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Maximum oocyte size was used to assess seasonal ovarian development in sole. Fish age, especially the adolescent period, appeared to affect the start of vitellogenin-dependent oocyte development in the annual reproductive cycle and the subsequent oocyte growth rate. The majority of oocyte growth occurred between September and March. Several other aspects of ovarian development were also age-dependent, including the increase in ovary condition factor (ovary weight/fish length3) and the size of oocytes commencing nuclear migration. Evidence is presented that in the recruiting year class of sole abortive maturation occurs where oocytes develop yolk but spawning does not take place. The implications of this study on the estimation of female spawning stock biomass are discussed. 相似文献
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采用数理统计的方法,对1991~1992年海湾扇贝控温促熟实验的有关数据进行分析。得到海湾扇贝在青岛地区性腺发育的生物学零度为6.6℃,产卵的有效积温为178.9℃。 相似文献
105.
花鲈亲鱼人工培育与催产技术研究 总被引:1,自引:0,他引:1
作者研究了花鲈人工培育及促熟催产中的技术措施。采用海捕的天然苗种 ,逐年筛选、精心培育 ,共获得 4~ 6龄的成熟亲鱼 50尾。在外源激素 HCG(70 0~ 150 0 IU/ kg)及 LHRH- A3(2~5μg/ kg)的作用下 (雄鱼减半 ) ,共人工采卵 156 0× 10 4粒 ,卵的平均上浮率为 6 1% ,平均受精率为78% ,平均孵化率为 85.7%。 相似文献
106.
Jaime Gmez-Gutirrez Leah R. Feinberg Tracy C. Shaw William T. Peterson 《Deep Sea Research Part I: Oceanographic Research Papers》2007,54(12):2145-2169
Brood sizes of 1259 adult female Euphausia pacifica and Thysanoessa spinifera were measured during 48 h incubations (10 °C, ±0.5 °C) on 27 oceanographic cruises between July 1999 and September 2004. The data set includes measurements from several stations off Newport, Oregon (Newport Hydrographic line, 44°39′N) made over a 5-year period and measurements from 14 more extensive cruises at stations representative of continental shelf, slope, and oceanic waters off Oregon and California, USA. E. pacifica had similar brood sizes at inshore (<200 m) and offshore (>200 m) stations with an average of 151 and 139 eggs brood−1 fem−1, respectively. T. spinifera brood sizes were considerably higher at inshore stations—particularly at Heceta Bank (44°N) and south of Cape Blanco (42°50′N)—than at offshore stations, 155 and 107 eggs brood−1 fem−1, respectively. Average brood sizes of E. pacifica increased during the study period, from 125 (in 2000) to 171 eggs brood−1 fem−1 (in 2003). Average percentage of carbon weight invested in spawning (reproductive effort) was higher in E. pacifica (14%) than in T. spinifera (6%), because both species have similar brood size but T. spinifera females are larger than E. pacifica females and produce smaller eggs. Reproductive effort for both species was higher during summer 2002, probably associated with anomalous cool subarctic waters and high chl-a concentration observed during that summer. Brood sizes and chl-a values remained relatively high in 2003–2004 compared to the 1999–2001 period. Geographical and temporal variability in brood sizes for both species were significantly correlated with in situ measurements of chl-a concentration but not with sea surface temperature. No gravid females were collected during late autumn and winter cruises, thus the spawning season along the Oregon coast appears to extend from March through September for both species. However, T. spinifera usually starts reproductive activity earlier in the spring (March) than E. pacifica. Both species had their highest brood sizes in summer during the period of most intense upwelling, which is associated with an increase in regional phytoplankton standing stock. 相似文献
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Marine environments, key life-support systems for the earth, are under severe threat. Issues associated with managing these common property resources are complex and interrelated. Networks of marine reserves can be valuable for mitigating threats to marine systems, yet the successful design and implementation of such networks has been limited. Efficient ways to conserve marine environments are urgently needed. This Focus Section of The Professional Geographer explores the development of marine reserve networks based on geomorphology, fish biology, ecological connectivity, and appropriate governance. The articles in this Focus Section offer examples of the following: (1) distinctive reef geomorphology dictating the spawning locations of reef fishes, which in turn serve as critical source sites for the replenishment of distant reefs by means of larval transport; (2) an example of a simplified oceanographic model that predicts larval transport from fish breeding sites to important nursery areas; and (3) a case study of the development of a marine reserve network that illustrates key elements of a successful strategy. In sum, this Focus Section offers case studies that show the value of marine geomorphology, oceanographic connectivity, and stakeholder involvement as key elements of multidisciplinary geographic studies applied to the design of marine reserve networks. Geographers can further contribute to the conservation and management of coastal and marine ecosystems in many ways that involve subdisciplines of remote sensing and geographic information systems, political and economic geography, political ecology, and ethnography. 相似文献
109.
Brandon T. Overstreet Clifford S. Riebe John K. Wooster Leonard S. Sklar Dino Bellugi 《地球表面变化过程与地形》2016,41(1):130-142
We present a set of river management tools based on a recently developed method for estimating the amount of salmon spawning habitat in coarse‐bedded rivers. The method, which was developed from a mechanistic model of redd building by female salmon, combines empirical relationships between fish length, redd area, and the sizes of particles moved by fish during spawning. Model inputs are the grain‐size indices D50 and D84 and an estimate of female fish length, which is used to predict the size of the redd that they will build and the size of the largest particle that they can move on the bed. Outputs include predictions of the fraction of the bed that the fish can use for redd building and the number of redds that they can build within the useable area. We cast the model into easy‐to‐use look‐up tables, charts, an Excel worksheet, a JavaScript web applet, and a MATLAB user interface. We explain how these tools can be used in a new, mechanistic approach to assessing spawning substrates and optimizing gravel augmentation projects in coarse‐bedded rivers. © 2016 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd. 相似文献
110.
《Marine pollution bulletin》2014,78(1-2):213-217
The rapidity of ocean acidification intensifies selection pressure for resilient phenotypes, particularly during sensitive early life stages. The scope for selection is greater in species with greater within-species variation in responses to changing environments, thus enhancing the potential for adaptation. We investigated among-male variation in sperm swimming responses (percent motility and swimming speeds) of the serpulid polychaete Galeolaria caespitosa to near- (ΔpH −0.3) and far-future ocean acidification (ΔpH −0.5). Responses of sperm swimming to acidification varied significantly among males and were overall negative. Robust sperm swimming behavior under near-future ocean acidification in some males may ameliorate climate change impacts, if traits associated with robustness are heritable, and thereby enhance the potential for adaptation to far-future conditions. Reduced sperm swimming in the majority of male G. caespitosa may decrease their fertilization success in a high CO2 future ocean. Resultant changes in offspring production could affect recruitment success and population fitness downstream. 相似文献