DDT对细巧华哲水蚤（Sinocalanus tenellus）摄食、呼吸、存活和生殖的影响研究

DDT(dichloro-diphenyl-trichloroethane) as a type of organochlorine pesticides, is an important component of pesticides pollution whose impact on the marine ecosystem is urgently to be evaluated. To investigate the biological effects of DDT on the marine ecosystem, copepods being the main contributor of secondary productivity in the marine ecosystem, were selected as target animals. The influence of DDT on the feeding, respiration, survival, and reproduction of Sinocalanus tenellus(S. tenellus) was analyzed and the antioxidant enzymes activities in the individuals were measured under different exposure concentrations of DDT. The 48 h median lethal concentration(LC50) and 96 h LC50 of DDT to S. tenellus were 5.44 and 2.50 μg/dm3, respectively. The filtration rates, grazing rates, and respiration of S. tenellus decreased apparently with increased DDT concentrations. Under lower concentration(625 ng/dm3) of DDT, the activities of the antioxidant enzymes, including superoxide dismutase and catalase in the animals increased significantly compared with those in the animals without any exposure to DDT, which suggested that the antioxidant enzymes can protect the animals from oxidative damage. However, the activity of the antioxidant enzyme decreased when the animals were exposed to higher concentration(1 250–2 500 ng/dm3) of DDT. The survival rate of both females and males was reduced when they were exposed to DDT less than 250 ng/dm3, but females showed higher survival rate than males when they are under the same concentration. The hatching ratio and the egg diameters of S. tenellus decreased significantly when they were exposed to DDT with a concentration of 25 and 250 ng/dm3, however, the cumulative egg production did not show any significant variation when the animals were exposed to the above DDT concentration. These data in the preset study suggested that exposure to DDT can cause the variation of the species composition of copepods, and further affect the marine ecosystem.     

饥饿对条纹锯鮨仔鱼的存活、摄食及生长的影响

在温度(22.9±0.8)℃、盐度30～32、DO≥5.0mg/L、pH7.8～8.2, 光照强度40～100lx条件下,对人工孵化的条纹锯鮨仔鱼开展饥饿胁迫对其存活、摄食、生长的变化规律的试验研究及影响,确定仔鱼的不可逆点（PNR）。结果显示,仔鱼在孵化后2d开口摄食,仔鱼体长开始下降,从内源营养期转入混合营养期,持续1d;3d时卵黄囊、油球消失,仔鱼体长增加,进入外源营养期,初次摄食率可达到68.25％。3d12h时初次摄食率最高达到88.24％,之后初次摄食率逐渐下降,5d时初次摄食率下降为37.5％,可知条纹锯鮨PNR=5。6d12h时试验组仔鱼全部死亡。结果表明,内源营养期对照组与试验组无显著差异,对卵黄囊与油球的利用率相似。混合营养期,仔鱼体长出现负增长,且试验组负增长速率明显高于对照组。外源营养期,试验组仔鱼体长持续下降,至PNR时体长负增长速率加快,死亡率增加,直至全部死亡;对照组仔鱼体长开始增长,死亡率逐渐下降并趋于稳定。对照组仔鱼生长模式：快速生长的内源性营养期-微弱负增长的混合营养期-正常生长的外源营养期;试验组生长模式：快速生长的内源性营养期-微弱负增长的混合营养期-可建立外源摄食的负增长期和不可建立外源摄食的负增长期4个阶段。条纹锯鮨仔鱼孵出后2～5d为摄食的关键时期。     

不同盐度对龙虎斑生长和摄食的影响

在盐度5、10、15、20、25、30条件下,以全人工配合饵料饲喂龙虎斑[鞍带石斑鱼(Epinephelus lanceolatus♂)×棕点石斑鱼(E.fuscoguttatus♀)]60 d,研究不同盐度对龙虎斑生长和摄食的影响。结果表明,不同盐度对龙虎斑生长的影响有统计学意义(P0.05),盐度5~20组增长率、特定生长率均高于盐度25、30组,差异有统计学意义(P0.05),盐度10组的增长率最高,为55.08%,盐度15组的特定生长率最大,为2.30%/d,盐度和龙虎斑生长速率的回归方程为K=0.000 09 S 4-0.006 S 3+0.131 S 2-1.055 S+4.832(R 2=0.984);不同盐度对龙虎斑的摄食率和饵料系数影响有统计学意义(P0.05),盐度15组的摄食率最高,为1.64%/d,其次为盐度10组,为1.60%/d,饵料系数在盐度15组最低,为0.820,其次为盐度10组,为0.827。因此,龙虎斑在低盐度条件下生长比高盐度快,摄食率高,饵料利用率高,最佳生长盐度为10~15。     

Feeding ecology of Ammothella longipes (Arthropoda: Pycnogonida) in the Mediterranean Sea: A fatty acid biomarker approach

Fatty acid analysis has proved valuable in determining seasonal trophic links and the feeding behavior in organisms in which these diet and trophic links cannot be inferred from stomach content analyses. Seasonal variations in total free fatty acid content (TFFA) and fatty acid composition of seston (<250 μm), the brown macroalgae Stypocaulon spp., polychaetes (Nereididae) and the pycnogonid Ammothella longipes have been used to establish their trophic links, with particular focus on seasonality and feeding ecology of A. longipes. Samples were collected in a coastal environment (NW Mediterranean Sea) at 7–10 m depth, in five different periods (August and October 2008, February, June and September 2009). Seston and Stypocaulon spp. samples did not show significant seasonal variations in TFFA content, while nereids showed a significant variation. Analysis of fatty acid profile showed high similarities of fatty acid composition between seston and Stypocaulon spp. Nereids were closer to seston and Stypocaulon spp. than A. longipes, which seemed to follow a seasonal trend. The results of this study reveal that A. longipes may change its feeding behavior depending on the season and available food. This pycnogonid species appears to be carnivore during spring and early summer but seems to feed on detritus when availability of prey diminishes during winter. Notable high amounts of odd-chain fatty acids are found in summer–autumn for this species, which may come from bacteria acquired from the detrital diet or from de novo biosynthesis from propionate. The results obtained provide new and valuable data on the understudied feeding biology of pycnogonids in general, and contribute to the understanding of their functioning of Mediterranean shallow oligotrophic systems and their trophic links.     

拟穴青蟹大眼幼体对卤虫的摄食率和摄食选择

研究了拟穴青蟹（Scylla paramam osain）大眼幼体在不同饵料密度和组合条件下对卤虫（Ar-tem iasp.）无节幼体及成体的摄食率、摄食节律等,发现：光照-视觉因素对拟穴青蟹大眼幼体捕食卤虫无节幼体的数量无显著影响,但对捕食卤虫成体的影响显著（p〈0.05）.饵料密度较低（如卤虫无节幼体密度〈10 ind/cm3）时,饵料密度与拟穴青蟹大眼幼体摄食率呈正相关;饵料密度较高时饵料密度变化对拟穴青蟹大眼幼体摄食率的影响不显著（p〉0.05）.禁食后投饵,在高饵料密度（如卤虫无节幼体密度≥10 ind/cm3）下拟穴青蟹大眼幼体的摄食率在短时间（如4 h）较高,随供饵时间的延续摄食率开始下降,较长时间（24 h）摄食率显著较低.以干重计,拟穴青蟹大眼幼体对卤虫成体的摄食率全面高于对卤虫无节幼体;但混合投喂卤虫无节幼体和成体时拟穴青蟹大眼幼体摄食的卤虫成体数量较少,表明在卤虫无节幼体和成体同时存在的情况下拟穴青蟹大眼幼体倾向于放弃卤虫成体捕食无节幼体.拟穴青蟹大眼幼体的摄食行为受到被捕食风险和饵料斑块分布的显著影响.育苗生产中对拟穴青蟹大眼幼体投喂卤虫无节幼体的密度无需高于10 ind/cm3.     

Feeding ecology of hairtail Trichiurus margarites and largehead hairtail Trichiurus lepturus in the Beibu Gulf, the South China Sea

We evaluated the feeding ecology of largehead hairtail (Trichiurus lepturus) and hairtail (T. margarites). We collected specimens from fishing ports in the Beibu Gulf (Gulf of Tonkin) from October 2008 to September 2009 and analyzed their gut contents. We collected 857 T. lepturus and 666 T. margarites samples. The number of stomachs examined in this study was sufficient to describe the monthly and ontogenetic diet shifts for the two species, as indicated by the trophic diversity curves. T. lepturus was a general omnivore, feeding primarily on Bregmaceros rarisquamosu, Decapterus maruadsi, and Acetes chinensis. Conversely, T. margarites preyed primarily on D. maruadsi, B. rarisquamosus, B. nectabanus, and A. chinensis. Both species exhibited distinct ontogenetic diet shifts. Although the two hairtail specie fed on similar sources in the same habitat, the diet overlap was relatively low. Our results suggest that hairtail play an important role in controlling small pelagic and benthic fish populations in the gulf. This trophic correlation shall be used for developing a marine ecosystem model for the Beibu Gulf.     

福州沿海龟足的食性研究

龟足(Capitulum mitella Linnaeus)的食物组成可分为4 类, 动物性食物、植物性食物、有机碎屑和无机颗粒。动物性食物主要以桡足类为主, 植物性食物主要以硅藻类为主, 有机碎屑在龟足的食物组成中占据重要地位。龟足食物的食物多样性指数在夏季最高, 冬季最低。小规格龟足主要摄食植物性食物和有机碎屑, 未见摄食动物性食物; 大规格龟足和中等规格的龟足的食性差异不大, 以桡足类和有机碎屑为主。龟足的摄食强度在8 月最强, 1 月、2 月和12 月最弱。龟足摄取食物的大小范围很广, 能够摄取包括2～2 130 μm 大小的食物。     

SESTON AND DISSOLVED ORGANIC CARBON DYNAMICS DURING MICROCYSTIS BLOOM WITH SPECIAL REFERENCE TO THE EFFECTS OF THREE CHINESE DOMESTIC FISHES IN EXPERIMENTAL ENCLOSURES

ImODUonONGrowingconcemovertheprobboofobnoxiouswaterbloornspromPtedagreatdealofresearchintothebiologyofblue-grmalgae(Reynolds&Walsby,l975,Reynothe,l984).PreviousstudiesonMimptiSwereaimedatitSphySinlogicalcharaCteristirsindudinggroWthandbuoyancyraegnolds,l975),0Vendteringandphotosynthesisfea-turesffokamuraetal.,l984,Takamura,l985),nutrientdemandsoprlofTetal.,l952,0kado&Sudo,l979).TherearerepoffethatMicropstiswasawidelydistributalspedesthatcouldeasilybloomWhenambientenvironrnentSweresuit…     

AVAILABILITY OF PHOSPHORUS FROM SELECTED INORGANIC PHOSPHATES TO JUVENILE ABALONE, HALIOTIS DISCUS HANNAI INO

The availability of phosphorus to juvenile abalone,Haliotis discus hannai from primary, secondary and tertiary calcium phosphate, primary sodium or potassium phosphate separately or in combination was determined in a 120-day feeding trial. Seven semi-purified diets were formulated to contain relatively constant dietary phosphorus, ranging from 0.78%–0.82%. The concentrations of dietary phosphorus were presumed to be slightly below the requirement for abalone. A brown alga,Laminaria japonica, was used as a control diet. Abalone juveniles of silimar size (average weight 1.18 g; average shell length 18.74 mm) were distributed in a single-pass, flow-through system using a completely randomized design with eight treatments and three replicates each treatment. The survival ranged from 71.1% to 81.1%, and was not significantly (P>0.05) related to dietary treatment. However, the weight gain rate (41.72%–65.02%), daily increment in shell length (36.87–55.07 μm) and muscle RNA-DNA ratio (3.44–4.69) were significantly (P<0.05) affected by dietary treatment. Soft body alkaline phosphatase activity (10.9–19.8 U/g wet tissue) and carcass levels of lipid (7.71%–9.33%) and protein (46.68%–49.35%) were significantly (P<0.05) responsive to available phosphorus of the diets. Dietary treatment had significant effect (P<0.05) on concentrations of phosphorus in the whole body (WB) and soft body (SB). Apparent digestibility coefficients (45%–97%) of phosphorus were also significantly (P<0.05) different between dietary treatments. The results indicated that among these inorganic compounds, primary calcium, potassium and sodium phosphates separately or in combination could be utilized effectively by juvenile abalone as dietary phosphorus sources (availability ranging from 87%–97%). However, secondary and tertiary calcium phosphates were found to be low in availability, the values being 45% and 77%, repectively. Project 39670572 supported by the Natural Science Foundation of China (NSFC).     

黑脊倒刺鲃仔稚鱼摄食的习性与生长

研究了养殖条件下黑脊倒刺仔稚鱼摄食习性与生长,结果表明:仔鱼4日龄开口摄食,全长9.0~9.99mm;仔稚鱼的摄食具有明显的昼夜节律性;仔稚鱼个体间生长速度具有一定的差异性;其体重与摄食量的关系为y=0.064 4X+1.433 1,全长与日龄的关系为L=8.861 4×exp(0.042 9T),体重与日龄的关系为W=3.736×exp(0.151 3T),全长与体重的关系为W=1.7×10-3×L3.531 4。