Growth stimulation of juvenile abalone <Emphasis Type="Italic">Haliotis discus hannai</Emphasis> by feeding with salmon growth hormone in sodium alginate gel

We examined the ability of salmon growth hormone (sGH) in sodium alginate (SA) gel to accelerate the somatic growth of juvenile abalone, Haliotis discus hannai, by feeding. After the feeding of sGH at 50 μg or 100 μg in 350 mg SA gel, immunoreactivity to sGH in body fluid was maximal after 12 h, and was still detectable at 24 h. No immunoreactivity was observed in the control group. Following the feeding of sGH at 0.5 mg or 5 mg/8 g of SA gel at 7- and 14-day intervals, there was a greater increase in shell length and body weight than in the control. In abalone, sGH can be transported from food into the circulatory system and subsequently improve somatic growth.     

盐度对九孔鲍摄食_生长及存活的影响

九孔鲍摄食人工饲料的盐度范围为２０￣３８,其中较适宜的盐度范围为２５￣３５,在此盐度范围内,小规格鲍（平均壳长１．３０ｃｍ,平均体重０．３７ｇ）的壳长日增长为９１．５￣１０２．３μｍ,日增重为８．６０￣１２．５５ｍｇ;大规格鲍（平均壳长２．７ｃｍ,平均体重２．３ｇ）的壳长日增长为５６．３０￣８１．８０μｍ,日增重为１２．６８￣２２．４８ｍｇ,其最适生长的盐度为３０￣３５,存活率为９７％￣１００％。     

人工培育秋大麻哈幼鱼的生长与形态研究

通过对在淡水中培育大麻哈幼鱼生长和形态测定发现:大麻哈幼鱼在2.5%日投喂量时特定生长率较高;大麻哈幼鱼体重与体长的关系符合幂函数,其关系式为W=0.661 L2.1635;随着大麻哈幼鱼的生长,其肥满度有所增加,但增加幅度较小;全长/体长、体长/头长、背吻距/背尾距的比值较体长/体高、头长/吻长、头长/眼径和头长/眼间距的比值变化小,背吻距/背尾距的比值接近1,而大麻哈鱼生殖群体的比值在1.13～1.31之间.     

Growth and feeding in juvenile triploid and diploid blacklip abalone, Haliotis rubra (Leach, 1814), at two temperatures

Growth and feeding of juvenile triploid and diploid blacklip abalone Haliotis rubra (Leach, 1814) were investigated at two temperatures of 17 and 21 °C over a 50‐day period. There were no differences in growth between triploid and diploid abalone as measured by shell length and body weight. Both triploid and diploid abalone increased in length but not in weight at 21 °C. Condition indices were similar for triploid abalone maintained at both temperatures; however, those for diploid abalone were significantly higher at 17 °C than at 21 °C. Food intake was significantly greater yet feed conversion efficiency was significantly lower in triploid than in diploid abalone. Both the feeding variables were independent of temperature. On average, diploid abalone were able to convert 1 g of dry food ingested to 0.58 g of body weight, but triploid abalone only 0.44 g.     

Effects of alternate starvation and refeeding cycles on food consumption and compensatory growth of abalone, Haliotis asinina (Linnaeus)

The effects of alternate starvation and refeeding on food consumption and compensatory growth of hatchery‐bred abalone, Haliotis asinina (Linnaeus), were determined. Two groups of abalone juveniles (mean shell length = 29 mm, body weight = 5 g) were alternately starved and refed a macro‐alga, Gracilariopsis bailinae at equal duration (5/5 or 10/10) over 140 days. A control group (FR) was fed the seaweed ad libitum throughout a 200‐day experimental period. Starved and refed abalone showed slower growth rates (DGR, 63 and 70 mg/day in the 5/5 and 10/10 groups respectively), as a result of reduced food intake (DFI 15% and 16% day^?1 respectively), after repeated starvation and refeeding cycles. Percentage weight gains (5/5 = 196%, 10/10 = 177%) were significantly lower than that of the control (397%). When refed continuously over 60 days, the starved groups exhibited increased DFI and fed at the rate of 24% and 25% day^?1, which were not significantly different from that of the control at 26% day^?1. At the end of the experiment, no significant differences were observed among three treatments in terms of shell length (range: 46–48 mm), body weight (range 25–28 g), % weight gain (392–465%) and per cent survival (range 87–98%). The results indicated that H. asinina had a complete compensatory growth following a return to full rations after a series of intermittent starvation and refeeding cycles.     

Suitability of cage culture for Pacific abalone Haliotis discus hannai Ino production in China

Pacific abalone (Haliotis discus hannai Ino) aquaculture is a thriving industry in China. This study describes a novel submerged cage culture system for abalone rearing in Fujian, South China. The cage consisted of five vertical slots that were oriented perpendicular to the flow of water. The slots were separated by six vertically connected plastic plates for abalone attachment and shelter at the bottom of the cage. Experiment 1 was designed to determine the appropriate stocking density at the start of the abalone sea‐based production cycle. Eight‐month‐old hatchery reared and size‐graded juveniles were transferred to the sea‐based culture system. For different stocking densities, shell length of juveniles obtained in this novel culture system on 2, 3.5 and 5 months, respectively, was compared with shell lengths obtained in a traditionally multi‐tier basket culture system. In Experiment 2, daily growth rates (DGRs) in shell length and biomass in terms of wet weight of 2‐year‐old abalones reared in cage and tiered basket culture systems were compared over a 6‐month period. Results of Experiment 1 showed that growth of abalone in the cage culture system is density‐dependent; the mean final shell length of juveniles obtained was 6.7–15.9% higher than in tiered baskets system even at the same initial stocking density. In Experiment 2, DGRs in shell length of 53.83–78.38 μm day^?1 obtained in cage system were significantly higher than that in tiered baskets (P < 0.01). And in terms of wet weight biomass, it was 1.48–3.01 times higher in the cage system compared with the traditional system. Abalone survival was more than 87.5% in both culture systems in both experiments. Advantages of the newly established cage culture system included better growth performance of the animals reared and potential improvement of rearing conditions, such as improved water flow velocity and dissolved oxygen.     

Effects of the initial size, stocking density and sorting on the growth of juvenile Pacific abalone, Haliotis discus hannai Ino

During winter months, a novel overwintering mode of transferring juvenile abalones to open seawaters in southern China rather than keeping them in closed land-based nursery systems in northern China is a popular practice. The initial size, stocking density and sorting are among the first considerations when establishing an abalone culture system. This study aimed to investigate the effects of these factors on the growth of juvenile Pacific abalone, Haliotis discus hannai Ino, during overwintering. Juvenile abalones were reared in multi-tier basket form for overwintering in open seawaters in southern China for 106 days. The daily growth rates (DGRs) in the shell length of all experimental groups ranged from 67.08 to 135.75 μm day⁻¹, while the specific growth rates (SGRs) were 0.2447–0.3259% day⁻¹. Variance analysis indicated that both DGRs and SGRs in shell length were significantly affected by the initial body size and stocking density. Furthermore, the effects of stocking density on DGRs and SGRs varied with the initial size. However, sorting abalones according to their initial sizes may not be necessary in practice as sorting did not alter growth significantly at all densities in this study. Factors potentially affecting abalone growth such as genetic control and intraspecific competition were discussed.     

Optimum dietary crude protein level for growth in South African abalone (Haliotis midae L.)

A 95‐day feeding trial was conducted to evaluate the effects of dietary crude protein level on total body weight gain and protein gain of juvenile (4.89 ± 0.57 g) South African abalone (Haliotis midae). Six semi‐purified diets containing casein, fish meal and cottonseed meal as protein sources, and with crude protein levels ranging from 54.8 to 479.2 g kg^?1 dry matter (DM), were fed to four tanks containing 30 abalone each in a continuous flow system. No differences (P > 0.05) were found in moisture, ash or lipid content of soft‐body tissue as dietary crude protein level increased, indicating that differences (P < 0.05) in soft‐body protein content were solely due to dietary crude protein level. The relationships between dietary crude protein level and total body weight gain and protein gain were analysed by broken‐line and second‐order polynomial regression models. Based on total body weight gain, 358.7 g kg^?1 DM dietary protein from good quality sources is recommended for maximum growth of juvenile H. midae, while, if dietary protein is reduced to 280.7 g kg^?1 DM, growth will be depressed with 5 g kg^?1.     

The effects of elevated pCO2 on growth,shell production and metabolism of cultured juvenile abalone,Haliotis iris

Reduced seawater pH and elevated pCO₂ are important considerations in tank‐based abalone aquaculture, while sea‐based farms may be at risk to ocean acidification reductions in pH. Juvenile Haliotis iris (5–13 and 30–40 mm shell length) were reared in two, 100‐day experiments at ambient pH_nbs (~ 8.1, 450 μatm CO₂), pH 7.8 (~1000 μatm CO₂) and pH 7.6 (~1600 μatm CO₂). Seawater pH was measured and adjusted automatically by bubbling CO₂ into water in replicated flow through tanks. Two separate trials were run, in winter (8.8°C) and summer (16.5°C). Survival and growth were monitored every 30 days, and post experiment measurements of morphometrics and respiration rate undertaken. Growth of shell length and wet weight were negatively affected by reduced pH, with a 2 to 3‐fold reduction in growth of both size classes between ambient and pH 7.6 treatments in the summer experiment. For small juveniles, growth reductions were in conjunction with decreases to shell weight, while large juveniles showed greater resilience in shell production. No changes to respiration rate occurred, suggesting that juveniles may maintain physiological functioning while tolerating dissolution pressure or that they are unable to upregulate metabolism to compensate for pH effects. These data show that CO₂ driven reductions in pH can impact growth, metabolism and biomineralization of abalone, and indicate that water quality and ocean acidification are of importance in aquaculture of the species.     

Growth and reproductive performance of triploid and diploid blacklip abalone, Haliotis rubra (Leach, 1814)

Growth and reproduction of triploid and diploid blacklip abalone Haliotis rubra (Leach, 1814) were compared in a 30-month study. Triploidy was induced by inhibition of the second polar body formation using 6-dimethylaminopurine (6-DMAP) or cytochalasin B (CB). There were no significant differences in growth and survivorship between triploid and diploid abalone. However, triploid abalone had a more elongated shell and greater foot muscles than diploid abalone. A slightly curvilinear growth in shell length was conformed to all treatments. While diploid abalone had reached sexual maturity and spawned during the study, gonadal development and gamete maturation were abnormal in triploids. Female triploids lacked an apparent gonad at the macroscopic level but microscopic examination revealed that they had a thin layer of oogonia development. In contrast, male triploids were able to form similar-sized gonads to diploids during most of the reproductive period, but with brown-yellow discolouration and stalled gametogenesis at spermatocyte formation. Sex ratio of triploid abalone did not deviate from 1:1. With the onset of sexual maturation, growth and gonadal maturation occurred concurrently in diploid abalone, and there was no indication that growth of (diploid) abalone was reduced.     

三倍体九孔鲍的育种和养成技术研究

当 5 0 %九孔鲍受精卵出现第一极体后 ,以 6 -DMAP为诱导剂 ,用不同的浓度和不同的持续时间抑制第二极体的释放诱导三倍体 ;并进行了生产性苗种培育和养成试验。结果表明 ,6 -DMAP的诱导浓度为30 0μmol·dm-3 、诱导持续时间为 10min时 ,其胚胎的三倍体率为 90 %以上 ,并且胚胎的孵化率高达 85 % ,幼体的畸形率较低 ,为 5 0 %～ 5 5 % ;经过 7个月培育 ,试验组养成鲍的三倍体率为 6 5 %以上 ;试验组养成鲍的平均壳长比对照组增长 10 % ,平均体重比对照组增重 30 %。与二倍体鲍相比较 ,三倍体鲍在壳长增长和体重增重等方面 ,显示了显著的优势 [t>t0 .0 1( 58) ]。     

Effects of photoperiod on gonadotropin-releasing hormone levels in the brain and pituitary of underyearling male barfin flounder

ABSTRACT:   A pleuronectiform fish, the barfin flounder Verasper moseri , expresses three gonadotropin-releasing hormone (GnRH) forms in the brain: salmon GnRH (sGnRH), chicken GnRH-II (cGnRH-II) and seabream GnRH (sbGnRH). To clarify the effects of photoperiod on GnRH systems, changes in brain and pituitary GnRH peptide levels were examined using time-resolved fluoroimmunoassays. In experiment 1, 5-month-old male barfin flounder (mean total length 9.0 cm, body weight 11.0 g) were divided into short (8:16 h light : dark [L:D] cycle; lights on 08.00–16.00 hours) and long photoperiod (16:8 h L:D cycle; lights on 04.00–20.00 hours) groups in mid September and maintained until November under natural water temperature (19.3–15.2°C). Brain sGnRH concentrations were significantly higher in the 16:8 h L:D group than in the 8:16 h L:D group, whereas no significant differences were observed in total length, body weight, plasma testosterone concentration, brain cGnRH-II concentration and pituitary sbGnRH content. In experiment 2, 7-month-old male barfin flounder (mean total length 16.5 cm, body weight 76.8 g) were divided into short and long photoperiod groups in mid December and maintained until February under natural water temperature (12.5–6.6°C). Total length, body weight and condition factor were significantly greater in the 16:8 h L:D group than in the 8:16 h L:D group, whereas no significant differences were observed in plasma testosterone concentration and GnRH levels in the brain and pituitary. These results indicate that levels of sGnRH in barfin flounder are influenced by photoperiodic treatment dependent on water temperature and/or body size.     

Changes in growth characteristics of the small abalone Haliotis diversicolor (Reeve, 1846) after one decade in a closed culture system: a comparison with wild populations

Small abalone Haliotis diversicolor (Reeve, 1846) is one of the smallest commercial abalone in the world. The successful application of artificial propagation and mass seed production techniques since the 1980s have resulted in the establishment of well-developed culture systems for small abalone in Taiwan. In the study reported here, we estimated the growth of a population of small abalone after a decade in a closed culture system and its growth characteristics with those of wild populations reported in previous studies. The von Bertalanffy growth equations of the shell length (L) and body weight (W) of cultured abalone were L _t  = 71.73 (1 ? e^{?0.84 (t?0.16)}) and W _t  = 47.70 (1 ? e^{?0.84 (t?0.16)})^3.180, respectively. The instantaneous rate of change for weight had an inflection point at the age of 1.54 years, indicating that cultured abalones reach their apex of body growth around this age. Compared with the wild populations, the cultured population exhibits a significantly smaller maximal shell length (L _∞) and a significantly larger growth coefficient (k). Based on our results, it appears that the artificial culture of generations of small albalone for one decade or more in a closed system could be one of the major factors causing the observed minimization of size in the cultured abalone; this may be an adaptation in which growth is traded off for the larger k.     

Effect of water temperature and diet on growth and mortality of Neptunea arthritica juveniles

The growth and mortality of Neptunea arthritica juveniles hatched from different egg masses (controlled conditions and field) reared at 10 and 15 °C, and provided with sardine (D1) and polychaete (D2) as foods were evaluated. Results showed that diet type and water temperature significantly affect the growth and mortality. Interaction between these factors reflected robust relationship among them, but restricted exclusively to growth. Through the study period, juveniles treated at 10 °C showed maximum increments of 2.5 mm (shell length), 2.3 mm (shell width) and 0.25 g (body weight) from their initial size. While maximum values of those treated at 15 °C for the above-mentioned parameters were 7.6 mm, 5.5 mm and 1 g respectively. In both cases, these increments were recorded for individuals fed with sardine. Mortality was significantly affected by diets and water temperature, which significantly increased under D2 [10 °C (20–67%), 15 °C (70–87%)] or 15 °C [D1 (30–83%), D2 (70–87%)]. According to the results, juveniles of N. arthritica could be maintained under controlled conditions, which allows growth improvement. Mortality appears to be the limiting factor, but this could be improved by the implementation of efficient culture method, basically oriented to increase the water quality.     

Growth performance of disk abalone Haliotis discus hannai in pilot- and commercial-scale recirculating aquaculture systems

The study investigated the growth performance of abalone from juvenile to marketable size in a commercial-scale recirculating aquaculture system. The rearing system consisted of 12 raceways (4.0 × 0.8 × 0.6 m) with a protein skimmer and a submerged biofilter for juveniles and 10 raceways (6.6 × 1.3 × 0.6 m) with a protein skimmer and a trickling biofilter for on-growing. Sea mustard (Undaria pinnatifida) and kelp (Laminaria japonica) were fed to the abalone. The total weight of abalone in the recirculating aquaculture system at the juvenile stage increased from 22.0 kg (average shell length 24.5 mm) to 75.5 kg (average shell length 42.5 mm) after 180 days. Feed conversion ratios increased slightly from 13.7 for the first 90 days to 16.3 thereafter. The shell growth rate of juvenile abalone between 24.5 mm and 34.8 mm was 3.4 mm month⁻¹, while for juveniles between 34.8 mm and 42.5 mm it was 2.6 mm month⁻¹. The total weight of abalone in the recirculating aquaculture system for the on-growing stage increased from 100.0 kg (average shell length 44.0 mm) to 433.3 kg (average shell length 72.7 mm) after 570 days. The feed conversion ratios for the first 173 days, the next 320 days, and the last 570 days were 19.6, 22.1, and 24.8, respectively. The growth rate of the average shell length during the on-growing period was 1.5 mm month⁻¹. Total ammonia nitrogen (TAN) concentrations were stabilized below 0.12 mg l⁻¹ in the juvenile recirculating system and 0.14 mg l⁻¹ in the on-growing recirculating system after conditioning of the biofilters.     

Grow‐out culture of abalone Haliotis tuberculata coccinea Reeve,fed land‐based IMTA produced macroalgae,in a combined fish/abalone offshore mariculture system: effect of stocking density

Haliotis tuberculata coccinea has been identified as a target species for European aquaculture development, in order to fulfil the rising demand for abalone. The effects of different stocking densities on the growth performance, feed utilization and survival of two different initial size groups (30 and 40 mm) of abalones, during the final grow‐out to cocktail/market size (45–60 mm), were determined over a 6‐month period. Trials were performed in abalone cages installed in a commercial open‐sea cages fish farm. Animals were fed the red algae Gracilaria cornea and the green one Ulva rigida, both obtained from a land‐based integrated multi‐trophic aquaculture system. Survival rates were very high (94–98%) regardless the density employed. Sustained high linear growth was recorded both in shell and weight. However, a 17–19% reduction in weight gain was obtained by doubling the initial stocking density, suggesting a higher competition for space or food. Nevertheless, the high growth performance (70–94   μm day^?1; 250–372% weight gain) and survival attained, even at high densities, denoted the suitability of the offshore mariculture system as well as the biofilter produced macroalgae for grow‐out culture of H. tuberculata coccinea that overall could reach cocktail/commercial size in only 18–22 months.     

不同饵料及其组合对黑鲍幼鲍生长及存活的影响

试验研究人工配合饲料、细基江蓠繁枝变种(Gracilaria tenuistipitata)(下称江蓠)、江蓠 裂片石莼(Ulva faxciata)、江蓠 肠浒苔(Enteromorpha intesinalis)、江蓠 裂片石莼 肠浒苔共5种饵料搭配方式对黑鲍幼鲍生长和存活的影响。试验进行35d,结果表明:(1)不同试验组之间的幼鲍的存活没有显著影响(P>0.05)。(2)不同试验处理对幼鲍的生长有显著影响(P<0.05)。江蓠 浒苔组、人工配合饲料组的黑鲍的特定生长率都显著大于其它饵料组(P<0.05);饲喂混合海藻的黑鲍的特定生长率显著大于单一海藻组(P<0.05)。壳长增长率、湿重增重率和干重增重率亦呈相似趋势。(3)幼鲍对不同饵料组合的转化效率存在显著差异(P<0.05)。试验结果表明,在水温较高时用江蓠、石莼和浒苔组成的混合饵料代替人工配合饲料饲养幼鲍,同样可以达到高的生长率。     

Distillers dried grain can be used as a feed ingredient for the growth of freshwater snail (Semisulcospira coreana) and abalone (Haliotis discus hannai)

Two feeding experiments were conducted to evaluate dietary distillers dried grain (DDG) as a feed ingredient that partially replaces soybean meal and wheat flour for the growth of juvenile freshwater snail (Semisulcospira coreana) and abalone (Haliotis discus hannai). Three experimental diets were formulated to contain 0 g kg^?1 DDG (DDG0), 200 g kg^?1 DDG from rice (diet DDG‐R) and 200 g kg^?1 DDG from rice and wheat flour (diet DDG‐RW). In the first experiment, three replicate groups of the freshwater snails averaging 133.0 ± 2.48 mg were fed one of the experimental diets for 12 weeks. Weight gain of the juvenile freshwater snails was not affected by dietary DDG (P > 0.05). In the second experiment, three replicate groups of the juvenile abalones averaging 296.3 ± 1.73 mg were fed one of the three experimental diets for 22 weeks. Weight gain of the abalones was not affected by dietary DDG (P > 0.05). Proximate and amino acid compositions of the whole body in the freshwater snails and soft body in the abalones were not affected by dietary DDG (P > 0.05). The results of the two experiments indicated that DDG can be used as a suitable feed ingredient for partial replacement of soybean meal and wheat flour at a level of 200 g kg^?1 in diets without any adverse effects on the growth performance of freshwater snail and juvenile abalone.     

Shell growth and age determination of the brackish water bivalve Corbicula japonica in Lake Shinji, Japan

ABSTRACT:   Shell growth and age determination of Corbicula japonica were investigated from samples collected monthly at two sites and field growth experiments from November 1999 to November 2000 in Lake Shinji. Both specimens did not grow in winter when the water temperature was below 11°C, but grew rapidly from spring to early summer when the water temperature rose from 15°C to 30°C, before further growing slowly from summer to autumn after the main breeding period. The monthly marginal growth distribution of the samples indicated that the concentric groove on the shell surface was an annual growth ring. It is concluded that the age of C .  japonica in the i -ring group when the shell growth resumed in spring was i  + 0.5 ( i  = 1, 2, · · ·), because the first true growth ring was formed at 0–2 mm in shell length, which then faded with growth. Lee's phenomenon was observed in the age determination results, and thus the growth coefficient and the asymptotic shell length of the von Bertalanffy growth equation were not estimated from the samples. However, these parameters were estimated from the annual shell length increments of the experimental individuals, which were 0.331/year and 28.2 mm, respectively.     

配合饲料投喂量和粒径对绿盘鲍稚鲍生长和存活的影响

在水温15.8～24.7℃下,将小规格(壳长为1.03±0.02 cm)和中规格(壳长为1.57±0.03 cm)绿盘鲍(GS-02-003-2018)(皱纹盘鲍Haliotis discus hannai Ino♀×绿鲍H.fulgens♂)稚鲍分成A、B、C和D 4个组,饲养在240 mm×170 mm×285 m...