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Gills of fish are involved in respiration, excretion and osmoregulation. Due to numerous interactions between these processes, branchial diseases have serious implications on fish health. Here, "koi sleepy disease" (KSD), caused by carp edema virus (CEV) infection was used to study physiological, immunological and metabolic consequences of a gill disease in fish. A metabolome analysis shows that the moderately hypoxic-tolerant carp can compensate the respiratory compromise related to this infection by various adaptations in their metabolism. Instead, the disease is accompanied by a massive disturbance of the osmotic balance with hyponatremia as low as 71.65 mmol L−1, and an accumulation of ammonia in circulatory blood causing a hyperammonemia as high as 1123.24 µmol L−1. At water conditions with increased ambient salt, the hydro-mineral balance and the ammonia excretion were restored. Importantly, both hyponatremia and hyperammonemia in KSD-affected carp can be linked to an immunosuppression leading to a four-fold drop in the number of white blood cells, and significant downregulation of cd4, tcr a2 and igm expression in gills, which can be evaded by increasing the ion concentration in water. This shows that the complex host-pathogen interactions within the gills can have immunosuppressive consequences, which have not previously been addressed in fish. Furthermore, it makes the CEV infection of carp a powerful model for studying interdependent pathological and immunological effects of a branchial disease in fish. [ABSTRACT FROM AUTHOR]

The Dapingian and lower Darriwilian graptolite succession of the Krapperup drill core from Scania, southern Sweden, provides a detailed insight into the axonophoran (biserial) graptolites and their early Palaeozoic evolutionary changes on the Scandinavian platform. Even though earliest Darriwilian axonophorans are not represented, the succession includes faunal elements of the basal Darriwilian Arienigraptus zhejiangensis Subzone of the Levisograptus austrodentatus Biozone, followed by Levisograptus mui and Levisograptus sinicus specimens higher up in the successsion. The highest interval is referred to the Eoglyptograptus cumbrensis Biozone and bears a number of axonophoran elements, including Oelandograptus oelandicus and Undulograptus camptochilus, previously known exclusively from chemically isolated material from the island of Öland. The top of the interval investigated is below the base of a carbonate-rich interval correlated with the Komstad Limestone of Scania, indicating that the investigated interval entirely belongs to the upper part of the Tøyen Shale Formation. Pseudisograptus manubriatus and Pseudisograptus koi are not restricted to the upper Dapingian, but range into the basal Darriwilian. Arienigraptus robustus n. sp. from the uppermost Dapingian, and Arienigraptus delicatus n. sp. and Arienigraptus balticus n. sp. from the basal Darriwilian, are described as new species. [ABSTRACT FROM AUTHOR]

Principles of biosecurity and disease surveillance long applied in the salmonid industries to produce certified disease-free slock can equally be applied to the production of koi herpesvirus-free koi, despite limitations in diagnostic ability to detect asymptomatic carrier fish. To ensure freedom from koi herpesvirus, there is a strong case for eradication of known infected broodstock. Maintaining a closed population offish on a protected water source, adherence to strict biosecurity measures, and strategic sampling at a statistically relevant confidence level over a 2-year period can provide the guarantees needed for sale of certified disease-free fish. Propagation of such fish offers new entrepreneurial opportunities and has resulted in at least one breeder in South Africa achieving export certification for markets in the European Union. [ABSTRACT FROM AUTHOR]

Salt (NaCl) is a common therapeutant in fish culture. The use of salt containing iodine may be harmful to fish. The goal of this study was to determine if using iodized saltfor dips and baths increases morbidity/mortality of fish and establishes the LC50 of iodine for three commercially important species: koi, Cyprinus carpi; guppy, Poecilia reticulata; and Jack Dempsey, Rocio octofasciata. Fish were exposedto a salt bath (4 g/L) or a salt dip (25 g/L) using either iodized or non-iodized salt and observed for clinical signs of iodine toxicity or death. For the LC50 trials, one fish of each species was exposed to a range of iodine concentrations for a period of 24 h. There were no significant differences in mortality between fish treated with iodized vs. non-iodized salt. The use of iodized salt for baths and dips appears to be safe in the three species tested. LC50 of iodine in these species appears to be greater than 1.4 mg/L. [ABSTRACT FROM AUTHOR]

The article examines the age composition, growth and reproduction of koi carp Cyprinus carpio species from the lower Waikato river in New Zealand. A total of 566 koi carp were aged from scales and opercular bones, and growth was modeled with the von Bertalanffy growth function. Growth of these species between zero and three years of age was lower that of common carp in Europe and Australia. Within a spawning season, feral koi carp contained females that spawned once.

To test the effect of different stocking densities on their growth, survival rate and number of marketable fish, advanced larvae (0.14±0.035 g) of Koi carp, Cyprinus carpio vr. koi, were cultured for 90 days in 150-L concrete tanks at different densities: 0.1 fish/L (D1); 0.2 fish/L (D2); 0.3 fish/L (D3); 0.4 fish/L (D4); and 0.5 fish/L (D5). There were three replicates for each treatment, where the fish were fed daily slightly in excess of satiation to eliminate the possibility of food supply being a limiting factor to growth. The D4 and D5 treatments recorded significantly higher (P < 0.05) values of ammonium-N, nitrite-N, nitrate- N, phosphate, and specific conductivity, and significantly lower (P < 0.05) values of dissolved oxygen, compared to the other treatments. Weight gain for koi carps stocked at D1 (7.28 g) was significantly higher (P < 0.05) than that of fish in the other treatments. There was a significant difference in survival rates of koi carps among the treatments ranging from 62.43% in D5 to 93.26% in D1. The number of marketable fish above a set size of 4 g was significantly higher (P < 0.05) in D3, compared to other treatments with higher or lower stocking densities. Therefore, a stocking rate of 0.3 fish/L would be suggested as optimal. [ABSTRACT FROM PUBLISHER]

The eye-attacking behaviour of Koi fishes was recorded in a koi–goldfish polyculture system. The attacked fishes suffered from eye ablation, abnormal swimming and suppressed feeding behaviour. There was a significant difference in mean sizes of victims and attackers but the exact motivating stimuli for the observed action was not clear. For future research, the effects of different stocking ratios on aggressive behaviour of koi should also be examined. [ABSTRACT FROM PUBLISHER]