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41.
N Vendramin A Toffan M Mancin E Cappellozza V Panzarin G Bovo G Cattoli I Capua C Terregino 《Journal of fish diseases》2014,37(4):371-383
Viral encephalopathy and retinopathy (VER), otherwise known as viral nervous necrosis (VNN), is a severe pathological condition caused by RNA viruses belonging to the Nodaviridae family, genus Betanodavirus. The disease, described in more than 50 fish species worldwide, is considered as the most serious viral threat affecting marine farmed species in the Mediterranean region, thus representing one of the bottlenecks for further development of the aquaculture industry. To date, four different genotypes have been identified, namely red‐spotted grouper nervous necrosis virus (RGNNV), striped jack nervous necrosis virus (SJNNV), tiger puffer nervous necrosis virus and barfin flounder nervous necrosis virus, with the RGNNV genotype appearing as the most widespread in the Mediterranean region, although SJNNV‐type strains and reassortant viruses have also been reported. The existence of these genetically different strains could be the reason for the differences in mortality observed in the field. However, very little experimental data are available on the pathogenicity of these viruses in farmed fish. Therefore, in this study, the pathogenicity of 10 isolates has been assessed with an in vivo trial. The investigation was conducted using the European sea bass, the first target fish species for the disease in the Mediterranean basin. Naive fish were challenged by immersion and clinical signs and mortality were recorded for 68 days; furthermore, samples collected at selected time points were analysed to evaluate the development of the infection. Finally, survivors were weighed to estimate the growth reduction. The statistically supported results obtained in this study demonstrated different pathogenicity patterns, underlined the potential risk represented by different strains in the transmission of the infection to highly susceptible species and highlighted the indirect damage caused by a clinical outbreak of VER/VNN. 相似文献
42.
福建海区浮游动物种类组成及数量分布特点 总被引:5,自引:1,他引:5
根据2003~2004年福建海区春季和夏季2个季度月浮游动物调查资料,分析和研究该调查海区浮游动物种类组成和数量分布特点。结果表明:浮游动物经鉴定共有226种,其中桡足类114种,占总种数的50.4%,以广盐高盐亚热带和热带种为主。浮游动物总生物量分布夏季比春季高,春季平均值为90.3mg·m-3,夏季为150.8mg·m-3,春季总生物量呈现由北向南递减,以闽东渔场最高,闽中渔期次之,闽南台湾浅滩渔场最低,密集区不明显,夏季则相反,随着暖流势力的增强,闽中、闽南台湾浅滩总生物量明显增加,以闽南台湾浅滩最高,且密集区明显;在调查海区总生物量起主导作用的优势种为普通波水蚤、锥形宽水蚤、微陀隆哲水蚤、亚强真哲水蚤,其密集区基本上是各种作业的主要渔场,与历史资料和邻近海域相比较,一直保持优势种地位有普通波水蚤、亚强真哲水蚤等,生物密集区基本相同。 相似文献
43.
Takanobu Goto Shusaku Takagi Toshiaki Ichiki Tadashi Sakai Makoto Endo Terutoyo Yoshida Masaharu Ukawa Hisashi Murata 《Fisheries Science》2001,67(1):58-63
SUMMARY: The aim of this study was to investigate the cause of green liver in red sea bream fed substitute protein diets. Red sea bream Pagrus major was given either of the following diets for 28 weeks: (1) control diet (50% fish meal), (2) low level fish meal diet (15% fish meal), and (3) non-fish meal diet (0% fish meal). The green liver was observed in all groups tested, but the incidence was much higher in the experimental diet groups. The feeding of substitute protein diets reduced plasma triglyceride and cholesterol levels. However, there was no significant difference in plasma hepatic enzyme activities and plasma bile salts concentration among the treatments. Fish fed the substitute protein diets showed low hepatic taurine levels with an appearance of a biliverdin in the liver. Moreover, the proportion of ditaurobilirubin to total biliary bile pigments was significantly lower in fish fed the substitute protein diets. These data indicate that feeding of substitute protein diets did not induce any cholestatic hepatobiliary obstructions and that the low hepatic taurine level was one of the probable factors responsible for the occurrence of green liver in red sea bream fed substitute protein diets. 相似文献
44.
John Cotter 《Fish and Fisheries》2010,11(2):210-219
I summarize the total allowable catch (TAC) fishery management system, which forms part of the European Common Fisheries Policy (CFP) as complicated, inaccurate and ineffective. Total allowable effort (TAE), i.e. limits on fishing capacity and days‐at‐sea, provides a simpler, readily enforceable control to protect all species affected by a fishery. Fishing capacity of vessels in each region‐gear fleet could be capped through limits on engine power, gear, crew, and fittings, and/or reducing allowances of days‐at‐sea for large, powerful vessels. Two basic, fishery‐dependent indicators are put forward to assess sustainability of a fishery dependably even in the absence of fishery‐independent data. One is socio‐economic, the other is ecological. Fishery working groups within each marine region would recommend a TAE to sustain their fishery while also protecting the most critically affected species or processes. Regional working groups would supervise a consistent approach across the different fisheries in their region. A pan‐European group would set policy, implement external agreements, set rules for trading TAE if necessary and harmonize fishing opportunities across regions. To ease negotiations on TAEs with the fishing industry when an ecosystem needs to recover, I propose compensation payments funded by re‐direction of existing CFP subsidies that promote fishing. 相似文献
45.
Wenresti G Gallardo Myrna N Bautista-Teruel Armando C Fermin & Clarissa L Marte 《Aquaculture Research》2003,34(10):839-842
A method of marking abalone (Haliotis asinina Linne) for sea ranching and stock enhancement purposes was developed. Three‐month‐old abalone juveniles (11.8‐mm shell length, 0.28 g) were fed artificial diets for 1, 2, or 3 weeks. The width of the bluish‐green shell band produced by abalone juveniles was 1.7, 2.6, and 4.2 mm after 1, 2, or 3 weeks of feeding respectively. The growth and survival of juveniles fed artificial diets did not differ from that of juveniles fed the seaweed Gracilariopsis bailinae (control). Feeding the diet‐fed juveniles with the seaweed thereafter produced the natural brownish shell, thus forming a sandwiched bluish‐green band. An experimental release in outdoor tanks with natural growth of seaweeds and diatoms, and in a marine reserve showed that the shell band remained clear and distinct, indicating the usefulness of this shell marking method in sea ranching and stock enhancement of abalone. 相似文献
46.
为了解全氟辛烷磺酸钾(PFOS)对海洋鱼类抗氧化防御系统的毒性效应及致毒机理,在实验室条件下研究了PFOS胁迫和净水恢复过程中真鲷(Pagrosomus major)鳃组织和肝脏组织内谷胱甘肽(GSH)质量分数与谷胱甘肽转硫酶(GST)活性的变化。结果显示,胁迫开始时鳃中w(GSH)在低浓度组出现诱导,中、高浓度组出现抑制现象,随着胁迫时间的延长,各浓度组处于显著诱导水平(P〈0.01);肝脏中w(GSH)在胁迫第15天时各浓度组中出现显著的剂量效应,w(GSH)随着PFOS曝露浓度的升高而降低。真鲷2种组织的GST活性变化与各自组织中w(GSH)的变化趋势相近。净水恢复期内个别浓度组的指标恢复到对照组水平,说明真鲷可以修复PFOS胁迫造成的损伤。结果表明,PFOS在试验条件下对真鲷有显著的毒性作用,可能对海洋高等生物存在潜在性危害,应对其海洋环境风险评价加以关注。 相似文献
47.
48.
- 1. A known fishing hot spot for loggerhead sea turtles (Caretta caretta) in the Mediterranean Sea is in the waters of the Strait of Sicily where interactions with fish hooks and branchlines are believed to be a major cause of mortality for sea turtles.
- 2. Hooks with different shapes but a similar gape width (circle hook size 16/0 vs J hook size 2) were tested in order to determine the potential effectiveness of the hook design to both reduce sea turtle capture as well as to maintain acceptable levels of target species capture rates in a shallow‐set longline swordfish fishery in the Mediterranean.
- 3. Seven experimental fishing trips, 30 000 hooks total, were conducted on a single commercial fishing vessel (18 m in length) in the Strait of Sicily during the months of July through October over a period of three years from 2005 to 2007. Circle and J hooks were alternated along the mainline.
- 4. A total of 26 sea turtles were hooked, all immature‐size Caretta caretta. Turtles were caught at a statistically greater frequency on J hooks than on circle hooks. The capture rate, weight, and upper jaw fork length of the target species were not significantly different between the two types of hooks employed.
- 5. Five sea turtles swallowed the hook and in all such cases these were J type. Circle hooks tended to be located externally and were more easily detected by fishermen, and could be removed with the correct dehooking action before returning the turtle to the sea.
- 6. These findings suggest that 16/0 circle hooks can effectively reduce the incidental capture of immature loggerhead sea turtles in a Mediterranean swordfish longline fishery without affecting the catch size of the target species.
49.
Teruo Nakayama Keiko Hatae Midori Kasai Atsushi Ooi 《Journal Of Aquatic Food Product Technology》2017,26(5):578-592
The season for finding the firmest sashimi made from wild Japanese sea bass was investigated. Flesh rigor tension and contraction were measured by a “new” device with isometric (muscle length kept constant) and isotonic (balance beam moves freely) transducers. Both flesh rigor tension and contraction peaks appeared at the same postmortem times, with attainment of ultimate pH and adenosine triphosphate/inosine monophosphate ratio in four seasons. Seasonal seawater temperature correlated negatively to seasonal maximum rigor contraction and positively to seasonal flesh breaking strength at 72 h postmortem. After rigor peak tension attainment, the tension relaxation was much lower than that of other wild fish species, especially in summer. The sea bass muscle resisted structure disruption in rigor isometric tension generation. Wild sea bass sashimi was firmest in breaking strength in summer. 相似文献
50.
东海中北部小眼绿鳍鱼的摄食习性分析 总被引:2,自引:0,他引:2
根据2008年5月~2009年2月期间采集的渔获样品,对东海中北部小眼绿鳍鱼(Chelidonich-thys spinosus)胃含物进行分析。结果表明:小眼绿鳍鱼食物组成以磷虾类(IRI=1308.55)为主,其次依次为长尾类(IRI=563.09)、鱼类(IRI=170.59)和糠虾类(IRI=31.85);其优势饵料种类为太平洋磷虾、细巧仿对虾、细螯虾、戴氏赤虾、六丝矛尾鰕虎鱼、漂浮小井伊糠虾等。小眼绿鳍鱼终年摄食,其摄食率为83.25%,最高饱满指数达171.86‰,平均饱满指数18.84‰,这表明小眼绿鳍鱼具有较强的摄食强度。同时单因素方差检验表明,小眼绿鳍鱼的摄食强度无显著的季节变化,而有显著的体长变化。 相似文献