鱼类早期生活史研究与其进展

鱼类早期生活史的研究，主要涉及卵和仔鱼发育，仔鱼最佳饲养条件、饵料密度、营养、生长、临界期、饥饿、捕食、环境耐力和毒性反应等和渔业密切相关的诸因子，是鱼类自然资源繁殖保护和养殖业苗种培育的基础。近二、三十年来，鱼类早期生活史研究已成为水产科学的一个崭新领域，在国际上受到广泛重视并迅速发展。国际海洋开发理事会(ICES)曾三次举行鱼类早期生活史学术讨论会，     

金鳟发眼卵孵化及苗种培育试验

本首次报道了金鳟发眼卵孵化技术，孵化水温5－11℃，积温达到140－180度日破膜孵出稚鱼，孵化率北京房山78．0％，黑龙江渤海75．8％，经20－40d胚后发育上浮平游开食。同时介绍了苗种培育技术和管理方法。     

Improved performance of gilthead sea bream, Sparus aurata, larvae after ozone disinfection of the eggs

Ozone (O₃) dissolved in seawater (ODS) was evaluated, as an egg disinfectant, on the spawn of captive gilthead sea bream, Sparus aurata, brood stock. Four contact times (CT) were tested (0.6, 1.2, 2.4 and 4.8 mg min L⁻¹) where CT was calculated by multiplying the dissolved O₃ concentration (0.3 mg L⁻¹) by different exposure periods (2, 4, 8, 16 min). There was also a disinfected seawater treatment that contained no O₃ or derived compounds (CT 0) and an untreated seawater control. All ODS treatments reduced egg surface bacterial counts to zero, which was significantly (P<0.05) lower than the CT 0 and the control groups (194 and 1320 plate⁻¹ respectively). Nevertheless, the hatching rate was high in the control and the CT treatments 0, 0.6 and 1.2 (88.7%, 87.3%, 89.5% and 83.7% respectively) while eggs exposed to a CT 2.4 and 4.8 hatched poorly (36.5% and 20.4% respectively), which was likely due, at least in part, to larvae unable to break the egg chorion successfully. Swim‐bladder inflation was significantly higher in the ODS groups (>97%) compared with the control and CT 0 treatments (ca. 70%). The results suggest that a 2‐min exposure of eggs to 0.3 mg O₃ L⁻¹ of ODS (CT 0.6) would improve current protocols in marine larviculture.     

真蛸人工繁殖及受精卵孵化技术研究初报

真蛸为福建省近年来新兴的海水养殖优良种类,具有较高的营养价值、商品价值和产业化养殖前景。本文报道了福建省水产研究所2008年-2011年真蛸人工繁殖及受精卵孵化结果：127头雌亲蛸经强化培育,共有77头产卵,获卵194×10^4粒,孵出143．4×10^4头浮游幼体。雌亲蛸获产率46．2％～86．7％,卵子受精率75．6％-91．8％,受精卵孵化率77．9％～95．0％。在20．0～22．5℃水温条件下,真蛸受精卵经21～36d开始孵出,孵出后4～6d为孵出高峰,每窝卵开始孵出至孵化结束维持10—16d。     

海南香蕉根颈象甲卵的空间分布型及理论抽样数确定

香蕉根颈象甲[Cosmopolites sordidus(Gemar)1已在海南香蕉园发生,对香蕉生产造成危害.为了研究香蕉象甲的分布和发生规律、指导田间取样,应用几种聚集度指标的计算公式以及Taylor幂法则、Iwao的m*-m回归分析法,分析和测定了香蕉根颈象甲卵的空间分布格局和田间理论抽样数.结果表明:海南香蕉根颈象甲卵在一定密度下呈聚集分布,空间分布符合负二项分布;聚集度指标,I>0,m*/m>1,C>1,Cα>0;Tavlor幂模型表明香蕉根茎象甲卵在一定密度下的分布为聚集的,而且聚集强度随种群密度的上升而升高:Iwao的m*-m回归模型分析表明,m*和m呈显著相关,香蕉根茎象甲个体间相互吸引,最适抽样数n与卵密度m及相对误差D的关系为:n=1/D2(1.3717/m+0.046 3).     

2000年以来中国芦笋的国际贸易及产业竞争力研究

中国是世界芦笋生产大国,面积和产量都位居世界第一,芦笋产业已发展成为具有竞争优势的新兴产业,在全球芦笋贸易中占有举足轻重的地位。为了研究中国芦笋的国际贸易和产业竞争力,根据FAO、WTO和中国海关（一般贸易）的芦笋贸易数据,对中国芦笋的进出口贸易现状进行了分析,选取生产者价格、国际市场占有率、贸易竞争力指数和出口价格比4个分析指标,对中国芦笋的产业竞争力给予评价。结果表明：中国芦笋贸易以出口为主,一直处于贸易顺差状态,2008年以后,进口增长很快,进出口差距显著缩小,2019年进口量是出口量的1/3,而进口额超过了出口额。芦笋价格方面,中国芦笋生产成本和生产价格较低,占据优势,但是出口单价和出口额相对也较低,出口创汇不显著,2013年以来进口单价快速上涨超过了出口单价,进口芦笋价格昂贵,未来芦笋进口不会明显增加,出口保持稳定。在国际芦笋出口大国中,秘鲁、墨西哥基本上是芦笋净出口国家,具有极强的贸易竞争力;其次是希腊,竞争力指数也较高;美国、西班牙、荷兰的优势也比较明显。中国是全球最大芦笋生产国,但芦笋的国际市场占有率不高,贸易竞争力指数为正数时接近1,出口额远大于进口额,反映出中国芦笋...     

蜜蜂蜂群中未受精卵的辨认与监督

以中华蜜蜂和意大利蜜蜂为实验材料,研究了中华蜜蜂群间以及中华蜜蜂与意大利蜜蜂种间未受精卵的辨认与监督行为特性。结果表明:中华蜜蜂蜂群中工蜂对群间未受精卵的辨认与监督效果差异不显著,卵的剩余率都在93%以上;但在中华蜜蜂蜂群中,工蜂在2 h之内把意大利蜜蜂未受精卵全部清理,而保留了89%以上的中华蜜蜂未受精卵;在意大利蜜蜂蜂群中,工蜂会在4 h之内把中华蜜蜂未受精卵全部清理,但保留了94%的意大利蜜蜂未受精卵。     

Changes in thyroid hormone levels in eggs and larvae and in iodide uptake by eggs of coho and chinook salmon,Oncorhynchus kisutsch andO. tschawytscha

Developmental profiles of thyroxin (T₄), triiodothyronine (T₃) and radioactive iodide uptake were established for eggs and T₄ and T₃ profiles were established for larvae (whole-body, yolk-only and body-only) of coho and chinook salmon. T₄ and T₃ were consistently present in all samples. In eggs, hormone levels remained fairly constant in all cohorst for at least the first three weeks of incubation, but then fluctuated in both directions in some sample groups. Large increases in T₄ (from 9 ng/g to 245 ng/g) were seen in 1985 chinook eggs 28 days after fertilization. Radioactive iodide uptake (which was used as a possible indicator of thyroxinogenesis) increased at least 10-fold in both 1986 coho and chinook eggs from 23–30 days after fertilization. T₄ (62 ng/g) and T₃ (393 ng/g) were found in the bodies of 28-day-old 1986 chinook embryos. In whole larvae, hormone levels varied depending upon the cohort studied. In general, initial body-only concentrations of both T₄ and T₃ decreased as body weight increased, but before yolksac resorption was completed, both thyroid hormone content and concentration increased (except for chinook T₃). T₄ and T₃ content in larval yolk stayed constant as yolksac size decreased, resulting in increased thyroid hormone concentration in the yolksac. All of these data suggest that the initial source of thyroid hormones in coho and chinook salmon eggs is maternal, but that by approximately 3–4 weeks after fertilization, the developing embryos begin to produce their own thyroid hormones. After hatching, increases in tissue T₄ and T₃ concentration coupled with constant T₄ and T₃ content in diminishing yolksacs suggest that larvae also produce their own thyroid hormones; yolksac content then may reflect both the original maternal hormones and the larva-producted hormones.     

Lipid characterization of both wild and cultured eggs of cuttlefish (Sepia officinalis L.) throughout the embryonic development

The present work reports a characterization of mean wet weight and moisture, the lipid class and fatty acid (FA) composition from the total lipids (TL), of both culture and wild eggs of the cuttlefish, Sepia officinalis , throughout the embryonic development. Additionally, reproductive data, such as the number of spawnings, number and mean weight of eggs and duration of spawning period of cultured cuttlefish is provided. Both types of eggs were similar in mean wet weight, moisture content, TL content and lipid composition throughout embryonic development. Females from the cultured group spawned 13 times and laid 8654 eggs in 64 days, with a mean weight of 0.607 ± 0.179 g. A sex ratio of 1.57 (11♀ for 7♂) promoted an individual fecundity of 787 eggs/♀ (the biggest until now on our culture facilities), which might be related to increased bottom areas. The TL increased with day/stage of embryonic development ( P  < 0.05) only in the cultured egg group. However, no differences were found on TL between culture and wild eggs at the same day/stage ( P  > 0.05). Eggs displayed predominant levels of phosphatidylcholine, phosphatidylethanolamine (PE), cholesterol and triacylglycerol at the end of embryonic development. Polar and neutral lipids of both eggs groups remained consistently proportional (∼50% for each lipid fraction) and a significant increase ( P  < 0.05) was observed in phosphatidylserine, PE and free FA throughout the embryonic development. In either egg type and day, 16:0, 18:0, 20:5n-3 and 22:6n-3 accounted for approximately 70 g Kg⁻¹ of all FA and saturated and n-3 totals seemed to have the same proportion in the cuttlefish eggs. The present results suggest that lipids are not used as energetic substrate but as structural components in cuttlefish egg.