成鳖配合饲料主要营养物质可消化性研究

运用消化生理方法，测定成鳖配合饲料主要营养物质蛋白质、脂肪、碳水化合物的消化率。结果表明，所研制的成鳖配合饲料中蛋白质、脂肪、碳水化合物的消化率分别为８４６５％—９１８７％、８１５０％—８６１５％、６７０５％—７０７７％。     

在海湾扇贝亲贝促熟培养中混养海参的研究

首次在海湾扇贝亲贝的促熟培育中，在池底放养海参，利用海参来摄食扇贝的粪便和残饵，改善亲贝蓄养水质。经42天混养试验表明：实验组比对照组性腺指数明显提高，水质得到了明显的改善，换水量降低了25％-30％，降低了生产成本，同时海参也增重了约30％，取得了比较好的效果。     

磁化水蓄养海湾扇贝亲贝试验

试验表明，与对照组比，磁化水中氨氮含量及化学耗量降低，溶解氧增加，用磁化水蓄养海湾扇贝亲贝，性腺发育好，卵质优，平均每个亲贝产卵量１１７万粒，Ｄ型幼虫率８９％，亲贝成活率９６％，亲贝成活率９６％，分别比对照组提高１５．８％、２７％、７％。     

海湾扇贝亲贝室内越冬及育苗试验

利用冬季闲置以虾育苗池进行海湾扇贝亲贝室内越冬，提高了亲贝质量，缩短了促熟时间，越冬成活率，性腺指数，孵化率分别达９６．２％，８．１％和５０％分别比海上越冬提高了７４．９％，３５％和３００％。专家鉴定认为，本研究属国内首创。     

海湾扇贝亲贝室内越冬试验

海湾扇贝亲贝以３７．５个／ｍ＾３的密度在室内池越冬６０天，存活率９８％，平均性腺指数开始为１４．３％，最终为１３．９％。与自然海区越冬相比，亲贝存活率提高２５￣７５％，平均性腺指数提高５．６￣８．１％。     

海湾扇贝控温育苗稳产高产技术

海湾扇贝自80年代初由美国太平洋沿岸引进至今，已成为我国北方重要的养殖品种之一，它具有生长快（当年养成），抗病力强、适应范围广等特点。提高单位水体出苗量，是海湾扇贝苗种人工培育的关键，现将主要技术措施总结如下。l来贝的选择与强化培育1．l亲贝的选择首先选择越冬死亡率小于10％、贝柱指数大于8％的亲贝，其次应选择直肠粗，外套膜伸展、不萎缩，性腺光亮，壳高6厘米左右的亲贝。这样的亲贝摄食旺盛、活力强、成活率高、性腺易促熟，精卵排放比较集中。1．2亲贝入室时间及数量一般根据出苗时间来决定入室时间。实践表明，提前6…     

栉孔扇贝亲贝室外饲养试验

在室外塑料大棚中以自然（接种）繁殖方法，使饵料生物的总密度超过６万个细胞／ｍｌ；饲养栉孔扇贝亲贝３０天，亲贝的成活率在９６％以上，性腺成熟并产卵，亲贝的各项生物指标均明显好于自然海区。     

关于养殖品种越冬技术之二海湾扇贝亲贝浅海越冬需注意的几个问题

近两年山东省日照市东港区任家台村凭借地处鲁东南冬暖夏凉优越的地理位置和水质清新的自然条件，逐步成为海湾扇贝亲贝浅海越冬的重要基地，每年为各育苗场过渡大量的亲贝，效果非常理想。但也有个别的单位因经验不足等原因造成了不必要的损失，现将近两年的经验总结如下供育苗单位参考。 １．亲贝的选择 海湾扇贝亲贝的选择直接关系到浅海越冬成活率和育苗效果。海湾扇贝亲贝应来自无污染养殖海区、个体较大且均匀、无杂贝藻等附着物。养殖海区污染则亲贝性腺发育不良，个体差异大则性腺发育不同步，杂贝藻过多则洗刷时宜造成机械损伤。 …     

海湾扇贝亲贝高密度暂养促熟技术

在我国北方如胶州湾,海湾扇贝一年有春秋两个繁殖盛期,春季为5月下旬至6月,秋季为9～10月。由于在海湾扇贝育苗中对亲贝暂养育肥性腺促熟的关键技术尚未被育苗生产单位普遍掌握,造成每年仍有许多育苗生产单位因亲贝培育不理想而导致生产成本增加、亲贝产卵量低、产卵不集中、孵化率低,严重影响海湾扇贝的育苗生产,甚至直接导致育苗生产的失败。因此,海湾扇贝亲贝暂养育肥性腺促熟是育苗生产中最为关键技术之一。     

海螺酶酶解紫菜投喂扇贝亲贝的研究

用海螺酶将紫菜叶状体酶解分离成单细胞活饵料,用于扇贝亲贝饲养促熟,之前未见报道。本研究结果,加速了亲贝性腺发育和成熟,性腺指数呈上升趋势,排卵量大,孵化率高,亲贝死亡率明显下降。     

ALGAE AND DETRITAL MATTER AS FOOD FOR JUVENILE PURPLE-HINGE ROCK SCALLOPS,Hinnites multirugosus GALE

Feeding experiments using commonly-cultured algae were conducted with purple-hinge rock scallops, Hinnites multirugosus Gale, to suggest the application of these algae to hatchery culture of scallops. The uptake of finely divided particulate matter was also studied to ascertain the possible importance of detritus as a supplemental food for the rock scallop. A 1:1:1 mixture by culture volume of Tahitian Isochrysis, Tetraselmis suecica, and Dunaliella salina appeared to be superior as a diet for juvenile rock scallops. Significant growth also occurred in juvenile rock scallops fed T-Isochrysis, T. suecica, Isochrysis galbana, and Rhodomonas sp. Gymnodinium splendens, Monochrysis lutheri, and Dunaliella salina fed alone were poor foods for juvenile rock scallops. Finely divided particulate matter as radiolabeled abalone fecal matter was utilized as food. Significant radioactivity appeared in DNA, RNA, lipid, protein, carbohydrate, and free-reducing substances after one week providing evidence that particulate matter was incorporated into juvenile rock scallop metabolic pathways.     

Digestion of lipids and carbohydrates from microalgae (Chaetoceros muelleri Lemmermann and Isochrysis aff. galbana clone T‐ISO) in juvenile scallops (Pecten maximus L.)

The digestion of laminaran and neutral lipids from the microalgae Chaetoceros muelleri or mixtures of C. muelleri and Isochrysis galbana clone T‐ISO in 4‐mm scallops Pecten maximus were studied. The microalgae were cultivated at fixed low and high growth rate (5% and 60% of μ_max). The cultivation method clearly affected the lipid and carbohydrate contents, as well as their enzyme activity. Chaetoceros muelleri and T‐ISO grown at low growth rate exhibited a considerably higher content of lipids and carbohydrates than those algae grown at high growth rate. The specific activity of laminaranase and neutral lipase was the highest in C. muelleri grown at the low growth rate. Growth rate of scallops was best when they were fed a mono‐species diet of C. muelleri grown at low growth rate. The growth rate of the scallops was positively correlated to the dietary carbohydrate content as well as to the specific activity of neutral lipase and laminaranase in the diet. The capacity to digest carbohydrates (laminaran) might be limiting for the young scallops, and the content of carbohydrates and enzymatic activities of laminaran in the diet should be considered when formulating an optimal diet, both when the diet consist of live microalgae and formulated diets.     

A new sustainable formulated feed based on discards from food industries for rearing the sea urchin Paracentrotus lividus (Lmk)

During a 18‐week experiment in a sea‐based system, Paracentrotus lividus was fed with two formulations of a new sustainable feed whose main ingredients were food farming discards, mostly outermost lettuce leaves, in different percentage. Egg white was added as protein source and binder, and a little amount of commercial fish feed was added as lipid source. At the end of the experiment, a high survival rate (>80%) and an increase in test diameter (22%), total weight (130%), gonad weight (240%) and gonad index expressed as size‐adjusted gonad weight (288%) were recorded. Gonads achieved a good colour and high levels of essential and polyunsaturated fatty acids, hence representing a commercially valuable product. Comparing the two feed formulations, the one with the lower lettuce content (57% vs. 67%) led to the best product quality, in terms of gonad features (gonad index and colour) and content of essential fatty acids. In order to move towards a higher sustainability of the aquaculture sector, this study proposes a low‐cost feed, produced with cheap and sustainable ingredients such as food farming discards.     

Effect of variation in the protein value of the red macroalga Palmaria palmata on the feeding, growth and gonad composition of the sea urchins Psammechinus miliaris and Paracentrotus lividus (Echinodermata)

The sea urchins Psammechinus miliaris and Paracentrotus lividus were fed three macroalgal diets with varying protein content over a 90-day period. These diets were the red alga Palmaria palmata, which had been grown in seawater enriched with two levels of ammonia-N and contained a protein content of either 41% (High-N) or 32% (Low-N) and the brown alga Laminaria saccharina (23% protein). A significantly different response to the macroalgal diets by the two sea urchin species was found in terms of food consumption rate, food conversion efficiency, gonadal growth and gonad nutritional composition. P. miliaris was able to efficiently utilise the High-N P. palmata, whereas P. lividus exhibited a higher food conversion efficiency (FCE) and specific growth rate (SGR) when fed the Low-N compared with the High-N P. palmata. P. miliaris had a significantly higher food consumption rate and higher gonad index (GI) compared with P. lividus, irrespective of diet type. The lowest FCE, SGR and GI were shown by both species fed L. saccharina. No interspecific difference in gonadal nitrogen content was observed, although a positive relationship was shown between dietary and gonadal nitrogen content for both species. All three macroalgal diets produced bright orange or yellow orange gonad colour in P. lividus. High-N and Low-N P. palmata improved gonad colouration in P. miliaris compared with L. saccharina. The results suggest that P. miliaris can efficiently assimilate high protein plant-based diet, whereas P. lividus is less capable of benefiting from high dietary protein levels and this should be taken into consideration when culturing this species either in land-based or sea-based polyculture systems.     

Effect of different feed formulations on feed efficiency, gonad yield and gonad quality in the purple sea urchin Heliocidaris erythrogramma

The nutritive values of three pelleted prepared diets, based on animal (AP), vegetable (VP) and yeast protein (YP) were studied for the sea urchin Heliocidaris erythrogramma (Val.). Fresh macroalga Ulva australis was used as a natural control diet. Triplicate groups of five animals were fed one of the four diets ad libitum every second day for 85 days. Sea urchins fed pelleted feeds had significantly higher food consumption rates (dry basis) and significantly lower total and protein absorption efficiencies compared with the algal diet. The gonad yield and gonad production efficiency in sea urchins fed the natural diet were significantly higher compared with initial group (gonad yield only) and urchins fed animal and vegetable diets, but did not differ significantly from those of the animals fed the yeast diet. Percent protein and lipid in the gonads were not affected by the dietary source. The taste and smell of gonads were generally better in sea urchins collected from the wild or fed yeast and natural diets than in sea urchins fed animal and vegetable diets. The animal protein diet was the most stable in seawater while the yeast protein diet had the poorest water stability. The results of this study suggest that development of a more stable, single‐cell, protein‐based diet has a potential to promote gonad production of H. erythrogramma.     

The influence of temperature and presence of predators on growth,survival and energy allocation for reproduction in the Catarina scallop Argopecten ventricosus

Environmental factors are known to modify the life history of marine ectotherms. In a 16‐month laboratory experiment, we investigated the influence of temperature and presence of predators on life‐history parameters including shell growth, survival and the energy investment in reproduction and body mass of the short‐lived (2–3 years) scallop Argopecten ventricosus. In parallel, A. ventricosus was maintained in the field at the Pacific coast of Baja California, México, to compare growth, survival and reproductive effort under natural conditions. For the laboratory treatments, scallops were reared at simulated field temperatures (SFT), 5 °C above SFT and in the presence of predators. Elevated water temperatures caused higher growth and gonad production, although at the cost of increased mortality. Presence of predators induced energy allocation to muscle rather than gonad growth, deferred spawning and extended survival. Field scallops exhibited higher growth, higher reproductive investment and were able to reproduce twice, whereas all laboratory scallops died after the first spawning. The natural variability of environmental parameters such as food and temperature may thus support optimal growth in the field, and when animals are protected from predators, reproduction in the second year of life.     

The culture of the southern bay scallop in Tampa Bay, an urban Florida estuary

Bay scallop, Argopecten irradians concentricus (Say), stocks were collected from a Homosassa (Florida) population in 1991 and were kept in seawater from Bayboro Harbor on Tampa Bay, an urban Florida estuary. They were fed with Isochrysis galbana and Tetraselmis sp. Spawning was allowed to occur after the scallops became ripe. The hatching rate of the F1 eggs to D-shaped larvae was 72%. Settlement and metamorphosis began 11 days after fertilization. When spat reached a shell height of 0.8 mm in the laboratory, they were placed with substrates into 300 and 800 m mesh bags, and later in lantern nets, suspended from a dock in Bayboro Harbor. The F1 scallops successfully survived to gonad maturity in the fall of 1992, with mean (sd) shell height of 49.8 (4.0) mm on 6 September 1992. The scallops experienced heavy mortality during the summer, partially as a result of heavy fouling. From early August to October of 1992, F1 scallops grown in Bayboro Harbor were successfully spawned in the laboratory. Growth and survival of the F2 scallops were comparable to those of the F1 scallops. Results have shown that bay scallops can complete an entire life cycle in an urban estuary such as Tampa Bay, and a hatchery for bay scallops on the estuary can assist in the restoration of the population. Fouling represents a possible severe limitation and alternatives to caging for grow-out should be considered.     

Ingestion, Absorption, and Gonad Production of Adult Strongylocentrotus franciscanus Fed Different Rations of a Prepared Diet

Abstract.— Feed costs are a major portion of aqua-culture operations. Accurate estimates of daily ration are vital to prevent overfeeding which results in wasted feed. poor water quality, underfeeding, and reduced growth. Understanding the relationship of ingestion rate and absorption efficiency of Strongylocentrotus franciscanus should improve the cost effectiveness of aquaculture of this candidate species. Adult S. franciscanus were collected from a subtidal area devoid of algae and fed two rations of an extruded diet for 62 d. Mean test diameter and whole weight of an initial sample were 91 ± 2 mm and 295 ± 18.4 g (mean ± SEM; N = 16). The two rations used were l-g dry feed/d or 3 g/d. An unfed control group was also maintained. Eight urchins per treatment showed significant differences in food ingestion rate, total organic absorption, gonad index, gut index, and moisture content of the gonad (P < 0.001). Food intake was greatest in the high ration treatment, while total organic absorption was greatest in the low ration treatment. The gonad index of S. franciscanus in the high food ration was significantly greater than the initial gonad index and was also greater than the index of animals in the low ration and unfed treatments. The gonad index of animals in the low food ration treatment was significantly greater than the index of the initial sample and the index of animals in the unfed treatment. The gut index of urchins in the high food ration treatment was significantly greater than initially and was also greater than the gut index for animals in the low ration and unfed treatments. The gut index for urchins in the unfed treatment was significantly less than the initial index. The moisture content of the gonad of urchins fed the prepared diet was significantly greater than the gonad moisture content of the initial sample or unfed group. Test diameter. whole animal weight, and gonad production efficiency (increase in g dry gonad weight/g dry feed intake) were not significantly different (P > 0.200). Histological examination of the gonads showed S. franciscanus in the two ration treatments developed from the spent to the growing or premature stage while the unfed controls lost nutritive tissue and contained only relict gametes or remained in the spent condition. The results suggest S. franciscanus from food-limited environments can be fed appropriate rations to control gonad production.     

Effects of dietary fish oil and soya bean lecithin on gonad index,colour and biochemical composition of the purple sea urchin,Strongylocentrotus purpuratus (Stimpson 1857)

The effects of increasing soya bean lecithin (SL) levels (0%, 2% and 4% of diet dry matter, DM) at two fish oil (FO) levels (0% and 3% DM) on gonad index, colour and biochemical composition of Strongylocentrotus purpuratus were evaluated using a 3 × 2 factorial design with six iso‐nitrogenous formulated diets. All diets generated an increase in gonad index of more than 9%. Dietary FO had a positive effect on diet digestibility and accumulation of proteins in the gonad. Soy lecithin did not affect gonad composition, but improved its coloration, decreased gonad feed conversion ratio and increased gonad protein efficiency. There was a clear effect of diets on sea urchins gonad protein, ash and fatty acid content, in particular, decreasing the n‐3/n‐6 ratio associated with a decrease in 20:5n‐3 when SL levels increased. Nevertheless, 22:6n‐3 levels increased by week 12 in all treatments, and diets with SL increased the content of 20:4n‐6 in gonads. A decrease in bitter‐tasting amino acids such as histidine, cysteine, valine and methionine was observed in all treatments with a concomitant increase in isoleucine levels. We recommend using a diet containing 3% of FO and 2% of SL to increase food consumption, diet digestibility, improving marketable gonad colour and an increasing gonad n‐6 fatty acids and C22:6n‐3. In addition, the present study paves the way for future research in the use of FO and SL as an additive in diets for S. purpuratus towards the goal of increasing gonad size and nutritional quality.