莱州湾落网开发试验

莱州湾落网根据莱州湾水浅，流小特点设计而成，通过放大网目，在增端增设导鱼装置，改进固定装置，使网具结构更合理而有创新，９１年专家鉴定认为，本研究成果填补了莱州湾落网作业空白，达到省内先进水平。     

魁蚶中间育成试验研究

当年常温育苗的稚贝生长期主要在8～11月,12月～翌年2月为越冬期。采用 W—a·L~b 这一幂函数描述稚贝壳长与体重的相关关系(W 代表体重、L 代表壳长)。风浪小、饵料丰富的内湾及虾池是稚贝适宜的中间育成水域。早育苗、早出库增加稚贝有效生长时间是获得大规格种苗的关键。稚贝壳长达5.0～6.0mm 时应及时分苗,调整网目及密度,保持网袋流水畅通。沙蚕、海星、蟹类是稚贝的敌害,夏季高温容易造成1龄贝大量死亡。     

稻田养殖刀额新对虾技术简介

刀额新对虾俗称“基围虾”，其壳薄体肥、肉质鲜美爽口，胜似中国对虾，国内外市场十分畅销。它属广温、广盐性虾类。耐温范围为１０℃－３５℃，秋季水温降至６℃－７℃也能生存，最佳生长温度１７℃－３２℃，适应盐度范围０‰－３５‰；对低氧忍耐强于对虾，能在ＰＨ７．０－９．０水中正常生活。其食性为杂食偏动物食性。在幼虾阶段食性与对虾一样，成虾时期捕食以桡足类、多毛类为主，也摄食人工合成饵料和其它有机碎屑及底栖生物等。习惯潜伏在底层淤泥和水草处。根据辽宁省营口市北方水产开发总公司２０００年稻田养殖刀额新对虾试验…     

Isolation and Characterization of Pepsin-Soluble Collagen from the Skin of Peru Squid (Dosidicus gigas)

Pepsin-soluble collagen (PSC) was isolated from Peru squid (Dosidicus gigas) skin and physicochemical properties of the PSC were determined. The PSC exhibited a maximum absorbance at 220 nm. Sodium dodecyl sulfate polyacrylamide gel electrophoresis suggested the collagen containing α1 and α2 chain was classified as type I collagen. Amino acid composition indicated that the collagen had lower amino acid content than that of mammalian collagen. Denaturation temperature (T_d) of the PSC was 26.8°C. The PSC had relatively high solubility in alkaline condition or NaCl concentrations below 2%. Fourier transform infrared spectroscopy investigations showed the existence of helical arrangements of collagen. The lyophilized collagen had a uniform and regular network structure. These results suggested that Peru squid skin was a potential source of collagen for further research and application.     

Effects of dietary copper sources on growth,tissue copper accumulation and physiological responses of Japanese sea bass (Lateolabrax japonicus) (Cuvier, 1828) fed semipurified or practical diets

An 8‐week trial was conducted to compare the efficacy of a chelated copper (Cu) with the inorganic Cu (CuSO₄), in the diet of Japanese sea bass (Lateolabrax japonicus). Six diets were prepared based on two basal diets (semi‐purified or practical) at two Cu inclusion levels (0 and 4 mg kg^?1 from or chelated‐Cu), accordingly named as S0, SI4, SM4, P0, PI4 and PM4 respectively. Each diet was fed to quadruplicate groups of Japanese sea bass (initial weight: 65.0 ± 0.03 g) during the trial. Fish fed practical diets had higher feed intake, specific growth rate, protein efficiency rate (PER), liver Cu accumulation, liver Na⁺K⁺‐ATPase and plasma alkaline phosphatase, but lower hepatosomatic index than the groups fed semi‐purified diets (P < 0.05). Higher PER was exhibited by fish fed chelated‐Cu diets than that of fish fed CuSO₄ diets (P < 0.05). Although liver Cu accumulation was significantly higher in fish fed practical diets,, liver Cu content increased significantly with increasing dietary copper levels only in fish fed semipurified diets. Chelated‐Cu has higher efficiency than CuSO₄ when fed in practical diets. Poor growth performance of fish fed semipurified diets might induce underestimating the nutrient requirement of Japanese sea bass.     

Production of inbred larvae through self‐fertilization using oocytes and cryopreserved sperm from the same individuals after sex reversal in eastern oyster Crassostrea virginica

The eastern oyster Crassostrea virginica can change sex which makes self‐fertilization possible if sperm can be cryopreserved. In this study, small (~1 year old) and large (~2–3 years old) oysters were biopsied for sperm collection. Survival of the biopsied oysters after 1 year was 50% for small oysters and 17% for large oysters. Oocytes were collected from sex‐reversed females, and self‐fertilized with cryopreserved sperm. Of the 24 cryopreserved samples, 14 individuals had ≤1% fertility when crossed with oocytes from unrelated females, indicating that the cryopreserved sperm had reduced fertility. The other 10 individuals had a fertility of 39 ± 25% when crossed with oocytes from unrelated females (non‐selfing), but showed a significantly lower success of self‐fertilization (12 ± 16%) (P = 0.008), while aliquots of the same oocytes had a fertilization of 83 ± 11% when crossing with fresh sperm. Larvae were produced at day 3 in the self‐fertilized families (12–94% of the fertilized oocytes), and survived to eyed‐larvae stage at days 11–14. Genotyping with 9 microsatellite markers confirmed that the larvae resulted from self‐fertilization in four families. This study demonstrated the feasibility of creating self‐fertilized inbred lines of oysters by use of non‐lethal sperm collection and cryopreservation.     

Effects of salinity on osmoregulation,growth and survival in Asian swamp eel (Monopterus albus) (Zuiew 1793)

The Asian swamp eel Monopterus albus is normally considered a freshwater species, but can also occasionally be found in brackish water. It is an obligate air‐breather with highly reduced gills, making its osmoregulation physiology interesting because the gills normally represent the primary site of osmoregulation in teleosts. Being a popular fish for human consumption, the swamp eel is cultured extensively in freshwater ponds in the Mekong Delta of Vietnam. However, very little is known about its salinity tolerance, which is becoming topical due to the increasing salt‐water intrusions into tropical deltas. We therefore studied how increased salinity affects survival, growth, blood pressure, heart rate, blood osmolality and plasma ions. All eels survived prolonged exposure to 5 and 10 g L^?1, although plasma osmolality increased significantly at 10 g L^?1. Further elevation to 15 and 20 g L^?1 was associated with significantly elevated mortality, with a corresponding increase in plasma osmolality and ion con‐centrations. Our results show that swamp eels thrive in 0–10 g L^?1 with an optimum growth between 0 and 9 g L^?1, indicating that utilization of low saline brackish waters for aquaculture is possible.