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Temperate Fish (temperate + fish)
Selected AbstractsAccuracy and precision of the continuous underway fish egg sampler (CUFES) and bongo nets: a comparison of three species of temperate fishFISHERIES OCEANOGRAPHY, Issue 6 2005P. PEPIN Abstract We examine the accuracy and precision of the continuous underway fish egg sampler (CUFES) relative to bongo nets based on the catch ratio of Atlantic cod (Gadus morhua), American plaice (Hippoglossoides platessoides), and cunner (Tautogolabrus adspersus). We derived expectation of catch ratios based on the application of a one-dimensional model of the vertical distribution of fish eggs applied to cod and on prior data on egg vertical distribution. Samples were collected in May and August 2001, two periods when the vertical structure of the water column differed substantially. Stationary CUFES collections did not yield significant differences in accuracy or precision relative to the underway CUFES. In May, when there was relatively little stratification, the CUFES-to-bongo catch ratio of cod and plaice eggs was well within expectations based on model predictions. In August, the CUFES-to-bongo catch ratios of cod and cunner were higher than expected. Generally, there was a greater proportion of early stage eggs in bongo than in CUFES samples, with the strongest differences in American plaice. The replicate variance of the CUFES was ,25 times greater than that of the bongo nets, probably because of the large volumes sampled by bongo nets relative to the CUFES. Given that the CUFES provides greater accuracy in mapping but lower precision than bongo nets, multiple sampling gears may be the most effective method for surveying fish eggs of pelagic and demersal species. [source] The effects of thermal effluent exposure on the gametogenesis of female fishJOURNAL OF FISH BIOLOGY, Issue 1 2000D. Luk High temperature in Swedish and Lithuanian thermal effluent areas influenced gametogenesis of female perch Perca fluviatilis, roach Rutilus rutilus and pike Esox lucius negatively, indicating reduced reproductive capacity. Oocyte atresia started during vitellogenesis in autumn, and was often followed by asynchronous egg cell development. Among other anomalies, multi-nucleus oocytes and hermaphroditism were observed. No significant impact was seen in silver bream Blicca bjoerkna. Ruffe Gymnocephalus cernuus reacted by a tendency to produce an additional mature oocyte generation during the spawning period. Ovaries in roach from coastal areas were often infected by a microsporidian parasite Pleistophora mirandellae, causing severe damage to the gonad. Parasites were also detected in pike, but neither in perch nor in lake populations of roach. Fish living in open coastal environments did not avoid impact by moving out of the heated areas. There seems to be a conflict in some temperate fish between temperature preference behaviour and safeguarding normal reproduction. [source] A review of modified atmosphere packaging of fish and fishery products , significance of microbial growth, activities and safetyINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 2 2002Morten Sivertsvik Modified atmosphere packaging (MAP) extends shelf-life of most fishery products by inhibiting bacterial growth and oxidative reactions. The achievable extension of shelf-life depends on species, fat content, initial microbial population, gas mixture, the ratio of gas volume to product volume, and most importantly, storage temperature. The shelf-life of fishery products is usually limited by microbial activity, although for some fatty fishes or at superchilled storage, it can be limited by nonmicrobial activity. Packaging of fishery products under modified atmospheres (MA) increases shelf-life compared with those packaged under air, but confers little or no additional shelf-life increase compared with vacuum packaging. The specific spoilage organism (SSO) of MA packaged cod at 0 °C has been found to be Photobacterium phosphoreum. Whether or not this bacterium is the general SSO for all marine temperate fishes at different storage temperatures and under various CO2/N2/O2 mixtures needs to be resolved. Without proper control of storage temperature, the benefits of MAP may be lost. Higher temperatures inevitably lead to less dissolved CO2 in the product and consequently loss of inhibitory effect, which may result in higher microbial and enzymatic activity, and uncertainties concerning the microbial safety, as food-borne pathogens might be present in the product. [source] Effect of sampling interval and temperature on the accuracy of food consumption estimates from stomach contentsJOURNAL OF FISH BIOLOGY, Issue 1 2005A. G. Finstad The effect of temperature and sampling interval on the accuracy of food consumption estimates based on stomach contents was studied using simulation. Three temporal patterns of feeding were considered (scattered throughout the day, one 5 h period or two 5 h periods) and gastric evacuation was modelled according to published values. Sampling intervals of 3 h gave reasonable food consumption estimates (2 to 19% error) at all temperatures. Comparably, sampling intervals as large as 12 h gave reasonable estimates of food consumption (1 to 20% error) when temperature was set to ,10° C. At temperatures <5° C, even 24 h intervals (equivalent to one daily sampling) provided reasonable estimates of daily food consumption (2 to 19% error) for all but the highest gastric evacuation rate combined with one daily feeding period (47% error). The temperature effect on estimation error resulted from diminishing temporal fluctuations in stomach contents with slower gastric evacuation rates. It follows that sampling effort may be considerably minimized when estimating food consumption from stomach contents during periods with low temperatures such as the winter time experienced by temperate fishes. [source] | ||||||||||