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1.
利用虹鳟Oncorhyncus mykiss的引物,采用PCR及胶回收测序的方法找到一种高效区分白斑红点鲑Salvelinus leucomaenis和美洲红点鲑Salvelinus fontinalis的简单、快速、可靠的分子鉴定方法。采用该方法对无直接亲缘关系的白斑红点鲑、美洲红点鲑和虹鳟进行鉴定,结果发现:AF346686引物扩增的分子标记可以准确迅速地鉴别白斑红点鲑、美洲红点鲑和虹鳟。 相似文献
2.
S. I. Siikavuopio R. Knudsen A. C. Winger R. Kristoffersen 《Ecology of Freshwater Fish》2009,18(1):126-131
Abstract – Winter growth and survival of wild individually tagged juvenile Arctic charr (1+ age) from a riverine anadromous stock, were studied in a small ice-covered (∼6 months) ground water brook (temperature ∼1 °C) connected to Skibotnelva in subarctic northern Norway. The overall winter survival was estimated to be 68% from late October 2005 to early May 2006. The recaptured charr were not significantly different in initial length or weight compared with the nonrecaptured fish suggesting low size-dependent mortality. The majority (98%) of the recaptured charr showed significant increase in size, with a mean increment of 62% from their initial bodyweight and 12% of the charr parr had more than doubled their weight. The mean specific growth rate was calculated to be slightly lower (0.27) than estimated values from a growth model (∼0.35). In addition, the condition factor increased significantly during the field experiment. These results are the first individual growth data on riverine anadromous Arctic charr parr under natural winter conditions, and indicate that charr can grow relatively fast during periods with low temperature and also that ground water brooks can be good over-wintering habitat for juvenile Arctic charr. These results suggest that the winter period is perhaps a less severe bottleneck than previously recognised for the cold-adapted Arctic charr. 相似文献
3.
B. Bjerkeng K. Johnsen I. Mayer T. Storebakken K.J. Nilssen 《Fish physiology and biochemistry》1999,21(4):353-364
This investigation examines the influence of implants containing 11-ketotestosterone (11KT), 17-estradiol (E2), and 3,5,3-triiodo-l-thyronine (T3) on astaxanthin metabolism in sexually immature individually tagged Arctic charr. The fish (initial average weight 427 g) were maintained in freshwater for 40 days, and weekly implanted intraperitoneally with oil-based injections containing either 11 KT, E2 or T3 at levels of 0.1, 1.0 and 0.1 mg (100 g body weight (BW))–1, respectively. The control fish were given the oil medium alone (0.2 ml 100 g BW–1). The diet contained ca. 50 mg astaxanthin kg–1. Carotenoid composition was monitored in plasma, fillet, liver and skin, and 11 KT, E2 and testosterone (T) levels in plasma. All hormone treatments reduced plasma T compared to the control. E2-treated fish had a higher (p<0.05) hepatosomatic index (HSI) than the other treatments. Hormone treatment did not influence gonadosomatic index (GSI). T3 administration induced a silvery skin appearance. The fillet and plasma carotenoid content decreased during the experiment. 11 KT implantation reduced astaxanthin and idoxanthin concentrations of plasma and fillets, and increased the amount in liver and skin, compared to the other treatments. The relative proportion of astaxanthin to idoxanthin was higher in the control fish and T3 implanted fish, than in fish implanted with 11 KT or E2 (p<0.05). Fish treated with E2 had the highest skin carotenoid concentration. Male fish had significantly higher carotenoid content in plasma, fillet and skin than female fish. This study reveals that sex hormones affect carotenoid metabolism and partitioning among body compartments of Arctic charr, effects differently displayed by the sexes. 相似文献
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5.
Masashi Sekino 《Fisheries Science》2009,75(4):819-831
A cornerstone in conserving wildlife is to resolve taxonomic uncertainties over organisms so that conservationists can define
the entity that should be conserved. This is the case for two closely related Crassostrea oysters inhabiting the Ariake Sea (Kyushu, Japan) in sympatry, the kumamoto oyster C. sikamea and Pacific oyster C. gigas, where molecular markers have shed light on their taxonomic separation and species diagnosis. In the past, there was a concern
that Kumamoto oysters may be at risk of extinction. However, several field surveys equipped with species-diagnosis molecular
markers have provided solid evidence that this perception is incorrect. Nevertheless, previous studies have sometimes given
conflicting results, throwing us into confusion about the resource status. Research on natural Kumamoto oysters that the author
hopes could help to enhance our understanding of the conservation of this invaluable oyster is reviewed here.
相似文献
| Masashi SekinoEmail: |
6.
1花羔红点鲑的饲料营养组成特点
花羔红点鲑(Salvelinus malma)属于红点鲑属,我国仅一属一种,分布于鸭绿江、图们江、绥芬河水系,在东北地区生存点少于10个,每个栖息江段小于3 km,相互隔离.近年因人为因素和栖息环境的变化,其在自然水域中的种群数量急剧减少,已被国家列为易危物种.…… 相似文献
7.
There has been much recent discussion about the idea that large whales are potential competitors with fisheries for available marine resources. Based on this idea, often referred to as the ‘whales eat fish’ conflict, culling whales has been proposed as a way to increase resources available for human consumption and thereby ensuring global food security. However, the scientific basis for such arguments remains unclear, especially in the Caribbean waters where baleen whales generally do not feed. In this article, we (i) develop an ecosystem model describing the trophic interactions between whales, fish and fisheries in the Caribbean waters, (ii) calculate the level of overlap between cetaceans and fisheries for food resources, and (iii) simulate the removal of cetaceans from the Caribbean waters in order to quantify the potential increase in available biomass of commercially important fish. Ten groups of cetaceans are considered in the model, including baleen whales, toothed whales and small cetaceans. Our results suggest that baleen whales are not a threat to fisheries in Caribbean waters, while toothed cetaceans seem to be more impacted by fisheries than they actually impacting them. Whales target different types of food resources and consume significantly less than what is taken by fisheries. Moreover, simulated reductions in large whale abundance do not produce any appreciable increase in biomass of the commercially important fish species. In some cases, the presence of some whales actually improves fishery yield as a result of indirect predation effects. 相似文献
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Abstract. The Atlantic salmon, Salmo salar L., was once of major importance to the fishing industry along the River Rhine. This paper discusses the Dutch and German salmon catches over the years 1863–1950. Even up to the end of the last century, it was not uncommon for Dutch and German fishermen to land 100000 salmon a year. However, factors such as the increased use of locks and weirs along the Rhine, coupled with growth in pollution, soon led to a rapid decline in numbers. By 1933, the salmon fishing industry in the Netherlands had virtually ceased to exist. Analysis of the available catch statistics suggests that the decline in the salmon population could have started before official records began. Although the degree of scatter in the data and uncertainties in the assumptions preclude the possibility of drawing firm conclusions about the survival rate of salmon, these figures illustrate how difficult it will be to maintain a stable population in the Rhine. Moreover, a number of changes have taken place since the heyday of salmon in western Europe, which could compound the problem. Of particular importance in the context of the Rhine are:
- 1 the closure of two of the major migration routes to the sea (Haringvliet and Zuiderzee);
- 2 morphological changes in the river;
- 3 chemical and thermal pollution;
- 4 the loss of accessible spawning and nursery areas of the required quality;
- 5 the disappearance of salmon from other rivers that flow into the North Sea such as the Rivers Elbe, Weser and Ems. If salmon were only reintroduced into the Rhine, a certain proportion would probably stray and infiltrate these other rivers.
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11.
Does the wild‐caught Chinese mitten crab megalopae perform better than the hatchery‐produced seed during the juvenile culture? 
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下载免费PDF全文 Xugan Wu Jie He Xiaodong Jiang Qing Liu Feng Gao Yongxu Cheng 《Aquaculture Research》2018,49(5):2042-2050
Although wild Yangtze Eriocheir sinensis juveniles (coin‐sized seed) have better culture performance than the pond‐reared juveniles during the adult crab culture stage, the culture performance of wild‐caught megalopae (WC) remains unknown. Therefore, this study was designed to compare the growth, survival rate, crab yield, feed conversion rate (FCR), precocity, final weight and size distribution between WC and hatchery‐produced megalopae (HP) during the juvenile culture stage. Wild‐caught megalopae had significantly higher body weight, weight gain rate (WGR) and specific growth rate (SGR) during 0–4 weeks but lower WGR and SGR than HP during 4–8 weeks (p < .05). Although WC had a significantly lower survival rate and yield of normal juvenile crabs than HP, total yields of normal juveniles and precocious crabs were similar. Wild‐caught megalopae had a significantly higher precocious rate and yield of precocious crabs than HP (p < .05). Regardless of sex, no significant differences were found in the gonadosomatic index (GSI), hepatosomatic index (HSI) and final weight of normal juveniles and precocious crabs between WC and HP. As for the size distribution of normal crabs, WC had a higher percentage of small female juveniles (<3 g) but a lower proportion of middle size ranges (3–5.99 g and 6–8.99 g) than HP for females (p < .05), and there was no significant difference for males. In conclusion, wild megalopae of the Yangtze E. sinensis had worse culture performance than the hatchery‐produced seeds; therefore, wild megalopae would not be recommended for commercially juvenile culture of E. sinensis. 相似文献
12.
Genetic improvement programmes in abalone: what is the future? 总被引：3，自引：0，他引：3
N G. Elliott 《Aquaculture Research》2000,31(1):51-59
13.
2007年1月从鸭绿江上游自然保护区引进美洲红点鲑发眼卵,在山西省虹鳟鱼实验场经过近3年的养殖、繁殖实验研究,获得了美洲红点鲑的人工孵化、育苗、育种、亲鱼培育选育技术资料。实验研究的结果表明,美洲红点鲑是适合流水养殖的新品种。饲养在相同条件下的美洲红点鲑生长速度比虹鳟快10～12%。在水温为8℃～20℃,DO值为5.2～8.5mg/L的养殖环境条件下,当年个体均重达0.5～0.6kg,饲养到第二年体重可达1.2～1.5kg。雄性当年即可达到性成熟,雌性两年成熟。性成熟个体产卵时间早于虹鳟1～2月,且产卵的时间比较集中。成熟个体千克体重怀卵量2000～3000粒,与虹鳟相似,卵径3.5mm,小于同龄虹鳟,色泽也略淡于虹鳟。 相似文献
14.
Go Suzuki Seiji Arakaki Kiyoshi Suzuki Yukihiro Iehisa Takeshi Hayashibara 《Fisheries Science》2012,78(4):801-808
In situ larval seeding is a low-cost technique that is currently under development for the large-scale restoration of coral populations. One problem that still needs to be solved is the preparation of coral larvae for seeding, i.e., how many larvae are required to restore a certain area? In this study, we focused on the relationship between the numbers of larvae, settlers, and survivors for three?months post-settlement to determine the optimal larval seeding density. A comparison of three different larval densities (low, middle, and high) indicated that the number of settlers was proportional to the larval density, suggesting that settler density is determined by the number of larvae supplied. However, the survival rate of settlers on high-density plates was much lower than the corresponding rates on low- or middle-density plates during the first month after settlement. Moreover, most of the seeded corals had not survived on the low-density plates at three?months after settlement. Therefore, the middle larval density (i.e., 5000?larvae?m?2) appears to be optimal for seeding on grid plates. 相似文献
15.
The presence of 17,20-dihydroxy-4-pregnen-3-one (17,20-DHP) oocyte receptor activity has been demonstrated in brook troutSalvelinus fontinalis. Scatchard analyses of the cytosol fraction during various terminal stages of oocyte maturation gave a high equilibrium association constant (Ka) value of 1.394±0.669 108M–1 (n=7) and low maximum binding capacities (Nmax). The association kinetics of the receptor was second order k+1=2.292×106M–1 sec–1. The dissociation rate constant ka was 1.502×10–2 sec–1 for the first order dissociation reaction. The Ka=1.526×108M–1, when it was determined from k+1/k–1 a value close to that found from the Scatchard analysis. Competition studies showed the following binding affinities testosterone > 17-HP > 17,20-DHP > Promegestone > progesterone > estradiol > pregnenolone; cortisol showed no competitive inhibition. Cytosolic extracts when pre-equilibrated with various labelled steroids and eluted from a Sephacryl S-300 column gave multiple specific binding peaks. On sucrose density gradient centrifugation specific binding was observed at 3.05 S in cytosol containing 0.15M sodium chloride buffer. The receptor lost binding activity when incubated with various proteases, but DNase and RNase had no effect. Blood plasma without heparin at (110) dilution also bound [3H]17,20-DHP, Ka was 8.04×107 M–1.The nuclear pellet extract (750×g) gave very little specific binding activity even at high radiolabelled steroid concentrations and a linear Scatchard plot was not obtained. Nevertheless the nuclear extract, after dextran-charcoal treatment, pre-equilibrated with [3H]17,20-DHP, bound specifically to DNA cellulose, and cytosol from the same oocytes also bound to DNA cellulose under similar conditions. Although specific binding to DNA cellulose was obtained the salt concentrations at which the steroid-receptor complex elution took place was not reproducible in both nuclear extracts and cytosol samples. Also binding activity was extremely small compared to the total cytosolic binding. The nuclear extract when pre-equilibrated with high concentrations (20 nM) of the labelled steroid and then chromatographed on Sephacryl S-300 column gave a specific binding peak which was similar to that of the cytosolic preparation.The receptor levels in cytosol decreased progressively during final maturation (Stages 1–7). There is preliminary evidence for the presence of 17,20-DHP receptor activity in cytosol of landlocked Atlantic salmonSalmo salar ouananiche, and rainbow troutSalmo gairdneri. The zona radiata fraction from late stages oocyes 5, 6, and 7 in brook and rainbow trout oocytes were isolated by ultracentrifugation; from this fraction a protein was characterized which covalently bound [3H]R5020 after photoaffinity labelling. The same protein also bound [3H]17,20-DHP after solubilization in Brig 35 buffer. The SDS gel electrophoresis subunit composition of the above protein was similar to the cytosol counterpart binding [3H]17,20-DHP, although the molecular weights were different. The blood sample [3H]R5020 binding component subunit composition was different from that of the membrane extracted protein. These results demonstrate the presence of 17,20-DHP receptor activity in the cytosol and zona radiata membranes of the oocytes during final maturation.A. Maneckjee is presently NSERC postgraduate scholar at MSRL and Ph.D. candidate at Department of Biochemistry, Memorial University of Newfoundland. 相似文献
16.
The Great East Japan Earthquake and accompanying tsunamis occurred on 11 March 2011, causing huge damage to marine organisms. The invasive naticid gastropod Laguncula pulchella (Euspira fortunei), which was introduced with the imported clam Ruditapes philippinarum from China and Korea, survived the earthquake. The “growth break line” observed on the shell surface in over 90% of the individuals collected in Matsushima Bay and Matsukawa-ura Lagoon after the tsunamis was examined by scanning electron microscopy. Each shell presented three layers before and three after the growth break. However, the fracture surface consisted of five layers—two prismatic and three crossed lamellar—around the growth break line. This suggests that shell formation temporarily ceased following the tsunamis and that the five-layered shell may have developed in response to the stress caused by the tsunamis. The newly formed middle layer became thinner after the “tsunami break,” which may be the result of a rapid change in the mineralization process, including rapid shell growth and/or repair. These results suggest that the damage to and forcible removal of habitats by the tsunamis was stressful for L. pulchella. A decrease in or the cessation of shell formation after a tsunami may be a common phenomenon in mollusks that inhabit tidal flats. 相似文献
17.
- 1. The intensity of marine activities in the exclusive economic zone (EEZ) of British Columbia, Canada, was quantified.
- 2. Humans use the ocean for a multitude of purposes, many of which have a direct impact on marine life and habitat. Yet such uses are seldom assessed in an integrated fashion.
- 3. Using a GIS approach, spatial information for 39 marine activities was mapped, including commercial and recreational fishing areas, transportation and infrastructure uses, and terrestrial activities along the coast of British Columbia.
- 4. A relative scale was used to rank both the impact of marine activities and the extent of stressors beyond the location of occurrence. Limited information on the latter led to the application of three ranges of buffer distances to the data (0–1 km, 0–5 km, and 0–25 km).
- 5. The most conservative estimate (?1 km buffers) indicates at least 83% of the continental shelf and slope of British Columbia is currently being used by humans. The largest buffer assumption shows 98% of the continental shelf and slope being affected by stressors from anthropogenic activities.
- 6. This analysis provides a baseline for assessing future changes in the state of British Columbia's marine environment, and could assist in identifying areas of conservation potential.
18.
Leszek Satora Jennifer Mytych Anna Bilska-Kos 《Fish physiology and biochemistry》2018,44(5):1291-1297
Bronze corydoras (Corydoras aeneus) is a small diurnal activity fish from South America. Under hypoxia conditions, it uses the posterior part of the intestine as an accessory respiratory organ. The present PCR studies demonstrated higher expression of HIF-1α (hypoxia-inducible factor) gene in the respiratory than that in digestive part of bronze corydoras intestine. Further, immunolocalization studies using antibodies specific to HIF-1α and transmission electron microscopy (TEM) revealed the presence of HIF-1α epitopes in the intestine of Corydoras aeneus. In the respiratory intestine, the numerous clusters of gold particles visualizing HIF-1α antibody were observed within fibroblasts, whereas in the digestive tract of this species, single gold grains in the epithelial cells were noted. On the other hand, the presence of HIF-1α and the cytoplasmic domain of the epidermal growth factor receptor (EGFR) in the respiratory intestine of bronze corydoras assumes their interactions in the system where these factors appeared for the first time. The non-obligatory air-breathing fishes using their digestive tract as an accessory respiratory organ during hypoxia conditions are very interesting for the studies of the processes that control HIF-1α expression and squamous cell proliferation. 相似文献
19.
Introduction of non‐native freshwater fish: is it all bad? 总被引：3，自引：3，他引：0
Rodolphe Elie Gozlan 《Fish and Fisheries》2008,9(1):106-115
Risk perceptions are important to the policy process, but there is often a well‐established pattern of small risks being over assessed. This is also true with the issue of non‐native freshwater fish introductions, where a great majority of research focuses on the few negative cases. The attitude towards ‘non‐natives’ is a continually evolving process and varies according to current societal values. Here I show that on the global scale, the majority of freshwater fish introductions are not identified as having an ecological impact while having great societal benefits. Case studies from the African lakes are discussed in order to illustrate contrasting outcomes following fish introductions. Looking into the future, the environmental changes that freshwater ecosystems may encounter will have inevitable implications on the distribution of our native freshwater fish species and the need to rely on non‐native introductions may become a growing reality. Aquaculture production is regularly increasing and our dependence on it is likely to become greater as it provides an important substitute for the declining production of capture fisheries. With it the number of freshwater fish introductions will increase and a more realistic attitude, albeit controversial, will need to be debated. This would mean protecting some introductions that present beneficial outcomes for biodiversity alongside a more systematic ban of species or families of fish presenting a higher historical ecological risk. The public perception of risk is something which cannot be ignored by any government or ruling body, but in order to gain public support in the fight for conservation of freshwater fish biodiversity, the message needs to be clear, detailed and educational. 相似文献
20.
Takeshi Ito Yudai Iino Shizuko Nakai Shiro Itoi Haruo Sugita Noriyuki Takai 《Fisheries Science》2018,84(4):627-640
The early life history of girellid fishes in Japanese waters is unclear, and little is known about their species-specific reproductive strategies. We examined seasonal changes of distribution patterns for settlement-stage juveniles of Girella punctata and Girella leonina on the rocky shore in the regions of Kanto and Izu, Japan, to infer the influence of the Kuroshio Current on their reproduction. We collected 813 settlement-stage juveniles mainly in Sagami Bay and genetically identified the species. The juveniles of G. punctata were collected on the rocky shore in Sagami Bay during April to August, with the abundant catch in May and June. Thus, we infer that juvenile G. punctata ubiquitously inhabit the rocky shore in the area in spring and summer. By contrast, juveniles of G. leonina were rarely collected in Sagami Bay, with a total catch of only 66. Notably, no juveniles were collected during the wintertime in Sagami Bay, although an abundant catch of G. leonina had been previously reported for Sagami Nada off Sagami Bay during January to March. This clear-cut difference between the areas likely reflects the difference in proximity to the path of the Kuroshio Current. We expect that the Kuroshio Current strongly influences the reproductive success of G. leonina. 相似文献