双氧水预防白点鲑卵水霉病发生的效果研究

在白点鲑(Salvelinus leucomaenis Pallas)受精卵至发眼期间,为了替代甲醛,采用浓度分别为0mg/L(对照组)、600mg/L、900mg/L、1200mg/L、1500mg/L、1800mg/L的双氧水预防水霉菌的发生。消毒时间为隔天一次上午7:00-8:00,持续时间15min后换至正常流水孵化。在水温(4.5±0.4)℃,水体溶解氧(6.75±0.35)mg/L,pH(6.6±0.45)的情况下,经过40d的孵化,对各处理组的数据统计和分析,认为在浓度为1200mg/L可以有效预防水霉菌的发生,发眼率、上浮率和畸形率分别为89%、80.6%、0.7%、,而对照组相应为72%、70.2%、0.45%。当双氧水浓度低于1200mg/L时,受精卵孵化率和双氧水浓度呈正相关;高于1200mg/L时,受精卵孵化率和双氧水浓度呈负相关。另外,在孵化后期,发眼卵死亡率、仔鱼死亡率和畸形率则随着双氧水浓度的增加呈现明显上升的趋势。     

REVIEW Cultivation of Arctic charr: an update

There has been interest in farming Arctic charr, Salvelinus alpinus, since the 1970s, but expansion of the industry has not been as rapid as originally predicted due to problems experienced with obtaining supplies of viable eggs and juveniles, variable growth and flesh pigmentation during grow-out, problems with year-round culture in sea water, early maturation, and problems related to the marketing of portion-size fish. Several of these problems are probably a manifestation of a mismatch between the environmental requirements of the fish and the rearing environment. For example, variable rates of broodstock maturation and poor survival of eggs are probably the result of holding broodstock charr at temperatures that are unsuitable for optimal reproduction. Poor and heterogeneous rates of growth during grow-out may be the result of rearing the fish at sub-optimal stocking densities. Further, variable fillet pigmentation may be a manifestation of variable growth rates, rather than being a true reflection of the ability of charr to deposit carotenoids in their flesh. Provided that the fish are held under conditions that promote good rates of growth, charr appear to be able to deposit adequate amounts of pigment in their flesh when fed diets that contain 50–70 mg pigment per kg diet. © Rapid Science Ltd. 1998     

鸭绿江上游花羔红点鲑(Salvelinus malma)的食性分析及生态位

对鸭绿江上游花羔红点鲑（Ｓａｌｖｅｌｉｎｕｓ ｍａｌａｍ）的食性进行了分析,比较不了同年龄组和季节的食物组成及摄食强度的变化,探讨了鸭绿江上游花羔红点鲑的三维生态位及其分化。     

Alternative growth histories in populations of Lake Superior brook trout: Critical support for partial migration

As concerns for losses of migratory species heighten globally, scientists are being challenged to characterize diversity in the migratory behaviors to support scientifically defensible conservation programs. Anecdotal observations of brook trout (Salvelinus fontinalis) inhabiting Lake Superior and its tributaries suggest the occurrence of two forms: a large lake form hypothesized to originate in streams and reside in Lake Superior for significant parts of the year and a small stream form hypothesized to be stream resident. Declines in the lake form are a conservation concern and understanding of the variation in migratory behavior is needed to assist conservation efforts. We used analyses of vertebrae and otoliths to test whether the growth histories of lake and stream caught fish differed as expected for adult and juvenile stages from a migratory population (migration), individuals differing in the age of outmigration to the lake (staggered migration), or a combination of residents and migrants (partial migration). Lake caught fish grew faster and lived longer than stream caught fish and differences in length-at-age were apparent by the end of the first year of life. There was no evidence of individuals abruptly changing growth history in a way that would suggest habitat switches later in life. Growth histories of lake and stream caught brook trout were also similar to those of migrants and residents from other brook trout populations or sub-populations. Our findings support the hypothesis of partial migration as an explanation for the diversity observed in Lake Superior brook trout and demonstrate how analyses of growth histories can help clarify migratory systems in species whose movements are challenging to track.     

红点鲑属鱼类资源现状及保护利用

本文综述了国内外红点鲑属鱼类的种类，资源及其发展利用现状，并对我国保护和发展利用红点鲑资源提出措施和建议。     

Brook trout spawning areas in lakes

Abstract— Nine lakes containing self-sustaining populations of brook trout ( Salvelinus fontinalis ) were surveyed to provide quantitative information on the abundance and distribution of redd sites. We measured rates of groundwater flow at redds in four of these lakes, and in one of these lakes we also compared the frequency of site use over four years from spawning observations. The number of redd sites in each lake ranged from 1 to 53 (mean=30) with most found relatively close to shore (∼ 1 m deep). Spawning areas per lake (16.9–829.4 m²) were not related to lake size and were often not continuous areas of littoral zone habitat. Rates of groundwater flow in lakes, averaged across redd sites in each lake, ranged from 20.0 to 107.9 ml. m.⁻² min^−1. The intensive survey of redd site use in one lake demonstrated that only 11% of sites (10 of 92) were used in all four years of observation. The mean rates of groundwater flow at sites used in all four years were significantly greater than at sites used intermittently. Data from this and other studies point to the conservation of subcatchments associated with groundwater discharge areas used by spawning brook trout as a means of maintaining self-sustaining populations.     

Influence of feeding frequency on growth and size dispersion in Arctic charr Salvelinus alpinus (L.)

Abstract Dominance hierarchy formation in groups of fish is thought to be a major reason for the development of size heterogeneity. The objective of the current experiment was to examine the influence of different feeding frequencies on growth and changes in size distribution in groups of Arctic charr Salvelinus alpinus (L.). The fish were fed equivalent excess rations continuously for 24 h a day, for 2 h twice a day (early morning and evening), for 2 h once a day in the morning or for 2 h once every other day also in the morning. Growth was measured by individual weighing of fish four times during the 130‐day experiment. Coefficient of variation in size within rearing groups was used to assess size dispersion and the possible development of hierarchies within the groups. Feeding frequency did not influence variation in size within groups, and there were no signs of hierarchy formation.     

Optimal protein requirements of young Arctic charr (Salvelinus alpinus) fed practical diets

Young Arctic charr, Salvelinus alpinus (L.), mean weight 2.56 ± 0.02 g, were fed nine isoenergetic (?16.6 MJ digestible energy (DE) kg^?1) practical diets formulated to supply digestible crude protein (DCP) at 40g kg^?1 increments from 230 to 550g kg^?1, for 84 days. Mean weight gain (MWG) and specific growth rate (SGR) were determined every 14 days while carcass composition was determined at the start and end of the experiment. Growth responses attained the highest values in the fish fed the diet with 350 g kg^?1 DCP. Carcass moisture gain, protein gain and apparent net lipid accumulation increased as DCP levels increased to a maximum at 350 g kg^?1 after which there were no differences among treatments. Total carcass lipid and lipid gain decreased as dietary DCP increased up to 470 g kg^?1 with no differences thereafter. Apparent net protein accretion decreased with increasing DCP levels up to 350 g kg^?1 after which there were few differences among treaments. Protein requirements were estimated by fitting MWG and SGR data to broken line regression, quadratic and saturation kinetics models. Results from these analyses suggest that dietary DCP should be provided at between 340 and 392 g kg^?1 (equivalent to ?370 and 420g kg^?1 crude protein) for optimal growth of young Arctic charr reared in similar conditions.     

Movement of brook trout (Salvelinus fontinalis) in four small subalpine streams in northern Colorado

We studied the movement of brook trout (Salvelinus fontinalis) in four small streams in northern Colorado using mark-recapture methods and weirs. The recapture rates of marked adult trout were low for all streams, and large numbers of unmarked adult trout, apparently immigrants, were found each year. Significantly more trout, immigrated into sections that were experimentally modified by installing low log dams, which increased depth, pool volume and the amount of overhead cover. The number of immigrant and resident trout was significantly related to the amount of cover in the sections. Resident trout were larger than immigrants in all streams in the last year of sampling. Most mobile brook trout moved upstream during summer on the two streams where weirs were operated, and upstream migrants were significantly larger than downstream migrants on both streams. We suggest that a high degree of movement may be an adaptive response by brook trout to the heterogeneous nature of small mountain streams.     

A survey of salmon gill poxvirus (SGPV) in wild salmonids in Norway

In 2016, the Norwegian health monitoring programme for wild salmonids conducted a real‐time PCR‐based screening for salmon gill poxvirus (SGPV) in anadromous Arctic char (Salvelinus alpinus L.), anadromous and non‐anadromous Atlantic salmon (Salmo salar L.) and trout (Salmo trutta L.). SGPV was widely distributed in wild Atlantic salmon returning from marine migration. In addition, characteristic gill lesions, including apoptosis, were detected in this species. A low amount of SGPV DNA, as indicated by high Ct‐values, was detected in anadromous trout, but only in fish cohabiting with SGPV‐positive salmon. SGPV was not detected in trout and salmon from non‐anadromous water courses, and thus seems to be primarily linked to the marine environment. This could indicate that trout are not a natural host for the virus. SGPV was not detected in Arctic char but, due to a low sample size, these results are inconclusive. The use of freshwater from anadromous water sources may constitute a risk of introducing SGPV to aquaculture facilities. Moreover, SGPV‐infected Atlantic salmon farms will hold considerable potential for virus propagation and spillback to wild populations. This interaction should therefore be further investigated.