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1.
- During this study, the effects of epiphytic filamentous algae on the survival of demersal spawned fish eggs were investigated in one of the most important spawning grounds of herring in the western Baltic Sea, which is subject to intense and ongoing eutrophication.
- In coastal marine ecosystems all over the world, eutrophication is a primary water quality issue, often resulting in mass developments of bloom‐forming algae. Macro‐algal blooms have immense ecological effects, as they alter the structure and the function of an ecosystem. Numerous fish species are affected, as they depend on those coastal areas for spawning and as juvenile habitats.
- A comparison of the survival of herring eggs on two natural spawning beds re‐vealed an immense impact of a filamentous algal bloom. The mortality rate reached nearly 100% in the area with massive occurrence of filamentous brown algae.
- Hypothesizing that the presence of filamentous algae facilitates herring egg mortality, field and laboratory experiments were conducted and revealed particular effects of distinct algal species. The survival rate of artificially spawned eggs on algal substrates and control substrates was compared. Whereas filamentous forms of the green alga Ulva intestinalis induced no immediate effect, significantly higher egg mortality was documented in experiments with the filamentous brown alga Pylaiella littoralis.
- Considering the ecological and economical importance of herring and other coastal spawners on the one hand and the persisting and increasing effects of eutrophication and climate change on the other hand, the results of our study clearly underpin the necessity to increase global efforts to reduce nutrient loads in coastal waters.
2.
S. E. Shumway T. L. Cucci M. P. Lesser N. Bourne B. Bunting 《Aquaculture International》1997,5(1):89-99
Juvenile scallops (<2 mm shell height) of three species (Placopecten magellanicus, Patinopecten yessoensis, Argopecten irradians) were fed mixed, unialgal cultures. Scallops were fed a total of six algal clones simultaneously and clearance rates were
monitored using flow cytometric techniques. In another experiment, scallops were presented with natural assemblages of particulate
matter as a food source. Data are presented on differences in clearance rates for the individual algal species as well as
size-related differences of algal clones, and uptake of chlorophyll vs. non-chlorophyll cells, both within and between scallop
species. Significant differences in clearance rates of individual algal species have been found within and between scallop
species. Particle selection does not appear to be based upon size alone and is apparently based on other characteristics of
the algae as well. The results demonstrate pre-ingestive sorting. 相似文献
3.
Osamu Katano 《Fisheries Science》2013,79(2):221-230
To investigate the effects of environmental change on the trophic cascade from fish to benthic algae, two 26-day experiments were conducted in outdoor flow-through pools. Habitat heterogeneity was manipulated by filling grooves under tiles with wood. Disturbance was simulated by removing invertebrates and benthic algae from tiles with a stainless steel brush 10 days before the end of the experiment. Benthic invertebrates and algae rapidly colonized the pools. Japanese dace Tribolodon hakonensis that had been introduced as a top predator fed predominantly on ephemeropteran nymphs, chironomid larvae, trichopteran larvae, and benthic algae. Predation and intimidation by the dace reduced the number of ephemeropteran nymphs and lowered the percentage of invertebrates on the upper surfaces and sides of the tiles. Consequently, dace increased the algal biomass through a trophic cascade. When dace were present, a disturbance did not reduce the numbers of invertebrates at the end of the experiment, probably because most invertebrates recolonized the tiles and new invertebrates rapidly colonized the pools. The manipulation of habitat heterogeneity reduced the number of trichopteran larvae, but did not affect other invertebrates that used all surfaces of the tiles. Consequently, trophic cascades were not damped by these changes of habitat heterogeneity and disturbance. 相似文献
4.
《Journal Of Applied Aquaculture》2013,25(2):77-84
Silver scat, Selenotoca rnultifosciata were shown to consume seven species of aquatic weeds in the laboratory. The preferred species are the filamentous algae, Spimgyra sp. and the "hair plant," followed by other aquatic macrophytes. The potential of using Silver Scats to control fouling in grow-out ponds and aquaculture cages is discussed. 相似文献
5.
At present, marine reserves do not represent the full range of community types throughout New Zealand. To assist with the placement of a marine reserve along the Abel Tasman National Park coast (northern South Island), dominant subtidal laminarian and fucoid algae, echinoids and herbivorous molluscs were quantitatively investigated. Results from 100 quadrats collected from 19 random transects at six selected sites showed that algae and grazer assemblages varied between granite and limestone substrata. Granite had a high percentage cover of crustose coralline algae (mean 82%–90%), a sublittoral fringe of brown macroalgae and no Ecklonia radiata or red foliose algae. Limestone sites were distinguished by a relatively low percentage cover of coralline algae (mean 13%) and high cover of foliose red algae and E. radiata (2%–36% cover and 0.2–13.9 stipes m?2, respectively). On limestone, molluscs Turbo smaragdus and Cookia sulcata, and the echinoid Evechinus chloroticus were larger than those on granite. On limestone sites with little macroalgae, herbivore size was intermediate. Grazers were more abundant on granite than limestone (mean 34.6 m?2, and 10.8 m?2 respectively). Differences in herbivore composition were recorded between granite substrata, while both algal and herbivore composition varied between limestone sites. We suggest that a variety of environmental factors including substratum influence algal and herbivore assemblages along the Abel Tasman coast. It is recommended that selection of a marine reserve site or sites along the coast of Abel Tasman National Park recognizes differences in community structure both between and within limestone and granite substrata. 相似文献
6.
Effects of dietary microalgae on fatty acids and digestive enzymes in copepod Cyclopina kasignete,a potential live food for fish larvae 
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下载免费PDF全文 The copepod Cyclopina kasignete is a potential live food in aquaculture and its fatty acid components and digestive enzymes were investigated. Three dry algal products (mixed algae, Melosira sp. and Nannochloropsis oculata) and two fresh microalgae (Tisochrysis lutea and N. oculata) were fed to the copepod for 30 days. The essential fatty acids (EFA) in copepods were altered by feeding different types of dry algae. The copepod fed dry Melosira sp. or fresh T. lutea contained higher eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and arachidonic acid (ARA), protease and trypsin than fed on other algae. The copepod contained a similar fatty acid profile and digestive enzymes by feeding either dry or fresh N. oculata. Between fresh algal species, the copepod fed T. lutea contained higher EPA, DHA and ARA than that fed fresh N. oculata. The amounts of EPA and DHA in copepods were more concentrated than those in the dietary algae, suggesting that the copepod has the ability to accumulate some EFA. This study indicates that dietary algae can modify the nutritional composition and in digestive enzymes copepods, which in turn may be able to transfer suitable nutrients and digestive enzymes to fish larvae in aquaculture. 相似文献
7.
The initial ingestion age and size and the digestive index of Argopecten ventricosus-circularis Sowerby II, 1842 veliger larvae were investigated using epifluorescence microscopy. Ten microalgae were tested as feed during the first 7 days of life at this stage. Results of ingestion experiments showed there was a significant positive correlation between the smaller geometric dimension of the algae and the larval age and size of initial ingestion. Out of the 10 species offered, only Nannochloris oculata (NANO), Isochrysis galbana (TISO), Monochrysis lutheri (MONO), Chaetoceros muelleri (CM), Chaetoceros calcitrans (CC), Thalassiosira pseudonana clone 3H (3H), and Phaeodactylum tricornutum (PHT) were ingested. No ingestion was observed in Thalassiosira pseudonana clone s78 (S78), Tetraselmis suecica (TETRA) and Dunaliella tertiolecta (DUN) during the experiment. The digestion index of the larvae, defined as the degree of algal digestion at the third hour after ingestion, increased with larval age and size with TISO and MONO. With CC, 3H and CM, the digestion index was lower and no digestion was observed with NANO and PHT. 相似文献
8.
Patricio Dantagnan Aliro Bórquez Adrián Hernández Marisol Izquierdo 《Aquaculture Research》2010,41(9):e239-e244
Despite the importance of certain highly unsaturated fatty acids in osmotic regulation, few studies have been addressed to determine the essential fatty acid requirements for a given species cultured under different salinities. As Galaxias maculatus is a diadromic species, the present study aimed to determine the effect of salinity on the optimum dietary EPA/docosahexaenoic (DHA) ratio for survival and growth during the larval stages. Larvae were fed for 20 days with rotifers containing two different EPA/DHA ratios (low: 0.64 and high: 2.18) at three different salinities (0, 10 and 15 g L?1). The results of this study showed a marked effect of water salinity on larval dietary lipid utilization in G. maculatus larvae. These results suggested that G. maculatus larvae reared at higher salinities may have a higher dietary requirement for DHA, whereas larvae reared at 0‰ showed higher requirements for EPA. The overall results of the present study indicate that even small changes in salinity can determine the optimum dietary EPA/DHA ratio and the quantitative essential fatty requirements of fish. This may have important repercussions and affect the rearing performance of G. maculatus cultured under different salinities. 相似文献
9.
10.
Lili Ji Jianshe Liu Wendong Song Shijie Li Dongliang Miao 《Aquaculture Research》2013,44(8):1300-1306
In the present study, through a transmission experiment, the effects of europium complex and Eu3+ on the pearl colour in the pearl oyster Pinctada martensii were evaluated. Europium complex and europium salt were respectively enriched by dietary green algae platymonas subcordiformi, and their toxicity to algae were analysed by the 96‐h acute toxic experiment. Then, the green algae enriched europium complex and europium salt were respectively fed pearl oysters for 2 months, and the surface microstructures of cultured pearls were presented with scanning electron microscopy (SEM) and atomic force microscope(AFM). The results show that toxicity of europium complex to algae is much lower than Eu3+ from lowest no observable effect concentration LNOEC values and 96h‐EC50 values and two compounds can modify pearl structure and optimize pearl colour from SEM and AFM images. Taken together, our results, for the first time, show that rare earth complex can improve the pearl quality. This study provides an innovative approach for additional investigation of the influence of rare earth elements on pearls. 相似文献
11.
Masahiro Horinouchi Prasert Tongnunui Keisuke Furumitsu Yohei Nakamura Kouki Kanou Atsuko Yamaguchi Ken Okamoto Mitsuhiko Sano 《Fisheries Science》2012,78(3):577-587
To clarify the feeding habits of seagrass fishes, we examined the gut contents from 42 fish species collected in seagrass
habitats in Trang. Thirteen species showed ontogenetic and/or seasonal changes in food-use patterns. Smaller individuals generally
preyed on small planktonic items (e.g., copepod larvae) or small benthic/epiphytic crustaceans (e.g., harpacticoid copepods),
with subsequent changes to other prey items (e.g., shrimps, crabs, detritus and filamentous algae) with growth. The most important
dietary items for the seagrass fish assemblages comprised benthic/epiphytic crustaceans, detritus, and planktonic copepods.
Cluster analysis based on dietary overlaps showed that the seagrass fishes comprised eight feeding guilds (large benthic/epiphytic
crustacean, detritus, planktonic animal, small benthic/epiphytic crustacean, mollusc, invertebrate egg, polychaete, and fish
feeders). Of these, the first three guilds were the most abundantly represented, whereas the last three were each represented
by only a single species. 相似文献
12.
The natural food spectrums of the different size groups of abalone, Haliotis asinina L., from Tawi-Tawi, southern Philippines, were determined by analysis of gut contents. Laboratory experiments were conducted to determine the feeding and defecation patterns and functional response of the abalone to varying food density under ambient water conditions. Like other tropical haliotids, H. asinina prefers red algae to brown algal species. Eighteen algal species, 72.2% of which are red algae (Rhodophyta), were observed in the gut contents of all size groups of abalone; Laurencia, Hypnea, Amphiroa and Coelothrix are the most frequent food species. Hypnea and Laurencia are also the most abundant food items of H. asinina. A chi-square test indicated that frequency of occurrence (%) of most algal food species in the gut samples is independent of the size of the animal. About 84% of all algal species were observed in the gut contents of small abalone. Haliotis asinina (mean shell length ± SD = 3.48 ± 0.05 cm) showed a distinct nocturnal feeding periodicity and remained cryptic during daylight hours. Feeding activity was intense from 1800 to 0200 h, but it slowed down a few hours before sunrise, resulting in about 11 h of feeding time within a 24-h cycle. Defecation occurred during the feeding period in proportion to the amount of food consumed and faecal production during the night was significantly higher than during the daylight hours. The total daily faecal output was 1.26 mg dry weight abalone–1. The experiments showed that H. asinina (mean shell length ± SD = 3.55 ± 0.02 cm) consumed more food when food density increased in linear proportion to food abundance. However, food consumption levelled off at a food density equivalent to 35% of body weight. 相似文献
13.
Abdolmohammad Abedian Kennari Nasrollah Ahmadifard Jafar Seyfabadi Maryam Fallahi Kapourchali 《Journal of the World Aquaculture Society》2008,39(2):235-242
As algae and their concentrations are important factors for mass culture of rotifer, two experiments were conducted to find the effects of two types of algae, Chlorella sp. and Scenedesmus obliquus, and three concentration of chosen algae (0.1 × 106, 1 × 106, and 10 × 106 cells/mL) on growth and fatty acid composition of freshwater rotifer, Brachionus calyciflorus. The result of the first experiment showed that the maximum density of rotifer was significantly higher when fed with Chlorella sp. (478 individuals/mL) than fed with S. obliquus (328 individuals/mL). Mean population growth rate (r) was 0.61 and 0.44 for rotifer fed with Chlorella sp. and S. obliquus, respectively. The amount of highly unsaturated fatty acid (HUFA) in rotifer fed with Chlorella sp. (3.32%) was relatively more than those fed with S. obliquus (2.65%). Then, Chlorella sp. was selected based on better performance. In the second experiment, the maximum rotifer density of 108 ± 8, 489 ± 47, and 493 ± 51 individuals/mL was reached after 5 d for the respective Chlorella sp. concentrations; at concentration of 10 × 106 cells/mL, the maximum density of 1820 ± 47 individuals/mL was obtained. Mean growth rate at mentioned concentrations was 0.18, 0.42, and 0.51/d, respectively. Increase in algal concentration was associated with a relative increase in HUFA and decrease in monounsaturated fatty acid. 相似文献
14.
摘要：电解锰行业较聚集的松桃河流域锰污染问题突出，但其水生生态系统的风险尚不明确。本文根据现场调研和监测，了解了松桃河主要藻类的分布和生长情况，并对松桃河的水质指标、底泥和藻类的金属含量进行了研究和数据分析。结果发现：松桃河有藻类聚集生长的区域较少，主要在部分河水流速较缓、周边有居民区的受污染河段发现了附着在河底石块上生长茂盛的水绵属（Spirogyra）和刚毛藻属（Cladophora）丝状藻群落；松桃河水体中的主要污染物为氨氮和锰，流经锰聚集区的河段超标情况明显，丝状藻和底泥的Mn含量均较高且呈现出明显的空间差异，但两者的金属元素含量特征存在明显的差异，丝状藻呈现出对金属离子选择性的累积，特别是对Mn的累积能力较强，同时水绵属丝状藻和刚毛藻属丝状藻也展现出对金属元素累积能力的差异性；丝状藻中的Mn等金属元素主要来自底泥，其次来自河流，丝状藻的锰含量比较综合的反映了河流的锰污染水平和累积情况；松桃河的活体丝状藻对Mn的富集系数达到2.6以上，显示了超强的锰富集和耐受能力，具有广阔的应用前景。 相似文献
15.
Nile tilapia Oreochromis niloticus (L.) held in timed‐pulse feeding chambers, were provided with algal‐rich water dominated by either green algae (Scenedesmus, Ankistrodesmus, Chlorella and Tetraedron) or cyanobacteria (Microcystis) to determine the effect of temperature and phytoplankton concentration on filtration rates. Green algae and cyanobacteria filtration rates were measured as suspended particulate organic carbon (POC) kg?1 wet fish weight h?1. Ivlev's filter‐feeding model described the relationships between filtration rates and suspended POC concentration of green algae and cyanobacteria. Filtration rates of both green algae and cyanobacteria increased linearly as water temperature increased from 17 °C to 32 °C and were significantly higher in the warm‐water regime (26–32 °C) than in the cool‐water regime (17–23 °C). Filtration rates at 95% saturation POC (FR95) in green algal and cyanobacterial waters were 700 mg C kg?1 h?1 and 851 mg C kg?1 h?1 in the warm‐water regime and 369 mg C kg?1 h?1 and 439 mg C kg?1 h?1 in the cool‐water regime respectively. The FR95 in warm water were achieved at lower POC concentrations than in cool water. 相似文献
16.
Effects of porcine bile extracts added at three different dietary concentrations 0, 10 and 20 g kg?1 were studied on astaxanthin serum concentration in rainbow trout (mean weight 200 ± 7 g). Astaxanthin from micro‐algae Haematococcus pluvialis and synthetic astaxanthin (CAROPHYLL® pink) were incorporated in diets of rainbow trout at a rate of 100 mg astaxanthin kg?1 of feed. Fish were hand fed twice a day. After 5 days of feeding there was a significant effect of the pigment source on the ratio (total blood astaxanthin per unit body weight to cumulative astaxanthin intake per unit body weight). Trout receiving synthetic astaxanthin showed a significantly (P < 0.05) higher ratio than trout fed algal astaxanthin. Increasing dietary bile extract did not lead to produce any effect on this ratio. The power of the statistical analysis is discussed. Therefore, the interaction (pigment source × dietary bile concentration) showed no more effect. 相似文献
17.
Jihong Zhang Derong Shang Wei Wang Zengjie Jiang Suyan Xue Jianguang Fang 《Aquaculture Research》2010,41(12):1770-1777
In order to assess the potential of utilizing fouling macroalgae as feed for abalone Haliotis discus hannai, the species, biomass and total stock of fouling macroalgae attached on the aquaculture facility‐lines were investigated and assessed at Sungo Bay, China, in August 2007. The nutritional value of four fouling macroalgae (Codium fragile, Sargassum muticum, Ulva pertusa and Laminaria japonica) and one cultured macroalgae (Gracilaria lemaneiformis) as the diet of abalone was assessed by analysis of the chemical composition of the macroalgae and by measuring bioavailability and digestibility to abalone H. discus hannai under laboratory conditions in August 2007. The results showed that the biomass of fouling macroalgae at the two sites was 243.61 ± 26.23 and 1078.15 ± 50.28 g m?1 respectively. The contents of protein of G. lemaneiformis and C. fragile were 18.30% and 17.60%, respectively, which were significantly higher than the others. The five macroalgae were accepted by the abalone, and growth energies (P) and growth efficiency (%) were positive. However, significant differences were found among the different macroalgae. The growth efficiencies of abalone show a negative relationship with the levels of dietary lipid and a positive relationship with the protein contents. These results suggest that fouling macroalgae have a great potential to be used as diets of abalone. 相似文献
18.
Peter F. Shacklock 《Journal of the World Aquaculture Society》1992,23(3):241-249
The marine isopod, Idoreu baltica, was studied in conjunction with Chondrus crispus aquaculture to provide information necessary for managing populations of grazers in the biological control of algal weed species. Feeding rates, growth, and reproductive activities varied directly with temperature between 10 C and 20 C. The amount of Chondrus consumed at 20 C was approximately double that at 10 C. Female I. baltica released young at about 16 day intervals at 20 C, 25 days at 15 c and 60 days at 10 C. One female grown at 17 C produced a total of 8 broods of young over a 182 day period. The number of young per brood from this female increased from 84 (1st brood) to 310 (7th brood) as she matured. Ectocurpus, Enteromorpha and Palmaria were grazed preferentially over Chondrus and Gracilaria; a preference for haploid phases of Chondrus over diploid phases was also noted. Cannibalism was prevalent and it is suggested that this behavior might fulfill a dietary requirement. 相似文献
19.
The culture quality of rotifers, Brachionus plicatilis, was compared for yeast and algal-based cultivation diets. The rotifer quality was evaluated based on factors which may affect survival and growth of marine fish larvae, including individual length and biomass, nutritional value, bacterial content, and rotifer viability. The diets used were monocultures of Tetraselmis sp., Isochrysis galbana, Pavlova lutheri, and baker's yeast plus capelin oil.Rotifers grown to early stationary phase with equal food rations exhibited equal length distribution, but the rotifer individual biomass was 10–25% higher for yeast-grown rotifers than for algal-grown rotifers.All diets gave equal protein content of individual rotifers. The lipid content was slightly higher and the ratio of protein to lipid was slightly lower with yeast plus capelin oil than with algae. The fatty acid composition of the rotifers was closely related to that of their dietary lipids and the 3 fatty acid content was not systematically different for the two types of diets.Use of yeast plus capelin oil resulted in considerably higher numbers of both suspended and rotifer-associated bacteria than with use of algal diets. No differences were found for the algal species involved. The viability of the rotifers in a temperature and salinity test was far better in groups fed algae than in groups fed yeast plus capelin oil.The results indicated an overall better quality of rotifers cultivated with algae than for rotifers cultivated with yeast and oil. Questions related to proteins and the microflora of rotifers should be further emphasized in future research. 相似文献
20.
Effects of CO2 levels and light intensities on growth and amino acid contents in red seaweed Gracilaria lemaneiformis 下载免费PDF全文
下载免费PDF全文 The seaweed Gracilaria lemaneiformis is largely maricultivated in China, for use as food and as a material in the agar industry. This alga experiences ocean acidification caused by rising atmospheric CO2 levels, and experiences changing light levels caused by self‐shading during the later period of mariculture. In this study, growth and amino acid (AA) content responses of G. lemaneiformis to different CO2 levels (the present and the predicted increased levels) and varying light levels at 28 (±1)°C temperature conditions were investigated. The results showed that a higher light level enhanced algal growth and decreased water loss, but reduced AA accumulation. Decreased pH levels (as a result of CO2 elevation) also enhanced algal growth and reduced AA contents, but the decreases in the AA score at the lower pH levels were not significant under the two light level treatments. In this study, the light treatments had greater influences on growth and AA contents than CO2 levels. The results suggest that G. lemaneiformis quality will be negatively affected during the later mariculture production period as levels of CO2 rise and global temperatures increase. 相似文献