Salmon

Atlantic salmon farming is one of the largest aquaculture industries in the world. A major problem in salmon farms is the sea louse ectoparasite Lepeophtheirus salmonis, which can cause stress, secondary infection and sometimes mortality in the salmon host. Sea lice have substantial impacts on farm economics and potentially nearby wild salmonid populations. The most common method of controlling sea louse infestations is application of chemicals. However, most farming regions worldwide have observed resistance to the small set of treatment chemicals that are available. Despite this, there has been little investigation of treatment strategies for managing resistance in aquaculture. In this article, we compare four archetypical treatment strategies inspired by agriculture, where the topic has a rich history of study, and add a fifth strategy common in aquaculture. We use an agent-based model (ABM) to simulate these strategies and their varying applications of chemicals over time and sp...

The effect of different type of fish, marination methods, temperature, and cooking time as well as foil type on Al leaching into baked fish, was determinated. Two fish types, Al foils, and marinating ingredients were procured from a hypermarket. Fish was cooked in the baking tray of oven, using two foil types, at 150°C for 40 min and at 200°C for 20 min. Al content was determined. It was found that increase in acidity caused significant increase in Al leaching. When the relationship between temperature-time and Al leaching based on meat type was analysed, it was found that when the temperature was increased the extent of Al leaching was higher in salmon. Even in the highest estimated weekly exposure to Al (1.228 ± 0.1631 mg/kg per week), Al PTWI suggested by JECFA was not exceeded. Although using different Al foil did not leach significant amounts of Al into the fish and exposure values of Al did not exceed the PTWI, exposure of Al from fish samples may be dangerous to vulnerable gr...

The pesticides used by the salmon industry to treat sea lice, are applied in situ via a bath solution and are subsequently discharged into the surrounding medium. The effects of cypermethrin, deltamethrin, azamethiphos and hydrogen peroxide were assessed on the performance of Metacarcinus edwardsii larvae, an important crab for Chilean fishery. All larvae were dead or dying after 30 min of exposure to cypermethrin and after 40 min to deltamethrin at concentrations 100 and 20 times lower (0.15 and 0.1 μg L(-1), respectively) than the concentrations and exposure times recommended by the manufacturers (CRM) to treat sea lice. Azamethiphos affected all larvae at a concentration 10 times lower than CRM. Hydrogen peroxide had the lowest detrimental effects, but at the CRM, 100% of the larvae were affected. Sub-lethal effects, i.e prolonged developmental time, were observed at concentrations lower than CRM. Repeated exposure to azamethiphos (0.0625-0.5 μg L(-1)) and hydrogen peroxide (188-...

Rainbow trout, Oncorhynchus mykiss (Walbaum), sea trout, Salmo trutta L., and Atlantic salmon, Salmo salar L., were experimentally infected with Flavobacterium psychrophilum in order to evaluate any species differences in susceptibility to the bacterium. Furthermore, differences in pathological changes and distribution of the bacteria in internal organs were studied. The bacteria were injected intraperitoneally in two doses, high dose (Hd) 1 × 107 colony forming units (CFU) fish−1 and low dose (Ld) 1 × 106 CFU fish−1. The mortalities in the Ld groups varied between 0 and 7.5% and in the Hd groups between 55–70%. No significant differences in mortality between the species were recorded. Clinical signs and pathological findings were similar in the three species and in accordance with those of rainbow trout fry syndrome. Rainbow trout showed more pronounced lesions in the spleen compared with the other species. Necrosis of renal tubular epithelium and haematopoietic tissue was most pro...

The structural distortion of oligonucleotides upon cis‐PtCl2(NH3)2{d(T‐C‐T‐C‐G‐G‐T‐C‐T'‐C‐N7(5) N7(6)} reveals shifting of 4 phosphorus resonances due to platination. 3 Resonances could be assigned by selective 31P‐irradiation, showing P(6) (P between the two Gs) to be shifted 1.5 ppm to low field. In the concomitant double strands P(6) is shifted 0.9 ppm to lower field. A similar peak has been observed in platinated salmon sperm DNA (37°C), indicating that Pt‐binding to GpG‐fragments in DNA is similar to that found for the decanucleotide, so the distortion of DNA might be comparable.