塘堰轮捕轮放网具及其轮捕技术的研究

对塘堰鲢、鳙、草鱼的体形系数研究得出:鲢、鳙、草鱼的体长系数K_1分别为0.166,0.168和0.145;肥瘦系数K_2分别为6.36,6.40和5.50。直接采用体重公式α=K_2·G~(1/3)的计算结果来设计网具的网目大小。对所研究的三层拖刺网和革新地曳网经1984、1985两年的8个不同塘堰面积,近100网次的试验,证明它们是塘堰轮捕轮放的新型网具。     

Burrowing behaviour of unionid mussels in subtropical rivers: Implications for survey guidelines

1. Conservation efforts have increased in response to global mussel declines, and effective surveys are a crucial step in assessing and monitoring mussel populations and in determining their conservation status. The burrowing behaviour of mussels can affect their detectability, and a better understanding of these behaviours would help to improve survey design and guidelines.
2. The burrowing depth of mussels may differ between seasons, habitat conditions, species, and individuals, and little is known about the burrowing behaviour of mussels in subtropical rivers.
3. Burrowing depth variation was examined and compared at three sites in the San Marcos, Guadalupe, and San Antonio river drainages in central Texas. In addition, laboratory experiments were used to determine whether observed differences between field sites and seasons could be linked to differences in substrate type and water temperature and to examine differences between species.
4. Seasonal variation in burrowing depth was found at all field sites, and water temperature was a significant factor for explaining variation in burrowing depth, but there was no clear relationship between burrowing depth and temperature in shorter term laboratory experiments, where individual variation was high and burrowing behaviour seemed to be solely a function of time.
5. Mussels burrowed significantly deeper in finer substrate (sand vs. gravel) in both field and laboratory experiments. Few significant differences between species were found in the field, but no differences were found in the laboratory experiments.
6. The results suggest that surveys may need to follow different guidelines depending on local conditions, such as substrate and water temperature. Surveys will be less efficient and may fail to detect larger proportions of populations in colder water temperatures. In addition, a larger proportion of burrowed mussels can be expected at sites with finer substrate, such as sand. Under these conditions, visual searches will not suffice, as a large part of the population or specific species may be overlooked.

     

Gill net selectivity for perch (Perca fluviatilis) in the Szczecin Lagoon, Poland

This paper presents the scientific basis for changes in the minimum mesh size in gill nets, from 28 to 30 mm, introduced by fishery management in Poland to limit the catch of undersized perch (those less than 17 cm total length). Experimental fishing with six different mesh sizes was performed in accordance with commercial fisheries practice. A bi-normal selection curve was fitted to the data by including the between-set variation in the model. The locations of the primary and secondary modes of the bi-normal curve on the transformed length scale (length/mesh) were estimated to be 6.95 and 7.41, respectively. The results indicated that a minimum mesh size in gill nets of 28 mm should be sufficient to ensure a low level of discards as well as protecting the interests of fishermen.     

Methodological, conceptual and sampling practices in surveying recreational fisheries in the Nordic countries – experiences of a valuation survey

The planning and initial phases of a joint Nordic project for the valuation of recreational fisheries is described. The economic value of recreational fisheries was taken to include non-market value as well as the traditional market value. The design of the survey was similar for each country so as to facilitate future comparison. However, initially there were difficulties in defining categories of recreational fishermen in the different countries. Other background information also had to be adapted to national circumstances. National population registers were used as the sampling frames. The effect of this on the responses from a valuation survey is discussed. Accessibility to population register data varies by country and so do possibilities for random sampling. Legal constraints were faced when implementing a centralised mailing system.     

Aquaria and marine environmental education

Marine aquaria claim that they help to elevate the current low profile of marine conservation through public education. The effectiveness of aquaria as centres for marine conservation education was assessed using social survey techniques, at three large commercial aquaria in the south-west of England. The aquaria managers did not believe that most visitors were interested in receiving educational information, in particular on conservation topics. Textual analysis revealed that aquaria's interpretative material contained very few references to conservation and portrayed a distorted image of the marine environment. The feedback from the questionnaires revealed no evidence for an increase in visitors' sympathy towards and understanding of marine conservation following a visit to an aquarium. The majority of visitors wanted public aquaria to increase their levels of interpretation. In particular, visitors wanted more information on conservation and how they, as individuals , could contribute to preserving the marine environment. As well as benefiting conservation, increasing the educational impact of aquaria could have significant commercial advantages, e.g. increased visitor satisfaction and numbers. Suggestions on how these mutual benefits could be achieved are briefly outlined. Their success will depend on the degree of cooperation which can be forged between commercial aquaria and conservationistsThis revised version was published online in October 2005 with corrections to the Cover Date.     

南沙群岛中北部重要岛礁鱼类资源调查

1998年4月和1999年5月,采用手钓、延绳钓和流刺网作业在南沙群岛的渚碧、南薰、东门、美济、赤瓜、永署和华阳等7座珊瑚礁水域进行了2个航次的鱼类资源调查。累计投入的捕捞努力量分别为手钓357钩·时、延绳钓4220钩、流刺网19750m,单次作业努力量手钓6～18钩·时、延绳钓40～480钩、流刺网40～2400m。捕获鱼类180种,渔获量1860尾1540.4kg,其中手钓102种1225尾196.8kg,延绳钓36种82尾1234.7kg,流刺网70种553尾108.9kg。按岛礁平均,渔获率和单位捕捞努力量渔获量(CPUE)手钓为351.1尾·(100钩·时)-1、51.9kg(100钩·时)-1,延绳钓为2.6尾·(100钩)-1、39.0kg·(100钩)-1,流刺网为51.4尾·(1000m)-1、7.5kg·(1000m)-1。礁坪区流刺网的渔获率和CPUE为170.3尾·(1000m)-1、23.1kg·(1000m)-1,均高于礁缘浅水区和礁缘深海区。捕获的主要经济种类有鲨鱼、裸胸鳝、石斑鱼、笛鲷、裸颊鲷、鹦嘴鱼和隆头鱼科鱼类等。华阳和永暑礁鱼类资源比较丰富,具有较高的开发潜力;东门、美济和南薰礁次之,也有一定的生产价值;赤瓜和渚碧礁基本没有开发价值。     

2013年内蒙古地区蓝舌病流行情况调查

为了解内蒙古地区蓝舌病(BT)流行情况,本研究于2013年对内蒙古存在疑似BT病例地区进行流行病学调查,收集了内蒙古6个盟市不同种类动物的抗凝血及其对应血清样品212份,采用竞争ELISA及套式RT-PCR方法对样品进行检测.竞争ELISA检测结果显示212份血清样品中有63份为BT阳性样品,13份为BT弱阳性,总阳性率为35.85％(76/212).套式RT-PCR检测结果显示212份血液样品中有61份为BT阳性样品,总阳性率为28.77％(61/212),其中绵羊感染率为21.25％(17/80)、绒山羊感染率为35.35％(41/116)、牛感染率为18.75％(3/16).不同的饲养方式对动物感染BT也有影响,其中圈养感染率为16.67％(1/6),散养感染率为29.13％(60/206).本研究结果表明,内蒙古地区BT流行范围比较广泛,因此有必要加强该病的检测及预防.     

Public Perceptions of Significant Wildlife in Hyogo,Japan

Public perceptions of wildlife vary by species, context, and culture. Understanding these perceptions helps managers understand how their decisions may generate conflict among stakeholders. We mailed questionnaires to residents in the northern region of Hyogo prefecture in Japan to examine their willingness to tolerate wildlife species of greatest concern to government officials, including: (a) native species frequently causing agricultural damage (wild boar [Sus scrofa], sika deer [Cervus nippon], Japanese macaque [Macaca fuscata]), (b) vulnerable species (Asiatic black bear [Ursus thibetanus]), (c) endangered species (reintroduced oriental white stork [Ciconia boyciana]), and (d) non-native, invasive species (nutria [Myocastor coypus]). We used the Potential for Conflict Index (PCI₂) to analyze our data, and found that respondents’ (n?=?868) acceptance was highest for the endangered oriental white stork and lowest for the non-native nutria. These perceptions also varied with sociodemographic characteristics, including a significant negative relationship between age and willingness to have boar, deer, macaque, bears, and nutria nearby.     

A SURVEY OF VETERINARY RADIATION FACILITIES IN 2010

A survey of veterinary radiation therapy facilities in the United States, Canada, and Europe was done in 2010, using an online survey tool, to determine the type of equipment available, radiation protocols used, caseload, tumor types irradiated, as well as other details of the practice of veterinary radiation oncology. The results of this survey were compared to a similar survey performed in 2001. A total of 76 facilities were identified including 24 (32%) academic institutions and 52 (68%) private practice external beam radiation therapy facilities. The overall response rate was 51% (39/76 responded). Based on this survey, there is substantial variation among facilities in all aspects ranging from equipment and personnel to radiation protocols and caseloads. American College of Veterinary Radiology boarded radiation oncologists direct 90% of the radiation facilities, which was increased slightly compared to 2001. All facilities surveyed in 2010 had a linear accelerator. More facilities reported having electron capability (79%) compared to the 2001 survey. Eight facilities had a radiation oncology resident, and academic facilities were more likely to have residents. Patient caseload information was available from 28 sites (37% of radiation facilities), and based on the responses 1376 dogs and 352 cats were irradiated in 2010. The most frequently irradiated tumors were soft tissue sarcomas in dogs, and oral squamous cell carcinoma in cats.     

新疆部分地区牛支原体病的血清学调查

采用双抗原夹心ELISA法对新疆部分地区采集的103份牛血清进行了牛支原体抗体监测。试验显示,从采集的103份牛血清中检出牛支原体阳性血清30份,阳性率为29.1%。结果表明,牛支原体病在调查地存在,且感染率较高。相关人员应引起高度重视,并积极采取防控措施应对牛支原体病的发生和流行。