Review of morphological and behavioural differences between reared and wild individuals: Implications for sea-ranching of Atlantic salmon, Salmo salar L., Atlantic cod, Gadus morhua L., and European lobster, Homarus gammarus L.

Abstract The main question which must be raised when planning to enhance natural populations through sea ranching is whether reared organisms are fit for a life in the wild, or more specifically, whether there are differences between reared and naturally resident individuals. The causes and effects of these differences are reviewed, and results from the Norwegian enhancement programme, which compared reared and wild individuals of Atlantic salmon, Salmo salar L., Atlantic cod, Gadus morhua L., and European lobster, Homarus gammarus L., are discussed with emphasis on morphological and behavioural differences. It was concluded that exposure to an artificial rearing environment during ontogeny can affect both the phenotype and the behaviour of the reared individuals, and thereby, their potential for survival after release into the wild as well. Suggestions are made as to how to diminish observed differences, and thereby, improve the survival potential.     

Variations in dark respiration and mitochondrial numbers within needles of Pinus radiata grown in ambient or elevated CO2 partial pressure

Within-leaf variations in cell size, mitochondrial numbers and dark respiration rates were compared in the most recently expanded tip, the mid-section and base of needles of Pinus radiata D. Don trees grown for 4 years in open-top chambers at ambient (36 Pa) or elevated (65 Pa) carbon dioxide partial pressure (p(CO2)a). Mitochondrial numbers and respiratory activity varied along the length of the needle, with the highest number of mitochondria per unit cytoplasm and the highest rate of respiration per unit leaf area at the base of the needle. Regardless of the location of the cells (tip, middle or basal sections), needles collected from trees grown in elevated p(CO2)a had nearly twice the number of mitochondria per unit cytoplasm as those grown in ambient p(CO2)a. This stimulation of mitochondrial density by growth at elevated p(CO2)a was greater at the tip of the needle (2.7 times more mitochondria than in needles grown in ambient CO2) than at the base of the needle (1.7 times). The mean size of individual mitochondria was unaffected either by growth at elevated p(CO2)a or by position along the needle. Tree growth at elevated p(CO2)a had a variable effect on respiration per unit leaf area, significantly increasing respiration in the tip of the needles (+25%) and decreasing respiration at the mid-section and base of the needles (-14% and -25%, respectively). Although a simple relationship between respiration per unit leaf area and mitochondrial number per unit cytoplasm was found within each CO2 treatment, the variable effect of growth at elevated p(CO2)a on respiration along the length of the needles indicates that a more complex relationship must determine the association between structure and function in these needles.     

Abscisin II, an Abscission-Accelerating Substance from Young Cotton Fruit

Crystalline abscisin II, with a tentative molecular formula of C(15)H(20)O(4), has been isolated from young cotton fruit. It accelerates abscission when applied in amounts as low as 0.01 microg per abscission zone. It inhibits indoleacetic acid-induced straight growth of Avena coleoptiles but has no gibberellin activity on dwarf maize.     

Effects of light quality on conidiophore formation of the melon powdery mildew pathogen <Emphasis Type="Italic">Podosphaera xanthii</Emphasis>

The lengths of conidiophores in fungal colonies of the melon powdery mildew pathogen Podosphaera xanthii Pollacci KMP-6 N cultured under greenhouse (natural) conditions differed markedly from those cultured in a growth chamber. We hypothesized that light wavelength was responsible for the differences in conidiophore length. In this study, we examined the effects of light-emitting diode (LED) irradiation (purple, blue, green, orange, and red light) and white light on colony development and conidiophore formation in KMP-6 N using a stereomicroscope and a high-fidelity digital microscope. Colonies on leaves were flat under greenhouse conditions and under red LED light irradiation but were stacked under growth chamber conditions and under purple, blue, green, and orange LED light irradiation. In addition, KMP-6 N formed catenated conidia comprising six conidia per conidiophore under greenhouse conditions and red light but more than seven conidia per conidiophore under growth chamber conditions and purple, blue, green, and orange light. Furthermore, almost none of the conidia on top of the conidiophores grown under blue light were fully constricted. Therefore, these fungi could not scatter their conidia and spread infection. This is the first report of the effects of LED lights on conidiophore formation in the melon powdery mildew fungus P. xanthii. The results provide insight into the mechanisms underlying the responses of conidiophores to light of specific wavelengths and conidial scatter from conidiophores of melon powdery mildew fungi.     

The EFSA quantitative approach to pest risk assessment – methodological aspects and case studies

A new method for pest risk assessment and the identification and evaluation of risk‐reducing options is currently under development by the European Food Safety Authority (EFSA) Plant Health Panel. The draft method has been tested on pests of concern to the European Union (EU). The method is adaptable and can focus either on all the steps and sub‐steps of the assessment process or on specific parts if necessary. It is based on assessing changes in pest population abundance as the major driver of the impact on cultivated plants and on the environment. Like other pest risk assessment systems the method asks questions about the likelihood and magnitude of factors that contribute to risk. Responses can be based on data or expert judgment. Crucially, the approach is quantitative, and it captures uncertainty through the provision by risk assessors of quantile estimates of the probability distributions for the assessed variables and parameters. The assessment is based on comparisons between different scenarios, and the method integrates risk‐reducing options where they apply to a scenario, for example current regulation against a scenario where risk‐reducing options are not applied. A strategy has been developed to communicate the results of the risk assessment in a clear, comparable and transparent way, with the aim of providing the requestor of the risk assessment with a useful answer to the question(s) posed to the EFSA Plant Health Panel. The method has been applied to four case studies, two fungi, Ceratocystis platani and Cryphonectria parasitica, the nematode Ditylenchus destructor and the Grapevine flavescence dorée phytoplasma. Selected results from these case studies illustrate the types of output that the method can deliver.     

Evaluation of success rate of laparoscopic castration without orchidectomy in 32 mature horses

The surgical success of laparoscopic castration without orchidectomy results from avascular necrosis of the testes. However, failures and subsequent production of testosterone and stallion‐like behaviour have been previously identified. Laparoscopic castration without removal of the testes was performed in 32 horses with 2 normal descended scrotal testes between July 2006 and October 2012. The objectives of our study were to evaluate the success rate of laparoscopic castration without orchidectomy on descended testes in our population and assess complications and recovery time. Endocrine tests were performed after surgery and owners also asked to report on their horse's behaviour and ability to resume exercise. Castration was deemed successful if endocrine test results were in accordance with gelding values. Failed horses were castrated using a conventional technique and histology performed when possible. Basal testosterone levels decreased below 3 nmol/l after surgery in 30/32 cases. However, in 2 horses, stallion behaviour persisted and histological evaluation after inguinal castration showed residual viable tissue. Two horses maintained high testosterone levels after surgery associated with stallion‐like behaviour. Based on these results, 12.5% of horses (4/32 horses) failed to be considered a gelding based on either endocrine tests and/or histology. All horses, with one exception, were able to resume exercise less than a week after the procedure. Laparoscopic castration without orchidectomy appears to be a safe procedure. When assessing the success of laparoscopic castration, our total failure rate was 12.5% (4/32 horses) which is significantly higher than previously reported.     

First report of leaf spot caused by <Emphasis Type="Italic">Alternaria alternata</Emphasis> on <Emphasis Type="Italic">Drimia maritima</Emphasis>

Drimia maritima (squill) is a historically important medicinal plant. During the spring of 2016, small, yellow leaf spots, which became brown and finally necrotic, were observed on squill plants in Kohgiluyeh and Boyer-Ahmad Provinces in Iran. A fungus was consistently isolated from infected leaves and identified as Alternaria alternata based on morphological and phylogenetic analyses. Pathogenicity tests confirmed A. alternata to be the causal agent of the newly observed leaf spot disease. This is the first report of leaf spot on D. maritima caused by A. alternata in the world.     

Comparison of larval thermal maxima between <Emphasis Type="Italic">Fundulus heteroclitus</Emphasis> and <Emphasis Type="Italic">F. grandis</Emphasis>

Fundulus heteroclitus and F. grandis are resident salt marsh fishes that overlap in distribution over a narrow range in northeastern Florida. The objective of the present study was to examine whether the limits of the species’ ranges could be explained by differences in thermal tolerance. Two populations of each species were collected and then spawned in the laboratory, and 9-day-old larvae were used for critical thermal maxima trials. Mean LOE temperatures of larvae ranged from 43.04 to 43.65°C and showed little difference between species. Therefore, differences in high temperatures experienced cannot account for the differences of the distributions of the two species. Condition-specific competition may play a greater role in determining the observed range of the two species.