Diclidophora merlangi (Kuhn, 1829) Krøyer, 1838 (Monogenea : Diclidophoridae) as an indicator of hydrocarbon pollution in the North Sea

Acknowledgements We thank the crews and scientific staff on the cruises of FRS Scotia during which these samples were collected. We are grateful to Dr Coby Needle of Marine Scotland for his helpful comments on an earlier draft of the manuscript, and to the anonymous reviewer for his constructive comments. We wish to dedicate this study to the memory of Dr H.H. Williams, whose original idea it was to investigate D. merlangi as an indicator of hydrocarbon pollution.Peer reviewedPostprin

Increasing intensities of Anisakis simplex third-stage larvae (L3) in Atlantic salmon of coastal waters of Scotland

Background: Red Vent Syndrome (RVS), a haemorrhagic inflammation of the vent region in Atlantic salmon, is associated with high abundance of Anisakis simplex (s.s.) third-stage larvae (L3) in the vent region. Despite evidence suggesting that increasing A. simplex (s.s.) intensity is a causative factor in RVS aetiology, the definitive cause remains unclear.Methods: A total of 117 Atlantic salmon were sampled from commercial fisheries on the East, West, and North coasts of Scotland and examined for ascaridoid parasites. Genetic identification of a subsample of Anisakis larvae was per-formed using the internal transcribed spacer (ITS) region of ribosomal DNA. To assess the extent of differentiation of feeding grounds and dietary composition, stable isotope analysis of carbon and nitrogen was carried out on Atlantic salmon muscle tissue.Results: In the present study, the obtained ITS rDNA sequences matched A. simplex (s.s.) sequences deposited in GenBank at 99–100%. Not all isolated larvae (n=30,406) were genetically identified. Therefore, the morphotype found in this study is referred to as A. simplex (sensu lato). Anisakis simplex (s.l.) was the most prevalent (100%) nematode with the highest mean intensity (259.9 ±197.3), in comparison to Hysterothylacium aduncum (66.7%, 6.4 ± 10.2) and Pseudoterranova decipiens (s.l.) (14.5%, 1.4 ±0.6). The mean intensity of A. simplex (s.l.) represents a four-fold increase compared to published data (63.6 ±31.9) from salmon captured in Scotland in 2009. Significant positive correlations between A. simplex (s.l.) larvae intensities from the body and the vent suggest that they play a role in the emergence of RVS. The lack of a significant variation in stable isotope ratios of Atlantic salmon indicates that diet or feeding ground are not driving regional differences in A. simplex (s.l.) intensities.Conclusions: This paper presents the most recent survey for ascaridoid parasites of wild Atlantic salmon from three coastal regions in Scotland. A significant rise in A. simplex (s.l.) intensity could potentially increase both natural mortal-ity rates of Atlantic salmon and possible risks for salmon consumers due to the known zoonotic role of A. simplex (s.s.) and A. pegreffii within the A. simplex (s.l.) species complex

A Theory of Natural Addiction

Economic theories of rational addiction aim to describe consumer behavior in the presence of habit-forming goods. We provide a biological foundation for this body of work by formally specifying conditions under which it is optimal to form a habit. We demonstrate the empirical validity of our thesis with an in-depth review and synthesis of the biomedical literature concerning the action of opiates in the mammalian brain and their eects on behavior. Our results lend credence to many of the unconventional behavioral assumptions employed by theories of rational addiction, including adjacent complementarity and the importance of cues, attention, and self-control in determining the behavior of addicts. We oer evidence for the special case of the opiates that "harmful" addiction is the manifestation of a mismatch between behavioral algorithms encoded in the human genome and the expanded menu of choices faced by consumers in the modern world

The lifecycle and infection dynamics of Lepeophtheirus salmonis (Krøyer 1837), on typical and atypical hosts in marine aquaculture areas

The main parasite affecting the Scottish Atlantic salmon farming industry is Lepeophtheirus salmonis costing approximately £29 million annually through lost production and treatments. As such, the primary aim of this study was to investigate the infection pressure, fecundity and infection dynamics of L. salmonis in a west coast sea loch containing salmonid aquaculture. Atlantic salmon held in small sentinel cages were used to monitor sea lice infection pressure in Loch Shieldaig. Investigation of the factors affecting infection pressure within the loch found no evidence of a direct link between monthly gravid lice counts on local farmed salmon and lice burdens on sentinel cage fish. Copepodid L. salmonis were present throughout the year despite there being low numbers of wild salmonids in the system during much of the year and as such the source of this infection was unclear. In subsequent laboratory trials, L. salmonis from wild salmon were found to be more fecund than those from farmed salmon and similarly, fecundity and survival were also higher in summer compared to winter populations of L. salmonis. These findings raise the possibility that L. salmonis infecting wild salmonids may “seed” previously fallowed systems. Alternatively, trials with atypical hosts found that L. salmonis of farmed origin did re-infect Atlantic cod and produce viable egg strings which moulted through to the infective copepodid stage. Infection challenges demonstrated that L. salmonis copepodids were observed to settle on atypical hosts such as saithe and Atlantic cod in low numbers although failed to develop to the chalimus stages and complete its lifecycle. Challenges utilising the mobile pre-adult stage were similarily unsuccesful in allowing L. salmonis to moult to the adult stage on these atypical hosts. Previous work conducted on Pacific three-spined sticklebacks demonstrated the species could support large burdens. In infection trials with three-spined sticklebacks from Scotland’s west coast, settlement was found to be low, which suggests they play no role in the Scottish inshore infection dynamics of L. salmonis. These series of studies provide novel and timely data on the biology and infection dynamics of L. salmonis on typical and atypical hosts in Scottish marine aquaculture areas. The data will form part of the knowledge used to make informed pest management and policy decisions assisting the future development of the aquaculture industry in Scotland.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

RNA-interference methods for gene-knockdown in the sea louse, Lepeophtheirus salmonis: studies on a putative prostaglandin E synthase

Harnessing the full utility of extensive gene sequences recently available for the economically important sea louse, Lepeophtheirus salmonis, requires the adaptation of modern molecular biology approaches to this non-model organism. Using a putative microsomal prostaglandin E synthase type-2 (PGES2) as a candidate gene, we investigated gene-knockdown by double-stranded RNA interference (dsRNAi) in the small free-living and the larger parasitic stages of L. salmonis. dsRNA was administered to nauplius and copepodid stages by immersion for 7 h. Pre-adult and adults received dsRNA by intra-haemocoelic injection. The extent, speed and persistence of the knockdown effects were determined by RT-PCR. LsPGES2 was abundantly expressed in all life stages, including the non-parasitic stages. Administration of dsRNA to nauplius and copepodids by immersion had no effect on mortality rates and moulting through to copepodids was observed. Dramatic knockdown of LsPGES2 was observed within 7 h and persisted for at least 48 h. Injection of dsRNA had no effect on mortality in pre-adults and adults, but knockdown of LsPGES2 was apparent within 24 h, reaching 95% over the 72 h and was persistent for at least 120 h. The methods developed resulted in rapid and persistent knockdown in L. salmonis suitable for studies in the different stadia.E. M. Campbell, C.C. Pert and A. S. Bowma

Spatial congruence and divergence between ecosystem services and biodiversity in a tropical forested landscape

Tropical forests are the storehouse of both ecosystem services and biodiversity but the interlinkages between these two components of ecosystems are yet to be fully explored. We utilized expert opinion to assess the key and multiple ecosystem services, and biodiversity in a tropical landscape. We found that key and multiple ecosystem services supply varies across the landscape and that forest disturbances reduce the capacity to supply those ecosystem services. We also found that a spatial congruence is likely to occurs between high-potential biodiversity and high-potential global climate regulation ecosystem service in the intact rainforest areas while a spatial divergence is likely to occurs in the sclerophyll and other disturbed and low tree abundance forested areas. Overall in a tropical forested landscape, a spatial congruence between high-potential multiple ecosystem services supply and high-potential biodiversity values is likely to occurs provided that the multiple ecosystem services are forest-based. Along with conserving relatively intact forests, management intervention priorities should focus on increasing tree abundance both in non-tree vegetated land cover areas and within disturbed forested areas to increase the high-potential multiple ecosystem services supply at the landscape level. A careful selection of multiple ecosystem services is required to integrate both high-potential multiple ecosystem services and high-potential biodiversity in tropical forest management. © 2018 Elsevier LtdAssociated Grant:Skyrail Rainforest Foundation, Australia for the partial funding of this research

Factors influencing the long-term dynamics of larval sea lice density at east and west coast locations in Scotland

Acknowledgements We thank the skipper and crew of the ‘Temora’ (Jim Brown and Paul MacDonald) as well as the willing volunteers who participate on the Stonehaven sampling rota as part of the Scottish Government project ST03p. We also thank Eileen Bresnan for the original idea of using the samples to analyse sea lice dynamics, Zoe Allcock for advice on the statistical analysis, Jim Raffell for assistance with the Shieldaig samples, Marine Harvest for providing west coast temperature data and Catherine Collins for guidance with the molecular identification. We recognise the valuable feedback provided by the 2 anonymous reviewers.Peer reviewedPostprin