Broad-scale effects of marine salmonid aquaculture on macrobenthos and the sediment environment in southeastern Tasmania

A comparison of sediments and associated macrobenthos at sites sampled within 20 fish farm leases distributed across southeastern Tasmania indicated major natural changes along a regional cline. Introduced taxa were strongly represented in the fauna, comprising 45% of total macrofaunal biomass. Large differences were evident between sites affected by different levels of organic farm waste. Sites located adjacent (< 10 m) to farm cages possessed significantly depressed sediment redox levels, a dominance of capitellid and dorvilleid polychaetes, and low macrofaunal species richness. Subtle impacts extended across farm lease areas in the form of depressed redox potential at 40 mm depth and changes to the macrobenthic community, including a prevalence of the dogwhelk Nassarius nigellus and a paucity of the heart urchin Brissus sp. and the maldanid polychaetes Asychis sp. and Rhodine sp. Minor farm effects were also evident at sites sampled 35 m outside farm lease boundaries, most notably as elevated population numbers of the polychaete Terrebellides sp., bivalve Mysella donaciformis and heart urchin Echinocardium cordatum. Amongst the univariate metrics examined, redox potential at 40 mm depth and the ratio of bivalves to total molluscs provided the most sensitive indicators of farm impacts, with the latter metric relatively insensitive to spatial variation between locations within the region studied.     

Freshwater finfish biodiversity and conservation: an asian perspective

Aspects on biodiversity and conservation of the ichthyofauna in the Asian region, in comparison to that of Africa, Europe and North America have been relatively less documented. This paper attempts to evaluate the above aspects in the East, and South and Southeast Asia based on available information in the literature. The familial diversity in inland waters in Asia (121 families) is considerably higher than in African and Latin American. Also, the finfish faunal diversity of 21 major river basins in East, and South and Southeast Asian indicate that species diversity is not necessarily related to familial diversity. The fish fauna in the region considered presently is highly diverse with an estimated cumulative total of 7447 species. Amongst the freshwater fishes the dominant groups are cyprinids (Cyprinidae, about 1000 species), loaches (about 400 species) of the families Balitoridae and Cobitiidae, gobids (Gobiidae, 300 species), catfishes (Bagridae, about 100 species), and the Osphronemidae (85 species). In the region, 462 freshwater finfish species are reckoned to be threatened, accounting for 17.5% of the all finfish species in this status in the world. In the region there are 66 species that are critically endangered and/or endangered, of which 32 are cyprinids, 14 of which are endemic to Lake Lanao, Mindano Island, Philippines. The diversity of freshwater fish species in the region was significantly related to the land area of the different countries in the following manner:

Probiotics in aquaculture: importance and future perspectives

Aquaculture is one of the fastest developing growth sectors in the world and Asia presently contributes about 90% to the global production. However, disease outbreaks are constraint to aquaculture production thereby affects both economic development of the country and socio-economic status of the local people in many countries of Asia-Pacifi c region. Disease control in aquaculture industry has been achieved by following different methods using traditional ways, synthetic chemicals and antibiotics. However, the use of such expensive chemotherapeutants for controlling diseases has been widely criticized for their negative impacts like accumulation of residues, development of drug resistance, immunosuppressants and reduced consumer preference for aqua products treated with antibiotics and traditional methods are ineffective against controlling new diseases in large aquaculture systems. Therefore, alternative methods need to be developed to maintain a healthy microbial environment in the aquaculture systems there by to maintain the health of the cultured organisms. Use of probiotics is one of such method that is gaining importance in controlling potential pathogens. This review provides a summary of the criteria for the selection of the potential probiotics, their importance and future perspectives in aquaculture industry.     

Fish Karyome: A karyological information network database of Indian Fishes

'Fish Karyome', a database on karyological information of Indian fishes have been developed that serves as central source for karyotype data about Indian fishes compiled from the published literature. Fish Karyome has been intended to serve as a liaison tool for the researchers and contains karyological information about 171 out of 2438 finfish species reported in India and is publically available via World Wide Web. The database provides information on chromosome number, morphology, sex chromosomes, karyotype formula and cytogenetic markers etc. Additionally, it also provides the phenotypic information that includes species name, its classification, and locality of sample collection, common name, local name, sex, geographical distribution, and IUCN Red list status. Besides, fish and karyotype images, references for 171 finfish species have been included in the database. Fish Karyome has been developed using SQL Server 2008, a relational database management system, Microsoft's ASP.NET-2008 and Macromedia's FLASH Technology under Windows 7 operating environment. The system also enables users to input new information and images into the database, search and view the information and images of interest using various search options. Fish Karyome has wide range of applications in species characterization and identification, sex determination, chromosomal mapping, karyo-evolution and systematics of fishes.     

用分子遗传学及免疫学方法控制鱼类寄生性甲藻

寄生性甲藻,例如Amyloodiniumocellatum,给鱼类养殖带来严重的危害。虽然,近年来针对Amyloodinium的药物治疗有一些新的进展,如使用氯喹、过氧化氢和3,N泛影葡胺拉沙洛西等,然而,含铜类药物仍然是最有效的。近年来分子遗传学和免疫学的进展,使得我们能够更好地了解寄生性甲藻的流行病学及其防治方法。分子系统学研究认为某些寄生性甲藻,如Amyloodiniumocellatum,可以聚类为高度同源性的一支;而其它的如Piscinoodiniumpillulare,则可以认为不止一种或更高的分类阶元。这些分子分析也发展出一些高灵敏的检测技术,可以检测出环境中极少量的寄生性甲藻。通过对Amyloodinium的免疫学研究表明,鱼类能对寄生物的感染产生强烈的高度特异的保护性免疫应答,其中主要是抗体介导的免疫应答。鱼体皮肤和鳃也能表达内源非特异性多肽抗生素(类组蛋白),它们能对Amyloodinium造成致命的破坏。利用这些特异或非特异的免疫防御,将更有助于我们控制这些具有严重危害性的寄生性甲藻     

Selenium nanoparticles are required for the optimum growth behavior,antioxidative capacity,and liver wellbeing of Striped catfish (Pangasianodon hypophthalmus)

Selenium (Se) is a multifunctional trace element required in specific amounts for the optimal growth of aquatic finfish species. For this reason, this study investigated the effect of Se nanoparticles on the growth behavior, antioxidative capacity, and liver wellbeing of Striped catfish (Pangasianodon hypophthalmus). Striped catfish fed varying Se nanoparticles levels (0. 0.5, 1, and 2 mg/kg) in triplicate units and kept for 60 days. Striped catfish delivered dietary Se nanoparticles had markedly increased growth performance, specific growth rate (SGR), consumed feed, and protein efficiency ratio but reduced feed conversion ratio (FCR). The whole body, liver, muscle, and gills have higher Se accumulation levels in fish that received Se nanoparticles than the control with the highest level in fish fed 2 mg/kg. The carcass composition showed higher protein content in fish fed 1 and 2 mg/kg (p = 0.001 and 0.001) and higher ash content (p = 0.001 and 0.002) in fish fed 2 mg/kg than the remaining groups. Superoxide dismutase was meaningfully activated in Striped catfish delivered 1 and 2 mg Se nanoparticles/kg compared with the control (p < 0.05). Also, catalase and glutathione peroxidase activities were higher, and malondialdehyde level was lower in Striped catfish fed Se nanoparticles at 0.5, 1, and 2 mg/kg than the control (p < 0.05). The villi exhibited a visible increase in both height and branching with an increased level of Se nanoparticles in addition to the increased number of goblet cells. The Se nanoparticles-treated fish revealed dose-dependent modifications fluctuated from diffuse fatty vacuolization in hepatocytes with eccentric pyknotic hepatocytes nuclei. In conclusion, Se nanoparticles are required for the optimum growth behavior, antioxidative capacity, and liver wellbeing of Striped catfish. Based on SGR and FCR data's regression analysis, Se nanoparticles are recommended at 1.02–1.11 mg/kg diet.