A multiplex polymerase chain reaction assay for the identification of Mannheimia haemolytica, Mannheimia glucosida and Mannheimia ruminalis

The objective of this study was to design a multiplex PCR assay to identify Mannheimia haemolytica, Mannheimia glucosida and Mannheimia ruminalis. The multiplex PCR included primer sets HP, amplifying a DNA region from an unknown hypothetical protein, Lkt and Lkt2, amplifying different regions of the leukotoxinD gene, and 16S to amplify universal bacterial sequences of the 16S rRNA gene. Based on positive amplification, isolates were delineated as M. haemolytica (HP, Lkt, 16S), M. glucosida (HP, Lkt, Lkt2, 16S), or M. ruminalis (HP, 16S). The validity of the assay was examined against 22 reference strains within the family Pasteurellaceae and 17 field isolates (nasal) that had been collected previously from feedlot cattle and tentatively identified as M. haemolytica based on morphology and substrate utilization. Additionally, 200 feedlot cattle were screened for M. haemolytica using multiplex PCR. Forty-four isolates from 25 animals were identified as M. haemolytica. The PCR assay positively identified all M. haemolytica, as confirmed by phenotypic tests and clustering based upon cellular fatty acid methyl ester (FAME) profiles. Selected nasal isolates that exhibited evidence of haemolysis, but were M. haemolytica-negative based on PCR, were also confirmed negative by phenotypic and FAME analyses. The multiplex PCR assay required no additional phenotypic tests for confirmation of M. haemolytica, within the group of bacteria tested.     

Weaknesses in stock assessment modelling and management practices affect fisheries sustainability

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Heavy metal concentrations and sediment quality of a cage farm on Lake Volta,Ghana

This study involved the determination of sediment quality and heavy metals in the water column and bottom sediment of a selected cage fish farm in Lake Volta, to assess the potential impact of metals and organic matter pollution on the lake due to cage fish farming. Sediment analysis indicated that the texture of all sampling sites was sandy clay loam with sand dominating with a range of 31.5%–81.2%. The organic matter (TOM) ranged from 4.42%–8.89%, while organic carbon (TOC) was from 2.57%–5.22%. Total nitrogen (TN) fluctuated between 0.22% and 0.45%; total phosphate ranged between 0.22% and 5.30%. The TOC, TOM and TN content in the farm sediment were significantly lower than those of the reference sites (ANOVA, p < .05). Lead, copper, cadmium and selenium were not detected in the water. The results revealed that heavy metal concentrations in the water column and sediments were low and within tolerable levels, indicating no influence of metals from fish feed was observed on the lake water quality. However, the farm seemed to have moderate impact on sediment quality from organic matter. Water and sediment quality monitoring should be embarked upon periodically to ensure sustainable cage culture in the Lake Volta.     

How do individual transferable quotas affect marine ecosystems?

Published papers were reviewed to assess ecosystem impacts of individual transferable quotas (ITQs) and other dedicated access systems. Under ITQs, quota shares increase with higher abundance levels, thus fishers may request lower total allowable catches (TACs) and pay for monitoring and research that improves fishery sustainability. Mortality on target species generally declines because catches are closer to TACs and because ghost fishing through lost and abandoned gear decreases. High-grading and discarding often decline, but may increase if landings (and not catches) count against ITQs and when there is little at-sea enforcement. Overall, ITQs positively impact target species, although collapses can occur if TACs are set too high or if catches are routinely allowed to exceed TACs. Fishing pressure may increase on non-ITQ species because of spillover from ITQ fisheries, and in cases where fishers anticipate that future ITQ allocations will be based on catch history and therefore increase their current catches. Ecosystem and habitat impacts of ITQs were only sparsely covered in the literature and were difficult to assess: ITQs often lead to changes in total fishing effort (both positive and negative), spatial shifts in effort, and fishing gear modifications. Stock assessments may be complicated by changes in the relationship between catch per unit effort, and abundance, but ITQ participants will often assist in improving data collection and stock assessments. Overall, ITQs have largely positive effects on target species, but mixed or unknown effects on non-target fisheries and the overall ecosystem. Favourable outcomes were linked to sustainable TACs and effective enforcement.     

A collaborative design to adaptively manage for landscape sustainability in north Australia: lessons from a decade of cooperative research

Approaches to manage for the sustainable use of natural and cultural resources in a landscape can have many different designs. One design is adaptive collaborative landscape management (ACLM) where research providers and users work closely together on projects to develop resources while adaptively managing to sustain or maintain landscapes in the long term. We propose that collaborative projects are more useful for achieving outcomes than integrative projects where participants merely join their separate contributions. To foster collaborative research projects to adaptively manage landscapes in northern Australia, a Tropical Savannas Cooperative Research Centre (TSCRC) was established in 1995. The TSCRC is a joint venture of major organizations involved in research and land management. This paper is our perspective on the four most important ‘lessons learned’ after using a ACLM-type approach for over 10 y. We learnt that collaboration (working in combination) not necessarily integration (combining parts into a whole) achieved sustainable outcomes. We found that integration across culturally diverse perspectives seldom achieved sustainable solutions because it devalued the position of the less empowered participants. In addition, positive outcomes were achieved when participants developed trust and respect for each other by embracing and respecting their differences and by sharing unifying concepts such as savanna health. Another lesson learned was that a collaborative organization must act as an honest broker by resisting advocacy of one view point over another. Finally, we recognized the importance of strongly investing in communication and networking so that people could adaptively learn from one another’s experiences, understand each other’s challenges and respect each other’s choices. Our experience confirms the usefulness of the ACLM approach and highlights its role in the process of sustaining healthy landscapes.     

慢生型大豆根瘤菌(Bradyrhizobiurm japonicurm)USDA110菌株3-羟丁酸脱氢酶基因(bdhA)的克隆、序列及特性

通过功能互补试验，从慢性型大豆根瘤菌USDA110菌株基因文库中筛选到能互补广宿主根瘤菌NGR234的bdhA突变体菌株NGRPA2和苜蓿根瘤菌的bdhA突变体菌株Rm11107，使之恢复Hbu^ 表型的克隆；经酶活测定的Southern杂交证明该克隆含有bdhA基因。测定了bdhA基因全序列，并在GenBank登记（登记号为：AY077581）。该基因由789个碱基对组成，编码分子量为27.59ku，含262个氨基酸残基的3-羟基丁酸脱氢酶，在该基因的开放阅读框内插入interposonΩKm，并通过同源重组构建了Bradyrhizobium japonicum bdhA突变体（bdhA::ΩKm)。植株试验未显示bdhA基因的突变对结瘤，固痰有明显影响。     

Should we call them fishers or fishermen?

‘Fishermen’ and the gender‐neutral ‘fishers’ are the most common terms used to describe people who fish in the English language. However, there is a considerable debate as to which term is most appropriate. In academic journals, usage of ‘fishers’ for people who fish began in the 1960s and increased over time, until in 2013 and 2014 ‘fishers’ first exceeded usage of ‘fishermen’, despite being labelled ‘archaic’ in the Oxford English Dictionary. In journal searches ‘fishermen’ unambiguously referred to people who fish, but ‘fishers’ also referred to R.A. Fisher's statistical tests (22%), the mammal, Pekania pennanti (5%), and other terms. Journal policies have played a role in the shift to ‘fishers’: e.g. Conservation Biology requires the use of ‘fishers’ while Fishery Bulletin requires ‘fishermen’. Partly as a result, in academia there are disciplinary and geographic variations, with greatest usage of ‘fishers’ in the field of conservation biology and in Australia. Surprisingly, word choice did not differ by the gender of the lead author. Many other languages also have gender‐neutral terms for people who fish (e.g. Austronesian and Turkic languages), yet the word is still assumed to refer to men. While the gender‐neutral term ‘fisher’ is more inclusive it is far from universally accepted, particularly by women and men in the North American fishing industry. The current shift towards the more inclusive term ‘fishers’ highlights the increasing disciplinary diversity within fisheries science, particularly in terms of gender.     

Physical characteristics,and proximate composition of oocytes,liver and muscle of wild caught and tank-reared Macquarie perch

Macquarie perch (Macquaria australasica) is a freshwater percichthyid endemic to south-eastern Australia. In view of its conservation status (indeterminate), and its importance as a sport fish, natural stocks are replenished through a breeding programme using mature stock taken from the wild each year.This paper is the first of a series of investigations instigated to understand the underlying causes of the lack of response of Macquarie perch, caught from the wild and spawned and then tankreared for a year, to hypophysation techniques. In this paper, results of physical characteristics, proximate composition and ovarian histology of wild-caught and tank-reared fish (injected with salmon GnRHa and non-injected) are presented. Oocyte diameter distribution patterns indicate that Macquarie perch spawn once each year, and that in tank-reared fish oocyte maturation is incomplete with only a small proportion of oocytes reaching maturation. The mean (sd) gonadosomatic and hepatosomatic indices of wild fish were 11.25 (2.38) and 0.59 (0.10) and that of tank-reared fish were 4.84 (0.70) and 1.44 (0.09) respectively. These two parameters differed significantly (p<0.05) in the two groups of fish.Major differences also existed in the proximate composition of the liver and the way the liver components responded to GnRHa injection. The percent (sd) protein, lipid and ash by dry weight in the liver of wild injected fish were 57.02 (0.66), 30.63 (1.22) and 8.24 (0.05) respectively while in the liver of tank-reared uninjected fish these values were 30.87 (1.36), 24.59 (1.18) and 6.43 (0.13) respectively. When expressed as an absolute amount or an amount kg^–1 body weight, all of moisture, protein, lipid, ash and nitrogen free extract were greater in tank-reared than wild fish. No significant differences were observed between wild and tank-reared fish in the composition of the body musculature or the oocytes.