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本文在海湾扇贝筏式笼养不同放养密度试验的基础上,较详尽地分析了放养密度与成贝个体、鲜贝产量、贝柱产量和贝柱大小等几项主要养殖指标的关系。综合评价了不同放养密度的养成经济效益。提出了在长海县大长山海区。使用直径34厘米的养成笼,其放养密度以每层笼放养55个较为适宜。 相似文献
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秦皇岛地区海湾扇贝自然产卵从7月下旬开始,一直持续到11月中旬,产卵高峰有4次,分别是8月12日、9月7日、10月12日和10月28日,产卵率分别达到53.0%、89.0%、100%和78.0%,生物学最小型壳长为20.0mm。9月和10月份贝柱平均含水率均为78.2%,两月间没有显著差异(p>0.05)。11月份贝柱含水率略有增加,平均为79.6%,比前两个月增加1.4个百分点。自然产卵率达到100%时,贝柱含水率为(78.90±0.87)%;自然产卵率4.0%时,贝柱含水率为(79.70±0.34)%,两者没有显著差异(p>0.05)。相关性分析结果表明,贝柱的含水率与产卵率无显著相关(R=-0.14)。因此,养殖期间海湾扇贝主要依靠摄取外界的营养物质来完成生殖细胞发育。贝柱营养物质未参与生殖活动的原因,与养殖期间水温高、饵料丰富、海湾扇贝采取直接利用外部营养物质实现高效快捷的生殖活动的策略有关。11月份后,贝柱指数下降,含水率升高,海湾扇贝收获时间最好在10月底前后。 相似文献
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1997年以来,浅海筏式养殖的主导品种栉孔扇贝连续三年发生了大面积的死亡现象,栉孔扇贝的养殖优势如虾池养殖东方对虾一样跌入低谷。为此,我们渔技人员与广大养殖户一同探讨,采取了多品种混合养殖的模式,确保了浅海筏式养殖的健康发展。现把我们的做法总结如下,供同行参考。1．进行栉孔扇贝的换季养殖改变传统的春放冬收的养殖模式,购买当年培育的较大规格苗种或越冬渡夏的“老头苗”,把分苗时间提前至当年11月份,每层放苗40－50粒,第二年6、7月份收获,扇贝规格可达5－6cm,一般笼产6－8kg。2．进行海湾扇贝养殖搞好海湾扇贝养殖… 相似文献
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继林孔扇贝养殖发生大面积死亡后,海湾扇贝的养殖生产也发生了程度不同的死亡。笔者于1999年11月份,就我市海弯扇贝养殖生产的高产典型,进行了详细的调查了解,从中总结出了几点颇具新意的海上管理新方法。供本行业参考。一、基本生产情况。我市泊里镇尹家圈村扇贝养殖户安某,1999年养殖扇贝35亩,在市乡两级技术推广部门的技术指导下,取得亩加工每千克160粒左右鲜贝柱675千克,折合亩产壳贝4160千克的好收成,亩收入4万元（鲜贝柱售价64元／kg）成为该村700个养殖户,600亩养殖面积及周围海区养殖产量最高,亩收益最好的生产典型。二… 相似文献
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通过调查和养殖试验证明:在渤海湾内,5月中旬开始培育的海湾扇贝晚苗可以在当年10月中旬前养成至商品规格。晚苗比早苗附着杂物少、出肉率高、养殖成本低,经济效益较高.在养殖生产中使用几个批次的不同规格苗种有利于合理安排生产,有效地利用人力物力。 相似文献
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扇贝加工废弃物海鲜调味料的加工利用 总被引：10，自引：1，他引：9
扇贝是软体动物门扇贝科栉孔扇贝、海湾扇贝和虾夷扇贝的总称。海湾扇贝原主产于美国沿海,虾夷扇贝原主产于日本北海道及俄罗斯远东地区,两者均为雌雄同体。栉孔扇贝雌雄异体,主要产于我国北部沿海。扇贝是我国重要经济海产品之一,由其干制的贝柱,是非常名贵的海珍品。自20世纪80年代以来我国养殖业发展迅速,扇贝的养殖已相当普及,冻贝柱及干贝柱的加工和出口量非常大,成为我国大宗出口的水产品。而在加工贝柱的过程中产生了大量的下脚料,其中扇贝加工废弃物(包括内脏)约占整个扇贝的30%。仅以山东沿海地区年产4 0×105t扇贝计,每年将有… 相似文献
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2017-2018年在秦皇岛市北戴河新区人造河海湾扇贝养殖区进行了海湾扇贝新品种“海益丰12”与主养品种的养殖效果对比试验,试验结果表明:“海益丰12”具有生长速度快、个体大、养殖效益高的特点。与主养品种相比,“海益丰12”平均体重和壳长分别比主养品种高21.1%~48.7%和5.4%~13.8%;贝柱重量高33.1%~52.3%;养殖效益提高45.5%~92.2%。“海益丰12”是优良的养殖品种,适合于河北省大面积推广养殖。 相似文献
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关键种对生态系统结构和功能发挥了重要作用,其变化可以引起群落结构振荡和演替,导致生态系统功能紊乱乃至崩溃,因此,了解生态关键种的长期变化有助于解析整个生态系统演替过程。本研究基于莱州湾1959年、1982年、1993年、2003年和2015年春季(5月)底拖网渔业资源调查数据,构建了莱州湾春季鱼类群落食物网拓扑结构,分析了其关键种的长期变化。1959~2015年莱州湾鱼类食物网包含物种21~46个,摄食关系范围70~296个,食物网拓扑结构密度范围为0.155~0.300,种间关联度0.140~0.182,符合自然条件下群落种间摄食关系。1959~2015年莱州湾鱼类群落关键种如下:1959年为六丝矛尾虾虎鱼(Amblychaeturichthys hexanema)、花鲈(Lateolabrax japonicus)、蓝点马鲛(Scomberomorus niphonius)和黄(Lophius litulon),1982年为鳀(Engraulis japonicus)、黄和小黄鱼(Larimichthys polyactis),1993年为带鱼(Trichiurus lepturus)、鳀和蓝点马鲛,2003年为细纹狮子鱼(Liparis tanakae)、鳀和黄,2015年为细纹狮子鱼、大泷六线鱼(Hexagrammos otakii)和六丝矛尾虾虎鱼;关键种由经济价值较高的花鲈、小黄鱼和蓝点马鲛等演变为细纹狮子鱼、鳀和六丝矛尾虾虎鱼等经济价值较低的种类;同时,关键种的栖息环境也由中上层与底层生境(蓝点马鲛、花鲈、鳀等)演变为底层单一生境(细纹狮子鱼、大泷六线鱼和六丝矛尾虾虎鱼);关键种的这种更替导致食物网拓扑结构向简单化发展,在某种程度上也增加了鱼类群落结构脆弱性。 相似文献
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M. W. APRAHAMIAN P. HICKLEY B. A. SHIELDS G. W. MAWLE 《Fisheries Management and Ecology》2010,17(2):93-105
Abstract Inland fisheries in England and Wales have high economic and social values. Managing participation to maximise fishery performance is key to maintaining this status. The capital value of fishing rights for migratory salmonid fisheries is €165 million. Coarse fisheries contribute €1030 million to the economy. The central tenet to increasing participation in recreational salmonid fisheries is that an increase in stock size will result in more anglers accessing the fishery. This was examined for salmon on the rivers Usk and Lune where exploitation restrictions increased the number of salmon available to anglers. On the River Lune, the number of salmon available post‐intervention increased by 66%. There was no significant increase in catch while the number of anglers decreased by 16.3%. On the River Usk, the closure of the net fishery potentially resulted in an additional ～1200 salmon being available. Following closure, there was no significant change in rod catch or in the number of anglers. Increased participation is dependent less upon stock manipulation for coarse fisheries and more upon facilitating the activity. In recent years, urban fishery development programmes have provided improved access to local fishing opportunity. Also, new anglers have been targeted through campaigns such as Get Hooked on Fishing and the Scout Angler Badge. 相似文献
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C.D. de Silva 《Aquaculture International》1997,5(4):339-349
An electrophoretic analysis of six populations of Oreochromis mossambicus (Peters) and four populations of O. niloticus (L.) from several rivers and a fish hatchery in Sri Lanka was conducted to determine the degree of mixing within and between stocks. Genetic characterization of the O. mossambicus stocks showed that some degree of mixing with O. niloticus occurred in all but two of the populations examined, while in the case of the O. niloticus, all the populations had some degree of mixing of O. mossambicus alleles. Genetic identity calculated using Nei's coefficient gave values ranging from 0.9484 to 0.9895 for O. niloticus populations and 1.0 to 0.9940 for O. mossambicus populations, while interspecies comparisons ranged from 0.7531 to 0.9002. The implications of these results for fisheries management and aquaculture are discussed. 相似文献
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为研究斑海豹生长规律,达到科学饲养的目的,对大连圣亚旅游控股股份有限公司豢养斑海豹进行体检,获取动物性别、年龄、体质量和体长等信息;通过SPSS 13．0软件对动物的生长曲线、体长-体质量关系和雌雄间生长差异进行分析。试验共获得30头豢养斑海豹的体检数据,雌性11头,雄性19头。统计分析发现：logistic、Gompertz和von Bertalanffy三种模型回归的斑海豹最大体长、体质量依次为167、170、171 cm和153、175、191 kg ;体质量-体长关系为（r2＝0．908）;研究还发现体长-年龄、体质量-体长间的相关关系模型能够较准确的反映斑海豹的生长规律,而体质量年龄模型准确度较差。控制年龄的协方差分析未发现雌雄斑海豹生长规律间的差异（体长：P ＞0．05;体质量：P ＞0．05）。 相似文献
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César Salazar Marcela Jaime Yanina Figueroa Rodrigo Fuentes 《Aquaculture Economics & Management (Blackwell Science)》2018,22(2):151-167
In light of the current depletion of extractive marine resources and the sustainability issues that have arisen in the aquaculture industry, the small-scale aquaculture sector has emerged as a viable and sustainable alternative for generating income. To integrate the small-scale aquaculture sector into the food value chain, understanding the decision-making process to innovate becomes essential. This paper explores the factors underlying both innovation choices and intensity among small-scale aquaculture producers by utilizing exclusive census data from the small-scale aquaculture sector in Chile. The results indicate that education, secure property rights, internet access, participation in organizations, commercialization methods, government instruments, understanding of credit, and social learning promote innovation decisions. We also find that largest producers innovate in more areas, suggesting a role of size for both technological and non-technological innovations. 相似文献
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Declines in chinook salmon catches in the Strait of Georgia in relation to shifts in the marine environment 总被引：1，自引：0，他引：1
RICHARD J. BEAMISH BRIAN E. RIDDELL CHRYS-ELLEN M. NEVILLE BARBARA L. THOMSON ZIYANG ZHANG 《Fisheries Oceanography》1995,4(3):243-256
Chinook, Oncurhynchus tshawytscha, catches in the Strait of Georgia increased in the 1970s and reached maximum levels from 1976 to 1978. Catches then declined until they stabilized through regulation at levels approximately one-quarter of the 1976 to 1978 levels. The timing of the decline in catch was synchronous with an increase in the mean temperature of the Strait of Georgia, a decline in annual Fraser River flows, and an abrupt decrease in the marine survival of hatchery-reared chinook released into the Strait of Georgia. Surprisingly, the number of young chinook salmon (smolts) more than doubled over the period of declining catches compared with the number produced during the period of high catches. The increase in smolt abundance was a consequence of the production from hatcheries that was approximately equal to wild production. We conclude that there was a change in the carrying capacity for chinook salmon in the Strait of Georgia in the late 1970s that contributed to the declines in abundance and that rebuilding stocks to the high abundance of the late 1970s is unlikely until the carrying capacity for chinook salmon changes either naturally or through manipulation. Although we did not separate density-dependent and density-independent effects on marine survival, the current total number of chinook smolts produced appears larger than required for the current marine carrying capacity. 相似文献
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20 0 1年我们与河北水利厅合作 ,特聘请上海水产大学的专家对我们这里的三座水库进行资源调查 ,专家们认为小海子水库是天然的养蟹基地。这是一个浅碟型平原型水库 ,库底平坦 ,水草丰茂 ,枯水季节生长的水草可达水面 70 %左右 ,底部腐植淤泥层厚 15cm左右 ,水色呈绿褐色 ,透明度在5 0～ 80cm ,日照时间长 ,日照数波动在 12 2 7～2 74 8h ,年平均气温为 13 5℃ ,日平均气温变动在 - 4 7～ 2 8 2℃之间 ,库区最高气温 39 8℃ ,最低 - 13 8℃ ,月平均水温变化为 2 4～ 2 2 9℃之间 ,月平均最高水温在 7月和 8月 ,最低在 12月和 1月。由于水… 相似文献