黑棘鲷的命名和分类地位探究

以黑鲷(Acanthopagrus schlegelii ♀)×真鲷(Pagrus major ♂)杂交子一代为亲鱼,于2017年4月在水温(21.8±0.4) ℃条件下,对自然受精、人工孵化获得的杂交子二代(F₂)早期仔鱼进行发育观察,并就饥饿对仔鱼早期生长与存活的影响及不可逆点(point of no return,PNR)进行研究。结果表明,杂交F₂初孵仔鱼全长(2.40±0.15) mm,仔鱼3日龄开口摄食,混合营养期4~5 d,7日龄全长增长到(3.95±0.04) mm,生长态势正常;杂交F₂仔鱼开始摄食的初次摄食率及最高摄食率分别为45.8%及77.21%,6日龄时初次摄食率下降为29.83%,抵达PNR时间;饥饿仔鱼5日龄时负生长,全长与对照组有显著差异(P<0.05),6日龄时全长与对照组有极显著差异(P<0.01)。研究表明杂交F₂早期仔鱼具有较好的生长态势;其开始投饵的最适时机应于仔鱼开口后的3 d内。     

Nutrient efficacy of microalgae as aquafeed additives for the adult black tiger prawn,Penaeus monodon

This study used a small amount of several lyophilized microalgae (5% of dry weight in aquafeed) to feed adult black tiger prawns Penaeus monodon for 4 weeks, aiming to promote prawn health and nutritional level. Apart from slight increases in ash content, chlorophyll and β‐carotene in the microalgae‐added feeds, there was no difference from the commercial diet in their biochemical composition. After 28 days of feeding, prawn body length, body weight, condition index and also total amount of fatty acids and amino acids of the flesh (2nd abdominal segment) were not affected by microalgae additives as compared with the control commercial diet‐fed group (P > 0.05). Prawns fed the microalgae diets, however, had a relatively better survival rate than those fed the commercial control diet, although no statistical significance was detected in any except for the diatom Melosira sp. The elevated survival rate was concomitant with a higher phagocytosis rate and superoxide dismutase (SOD) activity in the immune response analysis, and significantly a higher astaxanthin content detected in the tail muscle of microalgae diet‐fed prawns (5.36–10.78 ng of astaxanthin per gram of muscle DW). These findings demonstrated that low‐inclusion microalgal additives in prawn diets over a short feeding period (4 weeks) can result in healthier adult prawn, and hence could contribute to the development of an optimized feeding strategy for prawn aquaculture close to harvesting.     

中华鳖不同生态养殖模式对池塘水环境及养殖效果的影响

利用条件相近的两组池塘,对中华鳖(Trionyx sinensis)的两种生态模式(Ⅰ组:中华鳖-吃食性鱼类鲤和草鱼模式;Ⅱ组:中华鳖-杂食性水生动物鲫和螺模式)对池塘水环境以及养殖效果的影响进行对比试验。结果表明,Ⅱ组CODMn在7、8、和9月显著低于Ⅰ组(P<0.05),NH3在6、7、8和9月显著低于Ⅰ组(P<0.05),TP在7月和8月显著低于Ⅰ组(P<0.05),TN在6、7和8月显著低于Ⅰ组(P<0.05),NO2--N在6月和7月显著低于Ⅰ组(P<0.05),Ⅱ组水环境质量较Ⅰ组好。Ⅱ组检出藻类47种,Ⅰ组34种,Ⅱ组种类显著增多(P<0.05);Ⅰ组蓝藻重量占83.18%,硅藻2.98%,隐藻2.65%,甲藻0%,Ⅱ组蓝藻58.59%,硅藻13.44%,隐藻14.00%,甲藻7.07%,Ⅱ组蓝藻明显下降,而硅藻、隐藻、甲藻明显上升(P<0.05)。6月Ⅰ组平均生物量4.18mg/L,Ⅱ组2.57mg/L,8月Ⅰ组29.04mg/L,Ⅱ组5.41mg/L,6月和8月Ⅰ组生物量均显著高于Ⅱ组(P<0.05)。Ⅰ组Shannon-Wiener指数H’在6月和8月均值分别为2.117和0.7467,Ⅱ组均值分别为2.5427和1.0178,Ⅱ组6月和8月H’均明显增加(P<0.05);在6月,Ⅱ组Margalef丰富度指数d为1.8516,Ⅰ组为1.2499,Ⅱ组较Ⅰ组上升明显(P<0.05);两组的Pielou匀度均指数J差别不大。Ⅱ组中华鳖平均产量11782.5kg/hm2,显著高于Ⅰ组11482.5kg/hm2(P<0.05)。     

CaCl_2和6-BA处理对枣果呼吸强度及贮藏品质的影响

 研究了赞皇大枣和胜利枣采后在 0℃条件下呼吸强度和果实品质的变化规律以及采前 Ca Cl2 和 6 - BA处理对采后枣果呼吸强度和果实品质的影响。结果表明 ,赞皇大枣和胜利枣属于非跃变型果实 ;在贮藏过程中 V- C含量先积累后降低 ;采后果肉硬度逐渐下降且与贮藏时间呈极显著负相关 (r1 =- 0 .936 46 ,r2 =0 .936 2 4)。采前Ca Cl2 、6 - BA以及 Ca Cl2 +6 - BA处理 ,均能降低采后枣果的呼吸强度 ,但作用效果不显著。 1% Ca Cl2 和 1% Ca Cl2 +15 mg/ L 6 - BA处理能明显降低 V- C损失率 ,抑制果肉硬度和好果率的下降。 1% Ca Cl2 处理可使赞皇大枣和胜利枣贮藏末期的果肉硬度分别比对照增加 1.2 kg/ cm2 和 1.5 kg/ cm2 ,好果率分别增加 8.2 %和 5 .4% ;1% Ca Cl2 +15 m g/L 6 - BA处理可使赞皇大枣和胜利枣贮藏末期的果肉硬度分别增加 1.5 kg/ cm2和 2 .1kg/ cm2 ,好果率增加 17.8%和 11.7%。 15 m g/ L6 - BA处理对枣果的呼吸强度及果实品质有一定影响 ,但作用效果总体上不及 Ca Cl2 。     

向家坝水电工程蓄水后坝下河段水质现状分析

为掌握向家坝蓄水后坝下河段的水质现状,本研究在坝下长江上游珍稀、特有鱼类国家级自然保护区内选取六个断面,在鱼类不同的生活阶段进行监测。基于蓄水后2013-2014年水环境因子的监测数据,对各断面的21项水质指标的总体特征进行研究,分析其变化规律并进行水质评价得出目前水质现状。结果显示,蓄水后该江段水质指标特征总体良好,水温初期滞温变化值在2℃左右,超标因子主要是总氮、总磷、高锰酸盐指数、挥发酚以及重金属铅汞。总氮、砷及六价铬差异性极显著,是影响数据差异的众多因素中的主要因素。对各样点的水质因子进行聚类分析表明,坝下三块石与其他地点分类明显,距大坝较远与较近的点位各指标存在较大的差异性,表明大坝蓄水对水质带来不同程度的影响。     

Influences of feeding frequency of extruded pellet and moist pellet on growth and body composition of juvenile Japanese flounder <Emphasis Type="Italic">Paralichthys olivaceus</Emphasis> in suboptimal water temperatures

This study was carried out to investigate the influences of feeding frequency of extruded pellet and moist pellet on growth and body composition of juvenile flounder (initial mean weight 6.3 g) in sub optimal water temperatures. A 2 (diets: extruded pellet and moist pellet)×2 (feeding frequencies: two and three times daily)×2 (water temperatures: 12 and 17°C) factorial design with three replications was used. After 60 days of feeding, the feeding frequency did not significantly affect growth performance of fish. Weight gain, daily feed intake, feed efficiency and protein efficiency ratio were significantly (P<0.05) higher for fish reared at the higher water temperature. At the same water temperature, weight gain, feed efficiency, and protein efficiency ratio were significantly (P<0.05) higher for fish fed the extruded pellet than moist pellet. The results of this study indicate that feeding frequency of two times daily is sufficient for optimal growth of juvenile flounder when reared in suboptimal water temperatures, and an increase in water temperature from 12 to 17°C improved growth and feed efficiency.     

Growth changes in bighand thornyhead <Emphasis Type="Italic">Sebastolobus macrochir</Emphasis> off the Pacific coast of northern Honshu,Japan

ABSTRACT:     The biomass of bighand thornyhead Sebastolobus macrochir was increased by the high recruitment success of the 1999–2002 year classes off the Pacific coast of northern Honshu, Japan. In this study, the growth of bighand thornyhead was examined over a 9-year period from 1996 to 2004 in this area. The growth of the 1999 year class and the 2000–2002 year classes was reduced at 3 and 2 years old, respectively, while the 1999–2002 year classes were smaller than the 1993–1998 year classes. In 2-, 3- and 4-year-old fish, the relationship between abundance and mean standard length was expressed by negative linear regressions, while fish became smaller when abundance of the year class was larger. Mean bottom temperatures were stable at depths of 350–900 m; variations in water temperature were small in the main distribution area of bighand thornyhead. We discuss the factors affecting the growth of bighand thornyhead via changes in the demersal fish community and feeding habits.     

辽宁省近岸海洋环境质量状况与趋势评价

根据2004—2006年辽宁省近岸海域的生物和沉积物质量监测,对该区域的环境质量状况和趋势作出分析和评价。结果表明,辽宁省近岸海域环境质量呈逐年恶化的态势,尤其是重金属Pb和Cd残留量超标较严重,2006年生物体重金属Pb、As和沉积物As残留量超标率接近100%。     

Ontogeny of the digestive system in hatchery produced Beluga (Huso huso Linnaeus, 1758); a comparative study between Beluga and genus Acipenser

The study on histological characteristics of the digestive system of Beluga (Huso huso) was conducted from hatching until 50 days posthatching at 16.5 °C. Development of the digestive system in this species followed the general pattern described for other Acipenserids, although there were differences in the timing of organ development among species. At hatching, the mouth was opened and digestive system was represented by a gastric cavity filled with yolk and lined by endodermal cells, and a partially differentiated hindgut. Gastric glands started to differentiate at 46.5 degree‐ days posthatching (ddph), the earliest appearance time among sturgeon fishes studied to date. At the onset of exogenous feeding (144.9 ddph), yolk sac reserves were not completely depleted in the stomach, suggesting a period of mixed nutrition. The complete development of the digestive system was not accomplished until 235.2 ddph when it showed all histomorphological features typical of juvenile specimens. According to histological results, it seems advisable to start co‐feeding H.huso larvae with inert diets at the onset of exogenous feeding, because exocrine pancreas and glandular stomach are fully differentiated, although the complete substitution of live prey by inert feed is not recommended until 235 ddph.     

Effect of different feed formulations on feed efficiency, gonad yield and gonad quality in the purple sea urchin Heliocidaris erythrogramma

The nutritive values of three pelleted prepared diets, based on animal (AP), vegetable (VP) and yeast protein (YP) were studied for the sea urchin Heliocidaris erythrogramma (Val.). Fresh macroalga Ulva australis was used as a natural control diet. Triplicate groups of five animals were fed one of the four diets ad libitum every second day for 85 days. Sea urchins fed pelleted feeds had significantly higher food consumption rates (dry basis) and significantly lower total and protein absorption efficiencies compared with the algal diet. The gonad yield and gonad production efficiency in sea urchins fed the natural diet were significantly higher compared with initial group (gonad yield only) and urchins fed animal and vegetable diets, but did not differ significantly from those of the animals fed the yeast diet. Percent protein and lipid in the gonads were not affected by the dietary source. The taste and smell of gonads were generally better in sea urchins collected from the wild or fed yeast and natural diets than in sea urchins fed animal and vegetable diets. The animal protein diet was the most stable in seawater while the yeast protein diet had the poorest water stability. The results of this study suggest that development of a more stable, single‐cell, protein‐based diet has a potential to promote gonad production of H. erythrogramma.