养殖海水和淡水鲈鱼的营养组成比较分析

为分析大宗养殖海水鲈鱼和淡水鲈鱼的营养组成,有助于后续开发加工,本文对养殖海水鲈鱼(海鲈鱼)和淡水鲈鱼(大口黑鲈)肌肉的常规营养成分、氨基酸组成、脂肪酸组成、无机盐、微量元素和有毒有害物质进行测定和分析比较。结果表明,海水养殖的海鲈鱼营养价值比淡水养殖的大口黑鲈高,其蛋白质含量显著比大口黑鲈高(p<0.01);两种养殖鲈鱼均含有人体所必需的优质氨基酸,海鲈鱼氨基酸总量显著比大口黑鲈高(p<0.05),且各种氨基酸含量均略高于大口黑鲈,鲜味氨基酸中谷氨酸含量最高,海鲈鱼的肉味更鲜甜。海鲈鱼肌肉脂肪含量与大口黑鲈相近,但内脏脂肪含量显著比大口黑鲈高(p<0.01)。海鲈鱼肌肉中不饱和脂肪酸含量显著比大口黑鲈高(p<0.01),但二十碳五烯酸(EPA)和二十二碳六烯酸(DHA)含量均低于大口黑鲈(p<0.01),大口黑鲈是人体补充EPA和DHA的优质食用鱼类。鲈鱼的矿物元素含量均很丰富,特别是富含钙和微量元素锌,而养殖海水鲈鱼在无机盐和微量元素含量方面均优于淡水鲈鱼。      

Stocking wild adult Florida largemouth bass (Micropterus salmoides floridanus): An additional fish management tool

Stocking of largemouth bass is an important management tool for fish management. The stocking of hatchery‐produced fingerling or advanced‐fingerling bass to supplement bass year‐classes, however, has exhibited varying success. Utilizing a different approach, a multiyear stocking programme using wild adult largemouth bass was initiated at the Harris Chain of Lakes (3800 ha Lake Griffin; 1811 ha Lake Dora) in central Florida. Wild adult bass (24 781 fish), ranging in size from 200 mm total length (TL) to over 600 mm TL, were stocked in Lake Griffin (13 932 fish) and Lake Dora (10 849 fish). One month after stocking, the number of stocked bass caught in electrofishing catches in Lake Griffin and Lake Dora was ~10% and 22%, respectively. Estimates of mortality were similar to the native largemouth bass, although the movement of stocked fish into other connecting water bodies was extensive. For the Lake Griffin/Lake Dora stocking programme, bass were transferred at a cost of $10.09–19.89 per fish, depending on how the costs of the project are calculated ($250 000 for just the capture and transport of the fish vs. $492 775 for the total project). Considering only capture and transport costs, conservative benefit/cost ratio estimates would be $1.77/$1.00 spent for replacement and $1.85/$1.00 spent recreational costs, although the benefit/cost ratios could exceed $10/$1. Based on the present study, stocking wild adult largemouth bass is a cost‐effective tool for managing largemouth bass.     

装饰合金的研究

本文通过正交试验设计了最佳的合金成分,并简要介绍了合金的生产工艺。试验结果明表,该合金具有优良的加工性能,良好的耐蚀性,其表面呈现与18开金相似的金黄色泽。合金初步应用于生产证明,它的综合性能是比较好的,并可以获得良好的经济效益。