Methods of assessing extinction risk in marine fishes   总被引：1，自引：0，他引：1  

Nicholas K Dulvy  Jim R Ellis  Nicholas B Goodwin  Alastair Grant  John D Reynolds  & Simon Jennings 《Fish and Fisheries》2004,5(3):255-276

The decline and disappearance of species from large parts of their former geographical range has become an important issue in fisheries ecology. There is a need to identify which species are at risk of extinction. The available approaches have been subject to considerable debate – particularly when applied to commercially exploited species. Here we have compiled methods that have been used or may be used for assessing threat status of marine organisms. We organize the methods according to the availability of data on the natural history, ecology and population biology of species. There are three general approaches to inferring or assessing extinction risk: (i) correlative approaches based on knowledge of life histories and ecology; (ii) time‐series approaches that examine changes in abundance; and (iii) demographic approaches based on age‐ or stage‐based schedules of vital rates and fisheries reference points. Many methods are well suited to species that are highly catchable and/or have relatively low productivity, but theory is less well developed for assessing extinction risk in species exhibiting narrow geographical distributions or ecological specialization. There is considerable variation in both definitions of extinction risk and the precision and defensibility of the available risk assessment methods, so we suggest a two‐tiered approach for defining and assessing extinction risk. First, simple methods requiring a few easily estimated parameters are used to triage or rapidly assess large numbers of populations and species to identify potentially vulnerable populations or species. Second, the populations and species identified as vulnerable by this process can then be subject to more detailed and rigorous population analysis explicitly considering sources of error and uncertainty.  相似文献   

Duration and method of fixation affects the sensitivity of a digoxygenin-labelled DNA probe in detecting Kudoa thyrsites in Atlantic salmon skeletal muscle     

Simon R. M. Jones  Benjamin Goh  Gina Prosperi-Porta 《Aquaculture (Amsterdam, Netherlands)》2003,220(1-4):157-164

The effect of fixative and duration of fixation on the sensitivity of a non-radioactive in situ hybridisation (ISH) protocol to detect Kudoa thyrsites small subunit ribosomal deoxyribonucleic acid (DNA) was investigated. Strong ISH reactions were detected in 5-μm sections of paraffin-embedded Atlantic salmon muscle after fixation for 1 day in Davidson's solution (DS). Reactions were weak following 3 or 5 days fixation and absent after 17 or 28 days fixation. Strong ISH reactions were observed after 1, 3 or 5 days fixation in neutral buffered formalin (NBF). The reactions were weak after 17 days and weak to nonexistent after 28 days of fixation. Reactions were consistently strong after fixation in 95% ethanol for up to 28 days. Some mature spores reacted weakly or not at all by ISH. Parasite DNA was weakly amplified by polymerase chain reaction (PCR) from paraffin-embedded muscle after 1 day of fixation in DS but not after fixation for 3, 5, 17 or 28 days. Amplified DNA was detected after fixation in NBF for 1, 3 and 5 days, but not after 17 or 28 days. In contrast, PCR consistently amplified DNA from paraffin-embedded, ethanol-fixed muscle. Caution should be used in the choice of fixative and duration of fixation when preserving Atlantic salmon tissues for molecular diagnosis of K. thyrsites.  相似文献   

The impact of small-scale design interventions on the behaviour patterns of the users of an urban wasteland     

Anna-Liisa Unt  Simon Bell 《Urban Forestry & Urban Greening》2014,13(1):121-135

Urban derelict space can form a valuable complementary element to the formal green spaces of a city: wastelands are often biologically diverse and their unregulated status can provoke innovative spatial activities by a wide range of users. Using the case of an urban brownfield in Tallinn, Estonia, this paper examines how such a space is used and evaluates the magnitude of the impact of minor design interventions – so-called urban acupuncture – on the activities carried out by the users. The study used field observations and behaviour mapping to compare the spatial pattern of the users before and after small design interventions. Although there was widespread use beforehand there was both an increase in use and a different pattern afterwards, which was clearly detectable from the composite behaviour maps of both arrangements, where users follow the properties of the particular environment. The small improvements tested showed the largest effect on the female and the older user groups, raising the number of overall visits and increasing the occurrence of active behaviour almost five times. The research demonstrates that small, inexpensive and possibly temporary interventions can have a major positive effect.  相似文献   

Diagnosis and management of small-scale fisheries in developing countries   总被引：2，自引：0，他引：2  

Neil L Andrew  Christophe Béné  Stephen J Hall  Edward H Allison  Simon Heck  & Blake D Ratner 《Fish and Fisheries》2007,8(3):227-240

Small‐scale fisheries (SSF) make important but undervalued contributions to the economies of some of the world’s poorest countries. They also provide much of the animal protein needed by societies in which food security remains a pressing issue. Assessment and management of these fisheries is usually inadequate or absent and they continue to fall short of their potential as engines for development and social change. In this study, we bring together existing theory and methods to suggest a general scheme for diagnosing and managing SSF. This approach can be adapted to accommodate the diversity of these fisheries in the developing world. Many threats and solutions to the problems that beset SSF come from outside the domain of the fishery. Significant improvements in prospects for fisheries will require major changes in societal priorities and values, with consequent improvements in policy and governance. Changes in development policy and science reflect these imperatives but there remains a need for intra‐sectoral management that builds resilience and reduces vulnerability to those forces beyond the influence of small‐scale fishers.  相似文献   

Tanjungides A and B: New Antitumoral Bromoindole Derived Compounds from Diazona cf formosa. Isolation and Total Synthesis     

Carmen Murcia  Laura Coello  Rogelio Fernández  María Jesús Martín  Fernando Reyes  Andrés Francesch  Simon Munt  Carmen Cuevas 《Marine drugs》2014,12(2):1116-1130

Tanjungides A (1) (Z isomer) and B (2) (E isomer), two novel dibrominated indole enamides, have been isolated from the tunicate Diazona cf formosa. Their structures were determined by spectroscopic methods including HRMS, and extensive 1D and 2D NMR. The stereochemistry of the cyclised cystine present in both compounds was determined by Marfey’s analysis after chemical degradation and hydrolysis. We also report the first total synthesis of these compounds using methyl 1H-indole-3-carboxylate as starting material and a linear sequence of 11 chemical steps. Tanjungides A and B exhibit significant cytotoxicity against human tumor cell lines.  相似文献   

Residential movements of top predators in Chile’s most isolated marine protected area: Implications for the conservation of the Galapagos shark,Carcharhinus galapagensis,and the yellowtail amberjack,Seriola lalandi     

Naití A. Morales  Maike Heidemeyer  Robert Bauer  Sebastian Hernández  Enzo Acuña  Simon Jan van Gennip  Alan M. Friedlander  Carlos F. Gaymer 《水产资源保护:海洋与淡水生态系统》2021,31(2):340-355

1. Marine protected areas (MPAs) are becoming a widely used tool for the conservation of biodiversity and for fishery management; however, most of these areas are designed without prior knowledge of the basic ecological aspects of the species that they are trying to protect.
2. This study investigated the movement of two top predators: the Galapagos shark, Carcharhinus galapagensis, and the yellowtail amberjack, Seriola lalandi, in and around the Motu Motiro Hiva Marine Park (MMHMP) using MiniPAT satellite tags to determine the effectiveness of this MPA for the protection of these species.
3. The Galapagos sharks (n = 4) spent most of their tag deployment periods inside the MMHMP. However, high intraspecific variability was observed in their movement dynamics. Daily individual maximum movements ranged from 17 to 58 km and the maximum distance from Salas y Gómez Island, the only emergent island within the MMHMP, ranged from 31 to 139 km.
4. The maximum linear distance travelled for a female juvenile Galapagos shark (152 cm total length) was 236 km, which is greater than the maximum distance previously documented for juveniles of this species (<50 km).
5. For the yellowtail amberjack (n = 1), 91% of the satellite geolocations were within the MMHMP, with a maximum daily distance travelled of 6 km. The maximum distance travelled between points was 111 km and the maximum distance from Salas y Gómez Island was 62 km.
6. All archival tagged fish spent most of their time at depths of <50 m and never left the epipelagic zone. Daytime versus night-time differences were pronounced in all individuals but showed high interindividual variability.
7. This study provides a baseline on the movement of these two top predators in the MMHMP and provides valuable insights for the creation of MPAs in the region and elsewhere.

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Methodology for recovery and identification of enteropathogenic Escherichia coli     

I J Mehlman  A C Sanders  N T Simon  J C Olson 《Journal of the Association of Official Analytical Chemists》1974,57(1):101-110

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Effect of equilateral administration of monensin and tiamulin on the peripheral nerve function and the electrocardiogram of broilers     

P Laczay  F Simon  J Lehel 《DTW. Deutsche tier?rztliche Wochenschrift》1991,98(8):306-310

The influence of the simultaneous administration of monensin and tiamulin on the motor nerve conduction velocity and the refractory periods of the N. ischiadicus was studied on 4-week old cockerels. The combined administration of the two substances resulted in significant decrease of the conduction velocities of the peripheral nerve, while the relative and absolute refractory periods were seen to increase significantly as a result of the medications. The observed alteration of the peripheral nerve function in the early phase can already attribute to the development of the serious clinical signs of the toxic interaction. The simultaneous application of monensin and tiamulin caused also changes in the electrocardiogram which was expressed in a prolongation of the RS interval and the ST segment. At the same time the heart rate was reduced.  相似文献   

RADIOGRAPHIC DIAGNOSIS-LATERALIZED VERTEBRAL OSSEOUS COMPRESSION CAUSING CERVICAL SPONDY-LOMYELOPATHY IN A GREAT DANE     

Carley J.  Abramson  DVM  Ruth  Dennis  MRCVS  Ken C.  Smith  BMV & S  PHD  MRCPath  MRCVS  Simon R.  Platt  BVM & S  MRCVS 《Veterinary radiology & ultrasound》2003,44(1):56-58

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Influence of a probiotic Enterococcus faecium strain on selected bacterial groups in the small intestine of growing turkey poults.     

W Vahjen  Anke Jadamus  O Simon 《Archives of Animal Nutrition》2002,56(6):419-429

A feeding trial was carried out with turkey poults, which were fed a diet containing 10(10) viable probiotic E. faecium NCIB 10415 cells/kg feed. Samples of the intestinal tract were analyzed for lactate, colony forming units of total anaerobic bacteria, lactic acid bacteria, enterobacteria and enterococci. Furthermore, metabolic activity of total eubacterial, lactobacilli and enterococci was recorded in selected RNA-extracts with specific ribosomal RNA oligonucleotide probes. Animals fed the probiotic diet showed continously increasing lactate concentrations throughout the sampling period up to day 42 of life. No correlation was found for colony forming units (cfu) of lactic acid bacteria, but metabolic activity of lactobacilli showed very close relation to continously increasing lactate concentrations. Throughout the feeding trial, enterococci in the control group continously increased to a maximum of 10(4) cfu/g wet weight, but 10-fold higher enterococci cfu were generally found in the treated group. However, rRNA content as measure for metabolic activity showed a drastic decline in both groups after high metabolic activities on day 7. This study shows that E. faecium NCIB 10415 (E. faecium SF68) stimulates other lactic acid bacteria in the small intestine, especially lactobacilli.  相似文献