Time-capsule: Explorations of Concepts of Time and Law in Colonial New Zealand

Postcolonial legal culture in New Zealand (Aotearoa) has sought to revise the past by reinterpreting Victorian legal contexts in the light of contemporary understandings of inter-cultural differences. This article develops an argument that demonstrates the relationship between cultural and legal notions of time during nineteenth century New Zealand. It examines the way in which Victorian attitudes were expressed in the expansion of colonial empire and the discursive ideologies which may have informed them. It explores the notion of time as expressed in lawmaking in colonial New Zealand through an examination of legal and philosophical commentary derived from contemporary jurisprudence and para-legal literature. The article is concerned with presenting an argument for the way in which colonial law and lawmakers manipulated the symbolic notion of time to the possible occlusion of indigenous interests in colonial New Zealand

Comparing the crystallographic structures of the Howardite, Eucrite and Diogenite (HED) Meteorites

The Howardite, Eucrite, Diogenite (HED) meteorites are a group of achondrite meteorites that likely originate from the same parent body (e.g. [1,2]), which is believed to be 4 Vesta [3]. AsHED meteorites are some of the oldest achondrites in our collections [4], they can provide valuable insights into processes occurring on small bodies early in the Solar System. To provide further constraints of the geological history of the HED parent body, we are undertaking a systematic cryatallographic analysis of a suite of HED meteorites by using electron backscatter diffraction (EBSD)analyses. Preliminary work has focused on the meteorites Allan Hills (ALH) 88135, a howardite polymict breccia, and Camel Donga, a eucrite monomict breccia

Herd health status and management practices on 16 Irish suckler beef farms

peer-reviewedBackground: There have been few studies published internationally which document herd health management practices in suckler beef herds and no published Irish studies. The study objective was to document herd health status and management practices on sixteen Irish suckler beef herds over a two year period (2009–2010). The farms used in the study were part of the Teagasc BETTER farm beef programme. The mean (s.d.) herd size, stocking rate and farm size was 68 cows (27.6), 2.0 LU/ha (0.3) and 64.3 (21.6) adjusted hectares, respectively. Two questionnaires were designed; 1) a farmer questionnaire to collect information on farm background and current herd health control practices and 2) a veterinary questionnaire to collect information on the extent of animal health advice given by veterinarians to their clients and identification of any on-farm herd health issues. Results: Dystocia, calf pneumonia, and calf diarrhoea, in that order, were identified as the primary herd health issues in these Irish suckler beef herds. In addition, substantial deficiencies in biosecurity practices were also identified on these farms. Conclusions: The findings of this study may serve as the focus for future research in animal health management practices in Irish suckler beef herds

Where art thou louse? A snapshot of attachment location preferences in salmon lice on Atlantic salmon hosts in sea cages

Problematic sea lice infestations on farmed Atlantic salmon (Salmo salar) have motivated extensive research and development into new methods to prevent, monitor and control sea lice. Most of these technologies require detailed information on the behaviour, spatial distribution and demography of lice on host fish. This study investigated how salmon lice (Lepeophtheirus salmonis) infestation density varies across the host's surface under sea cage farming conditions. Lice abundance, demography and attachment location were tracked over time, with repeated sampling of 300 individually tagged salmon across three replicate experimental sea cages. The data reveal clear differences in attachment locations according to sex and stage, but with an overall preference for the dorsal surface among mobile stages—dorsal head for adult females and dorsal‐posterior section for males and pre‐adults. Total lice abundance was highly variable between repeated measures of individual fish, consistent with frequent host‐switching or mortality. Total lice numbers also declined between sampling dates, likely due to handling, with lost mobile lice being almost exclusively adult males. As the distribution of sea lice on hosts is likely determined by numerous factors, future image‐based automated detection systems should be validated in settings that reflect the complex host–parasite interactions that occur in open farming systems.publishedVersio

Salmon lice survive the straight shooter: A commercial scale sea cage trial of laser delousing

Ectoparasitic salmon louse (Lepeophtheirus salmonis) infestations are costly for Atlantic salmon (Salmo salar) farmers in Norway. As a result, there is a strong desire for solutions to prevent and control infestations, and new technologies are typically developed and commercialised rapidly, without rigorous validation. Here, we tested the efficacy of a new commercially available control measure—delousing by underwater lasers—using a replicated design at full commercial scale. Laser delousing was used in combination with a preventive method (snorkel cages), with laser nodes deployed in 3 of the 6 sea cages at the site. The trial ran for 54 days, after which time there was no difference in infestation density of mobile salmon louse stages (pre-adult, adult male or adult female) in cages with or without laser nodes installed. By the end of the trial, adult female lice numbers in all cages were close to the legislated trigger for mandatory delousing (0.5 adult female lice per fish). The laser nodes delivered a large number of pulses relative to the number of lice in the cages, indicating that a lack of lethality rather than a lack of target detection was the limiting factor. If all pulses had been effective, they should have removed between 4–38 % of mobile lice each day. There was no effect on salmon welfare indicators such as skin condition or eye status. Our results highlight the importance of rigorous validation of new technologies across a range of conditions before widespread implementation by industry.publishedVersio

Prevention not cure: a review of methods to avoid sea lice infestations in salmon 1 aquaculture

The Atlantic salmon aquaculture industry still struggles with ectoparasitic sea lice despite decades of research and development invested into louse removal methods. In contrast, methods to prevent infestations before they occur have received relatively little research effort, yet may offer key benefits over treatment‐focused methods. Here, we summarise the range of potential and existing preventative methods, conduct a meta‐analysis of studies trialling the efficacy of existing preventative methods and discuss the rationale for a shift to the prevention‐focused louse management paradigm. Barrier technologies that minimise host–parasite encounter rates provide the greatest protection against lice, with a weighted median 76% reduction in infestation density in cages with plankton mesh ‘snorkels’ or ‘skirts’, and up to a 100% reduction for fully enclosed cages. Other methods such as geographic spatiotemporal management, manipulation of swimming depth, functional feeds, repellents and host cue masking can drive smaller reductions that may be additive when used in combination with barrier technologies. Finally, ongoing development of louse‐resistant salmon lineages may lead to long‐term improvements if genetic gain is maintained, while the development of an effective vaccine remains a key target. Preventative methods emphasise host resistance traits while simultaneously reducing host–parasite encounters. Effective implementation has the potential to dramatically reduce the need for delousing and thus improve fish welfare, productivity and sustainability in louse‐prone salmon farming regions.submittedVersio

In situ sea lice egg sterilization with UVC light

Sea-cage salmon farming creates ideal conditions for population growth of the salmon louse Lepeophtheirus salmonis, potentially leading to poor welfare and mortality in farmed salmon and nearby wild salmonids. Frequent delousing treatments are necessary, but current treatments have drawbacks in terms of financial cost, stress to stock, and/or environmental impacts. We tested whether 254 nm ultraviolet-C light (UVC) could function as a new treatment to reduce production of infective copepodids in infested sea-cages. In Experiment 1, we removed mature egg strings from female lice and exposed the egg strings to precise doses of UVC light. A total dose of 0.008 J cm-2 reduced copepodid production by 5 %, while a 95 % reduction occurred at 0.09 J cm-2. In Experiment 2, we exposed salmon with attached adult lice to UVC light while they swam freely in tanks over a 6 day period, achieving a dose of ~0.1 J cm-2. The treatment resulted in a 99 % reduction in copepodid production relative to control groups. However, UVC negatively impacted fish welfare, causing higher rates of cataracts and skin irritation. In Experiment 3, we tested the sensitivity of fish (without lice) to increasing doses of UVC light, and found that minor skin injuries occurred at >60 % effective doses, while cataracts began to develop at very low doses. We conclude that UVC should only be used with caution, either for treatment of waste water to prevent louse eggs and larvae entering the environment (e.g. after delousing), or for short periods of time in-cage to suppress lice reproduction until fish are harvested.publishedVersio

Host promiscuity in symbiont associations can influence exotic legume establishment and colonization of novel ranges

Aim Invasive Acacia species have negatively impacted natural areas in multiple regions around the globe. Almost 400 Acacia species have been introduced outside their native ranges in Australia; approximately 6% have become invasive, 12% are naturalized, and 82% have no record of naturalization or invasion. This variation in invasiveness provides a comparative framework in which to examine mechanisms that either promote or constrain establishment and colonization of species in novel regions. Here, we experimentally examine the role that the legume–rhizobia symbiosis plays in the differential invasiveness of acacias introduced outside their native Australian ranges. Location Canberra, Australia. Methods We paired 12 Acacia species ranging in invasiveness globally with 12 rhizobial strains ranging in average symbiotic effectiveness. We measured plant growth and nodulation success and abundance to assess whether invasive acacias were more promiscuous hosts, that is had positive growth and nodulation responses to a broader range of rhizobial strains than naturalized and non-invasive species. Results Invasive acacias had a higher growth response across more rhizobial strains (six of 12 strains) than naturalized and non-invasive species, but invasiveness categories differed only moderately with regard to the percentage of plants with nodules and nodulation abundance. Main conclusion With respect to plant growth, invasive acacias appear to be more promiscuous hosts than naturalized and non-invasive Australian Acacia species. Plant growth response to nodulation, however, is likely more important than nodulation alone in the successful invasion of species in novel ranges. Results from this study help elucidate an important mechanism in the invasive capacity of legumes

Differential plant invasiveness is not always driven by host promiscuity with bacterial symbionts

Identification of mechanisms that allow some species to outcompete others is a fundamental goal in ecology and invasive species management. One useful approach is to examine congeners varying in invasiveness in a comparative framework across native and invaded ranges. Acacia species have been widely introduced outside their native range of Australia, and a subset of these species have become invasive in multiple parts of the world. Within specific regions, the invasive status of these species varies. Our study examined whether a key mechanism in the life history of Acacia species, the legume-rhizobia symbiosis, influences acacia invasiveness on a regional scale. To assess the extent to which species varying in invasiveness correspondingly differ with regard to the diversity of rhizobia they associate with, we grew seven Acacia species ranging in invasiveness in California in multiple soils from both their native (Australia) and introduced (California) ranges. In particular, the aim was to determine whether more invasive species formed symbioses with a wider diversity of rhizobial strains (i.e. are more promiscuous hosts). We measured and compared plant performance, including aboveground biomass, survival, and nodulation response, as well as rhizobial community composition and richness. Host promiscuity did not differ among invasiveness categories. Acacia species that varied in invasiveness differed in aboveground biomass for only one soil and did not differ in survival or nodulation within individual soils. In addition, acacias did not differ in rhizobial richness among invasiveness categories. However, nodulation differed between regions and was generally higher in the native than introduced range. Our results suggest that all Acacia species introduced to California are promiscuous hosts and that host promiscuity per se does not explain the observed differences in invasiveness within this region. Our study also highlights the utility of assessing potential mechanisms of invasion in species’ native and introduced ranges