental variability, and the pace of technological development in aquaculture overshadows effects of climatic change. However, this review of broader aquaculture literature and the likely effects of climate change suggests that over the next century, climate change has the potential to directly impact the industry. Impacts are related to the industry's dependence on the marine environment for suitable biophysical conditions. For instance, changes in the frequency and strength of storms pose a risk to infrastructure, such as salmon cages. Sea-level rise will shift shoreline morphology, reducing the areal extent of some habitats that are suitable for the industry. Changes in rainfall patterns will increase the turbidity and nutrient loading of rivers, potentially triggering harmful algal blooms and negatively affecting bivalve farming. In addition, ocean acidification may disrupt the early developmental stages of shellfish. Some of the most damaging but least predictable effects of climate change relate to the emergence, translocation and virulence of diseases, parasites and pathogens, although parasites and diseases in finfish aquaculture may be controlled through intervention. The spread of nuisance and non-native species is also potentially damaging. Rising temperatures may create the opportunity to rear warmer water species in the UK and Ireland. Market forces, rather than technical feasibility, are likely to determine whether existing farmed species are displaced by new ones.

Review of climate change impacts on marine aquaculture in the UK and Ireland

Biofouling in marine aquaculture is one of the main barriers to efficient and sustainable production. Owing to the growth of aquaculture globally, it is pertinent to update previous reviews to inform management and guide future research. Here, the authors highlight recent research and developments on the impacts, prevention and control of biofouling in shellfish, finfish and seaweed aquaculture, and the significant gaps that still exist in aquaculturalists’ capacity to manage it. Antifouling methods are being explored and developed; these are centred on harnessing naturally occurring antifouling properties, culturing fouling-resistant genotypes, and improving farming strategies by adopting more sensitive and informative monitoring and modelling capabilities together with novel cleaning equipment. While no simple, quick-fix solutions to biofouling management in existing aquaculture industry situations have been developed, the expectation is that effective methods are likely to evolve as aquaculture develops into emerging culture scenarios, which will undoubtedly influence the path for future solutions.

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Biofouling in marine aquaculture: a review of recent research and developments

Jellyfish have been implicitly linked to a number of fish kill events in marine-farmed fin- fish over recent decades. However, due to insufficient data, it is difficult to identify small hydrozoan jellyfish as the causative agents of the more common and chronic problem of gill disorders. Gill dis- orders (physical, pathogenic or parasitic damage to the gills) can be caused by a number of water- borne agents and are an increasing though poorly understood problem for the aquaculture industry. Hence, the first year-long monitoring programme to study hydrozoan jellyfish, other gelatinous zoo- plankton, phytoplankton and fish health was initiated at 2 aquaculture sites on the west coast of Ire- land. At the southern site, 2 jellyfish species previously implicated in aquaculture fish kill events (Muggiaea atlantica and Solmaris corona) occurred at high abundances (combined density of ~450 jellyfish m -3 , an order of magnitude lower than during previous mass mortality events). The fish at this site exhibited clinically significant gill damage throughout the peak in jellyfish abundance. Analyses revealed a significant positive correlation between daily fish mortality and the abundance of these jellyfish but not with any other factors. At the northern site, there were low abundances of jellyfish; nevertheless, gill damage due to the protozoan parasite Trichodina sp. was observed over a shorter time period. As the European aquaculture sector experiences annual economic losses due to gill disorders, these findings raise concerns for the expected growth of the industry, especially as jellyfish populations are predicted to increase in some areas. Therefore, mitigation methods need to be developed and implemented.

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Gill disorders in marine-farmed salmon: ­investigating the role of hydrozoan jellyfish

This chapter begins by reviewing the fisheries and culture of jellyfish for human food, multi-million-dollar industries with markets currently centered in Asia. Second, we present guidelines for culture conditions and tank construction for display or study of 27 jellyfish species. Most types of jellyfish (scyphomedusae, hydromedusae, siphonophores and ctenophores) also damage the aquaculture industry by causing fish gill disorders and by fouling net pens. We review the lifecycles of these groups and the damage they cause. Finally, we offer recommendations on how to minimize this damage. Ironically, aquaculture may be inadvertently exacerbating the problems with jellyfish blooms.

Jellyfish as products and problems of aquaculture

Peer-reviewed. Copyright © 2011 E.J. Baxter et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

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Gill damage to Atlantic salmon (Salmo salar) caused by the common jellyfish (Aurelia aurita) under experimental challenge

Gill health and disease in farmed Atlantic salmon (Salmo salar) were studied at a marine site on the west coast of Ireland. Fish were sampled on a regular basis during the summer and autumn of 2009. A novel histopathological scoring system was devised to give a semi-quantitative measure of gill pathology. The index criteria for gill histopathology were lamellar hyperplasia, lamellar fusion, circular anomalies (necrosis or sloughing) and lamellar oedema, a score from 0 to 3 being assigned for each parameter. Ancillary criteria, such as hypertrophy, haemorrhage and the presence of specific pathogens, were assigned a score of 0 or 1. Environmental monitoring undertaken included zooplankton and phytoplankton sampling, as well as temperature and oxygen recordings for the site. Epitheliocystis was frequently observed at low levels but was not associated with any significant gill pathology. Clinically significant gill pathology was observed on one occasion during the sampling period, coinciding with the occurrence of Pelagia noctiluca, Muggiaea atlantica and Solmaris corona. Throughout the longitudinal study, the scoring system provided an accurate and effective means of assessing gill health, demonstrating the ability of this practical tool to be used in future studies of gill health and disease.

Development of a novel histopathological gill scoring protocol for assessment of gill health during a longitudinal study in marine-farmed Atlantic salmon (Salmo salar)

The development and the application of a quantitative real-time PCR for the detection of Tenacibaculum maritimum are described. A set of primers and probe was designed to amplify a 155-bp fragment specific to the T. maritimum 16S rRNA gene. The test was shown to be very sensitive, able to detect as little as 4.8 DNA copies number μL(-1) . In addition, the assay was found to have a high degree of repeatability and reproducibility, with a linear dynamic range (R(2)  = 0.999) extending over 6 log(10) dilutions and a high efficiency (100%). The assay was applied to DNA samples extracted from 48 formalin-fixed paraffin-embedded (FFPE) Atlantic salmon, Salmo salar, gill tissues showing varying degrees of gill pathology (scored 0-3) and from 26 jellyfish samples belonging to the species Phialella quadrata and Muggiaea atlantica. For each sample, the bacterial load was normalised against the level of the salmonid elongation factor alpha 1 (ELF) detected by a second real-time PCR using previously published primers and probe. Tenacibaculum maritimum DNA was detected in 89% of the blocks with no signs of gill disease as well as in 95% of the blocks with mild-to-severe gill pathology. Association between bacterial load and gill pathology severity was investigated. T. maritimum DNA was detected at low level in four of the 26 jellyfish tested.

E. J. Baxter

Papers

Gill disorders in marine-farmed salmon: investigating the role of hydrozoan jellyfish

Jellyfish as products and problems of aquaculture

Gill damage to Atlantic salmon (Salmo salar) caused by the common jellyfish (Aurelia aurita) under experimental challenge

Development of a novel histopathological gill scoring protocol for assessment of gill health during a longitudinal study in marine-farmed Atlantic salmon (Salmo salar)

Development of a quantitative real-time PCR for the detection of Tenacibaculum maritimum and its application to field samples.

E. J. Baxter

Papers

Gill disorders in marine-farmed salmon: ­investigating the role of hydrozoan jellyfish

Jellyfish as products and problems of aquaculture

Gill damage to Atlantic salmon (Salmo salar) caused by the common jellyfish (Aurelia aurita) under experimental challenge

Development of a novel histopathological gill scoring protocol for assessment of gill health during a longitudinal study in marine-farmed Atlantic salmon (Salmo salar)

Development of a quantitative real-time PCR for the detection of Tenacibaculum maritimum and its application to field samples.

Gill disorders in marine-farmed salmon: investigating the role of hydrozoan jellyfish