Microtagging cultured lobsters, Homarus gammarus (L.), for stock enhancement trials

Abstract. The adaptation of proprietary fish-tagging equipment for tagging small lobsters, Homarus gammarus (L.) (9–15mm carapace length), with internal microware tags is described. Tag retention was 85–100% as the animals grew through up to 22–29 moults (90–102mm carapace length) in captivity. Claw loss during handling was reduced from 4% lo less than 1% at a tagging rate of 240 lobsters per has experience was gained.     

White Spot Syndrome Virus in cultured shrimp: A review

Shrimp is one of the main aquaculture species in the world. Different viruses affect them, which causes serious mortality to economically important species, such as Penaeus monodon, Litopenaeus vannamei and L. stylirostris, among others. White spot syndrome virus or WSSV is a highly lethal, stress‐dependent virus, which belongs to the family Nimaviridae, genus Whispovirus. Three WSSV virus isolates were first detected in 1992 in Thailand, Taiwan and China. Later, a fourth isolate of the virus was detected in the Americas in 1999. This virus has a large circular double‐stranded DNA genome with different sizes (292.9–307.2 kb), where the diverse isolates show differences in virulence. This virus infects a wide range of aquatic crustaceans by vertical and horizontal transmission, with different mortality results. The spread of infection between regions may be due to infected shrimp and carriers such as other crustaceans, seabirds, aquatic arthropods or other vectors. The aim of this work is to describe the current knowledge on the status, transmission, pathology, isolation, control and genomic characteristics of WSSV.     

Stimulation of crusher claw development in cultured lobsters, Homarus gammarus (L.)

Abstract. During the culture of large numbers of lobsters, Homarus gammarus (L.), it was noticed that more than half the animals lacked a distinct crusher claw. The majority bore two morphologically similar cutter claws even though their ages ranged up to 3 years (92mm carapace length). The proportion of 3-month-old juveniles (11–13 mm carapace length) bearing clearly differentiated crusher claws was increased from approximately 30% to over 80% by adding live oyster spat to the rearing chambers. The differentiation of the crusher claws was completed within approximately 4 moults (71–83 days) and was morphologically more pronounced in lobsters grown in the presence of spat than in the 30% of control lobsters which developed crusher claws spontaneously.     

Feeding and gut evacuation of cultured juvenile spiny lobsters, Jasus edwardsii

Low feed consumption has been suggested as a major impediment for the development of effective formulated diets for spiny lobsters. To seek an explanation for the low feed consumption, this study compared the feed consumption, appetite revival, foregut evacuation and fecal production of different sizes of spiny lobster Jasus edwardsii juveniles fed a fresh natural diet (i.e. mussel flesh) and a dry formulated diet. In addition, the effect of feeding frequency was determined by feeding juvenile lobsters the same ration of formulated diet at different time intervals. i.e., same ration delivered 3 week^− 1, 1 day^− 1, 2 day^− 1, 5 day^− 1 and 5 night^− 1. Lobster (10–15 g) growth and feed consumption (1.15% BW day^− 1) was maximized when receiving a single ration daily of the formulated diet. A slow appetite revival (AR > 18 h) on the formulated diet was consistent with the negative effect of increasing feeding frequency on growth and consumption. In addition, there appeared to be no major advantage in dry matter intake by providing the nutrient dense dry formulated diet to Jasus edwardsii. Lobsters fed fresh mussel flesh (79.8% moisture) consumed similar levels of dry matter as those lobsters fed the dry formulated feed (7.3% moisture). This appears to be due to high moisture gain and expansion of the dry feed in the lobster foregut. Foregut evacuation lasted 10 h for the two diets but a delay in initial foregut evacuation and processing of the formulated diet was evident, and may have negatively affected feed consumption, appetite revival and dry matter digestibility (61.2%) of the dry formulated diet compared to the mussel flesh diet (89.2%). Appetite revival on mussel flesh was almost complete by 12 h after a satiation ration and was governed primarily by the rate of foregut evacuation. Differences in the timing of foregut evacuation and fecal production between the two diets suggested that a greater proportion of the formulated diet entered the midgut directly.The results indicate that J. edwardsii cannot achieve high levels of feed consumption on formulated diets because gut throughput is reduced due to a small foregut capacity, expansion of the feed post-ingestion, lengthy foregut filling time (1–2 h) and clearance time (10 h), combined with slow gut throughput time (34–42 h) and appetite revival (> 18 h). A slow appetite revival and difficulties in processing and digestion of formulated diets appear as major issues to be resolved to improve the performance of formulated diets required for the commercial aquaculture of J. edwardsii and possibly other spiny lobsters.     

我国养殖对虾细菌性疾病

<正> 我国养殖对虾主要有11种细菌性疾病。 1 红腿病(红肢病) 1.1 病原 均为革兰氏阴性杆菌:①鳗弧菌(V.anguilarum)对VP、阿拉伯糖产酸有反应。②副溶血弧菌(Vibrio parahaemolyticus)大小为(0.8～1.2)um×(2.2～3.0)um,杆状或弧状,端生鞭毛。③溶藻弧菌(V.alginolyticus)短弧状或杆状,大小为(0.9～1.3)um×(1.6～2.2)um,端生单鞭毛。④嗜水气单胞菌短杆状或椭球状,大小为(0.5～0.7)um×(0.8～1.5)um,有运动力,菌体两端钝圆,端生单鞭毛。     

Variability in size at moult among individual broods of cultured juvenile lobsters, Homarus gammarus (L.)

Abstract. Information on carapace length (CL) and its variability at each instar from settlement (instar 4) to pre-recruit size (instar 24) is presented for 10 individually reared single parent broods and one mixed brood of European lobster, Homarus gammarus (L.). The lobsters grew from 5mm CL to 74mm CL in approximately 130 weeks at 20°± 2°C. There was some evidence that growth variability of the largest lobsters was influenced by the size of the rearing compartments used during the final growth period.     

A novel method of collecting fecal samples from spiny lobsters

A novel method is described for collecting feces from the spiny lobster Panulirus ornatus. Established methods for the collection of feces from crustacean species are not effective with P. ornatus. The feces produced by adults and juveniles of this species are not in a form that can be easily recovered by traditional methods. To overcome this problem, a plastic flange was glued onto the integument, around the anal pore. A small latex balloon was placed over the flange and provided a watertight collection vessel for voided feces. The flange was made from the modified cap from a 2 ml Eppendorf vial. Fixing the flange and changing the balloon after feeding was achieved without the use of anaesthetics and appears not to impose undue stress on the lobsters and they continued to feed. The method was successfully used to collect uncontaminated fecal samples from lobsters ranging from 150 to 800 g. This method may have wider application for other crustacean species.     

A comparison of techniques for the measurement of growth in adult lobsters

Four non-destructive measures of growth (wet weight in air, wet weight in water, displacement volume and carapace length) were correlated to two destructive measures of growth (dry weight and total body protein level) in adult American lobsters (Homarus americanus). All non-destructive parameters were significantly (P < 0.05) correlated to dry weight and protein for female lobsters. Only wet weight in water was significantly correlated to dry weight and total body protein level in male lobsters.     

四川地区养殖鲑鳟鱼主要流行病害

一、四川地区鲑鳟鱼养殖概况随着苗种繁育技术的突破和养殖技术的提高,鲑鳟鱼的养殖在四川地区已有十余年的历史,从20世纪90年代开始,依托省内丰富的冷水资源,开始逐步从国内外引进鲑鳟鱼进行养殖,随之获得成功并逐步扩大。四川省内鲑鳟鱼养殖覆盖面大,在四川省都江堰、彭州、崇州、大邑、邛崃、蒲江及凉山、甘孜、阿坝等县(市)均有分布,尤其是以成都市的彭州、都江堰一带形成以休闲渔业为主的良好消费形态,其中以彭州地区“小鱼洞”较为出名。     

养殖(鱼康)（鱼良）白鱼常见病害防治技术

鱼康鱼良白鱼人工育种和驯化的成功,奠定了其养殖业的发展基础。近年来,随着养殖技术的不断发展,池塘养殖鱼康鱼良白鱼得到了快速的推广和发展。然而,随着集约化养殖程度的提高和养殖密度的增加,养殖鱼康鱼良白鱼的病害逐渐增多,呈现出寄生虫病增多,多病原、多病种同时发生,流行时间长,危害重的趋势。文章根据养殖实践,总结介绍了鱼康鱼良白鱼养殖过程中出现的真菌病、寄生虫病、细菌病及其主要症状、流行情况和防治方法。     

A review of reported seaweed diseases and pests in aquaculture in Asia

Seaweeds have been used as a food for centuries in Asia and are increasingly exploited as a source for dietary supplements, animal feed, chemicals, and biofuels. In recent years, there has been an increase in the prevalence of diseases and pests in these aquaculture crops, with a subsequent reduction in their quantity and commercial value. In this article, we review diseases that have been reported in the scientific literature for species of red and brown seaweeds. We have focused on the major seaweed crops grown in Asia, where much of this production is centered. We also provide information on disease management and biosecurity and some observations on future directions.     

淡水养殖鱼类常见鳃病的诊断及防治

鱼生活在水中,靠鳃吸入水中的溶解氧,水中存在的病原体很容易感染到鳃上,鳃的发病率很高,当鱼鳃患病影响鱼类的正常呼吸,鱼体会通过自身调节提高呼吸运动节律来弥补病鳃气体交换的不足,当鳃的气体的交换量(即呼出二氧化碳,吸收水中氧气)降低到不能维持最低生命活动需要时,鱼类就会发生窒息死亡,因此有"养鱼先养水,治病先治鳃"之说.防治鱼类鳃器官的常见病多发病十分重要.鱼类鳃病,按其致病病原体可分为细菌性鳃病、真菌性烂鳃病(又称鳃霉病)、寄生虫性鳃病三大类,其中寄生虫又分为原虫、蠕虫、甲壳动物及软体动物等.     

Breakpoints for disc diffusion susceptibility testing of bacteria associated with fish diseases: A review of current practice

A survey of the methods being employed to determine antimicrobial susceptibility of bacteria associated with aquaculture was performed on behalf of the Permanent Advisory Network for Diseases in Aquaculture. Thirty-two laboratories in 18 countries responded and 25 reported the breakpoints they used for disc diffusion assays applied to Group 1, non-fastidious organisms isolated from finfish. A total of 117 breakpoints were reported for assays in which the disc contents were those specified by the current standard protocols. Data on the source of these breakpoints and the confidence the laboratories had in them are presented. Overall there was a considerable variation in the breakpoints employed by different laboratories and this variation is discussed in terms of the inter-laboratory precision that can be expected from the application of disc diffusion protocols. This paper discusses the possible clinical significance of the variations in the breakpoints and, where there are available data, the extent to which those in use are consistent with breakpoints suggested by other approaches.The data presented in this paper represent a starting point for the movement towards harmonising breakpoints used in association with the standard disc diffusion protocols that have been proposed for susceptibility testing of bacteria associated with fish diseases.     

A two-chambered trap reduces within-trap predation by octopus on rock lobsters in aquarium trials

A two-chambered lobster trap was developed that in aquarium trials significantly (p < 0.01) reduced octopus predation on trap-caught spiny lobster. The trap was designed using information gained from an investigation of the behavioural interactions of the maori octopus (Octopus maorum) with traps used in the South Australian commercial lobster (Jasus edwardsii) fishery. This study showed that octopuses were primarily attracted to traps by the presence of bait as opposed to lobsters and that octopus entry into traps was ‘fortuitous’ and mediated by speculative exploration. The outer chamber of the modified trap contained bait and allowed entry by octopuses but not lobster and the inner chamber allowed access to both animals. The trap worked on the principle that octopuses would enter the outer chamber containing bait via a side entrance in preference to entry to the inner chamber containing lobsters via the neck. This was found to be the case and lobster mortality was 70% lower in the two-chambered trap than a standard trap. Successful adaptation of this trap design to commercial fishing conditions could significantly reduce rates of octopus predation on rock lobsters in several important southern hemisphere fisheries for spiny lobsters.     

Review of the principal diseases affecting cultured meagre (Argyrosomus regius)

Argyrosomus regius was recently introduced in European aquaculture as a promising species for diversification and with high potential for expansion in the coming years. The reports on pathologies affecting this species are still scarce in the bibliography, however, they can severely affect production and result in major economic losses. Some few reports were made on outbreaks and mortalities associated with the presence of bacteria such as Vibrio anguillarum and Photobacterium damselae subsp. piscicida. Although no viral diseases have been recognized as affecting meagre, it is known that meagre can be an asymptomatic carrier of two genotypes of nodavirus, the striped jack nervous necrosis virus and red‐spotted grouper nervous necrosis virus. Up‐to‐date, parasites affecting meagre are included in the genera Monogenea, Nematoda and Dinoflagelate, but without major mortality outbreaks associated to this type of infections. Osteological deformities have been observed in all life stages particularly affecting the axial system in larval and early juvenile specimens, with a higher incidence in the vertebral column, being affected by vertebral fusions, lordosis and kyphosis. With this review the authors provide an overview of all the pathological and non‐pathological diseases affecting aquaculture produced meagre and provide a comprehensive overview of possible problems for the industry.     

A review of extracellular virulence product of Vibrio species important in diseases of cultivated shrimp

Shrimp aquaculture is an important industry that experiences significant losses from Vibrio species, especially at the larval and juvenile stages. Proteinaceous virulence factors, including alkaline proteases, metalloproteases, cysteine proteases and alkaline serine proteases, have been identified as important elements in Vibrio pathogenesis. This review summarizes current knowledge regarding the principal pathogenic Vibrio species in shrimp, with emphasis on relevant exotoxins and their modes of action, principal characteristics and molecular database. This pathogenic factors and their relation with other molecules produced by microorganisms may be help to understand the virulence mechanisms present in Vibrio strain.