Monitoring tourism schooners observing estuarine dolphins (Sotalia guianensis) in the Estuarine Complex of Cananéia,south‐east Brazil

• 1. Surveys were carried out between December 2004 and March 2006 on board tourism schooners to detect possible impacts due to tourist activities on estuarine dolphins (Sotalia guianensis) in the Estuarine Complex of Cananéia.
• 2. The estuarine dolphins exhibited different reactions according to the different periods of time that the boats remained close to them: the longer the period, the estuarine dolphins reacted less negatively, and for periods between 2 and 30 min, more positive reactions were observed.
• 3. Estuarine dolphin reactions also varied according to the different procedures followed by the skippers. The approach methods considered ‘correct’ resulted in a positive reaction from 97% of the animals encountered and 100% of occasions where there were no apparent reactions.
• 4. Direct approaches to within less than 50 m were responsible for a large number of negative reactions from the estuarine dolphins. Procedures classified as ‘chasing’ and ‘direct approach with no intention of stopping’ had a 100% negative reaction. If the skippers used a correct approach, estuarine dolphins reacted positively or did not show any reaction.

Copyright © 2009 John Wiley & Sons, Ltd.     

Technological Aspects of Extending Prime Quality of Seafood:

Technologies to extend market lives of fresh fish have focused on the period when the product becomes unacceptable to the consumer. There is, however, a paucity of information on initial changes of fresh fish quality, i.e., on the prime or grade A market lives. Factors responsible for loss of prime fish quality, with emphasis on biochemical reactions, are discussed in this review. Technologies designed to extend the market life of fresh fish include partial freezing, ionizing radiation, modified atmospheres, and chemical treatments. With the possible exception of partial freezing, these methods do not extend the grade A market life of fresh fish products. In order to lengthen grade A market life of fresh fish it will be necessary for technologists to devise ways to control endogenous biochemical reactions that contribute to loss in prime quality.     

Tissue reactions to microsporidian infections in fish

Abstract. Histopathological studies on natural and experimental infections of nineteen microsporidian species from fishes distinguished two types of tissue reactions.
The first type is characteristic of infections with xenoma-inducing microsporidian species and comprises three successive stages: a weakly reactive stage, a productive stage with the formation of granulomas and a stage of granuloma involution. Following the first stage, tissue reactions are directed towards the isolation of the parasite and result in its complete elimination and host tissue repair. The extent of pathological changes probably depends on the number of parasite cells which initiated the infection.
The second type is represented by Pleistophora species infecting muscles or oocytes. Host tissue reaction is surprisingly slight during the schizogony and sporogony and does not tend to isolate the invaded muscle fibres. A slight lymphocytic infiltration of myosepta indicates the first stage of tissue reaction. The tissue reaction only reaches the productive stage when mature spores completely fill the contents of the infected muscle fibre. A thick wall of fibroblasts may be formed to demarcate the parasite mass as soon as it undergoes necrotic changes. The extent of pathological changes probably depends on the ability of early developmental stages of the parasite to spread the infection within the host.
In both types of tissue reaction, the spores are destroyed by complete digestion within host phagocytic cells.     

海洋低温碱性蛋白酶的急性毒性研究

应用酶工程技术,得到在室温下有较高酶活力的海洋低温碱性蛋白酶。为对海洋低温碱性蛋白酶进行安全性评价,作者应用小鼠和大鼠急性毒性试验及最大耐受量（MTD）测定,观察海洋低温碱性蛋白酶对小鼠1次口服后产生的急性毒性反应和大鼠完整皮肤短期内接触海洋低温碱性蛋白酶所产生的毒性反应。结果表明,小鼠1次口服海洋低温碱性蛋白酶的MTDM＞20g/kg为实际无毒物,其中毒的靶器官是肝脏,未见大鼠经皮的急性毒性反应。     

中国明对虾主要过敏原基因分子克隆与序列分析

就中国明对虾主要过敏原原肌球蛋白基因进行了分子克隆与序列分析.从中国明对虾肌肉中提取总RNA,反转录合成第一链cDNA;根据原肌球蛋白cDNA的保守序列设计引物并进行PCR扩增,最后测序获得了中国明对虾原肌球蛋白的cDNA序列(GenBank accession:GU233303).该cDNA 序列含有长855nt的完...     

对印度尼西亚海域中国渔船使用拖网渔具的分析和探讨

本文探讨了中国渔船在印度尼西亚海域使用的拖网渔具,从渔具使用规格、缩结状态和结构等方面进行了分析,指出这类渔具在浅水渔场捕捞带鱼时有良好适应性,但局部配纲不当,网具贴底程度未达到最佳状态。由于网目大,有些局部改革可能导致敏感的负面反应。作者认为,这类网具今后的改革应着眼于提高拖速,以增加对某些优质鱼的兼捕比例。     

A technique for electrically stimulating extrusion of spermatophores from the lobster, Homarus americanus

A technique for electrically inducing spermatophore extrusion from live lobsters (Homarus americanus) is described. When a 12-V stimulus is applied around the coxa of the fifth walking leg, a single spermatophore is extruded through the gonopore. The sperm in extruded spermatophores are morphologically normal and undergo normal acrosome reactions. The technique provides a ready source of viable sperm for in vitro studies on fertilization and for artificial insemination of freshly molted female lobsters. The spermatophore itself is a natural package for sperm storage and may be useful in the future development of lobster sperm banks.     

A closer look at the bacteriology of nitrification

The mineralizing ability of nitrifying bacteria is well known among aquaculturists, but the underlying bacteriology is abstruse. The proceeding literature review details sources of nitrogenous fish waste and peculiarities of the Nitrobacteraceae family, including survival mechanisms, frailties, and intrinsic kinetics. Fundamental catabolic and anabolic reactions are elucidated, as is the implication of reducing power allotment for respiratory efficiency. Attention is paid to the paramount role of nitrifiers in biofiltration and recommendations are made for future recirculating aquaculture research.     

Comparison of the intradermal and prick tests for diagnosis of allergy in the dog

The diagnosis of allergic dermatitis and respiratory disease is increasing in veterinary practice. Searching for the initiating allergen(s) can be done with several kinds of dermal tests. In four healthy dogs and in 18 patients with a dermal or respiratory allergy problem the intradermal and prick tests were compared. Intradermal test reactions were readily identifiable and correlated well with anamnestic investigations. The prick tests generally did not give easily interpretable reactions.     

Immunological approaches to control maturation in fish II. A review of the autoimmune approach

Recent progress in the experimental induction of autoimmunity against the gonad of salmonids, as a method of producing sterile fish is reviewed. Autoantibodies against spermatozoa are characteristic of experimental allergic orchitis in fish, as is macrophage invasion of seminiferous tubules which culminates in severe granulomatous lesions. The roles played by humoral and cell-mediated immunity in this response are described. The appearance of autoantigens capable of eliciting these reactions occurs relatively late during spermatogenesis and germ cells possessing such autoantigens are considered to be normally protected by a blood-testis barrier. These findings are discussed in relation to their practical application in aquaculture.     

Myxozoa as parasites of the central nervous system of fishes

Myxosporea species in the central nervous system of fish and host-parasite interactions are described. Whereas parasites living in the nervous tissue itself do not induce clinical signs or host reactions, Myxosporea localized in neighbouring mesenchymatous tissues (blood vessels, cartilages, meninges) may induce disease of economic significance.     

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

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.     

Influence of fish feed composition on oxygen utilization during decomposition of aquaculture effluents

The decomposition of the organic matter, in the form of excess feed and excreted faeces, introduced to the environment by aquaculture can endanger living organisms by lowering oxygen levels. To increase the accuracy of the oxygen utilization assessment, we developed linear (L‐MOD) and non‐linear models (NL‐MOD) for the dynamics of decomposition and accumulation of the organic matter, oxygen utilization and ammonium production. The models are based on mass‐balance stoichiometric reactions for conversion of organic matter into bacterial biomass under aerobic conditions. Organic matter is represented by a general chemical formula sensitive to protein, carbohydrate and lipid content. The mass of organic matter is expressed in chemical oxygen demand (COD) units, providing more convenient tracking of oxygen utilization. Degradable part of the organic matter is distinguished from a non‐degradable part. The model results are compared with the data sets from simulated aquaculture pond experiment.     

Effects of Sodium Alginate and Chitosan Coating Combined with Three Different Essential Oils on Microbial and Chemical Attributes of Rainbow Trout Fillets

ABSTRACT

Meat products, such as fish meat, are known to be susceptible to undesirable chemical and microbial reactions that characterize spoilage. In this study, the effect of a sodium alginate and chitosan coating incorporated with Mentha piperita, Artemisia dracunculus, and Zataria multiflora essential oils on chemical and microbial attributes of rainbow trout meat was evaluated during storage at 4°C. Chemical and microbial assays were performed on rainbow trout fillets with alginate and chitosan coatings and 0.2% concentration of test essential oils. The results showed that the alginate coating with essential oils significantly decreased production of thiobarbituric acid (TBA) and total volatile basic nitrogen (TVBN) and reduced the growth of foodborne spoilage bacteria during storage at 4ºC. At day 12, the best results were obtained in chitosan coating + Z. multiflora, with 5.96 ± 0.12, 4.93 ± 0.12, and 3.83 ± 0.2 for total viable counts, psychrotrophic bacterial count, and lactic acid bacteria count, respectively. Moreover, the lowest amounts of chemical analysis were observed in chitosan coating + Z. multiflora at the final day (0.54 ± 0.03 and 20.31 ± 0.1 for TBA and TVBN, respectively). Our study revealed that essential oils can be used as effective natural components against undesirable chemical and microbial reactions in fish meat.     

Shark reactions to scuba divers in two marine protected areas of the Eastern Tropical Pacific

• 1. Worldwide, there are concerns about the potential impact of a growing tourism industry on the behaviour and ecology of sharks. Several shark species are key attractions in the scuba diving industry in both the Galápagos Marine Reserve (Ecuador) and the Sanctuary of Fauna and Flora Malpelo (Colombia).
• 2. In this study, the reactions of five species of shark to the behaviour of scuba divers were investigated in the Galápagos and Malpelo.
• 3. Four discrete categories of shark reaction (evasion, spontaneous approach, alert and no reaction) were identified and analysed against five categories of diver behaviour (direct approach, camera flash, sudden movement, noise and simple presence), two categories of observation strategy (still and movement) and the distance of the focal diver group to the sharks.
• 4. The type of reaction in the sharks was determined by the behaviour of the divers, their distance to the fish and, especially, by their observation strategy. Shark reactions varied between species and locations and divers acted more intrusively towards those species they were not afraid of, and which they could access more easily due to the conditions of their environment.
• 5. ‘Direct approach’, ‘sudden movement’, the observation strategy ‘moving’ and distances closer than 4 m between divers and sharks elicited stronger behavioural responses by the species targeted. Recommendations are given for the preferred actions divers should employ in order to diminish the effects on the target species analysed in this study. Copyright © 2011 John Wiley & Sons, Ltd.

     

盐碱和pH对鱼类生长和发育的影响

＂以渔改碱＂是开发利用我国约6.9×108km2低洼盐碱水域的有效途径。水体中的盐度过高会显著影响鱼类的渗透压调节、能量收支、生长发育、组织功能以及血浆电解质浓度等;碱度过高会引起＂碱病＂和多种异常生理、生化而迅速死亡。盐碱和pH对鱼类理化的影响还有协同作用,盐碱过高时对鱼产生联合毒性作用,pH值升高时同样也会加剧这种作用。本文综述了盐碱和pH对鱼类的理化影响、毒性作用等,探讨了鱼类在盐碱水中的生长机制,以期为盐碱水域的开发利用提供基础资料。     

中国对虾卵子激活过程的形态学研究

报道了对中国对虾卵子激活反应的形态学研究。中国对虾卵子皮层中有由卵黄膜下陷形成的与卵表垂直的皮层囊,内有棒状结构称棒状周边体,其内物质为凝胶前体。对虾卵子的激活并不需要精子的发动,而是在卵子与海水接触后即开始进行。在卵子激活过程中,棒状周边体向外放出形成花冠状的凝胶层,然后从基部开始逐渐消失并向远端扩展,最后完全消失,同时卵子进行成熟分裂放出第一、第二极体,并举起受精膜,完成激活反应。还对中国对虾卵子激活的作用进行了讨论。     

南海北部大陆架鱼种组群初步分析

根据南海北部大陆架水深40—200米范围内200网次底拖网鱼类调查资料,计算125个鱼种在采样中同时出现的 Jaccard 群落系数,用聚类分析导出8个组群。分析鱼种组群格局与环境因素之间关系的结果表明,组群中所包含的鱼种具有相似的环境需求特性,从而按组群概括阐述了各鱼种的环境适应特点和分布区域。优势鱼种组群对环境的适应范围广,分布遍及整个调查海区。其余各组群的形成与一定的环境条件相联系,并沿等深线分布在特定水深范围内。陆架外缘环境因素的明显变化,成为大多数陆架鱼种分布的阻限。本研究还以鱼种组群为基础对群落格局作了反相分析。     

Development of a widely applicable positive control strategy to support detection of infectious salmon anaemia virus (ISAV) using Taqman real-time PCR

Real-time PCR assays are being increasingly applied to the detection of fish pathogens due to their sensitivity, specificity and potential for high throughput sample processing. Such assays allow for the ready and efficient inclusion of appropriate quality controls which are fundamental to scientific integrity and to satisfying the demands of diagnostic test accreditation. In this article, we report development of a universal positive control strategy for real-time PCR assays, which has been used to support and improve a previously published method for detection of infectious salmon anaemia virus (ISAV). The strategy employed uses an RNA mimic template, which is based on the ISAV segment 8 target sequence but includes an artificial universal positive control sequence. Inclusion of this sequence, which is targeted by a second specific probe carrying a different fluorophore to the primary assay, allows for convenient screening of all real-time PCR reactions for the presence of contaminating positive control material. The development of readily distinguishable artificial positive control material offers distinct advantages to real-time PCR assays over using control material derived from clinical material.     

Recent perceptions on the development, assembly and function of the immune system

The immune system developed through many stages during evolution. It is fascinating that none of the diverse defense mechanisms vanished in such a long period of nearly 3.5 billion years. They still function in the integrated immune system. The barrier system can be compared to the immune system. The immune system itself is subdivided in antigen-independent, paraspecific (primitive immune system) and antigen specific (specific immune system), restricted immune reactions. The role and use of the phylogenetically older, paraspecific mechanisms, that will react immediately after antigen exposure, are discussed in detail. The immune system is not autonomous. It is closely linked to the hormonal, circulatory, metabolic and nervous systems. Its function is comparable to a sensory organ. Psychoneuroimmunology as a new discipline is mentioned. Immunity and paramunity are not seen as opposing phenomena but are linked in their functions. The terminology of immunology is discussed.