茶树品种新梢主要生化成分与黑刺粉虱选择性的关系     

陈常颂  王庆森  黄建  张应根  王秀萍  陈荣冰  吴光远  曾明森 《福建农林大学学报(自然科学版)》2007,36(6):576-580

对9个茶树品种(福云6号、玉龙、丹桂、优3、优510、黄旦、毛蟹、福云10号和铁观音等)新梢主要生化成分与黑刺粉虱的单位叶面积产卵量和世代存活率的相关性进行研究分析.结果表明:黑刺粉虱单位叶面积产卵量与茶树品种新梢苯丙氨酸含量之间存在极显著负相关,与可溶性蛋白质、丙氨酸和蛋氨酸含量之间存在显著负相关,而与可溶性糖、咖啡碱、茶多酚含量,儿茶素、游离氨基酸总量等的相关性不显著;黑刺粉虱的世代存活率与茶树品种新梢苯丙氨酸含量之间存在极显著负相关.  相似文献   

毛蚶对单胞藻的滤除率、选择性和消化状况     

沈和定  张饮江  卢华春  周培根  吴建中 《上海海洋大学学报》2006,(2):195-200

测定了不同水温下毛蚶对5种单胞藻的滤除率、选择性和表观消化状况,结果表明,在16℃~24℃的水温范围内,毛蚶对海洋小球藻的滤除率逐步升高,24℃时的最大滤除率为1.849 4(mL/ind.min),24℃~26℃时的滤除率逐步下降。22℃为毛蚶对微绿球藻、球等鞭金藻3011和三角褐指藻的最佳滤食温度,最大滤除率分别为1.142 4、3.804 5和4.430 4。水温8℃~24℃之间,毛蚶对巴夫藻的滤除率变化不明显,平均滤除率为2.797 2。毛蚶不仅对不同大小、形状的藻类具有选择性,而且对大小、形状相似的藻类也具有明显的选择性。水温22℃下,毛蚶对5种单胞藻的表观消化状况不同。贝类对其滤除率大、消化状况差的藻类在促进贝类净化进程中有良好的应用参考价值。  相似文献   

应用JABBA和JABBA-Select模型评估印度洋剑鱼资源     

江俊涛  朱江峰  耿喆 《上海海洋大学学报》2022,31(3):677-690

剑鱼（Xiphias gladius）是具有较高经济价值的大型旗鱼类鱼种,处于食物链的上端,对其资源评估并制定管理策略,在资源的可持续利用和生态系统保护上具有重要意义。本研究基于贝叶斯剩余产量模型(just another bayesian biomass assessment, JABBA)和它的拓展版JABBA-Select对印度洋剑鱼资源状况进行评估,分析资源丰度指数（标准化CPUE）、捕捞选择性对评估结果的影响。结果表明：JABBA-Select模型因考虑捕捞选择性和生活史信息,对资源状态的评估表现要优于JABBA模型。印度洋剑鱼的最大可持续产量（Maximum Sustainable Yield, MSY）估值为3.17万 t,当前渔获量3.01万 t,资源处于健康状态的概率为98%。评估结果对种群内禀增长率参数r的先验分布敏感性较小,参数r与环境容纳量参数K的后验分布存在负相关。所建模型不存在明显的回顾性误差,模型较稳健。预测分析显示,当总可捕量控制在3.60万t以下时,在2028年前不会处于资源型过度捕捞（overfished）和捕捞型过度捕捞(overfishing)。  相似文献   

Size selectivity of diamond and square mesh codends for hairfin anchovy Setipinna taty in Chinese stow net fisheries   总被引：3，自引：0，他引：3  

Man Chang Sun  Jian Zhang  Liu Xiong Xu 《Fisheries Science》2006,72(3):530-539

ABSTRACT:   Selectivity experiments of diamond and square mesh codends with different mesh size (30, 35, 40 and 45 mm) for hairfin anchovy Setipinna taty were carried out using the covered codend method in Chinese stow net fisheries. In the present study, 5151 specimens were subsampled and asymmetric and symmetric selectivity curves (Richards and Logistic curves) were fitted to the catch data, using the maximum likelihood method according to the SELECT model. The results show that the Richards curve gives a better fit to the selectivity curve for diamond mesh codends with 30, 35 and 40-mm mesh sizes, whereas the logistic curve gives a better fit for the diamond mesh codend with 45 mm mesh size and square mesh codends with 30, 35, 40 and 45-mm mesh size. With the exception of 45-mm mesh size codends, the L ₅₀ of diamond mesh codends were insignificantly larger than those of square mesh codends. However, the selectivity curves of square mesh codends were steeper than those of diamond mesh codends, except the 30-mm mesh size codends. As for diamond mesh codends, according to the linear relationship between the L ₅₀ and mesh size, 36.5-mm mesh size codends could release 50% juvenile hairfin anchovy (below 1-year old). However, diamond mesh codends with such a mesh size are not selective for other species.  相似文献   

Determining an optimal mesh size for use in the lampara net fishery for eastern sea garfish, Hyporhamphus australis   总被引：1，自引：0，他引：1  

J. Stewart  C. Walsh  D. Reynolds  B. Kendall  & C. Gray 《Fisheries Management and Ecology》2004,11(6):403-410

Abstract  The selection properties of three experimental mesh sizes were examined in the lampara net fishery for eastern sea garfish, Hyporhamphus australis (Steindachner), in New South Wales, Australia. The sizes of fish retained in 25-, 28- and 32-mm mesh nets were compared with those retained in a control 12-mm mesh net. The 25-mm mesh net retained significant numbers of immature H. australis , the 28-mm mesh net retained predominantly only mature fish and the 32-mm mesh had very low catch rates. Catch rates decreased linearly with increasing mesh size and there was a significant linear relationship between mesh size and the 50% selection size ( L ₅₀ ). Given this species is being overfished, the 28-mm mesh size is recommended as the most appropriate for use in the fishery.  相似文献   

套网法对张网渔具选择性的影响   总被引：6，自引：2，他引：6  

孙满昌 《水产学报》2004,28(6):709-715

套网法是一种比较常用的选择性研究试验方法,但是,使用套网法会对网囊网目选择性产生一定的影响.通过使用5种不同规格的方形网目网囊分别进行试验,比较两种不同的试验方法即套网法和平行作业法对张网渔具网囊网目选择性进行研究.结果显示,使用平行作业法估算的50%选择体长比使用套网法所得的大7.8%,选择范围比套网法的估算值小24.5%,选择性因素比套网法估算值大7.4%,但差异并不显著(P＞0.05).在张网渔具最适网目试验中,如果直接使用套网法的试验结果制定最小网目,那么这一尺寸会偏大,造成部分鱼类过多释放.  相似文献   

Size selectivity of escape holes in conger tube traps for inshore hagfish <Emphasis Type="Italic">Eptatretus burgeri</Emphasis> and white-spotted conger <Emphasis Type="Italic">Conger myriaster</Emphasis> in Tokyo Bay     

Mami Harada  Tadashi Tokai  Michiyo Kimura  Fuxiang Hu  Takamichi Shimizu 《Fisheries Science》2007,73(3):477-488

ABSTRACT:   In Tokyo Bay, conger tube-trap fishers voluntarily deployed escape holes of at least 13 mm diameter to reduce the by-catch of young conger smaller than the marketable size of 35 cm total length. Comparative fishing experiments in Tokyo Bay were carried out using tube traps with seven hole diameters (3, 9, 13.5, 14, 15, 17, and 19 mm), to obtain the size-selectivity of the escape-hole size for inshore hagfish Eptatretus burgeri and white-spotted conger Conger myriaster . On the assumption of the geometrical similarity in the combination of body g and hole perimeter m at a given retention probability, a single master curve s ( R ) = exp(−13.52 + 11.31 R )/(1 + exp [−13.52 + 11.31 R ]) was estimated for the two species in terms of relative R  =  g / m using the Share Each LEngth's Catch Total (SELECT) process based on a multinomial distribution. Almost all conger and hagfish with a girth equivalent to the hole perimeter were able to pass through the hole. Thus, the two species have a high ability to escape through a narrow space by squeezing the body through the hole in the rigid PVC tube. Optimum escape-hole size is discussed from several objectives for conger tube-trap fishery management, e.g. reduction of hagfish by-catch. This study also specifies the conditions for pooling data when fishing experiments using more than two fishing gears are replicated.  相似文献   

广东大鹏湾虾拖网网囊网目选择性研究   总被引：2，自引：4，他引：2  

张健  孙满昌  罗炎标 《海洋渔业》2007,29(2):166-173

虾拖网渔业是南海海域重要的作业方式之一,但尚未有关该渔业网目尺寸选择性的报道。为评价虾拖网渔具的渔获性能、合理利用虾类资源,在广东大鹏湾进行了网目选择性试验。试验采用双支架虾拖网作为试验网具,并使用套网法估算了网目内径为35、40和45 mm的网囊对主捕虾类的选择性。结果显示,虾类渔获中刀额新对虾、须赤虾、周氏新对虾和日本囊对虾渔获数量较多,比较以往资料,刀额新对虾和周氏新对虾优势体长、平均体长均有所下降,其它2种虾类平均体长未见明显变化;选择性分析结果显示,主捕虾类的L50随网目尺寸线性增大。根据试验结果并结合历史资料,笔者认为现阶段35 mm的网囊网目尺寸对于保护上述4种虾类资源是比较合适的。  相似文献   

Selectivity of the rotifer Brachionus plicatilis fed mixtures of algal species with various cell volumes and cell densities     

G N Hotos 《Aquaculture Research》2002,33(12):949-957

The ability for food selectivity of rotifer Brachionus plicatiliswas studied in the laboratory by feeding mixtures of microalgae with various cell volumes. Chlorella sp. (≈22 µm³) was the reference algal species, and Asteromonas gracilis, (Chlorophyta) (≈2150 µm³), Tetraselmis suesica (≈268 µm³), Dunaliella salina (≈52 µm³) and Chaetoceros sp. (≈150 µm³) the experimental species. Each was mixed with Chlorella and fed in three experiments. In the first experiment, filtration and ingestion rates of rotifers each fed with algae revealed that the highest values were measured with the mixture of Chlorella + Asteromonas, and the lowest for Chlorella + Chaetoceros. In the second and the third experiments, by using several combinations of algal densities with the mixture of Chlorella + Asteromonas, a selectivity ability of the rotifers for Asteromonas was found. A hypothesis is presented that accounts for the preference of rotifers for Asteromonas, which is suggested as a new candidate species for use in live food production of fish hatcheries.  相似文献   

Fishery-specific differences in the size selectivity and catch of diamond- and square-mesh codends in two Australian penaeid seines   总被引：1，自引：0，他引：1  

W. G. MACBETH  M. K. BROADHURST  & R. B. MILLAR 《Fisheries Management and Ecology》2005,12(4):225-236

Abstract  The selectivities and catch compositions of conventional 30-mm diamond-mesh codends and a new square-mesh design made from 20-mm mesh hung on the bar for river and lagoon penaeid seines in south-eastern Australia were compared. The square-mesh design significantly improved the selectivities of the river seine for school prawns, Metapenaeus macleayi (Haswell), and the lagoon seine for greasyback prawns, Metapenaeus bennettae (Racek & Dall), by increasing their carapace length at 50% probability of retention ( L ₅₀) and by decreasing between-haul variability in selectivity. The presence of weed reduced the L ₅₀ for greasyback prawns caught in the conventional diamond-mesh codend during the lagoon-seine experiment. The differences among codend performances are discussed in terms of the differing methods of operation and composition of catches between the seines. These differences highlight the need to develop and manage modifications to improve the selectivity of fishing gears on a fishery-specific basis.  相似文献