Sex ratio changes in the long-term Windermere pike and perch sampling program

Abstract– Analysis of the Windermere (England), Perca fluviatilis (1965–1997) and Esox lucius (1943-1997) fishery data indicates there have been substantial changes in sex ratios through time. In the case of perch, a 1976 perch disease outbreak substantially skewed the sex ratio in favor of females. It took over a decade for the fishery to recover to its pre-1976 state. In the case of pike, both catch and year-class data are female biased, but this bias has significantly weakened through time. This trend towards proportionately more males through time may reflect an effect of increasing spring temperatures or an evolutionary or phenotypic response to female-biased fishing pressure.     

Larval pigmentation, survival and growth of Penaeus indicus fed the nematode Panagrellus redivivus enriched with astaxanthin and various lipids

The highly unsaturated fatty acid (HUFA) content of the free-living nematode Panagrellus redivivus was successfully increased when three different lipid sources (cod-liver oil, marilla oil and capelin oil) from marine animals were used in the nematode culture medium. The lipid enrichment significantly increased the ω3 HUFA content, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), of the nematodes compared with lipid non-enriched nematodes. Penaeus indicus larvae fed the lipid-enriched nematodes had significantly ( P < 0.05) greater larval survival (69–77%) until metamorphosis than those fed non-enriched nematodes (54%).
This nematode species was also enriched with astaxanthin to determine the effects of this carotenoid on pigmentation, survival and growth during the larval development of P. indicus . The pigment, delivered via nematodes, significantly ( P < 0.05) improved larval coloration and survival (88%) compared with that of placebo-pigmented nematodes (78%). However, there was no strong evidence to show the benefit of either pigment and/or lipid enrichment on larval growth and development of P. indicus .
This study has shown that the nutritional value of the nematodes can be enhanced by the addition of fish oil into the culture medium. Supplementation of EPA and DHA, together with synthetic astaxanthin, allow the nematodes to be used as a sole diet for the larval culture of P. indicus .     

Bridging the divide: Social–ecological coherence in Marine Protected Area network design

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Development of a Pseudomonas syringae–Eutrema salsugineum pathosystem to investigate disease resistance in a stress tolerant extremophile model plant

To improve the ability to understand how plants respond to multiple and/or concurrent stresses, disease resistance was investigated in Eutrema salsugineum, an extremophile model plant that is highly tolerant of abiotic stress. Compared to Arabidopsis (Col‐0), both Yukon and Shandong Eutrema accessions exhibit increased resistance to Pseudomonas syringae pv. tomato DC3000 (Pst) and pv. maculicola (Psm), with Shandong Eutrema exhibiting greater resistance to Pst than Yukon Eutrema. RT‐PCR of the EsPR1 (Pathogenesis‐related 1) defence marker gene confirmed RNA‐Seq data that healthy Shandong Eutrema constitutively expresses EsPR1. The data suggests that Shandong Eutrema exists in a highly primed state of defence preparedness, as it displays heightened resistance compared to defence‐primed natural accessions of Arabidopsis (Can‐0, Bur‐0). Pathogen‐triggered PR1 expression was delayed in Yukon Eutrema; however, these plants were resistant to Pst suggesting that Yukon Eutrema employs a PR1‐independent mechanism to resist Pst. This study demonstrates that Eutrema is an excellent model to investigate biotic stress tolerance. The Eutrema–P. syringae pathosystem will facilitate future studies to understand how this extremophile tolerates both abiotic and biotic stress, and will allow exploration of the interplay of these responses to inform efforts to improve stress tolerance in crops.     

Developing a critical nitrogen dilution curve for forage brassicas

Defining the critical nitrogen concentration (N_c; g N kg^?1) for maximum growth of forage brassicas will aid in the fertilizer management of these crops. Typically, the N_c value decreases with increasing crop biomass. In this paper, we used a nitrogen (N) response experiment with kale (Brassica oleracea) to define a critical N dilution (N_c = 55·3 × biomass^?0·47). However, at biomass <3·4 t ha^?1, a constant N_C of 31·2 g N kg^?1 was found. This N dilution curve compared favourably with published data sets for a range of forage brassicas but was substantially different from the established N dilution curve for oilseed rape (Brassica napus). This study also found a strong relationship (R² = 0·81) between the nitrogen nutrition index (NNI) and the NO₃ content of forage brassicas from a range of data sets. The NNI is the actual N concentration of the shoot as a ratio of the N_c from the established curve. The relationship between NNI and NO₃ contents was significantly different between leafy forage brassica crops and root forage brassicas. For each 0·1 increase in NNI, the proportion of total N that was in the form of NO₃ increased by 2·7% for leaf/stem brassicas and 0·60% for root crop brassicas. The critical dilution curve defined in this study can be used to manage fertilizer N in forage brassica crops, so that growth can be maximized but the risk of high NO₃ concentrations in the forage can be minimized.     

Validation of the BioPRYN enzyme‐linked immunosorbent assay for detection of pregnancy‐specific protein‐B (PSPB) and diagnosis of pregnancy in American bison (Bison bison)

This study assessed the accuracy of the commercial BioPRYN^® ELISA for the detection of pregnancy‐specific protein‐B (PSPB) using a single blood sample to determine pregnancy status in American bison (Bison bison). A total of 49 bison cows were used in the study, and sampled at two time‐points during the gestation period, fall and spring, correlating with early‐ to mid‐term gestation (average 62.9 days post‐mating) and mid‐ to late‐term gestation (average 229.2 days post‐mating), respectively. Sensitivity of the test during early‐ to mid‐term gestation sampling period (fall) was 87.1%, while specificity was 100%; sensitivity of the test during late‐term gestation sampling period (spring) was 96.3%, while specificity remained at 100%. In total, the test showed a total sensitivity of 91.4%, specificity of 100% and total accuracy of 93.8%, similar to domestic cattle. Use of the single‐sample BioPRYN^® ELISA in American Bison for pregnancy diagnosis is economical and practical, minimizing animal handling time, frequency and subsequent stress while providing accurate results for pregnancy diagnosis at 62 days post‐mating. This method should be considered over more traditional pregnancy diagnosis methods for use in managed bison herds.     

Retrospective Study: Incidence of ionized hypocalcemia in septic dogs and its association with morbidity and mortality: 58 cases (2006–2007)

Objective – To determine the incidence rate and prognostic significance of ionized hypocalcemia (iHCa) among septic dogs. Design – Retrospective study Setting – Veterinary teaching hospital Animals – Fifty‐eight septic dogs that were presented to Cornell University Hospital for Animals between January 2006 and December 2007. Procedure – Cases were diagnosed with sepsis if they exhibited 2 or more criteria of the systemic inflammatory response syndrome with a concurrent documented infectious focus. Cases were excluded if diagnosed with a concurrent illness reportedly associated with calcium derangements. Lowest, mean, and highest blood ionized calcium concentrations were recorded and statistically analyzed for an association with morbidity, as measured by duration of hospitalization and number of blood product transfusions, and outcome. In addition, the incidence rate of iHCa was recorded. Results – Of the 58 cases included in this study, iHCa was documented in 4 of 6 (67%) patients that died, 5 of 19 (26%) euthanized patients and 5 of 33 (15%) patients that survived to discharge, with an overall incidence of 24%. Dogs that died during hospitalization had more severe iHCa than patients that were discharged or euthanized as well as significantly lower mean ionized calcium concentrations than patients who were discharged. Severity of iHCa was also associated with a longer duration of hospitalization. The highest ionized calcium concentration was not associated with outcome. Conclusion and Clinical Relevance – This study is the first to document the incidence of iHCa among septic dogs. Because both low mean ionized calcium and the lowest documented ionized calcium concentration are associated with poor outcome, it is likely that both the severity and duration of hypocalcemia are important in these patients. Further prospective studies investigating the prognostic significance, etiology and treatment of iHCa among septic veterinary patients are needed to better understand its role in sepsis.     

Signal detection theory clarifies the concept of perceptual range and its relevance to landscape connectivity

Understanding functional connectivity is critical for several issues in ecology and conservation. When animals actively search for habitat across landscapes, their perceptual range of habitats can profoundly influence connectivity. Nonetheless, conceptual development and estimation of perceptual ranges and their influence on connectivity have been limited. Signal detection theory (SDT) has a long tradition in several disciplines to address the problem of detecting stimuli in noisy and uncertain environments. SDT is particularly useful for understanding perceptual ranges because it acknowledges uncertainty in the detection process and distinguishes between two key parameters that have previously been confounded when interpreting the perceptual range of animals: signal detectability and response bias of individuals. Here we extend SDT to the concept of perceptual range, provide approaches for estimating patch detectability and response bias, and apply this framework to interpreting the perceptual range of cactus bugs (Chelinidea vittiger). We find that signal detectability of habitat by C. vittiger, and thus their perceptual range, is between 1 and 2 m, based on generalized linear models aimed at estimating signal detection parameters. SDT provides new insights into perceptual ranges and functional connectivity, which may help understand intra and interspecific variation in animal responses to modified landscapes.