Macronutrient selection,absorption and energy budget of juveniles of the Australasian sea cucumber,Australostichopus mollis,feeding on mussel biodeposits at different temperatures

This study was set up to examine the selection and absorption of macronutrients (lipid, protein and carbohydrate) of juveniles of the Australasian sea cucumber Australostichopus mollis, feeding on an effective natural feed (mussel waste) at different temperatures. Our results indicate that the juveniles select and absorb lipid more efficiently than carbohydrate and protein at all temperatures. However, the overall magnitude of absorption of carbohydrate and protein make them the main source of nutritional energy for juvenile sea cucumbers. Seawater temperature affects the feeding behaviour of the juveniles, reducing the selection efficiency of macronutrients, while increasing metabolic energy demand, resulting in less energy available for growth. These results show the importance of each macronutrient in the diet of A. mollis as a source of energy for growth, which opens up the possibility to replace more expensive nutrient sources, such as protein and lipid, with less costly carbohydrate to reduce costs of diet formulation.     

Growth of Hatchery‐reared Juveniles of the Australasian Sea Cucumber,Australostichopus mollis,Fed with Artificial and Natural Diets

Australostichopus mollis is the most common and valuable sea cucumber species on the coasts of New Zealand and southern Australia. However, information supporting the development of artificial diets to advance the aquaculture of this species is scarce. In this study, the nutrient absorption, growth, pigmentation, and survival of small (111 mg) and large (434 mg) early juveniles were measured. The juveniles were fed with mussel biodeposits (MB); a commercial hatchery diet‐powdered macroalgae (HD); and artificial diets with different protein levels, 5% (5P) and 10% (10P), respectively. During the experiment, survival was greater than 66% in all diet treatments, with the juveniles feeding actively and absorbing all major macronutrients. The small juveniles, which were starting pigmentation, had higher growth rates (0.8–2.5%/d) than the large juveniles (0.2–1.2%/d), which were completing pigmentation. Growth was higher with the MB and HD diets than with the 5P and 10P diets, which could be explained by differences in the food consumption and nutrient absorption among the diet treatments. This study shows the feasibility of developing artificial diets without depending on naturally available ingredients; however, palatability and consumption need to be improved in order to make artificial diets for this species more effective and commercially available.     

Effects of temperature, salinity and pH on larval growth, survival and development of the sea cucumber Holothuria spinifera Theel

For large-scale seed production of sea cucumbers through a hatchery system, it is imperative to know the effects of environmental parameters on larval rearing. Auricularia larvae (48 h post-fertilization) were obtained from induced spawning of Holothuria spinifera and used in experiments to ascertain the effects of temperature, salinity and pH on the growth and survivorship of the larvae. The larvae were reared for 12 days at temperatures of 20, 25, 28 and 32 °C; salinities of 15, 20, 25, 30, 35 and 40 ppt; and pH of 6.5, 7.0, 7.5, 7.8, 8.0, 8.5 and 9.0. The highest survivorship and growth rate and fastest development of auricularia indicated that water temperature of 28–32 °C, salinity of 35 ppt and pH of 7.8 were the most suitable conditions for rearing larvae of H. spinifera.     

Shell marking by artificial feeding of the tropical abalone Haliotis asinina Linne juveniles for sea ranching and stock enhancement

A method of marking abalone (Haliotis asinina Linne) for sea ranching and stock enhancement purposes was developed. Three‐month‐old abalone juveniles (11.8‐mm shell length, 0.28 g) were fed artificial diets for 1, 2, or 3 weeks. The width of the bluish‐green shell band produced by abalone juveniles was 1.7, 2.6, and 4.2 mm after 1, 2, or 3 weeks of feeding respectively. The growth and survival of juveniles fed artificial diets did not differ from that of juveniles fed the seaweed Gracilariopsis bailinae (control). Feeding the diet‐fed juveniles with the seaweed thereafter produced the natural brownish shell, thus forming a sandwiched bluish‐green band. An experimental release in outdoor tanks with natural growth of seaweeds and diatoms, and in a marine reserve showed that the shell band remained clear and distinct, indicating the usefulness of this shell marking method in sea ranching and stock enhancement of abalone.     

Growth of the hatchery-produced juveniles of commercial sea cucumber Holothuria (Theelothuria) spinifera Theel

The present study was conducted to develop the hatchery technology for seed production of the widely exploited commercial sea cucumber Holothuria spinifera Theel 1886, to facilitate an effective stock enhancement programme. Broodstock collected by skin divers were used for spawning trials. The embryonic and larval stages were similar to other aspidochirotes. The larval survival rate was 43.5% on day 9, which decreased to 18.3% nearing metamorphosis on day 13, the growth rate was 48 μm day⁻¹ and the settlement rate was 3.5%. Algamac^® used to induce settlement also served as the food source for the early settled juveniles, followed by Sargassum spp. extract (<40 μm) for the first month. Sargassum spp. powder along with fine sand (1:1) was given to juveniles >20 mm. Addition of Spirulina spp. along with Sargassum spp. powder and fine sand (0.5:1:2) enhanced the growth rate of the juveniles. In the hatchery, the juveniles attained an average size of 1, 30 and 48 on 20, 80 and 120 days respectively.     

The effects of stocking density on gonad growth, survival and feed intake of adult green sea urchin (Strongylocentrotus droebachiensis)

In this study the effects of different stocking densities on survival, gonad growth and feed intake in adult green sea urchin (Strongylocentrotus droebachiensis) were examined. Two size groups of sea urchins with respective initial mean weight of 45 g (S) and 70 g (L) were used. The experiments were carried out in 755 l plastic tanks divided into chambers by vertical fibreglass lamellae. In the two experiments stocking densities of 6, 12, 14 and 16 kg m^− 2 (Exp I) and 3, 6 and 8 kg m^− 2 (Exp II) were used. Sea urchins reared individually in compartmentalised raceways were used as controls in both experiments. All groups were fed a formulated moist feed ad libitum for 60 days at 8 °C (± 0.5). Mortality was observed in all groups, except for the control group and the lowest density group of large sea urchins (3 kg m^− 2, L). Both mortality and occurrence of injuries increased significantly with increasing stocking density in both experiments and for both size groups. In the highest density groups mortality was 60% (L) and 80% (S). There was a significant increase in gonad index during the experimental period in both experiments. Increased stocking density had a significantly negative effect on gonad growth in both size groups while feed intake was unaffected. The results show that adult S. droebachiensis can maintain high survival rate and high gonad growth at stocking densities up 6 kg m^− 2 in holding facilities of the design used in the present study.     

饥饿及恢复投喂对刺参生长、耗氧率和排氨率的影响

在水温(16±1)℃、盐度27.6±0.5、pH值7.5~8.3条件下,将体重为(28.47±2.02)g的刺参Apostichopus japonicus分别饥饿0(空白对照)、5、10、15和20d(分别记为T0、T5、T10、T15和T20)后再饱食投喂至40d。实验结果表明,随着饥饿时间的延长,刺参的耗氧率呈急速下降、上升、再下降的变化规律;排氨率呈先上升、后下降的变化规律;氧氮比呈先下降、后上升的变化规律。饥饿结束时刺参的体重,除T5组外,其余各组均显著小于T0组(P0.05),且各自均有不同程度的下降,耗氧率和排氨率与T0组比较均呈显著性差异(P0.05)。饥饿对刺参O/N比值的影响显著(P0.05),饥饿初期刺参O/N比值平均为10左右,随着饥饿时间的延长,刺参O/N比值降为小于7。实验结束时,各饥饿组刺参的体重和特定生长率均小于T0组(P0.05),除T5组外,各组的耗氧率和排氨率,均未能恢复至T0组水平(P0.05)。可见,饥饿后恢复投喂的刺参不具有补偿生长的特征。     

不同培育水温和饲料对刺参人工促熟效果的影响

本文采用单因素分析方法,研究了不同培育水温和饲料对刺参(Apostichopus japonicus)人工促熟效果的影响。在实验条件下,分别设置2种升温模式(水温从5℃逐渐升至12℃后恒温培育,从5℃逐渐升至15℃后恒温培育)和3种不同饲料[鼠尾藻(Sargassum thunbergii)粉组：50%鼠尾藻粉+50%海泥;海带(Laminaria japonica)粉组：50%海带粉+50%海泥;混合藻粉组：25%鼠尾藻粉+25%海带粉+50%海泥]。实验过程中,定期测量刺参体壁粗成分;实验结束后,分析雌性刺参性腺粗成分,同时检测雌参的繁殖力指标和子代质量指标。结果显示,在15℃水温培育的雌参性腺中粗蛋白和粗脂肪含量高于在12℃水温培育的雌参,分别为(62.54±1.78)%和(10.83±1.04)%。15℃水温下培育的雌参性腺指数、排放率和平均排卵量均高于12℃水温下培育的雌参,分别为(6.87±2.02)%、(16.00±2.31)%和(312.0±59.3)×104粒。饲料实验中,鼠尾藻粉和混合藻粉组雌参性腺中的粗蛋白含量显著高于海带粉组(P<0.05),为(60.82±0.52)%和(59.18±1.26)%,海带粉组雌参性腺中粗脂肪含量为(8.82±1.55)%,高于鼠尾藻粉和混合藻粉组。3个饲料实验组的雌参在繁殖力指标上差异不显著,但混合藻粉组的雌参繁殖力指标最高。混合藻粉组受精卵孵化率和早期幼体体长均显著高于海带粉组。研究表明,采用15℃水温培育的雌参繁殖力高于12℃水温培育的雌参,但二者产生的子代质量差异不显著;在实验范围内,采用不同饲料培育的雌参繁殖力指标没有显著差异,但混合藻粉组亲参所产子代质量高于鼠尾藻粉组和海带粉组。     

The effects of season, temperature and initial gonad condition on roe enhancement of the sea urchin Evechinus chloroticus

A series of 10-week experiments were repeated during the austral autumn, winter, spring and summer to investigate the seasonal effects, independent of seasonal temperature variation, on roe development (enhancement) of Evechinus chloroticus over a 12-month period and whether this differed among urchins with different initial gonad index (GI) values. E. chloroticus collected from wild populations with high and low initial GI values were caught and held in either ambient or constant ( 14.7 °C) seawater temperatures. The study has shown that, given a suitable roe enhancement diet, it is possible to significantly increase the GI of urchins throughout the year and that a seasonal effect on both the final GI and increase in GI, is primarily caused by seasonal variation in temperature. There are also significant effects from other factors, such as the initial condition of the animals prior to the trial and the reproductive stage of the urchins, but these are not as significant as the effects of temperature. The results indicate that it would be possible to increase the productivity of sea urchins by capturing them in cooler water and enhancing them at a site with relatively warmer water. The initial condition (GI) of the urchins plays an important role in gonad production with animals taken in low initial GI condition producing significantly larger increases in GI throughout each of the four seasons, than those with a high initial GI value. The urchins from the two populations developed through the stages of the reproductive cycle at a similar rate despite different final GI values and rates of increase in GI in both the temperature and population treatments, indicating that the differences in gonad production are related to environmental effects rather than the reproductive stage of the urchins. The exception to this occurred in the autumn samples where lower GI values and increase in GI were found during this season compared to in other seasons for the constant temperature treatment.

There is an overabundance of low GI urchins in the coastal waters of New Zealand and these animals are relatively easily found and fished on snorkel compared to high GI animals for which fishing pressure is much higher. It would appear to be more economic to fish and enhance low GI animals in New Zealand due to their relative abundance, ease of access and higher productivity during enhancement.     

Effectiveness of four methods for tagging juveniles of farm-reared gilthead sea bream, Sparus aurata, L.

This study tested different tags for each size of farm-reared gilthead sea bream, Sparus aurata L. juveniles, used in enhancement programmes. The following tags were tested: dye mark, fingerling tag, opercular tag, anchor tag A (filament diameter of 1.20 mm) and anchor tag B (0.85 mm). Tag/mark retention, wounds produced by the tag, ease of application, ease of detection and cost were examined. Epidermal dye marks had poor retention and detection rates. Of the tags tested, retention was greater for the anchor tag A (80–100%) after 7 months; anchor tag B showed a retention rate of only 20% after 3 months. The fingerling tag had a retention rate of 27.5% after 12 months. The opercular tag had a retention rate of 44% after 20 days but fractured the opercular bone in many cases. Tag incisions and wounds persisted in some fish for the duration of the experiment.     

Effect of meal size modulation on growth performance and feeding rhythms in European sea bass (Dicentrarchus labrax, L.)

The combined effect of feeding time and meal size on the growth performance and feeding rhythms were studied in European sea bass maintained under natural summer–autumn conditions. Three feeding strategies were compared: a modulated automatic-feeding (MF), a fixed automatic-feeding (FF) and a free access to self-feeders (SF). Under MF, feed was supplied in meals of different size, three times a day (morning, afternoon and evening, 33.33:16.67:50% of daily feed ration, respectively) during the first (31 days) and second (35 days) period of the experiment, and twice a day (morning and evening, 33.33:66.67% of daily feed ration, respectively) during the third period (27 days). In FF feed was supplied in equally-sized meals, three times a day (morning, afternoon and evening, 33.33:33.33:33.33% of daily feed ration) in all three periods of the experiment. Under SF, fish showed a diurnal self-feeding pattern, with the greatest percentage of self-feeding activity concentrated in the evening. In MF and FF, although feed was delivered automatically, the trigger was left in the tank to register activations as an indicator of feeding activity. The trigger activation of both treatments MF and FF was associated with the time of feed delivery. Feeding strategies affected biomass increase, specific growth rate (SGR) and feed conversion ratio (FCR), the greatest biomass increase and highest SGR being obtained with MF and the poorest FCR with FF. The results demonstrate that automatic-feeding systems, in which the quantity of feed supplied is modulated in accordance with the natural feeding rhythms of sea bass, may improve growth and feed efficiency.     

High stocking density and food restriction have minimum impact on size dispersal of cultured Senegalese sole (Solea senegalensis, Kaup 1858) juveniles. Evidence for individual growth being regulated by population structure

The individual growth being regulated by population structure was studied in cultured populations of Senegalese sole (Solea senegalensis Kaup) juveniles. Soles constituting an initial population were individually tagged and their specific growth rates (SGR) registered after two months of growth. Fish were then graded in order to achieve four new subpopulations based in their previous growths and cultured for other additional 60 days. Three subpopulations consisted of individuals that had previously shown an average SGR (% day⁻¹) of 1.04 ± 0.3, 0.66 ± 0.1 and 0.18 ± 0.1, respectively. A fourth sole subpopulation was established from randomly selected juveniles to constitute the ungraded control group. Growth of the three subpopulations originally graded according to high (1.04% day⁻¹), medium (0.66% day⁻¹) and low (0.18% day⁻¹) SGR soles, was always similar (P > 0.05) at any time (close to 0.60% day⁻¹). SGR distributions along time revealed a tendency of the three subpopulations to achieve similar growth rate dispersals to that of the ungraded group after 60 days of culture.The individual growth of sole juveniles was also determined in populations that were subject to increased stocking density and food restriction. Soles stocked at high density (N = 110 fish tank⁻¹; 30.97 ± 0.8 kg m⁻²) showed an increased growth standard deviation when compared with individuals kept at low density (N = 20 fish tank⁻¹; 6.20 ± 0.2 kg m⁻²). In contrast, it was found that population growth dispersal was unaffected in soles fed at a daily ration of either 0.25% or 1.0% of their biomass. Minimum consequences on overall size dispersal in terms of ΔCV were found when high stocking and restricted food ration conditions were compared to control groups. Overall results from this work indicate that individual growth of captive juvenile soles was mainly regulated at a population level, existing a strong tendency to achieve a social arrangement in terms of growth. High stocking density and low feeding ration assay suggests that potentially competitive rearing conditions do not contribute to increase population size dispersal during intensive production of S. senegalensis.     

The effect of the addition of algae feeding stimulants to artificial diets for the sea urchin Tripneustes gratilla

A key concern when developing artificial aquaculture diets is their palatability. This study investigated whether the palatability of artificial diets could be improved by incorporating a small quantity of highly preferred natural foods as feeding stimulants. The preference of Tripneustes gratilla for marine plants with which it co-occurs naturally in New South Wales, Australia, was assessed in a laboratory choice feeding experiment. T. gratilla displayed significant preference for the brown alga Ecklonia radiata over five other algae and one seagrass when they were offered simultaneously. Total protein or energy in the plants was not found to account for this preference. However, T. gratilla showed no preference among E. radiata, Sargassum linearifolium and Ulva lactuca when they were dried. Three artificial diets were made by incorporating one of each of these dried seaweeds at 5% dry weight. Although not statistically significant, T. gratilla ate more than twice as much the artificial diet containing S. linearifolium compared to the control diet containing no algae in a choice feeding experiment. In a no-choice feeding experiment, T. gratilla consumed significantly more of the Ecklonia and the Sargassum diets than the control diet despite each of the diets containing approximately the same protein and energy levels. T. gratilla consumed 49 and 43% more protein, and 37 and 44% more energy, respectively, when fed with the Ecklonia and the Sargassum diets compared to the control diet. Juvenile T. gratilla grew significantly faster on a wet weight basis on the Sargassum diet than the control diet at an average increase of 2.4% per day. These results indicate that the small amounts of palatable seaweed added to the artificial diets act as feeding stimulants, increasing the acceptability of artificial sea urchin diets, boosting the protein and energy consumption, and significantly increasing the growth of T. gratilla. Moreover, the fast growth of T. gratilla achieved in this study also indicates that this species would be a good candidate for commercial aquaculture.     

饲料中间隔添加壳寡糖对仿刺参生长、非特异性免疫和抗病力的影响

壳寡糖是良好的免疫增强剂,但在水生动物的应用还十分有限。本研究通过间隔投喂方式研究壳寡糖对仿刺参生长性能、非特异性免疫能力、消化能力、组织学和抗病力的影响。实验挑选体质量(18.51 ± 0.28)g仿刺参,对照组饲喂基础饲料,实验组以3天1次的饲喂频率饲喂含0.5%的壳寡糖饲料,其余时间饲喂基础饲料,进行8周的养殖试验后,测定该饲喂方式下仿刺参的生长性能、非特异性免疫能力、肠道消化酶、肠道和呼吸树组织学以及对灿烂弧菌的抗病力。结果显示,3天1次的饲喂频率下,仿刺参特定生长率和存活率几乎未受影响,但显著提高了脏壁比和肠壁比(P < 0.05);在免疫指标方面,显著提高了仿刺参体腔细胞的吞噬活性和呼吸爆发能力(P < 0.05),以及体腔细胞和肠道的酸性磷酸酶(ACP)、碱性磷酸酶(AKP)、溶菌酶(LZM)和总一氧化氮合酶(T-NOS)的活性(P < 0.05),其中肠道AKP和LZM活性分别提高了70.06%和156%,且acp、akp、lzm基因表达量显著提高(P < 0.05),其中肠道akp和lzm基因表达量分别提高了13.47%和22.36%;抗氧化指标结果显示,显著提高了仿刺参体腔细胞过氧化氢酶(CAT)活性(P < 0.05),而体腔细胞和肠道的丙二醛(MDA)含量无显著差异(P > 0.05);组织学结果显示,该饲喂频率显著提高了前肠肌肉层厚度和浆膜层厚度,中肠和后肠的皱襞高度和宽度;灿烂弧菌(Vibrio splendidus)攻毒结果显示,实验组仿刺参的相对保护率达到66.67%。综上,3天1次的饲喂频率能够一定程度上提高仿刺参的生长性能,非特异性免疫酶活性,明显改善肠道结构,研究结果可为壳寡糖对仿刺参作用机制的研究及投喂频率的确定提供数据支撑和理论依据。     

Evaluation of the growth and survival rate of the Caribbean Sea cucumber,Isostichopus badionotus (Selenka, 1867), early juveniles produced in captivity

Isostichopus badionotus is a new commercially important sea cucumber in the Caribbean that has rapidly shown signs of overexploitation. There is no information on the growth and survival rates for wild or hatchery‐produced early juveniles. Hatchery production and determination of juvenile growth rates are essential for future aquaculture efforts for this species. In this study, daily growth rate (GR), specific growth rate (SGR), weight gain (WG), survival rate (SR), and weight–length relation (WLR) were evaluated using small (0.01 g) and large (0.25 g) hatchery‐produced early juveniles under laboratory conditions. Growth was rapid compared to other cultured sea cucumber species; maximal values of SGR and WG were obtained for small juveniles (4.58%/day and 2,191%, respectively), while maximal GR and SR were obtained for large juveniles (0.29 mm/day and 99.17%, respectively). A wide range of sizes was evident at the end of each trial. The WLR of small and large juveniles fit with a negative allometric growth trend. This study highlights the potential production of I. badionotus as early juvenile stages withstand hatchery handling well and exhibit a high SR, reaching commonly released mean sizes (>0.7 g and 25 mm) after almost 3 months (120 days postfertilization).     

Natural growth of juveniles of the sea cucumber <Emphasis Type="Italic">Apostichopus japonicus</Emphasis>: studying juveniles in the intertidal habitat in Hirao Bay,eastern Yamaguchi Prefecture,Japan

In order to determine the population dynamics of juvenile Apostichopus japonicus, successive surveys were conducted in the stony intertidal zone of Hirao Bay, Seto Inland Sea. The juveniles of the green and black types of this species grew well from January to June. Before this high growing season, zero year old juveniles were too small to be readily detected by visual observations during field surveys. During the high water temperature season from August to November, juveniles over 1 year of age estivated underneath rocks. They awakened from their estivation in November, and it took another month before they could eat and discharge. The juveniles mainly migrated from the intertidal zone before they reached 3 years of age. In the present work, three patterns of juvenile growth were found. It is suggested that these differences in juvenile growth are mainly caused by differences in their start times for growth initiation when they are zero years old.     

Dietary supplement of fructooligosaccharides and Bacillus subtilis enhances the growth rate and disease resistance of the sea cucumber Apostichopus japonicus (Selenka)

The effects of two dietary supplements, entrapped fructooligosaccharide (FOS) and microencapsulated Bacillus subtilis, on the growth and disease resistance of the sea cucumber Apostichopus japonicus were investigated. Sea cucumbers (a total of 810 animals, with initial weight of 3.72 ± 0.16 g each) were fed with basal diet only or basal diet supplemented with three different doses of B. subtilis (0.2, 0.4 and 0.8%), three different doses of FOS (0.4, 0.8 and 1.6%), 0.2% B. subtilis plus 0.4% or 0.8% FOS. Growth and lysozyme activity were measured after 50 days feeding. The results showed that dietary 0.2% and 0.4% B. subtilis alone or 0.2% B. subtilis plus 0.8% FOS significantly increased the specific growth rate (SGR) of sea cucumbers compared with control (P < 0.05). The addition of B. subtilis with or without FOS had no significant effect on lysozyme activity. The animals were also challenged with Vibrio splendidus to assess the level of disease resistance provided by the two dietary supplements. Sea cucumbers fed with 0.8% B. subtilis or 0.2% B. subtilis plus 0.8% FOS exhibited the highest survival (P > 0.05). Under these experimental conditions, dietary B. subtilis and FOS had no synergistic effect on enhancing SGR and disease resistance of sea cucumber.     

不同管理方式对参池颗粒物质沉降作用及沉积物的影响

为探究不同管理方式对刺参养殖池塘(简称参池)沉降颗粒物及相关底泥、水体指标的影响,分别测定9 口参池(分为养水机、自然纳潮、微孔曝气3组参池,每组3个重复)颗粒物质在四季的平均沉降量和水平空间分布情况,底泥有机质含量和弧菌(Vibrio)总数,水体营养盐含量、浮游植物生物量和净初级生产力.结果显示,自然纳潮和微孔曝气池...     

牟氏角毛藻和海洋红酵母对玉足海参浮游幼体发育、生长及成活率的影响

为了考察海洋红酵母是否适合作为替代饵料用于玉足海参浮游幼体培育,实验利用牟氏角毛藻和海洋红酵母单独投喂和按照一定比例混合投喂,对玉足海参浮游幼体生长、发育以及成活率的影响进行研究.将牟氏角毛藻液与海洋红酵母稀释液分别按照4 ∶0、3∶ 1、2 ∶ 2、1∶3和0∶4的体积比混合后投喂玉足海参浮游幼体,依次标记为A、B、...