The effects of epibionts and predators on the growth and mortality rates of Argopecten purpuratus cultures in southern Chile

Epibiont and predator effects on the growth and mortality of the northern scallop Argopecten purpuratus were evaluated in cultures in southern Chile.The most common epibionts were bryozoans, hydrozoans and algae in both study sites, Metri Bay (41°36; 72°43W) and Chidhuapi Channel (41°49S; 73°05W).After 12 months of culture in pearl nets and lantern nets, the scallops size did not show statistically significant differences in cultures with and without epibionts in both study sites nor were there differences in the growth either with or without the presence of predators (decapod crustaceans). The growth rate was higher in Chidhuapi Channel than in Metri Bay.Mortality was concentrated in the initial phase of culture in pearl nets. During the culture phase in lantern nets, the mortality rate was lower than 3%. The mortality rate in scallops with epibionts was higher than when these were removed in the culture phase in pearl nets. In Metri Bay the mortality rate with predators was higher than without predators. Epibionts and predators did not affect mortality in the culture phase in lantern nets.Epibionts and predation are important factors in the early mortality of scallops and therefore in the success of culture. Epibiosis, however, is not important in scallop growth in southern Chile. This is related to the composition of the epibionts and to the low temperatures which probably limit the growth of algae and invertebrates.     

Strategies for enhancement of natural bay scallop, Argopecten irradians irradians, populations; A case study in the Niantic River estuary, Connecticut, USA

We investigated strategies to enhance populations of bay scallops,Argopecten irradians irradians (Lamarck, 1819), in a presumablyrecruitment-limited natural habitat. At present, the Niantic Riverestuary supports only a minor bay scallop population that is harvestedrecreationally. Three enhancement strategies were evaluated; (1)collection and redistribution of natural spatfall, (2) introduction andover-wintering of hatchery-reared stock into natural habitat to providenew spawning stock, and (3) over-wintering of hatchery-reared stock insuspension culture for creation of mobile spawner sanctuaries. Anassessment of natural bay scallop recruitment in the Niantic Riverconducted in 1997 indicated that few spat were found, they were widelydispersed within the river, and peak spawning occurred in late July1997. Direct re-seeding was evaluated as an enhancement measure byplanting hatchery-reared scallops ( 38 mm shell height) insmall-scale, 100-m² plots at different times and densities.Time of planting and the inferred predation intensity were major factorsaffecting survival; whereas, planting density had no significant effect.Approximately 9,000 scallops (35–45 mm shell height), broadcastwithin an eelgrass bed in November 1997, had high over-winter survivaland underwent gametogenesis and spawning during 1998. Of 26,000 bayscallops ( 45 mm shell height) over-wintered in suspensionculture from 1998–1999, approximately 60–80%survived, and these scallops spawned in mobile sanctuaries, during thesummer of 1999. There is good potential for using aquacultural methodsfor enhancement of bay scallop populations when natural recruitment ispoor and habitat and environmental conditions are not limiting.     

海水贝类苗种循环水培育水处理技术的研究与应用

封闭循环水育苗作为一种高技术育苗模式,其核心是养殖废水的净化处理。对于循环水系统的每一道处理工序,都有大量可选择的工艺。本试验利用自建的100 m3的海湾扇贝苗种封闭循环水培育系统,通过用各个阶段的出水养殖扇贝幼体,以及测定出水指标等来判断水处理系统的处理效果。结果表明,封闭循环水处理系统的效果是成功的。     

Bacteria in the culture of the scallop Argopecten purpuratus (Lamarck, 1819)

The scallop Argopecten purpuratus is one of themajor resources of commercial importance in Chilean aquaculture. One of themajor limiting factors for the culture of this species has been mass mortalityoccurring during production of juvenile seed organisms where massmortality of veliger larvae has been attributed to the presence of pathogenicbacteria in scallops and hatchery systems. Bacteriological studies havedemonstrated that in addition to bacterial pathogens, beneficial bacterialspecies capable of improving scallop larval survival may also be isolated fromscallops and hatchery systems. Research has been carried out on thedetermination of the feasibility of implementing beneficial bacteria in thecontrol of culture pathogens, thus reducing the need for chemotherapeuticmethods. The present review analyzes bacteriological research data on thedifferent roles of bacteria associated with scallop culture and discussesrecentdata on the implementation of beneficial bacteria in biological control ofpathogens in larval mass cultures of Argopectenpurpuratus.     

墨西哥湾扇贝的变压真空冷冻干燥的实验研究

文章是在前期实验研究基础上的后续。前期对墨西哥湾扇贝恒压法的冷冻干燥过程作了研究,得到优化的冻干参数。但对较复杂的冻干过程来说,用简单的固定板温和固定箱内压力所得到的参数,不可能对冻干的每一时刻都是最佳的。该文研究了由实验探索调压法对冻干时间的影响,以获得较优的冻干参数。结果表明,变压法的较优参数为高压60 Pa,低压10 Pa,调压时物料中心温度0℃。变压法与恒压法的优化实验相比,冻干时间可以缩短10%左右,优化后可以缩短约20%。     

人工鱼礁材料添加物碳封存能力及其对褶牡蛎(Ostrea plicatula)固碳量的影响

本研究将农渔废弃物(花生秸秆和海湾扇贝壳)作为鱼礁材料添加物,利用礁体自身碳封存增加人工鱼礁碳汇潜能的可行性,并通过研究礁体附着生物的变化特征,探讨礁体材料添加物对人工鱼礁生态系统生物固碳的影响.结果显示,实验海区礁体附着生物的优势种为褶牡蛎(Ostrea plicatula Gmelin),添加了花生秸秆和海湾扇贝壳的人工鱼礁并未显著增加褶牡蛎的附着量(P＞0.05).通过对添加物礁体自身碳封存量的计算,海湾扇贝壳添加物单位实验礁的最小碳封存量为104.13kg,最大碳封存量为260.32kg;花生秸秆添加物单位实验礁的最小碳封存量为296.28kg,最大碳封存量为740.70 kg;实验礁体添加物的总碳封存量达2802.87 kg.以此估算,如将实验所在的66.67 hm2礁区已投放的圆管型混凝土礁材料加入添加物,以海湾扇贝壳替代率为10％计算,至少可完成52040.00 kg碳的封存,以花生秸秆替代率为25％计算,礁体自身的碳封存量可达370350.00kg.     

双层毛刷辊式扇贝清洗工艺参数优化

为获得双层毛刷辊式扇贝清洗机最优清洗参数,以清洗率、破损率为试验指标,以上层毛刷辊转速,下层奇数毛刷辊转速,下层偶数毛刷辊转速为主要影响因子对海湾扇贝进行清洗试验。清洗试验在单因素试验的基础上进行正交实验研究。结果表明:两层毛刷辊间距为15mm,上层毛刷辊转速Va=60r/min,下层奇数毛刷辊转速Vb=45r/min,下层偶数毛刷辊转速Vc=75r/min时获得最佳清洗效果。清洗率平均值达13.75%,破损率平均值达2.1%;5kg清洗时间平均为100s。结果可为扇贝清洗工艺设备的设计提供参考,为双层毛刷辊式扇贝清洗机工作参数的匹配提供理论依据。     

提高海湾扇贝孵化率技术

实验表明,海湾扇贝卵的孵化率与换水量有关,孵化率以12小时倒池一次最高,为81．2％。亲贝的流产主要是由NH33-N较高引起的,COD只是间接因素。高COD引起NH3-N过高。加大换水量会使亲贝流产减少、培养良好的亲贝,在亲贝培育过程中加入3×10-6的“去氨净”,经常倒池,有利于提高亲贝孵化率。     

海湾扇贝晚苗池塘底播及在褐潮暴发海区筏式养殖效果

为有效避开河北地区褐潮暴发与海湾扇贝养殖时间的重叠,为海湾扇贝产业健康持续发展提供技术支持,对海湾扇贝进行晚苗培育(4月初种贝入室,以下称晚苗)及池塘底播和筏式养殖实验。结果显示,池塘底播海湾扇贝晚苗培育的稚贝(壳长5.0–6.1 mm),经过139 d 的养殖,收获时平均壳长达59.7 mm,扇贝柱5.2 g。2012年筏式养殖海湾扇贝晚苗,收获时平均湿质量、鲜贝柱重和出贝柱率分别为28.7 g、3.8 g 和13.8%。2013年,晚苗收获时平均壳高、湿质量、鲜贝柱重和出贝柱率分别为50.3 mm、24.4 g、3.1 g 和12.7%。按1000 m3育苗水体计算,海湾扇贝晚苗培育可以节省燃煤45.5 t,节约成本6.75万元,养殖晚苗可以降低养殖成本11.6%。研究结果表明,海湾扇贝晚苗养殖技术可以有效规避褐潮暴发的不利影响,而且还可以节约养殖成本和节省能源。     

Connectivity of the bay scallop (Argopecten irradians) in Buzzards Bay,Massachusetts, U.S.A.

The harvest of bay scallops (Argopecten irradians) from Buzzards Bay, Massachusetts, U.S.A. undergoes large interannual fluctuations, varying by more than an order of magnitude in successive years. To investigate the extent to which these fluctuations may be due to yearly variations in the transport of scallop larvae from spawning areas to suitable juvenile habitat (settlement zones), a high‐resolution hydrodynamic model was used to drive an individual‐based model of scallop larval transport. Model results revealed that scallop spawning in Buzzards Bay occurs during a time when nearshore bay currents were principally directed up‐bay in response to a persistent southwesterly sea breeze. This nearshore flow results in the substantial transport of larvae from lower‐bay spawning areas to settlement zones further up‐bay. Averaged over the entire bay, the spawning‐to‐settlement zone connectivity exhibits little interannual variation. However, connectivities between individual spawning and settlement zones vary by up to an order of magnitude. The model results identified spawning areas that have the greatest probability of transporting larvae to juvenile habitat. Because managers may aim to increase scallop populations either locally or broadly, the high‐connectivity spawning areas were divided into: (i) high larval retention and relatively little larval transport to adjoining settlement areas, (ii) both significant larval retention and transport to more distant settlement areas, and (iii) little larval retention but significant transport to distant settlement areas.