• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 161
  • 94
  • 37
  • 12
  • 8
  • 5
  • 5
  • 4
  • 4
  • 3
  • 2
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 445
  • 49
  • 49
  • 43
  • 39
  • 36
  • 30
  • 30
  • 28
  • 25
  • 23
  • 23
  • 22
  • 21
  • 21
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Yearly variation in the abundance and distribution of fish larvae in the coastal zone off Yaquina Head, Oregon, from June 1969 to August 1972

Mundy, Bruce Carl 07 June 1983 (has links)
Graduation date: 1984
2

A classification of the larvae of the Tenthredinoidea

Yuasa, Hachiro, January 1900 (has links)
Thesis (Ph. D.)--University of Illinois, 1920. / "Contributions from the Entomological laboratories of the University of Illinois, no. 69." Bibliography: p. 135-140.
3

Ueber chitinöse Fortbewegungs-Apparate einiger (insbesondere fussloser) Insektenlarven

Leisewitz, Wilhelm. January 1906 (has links)
Thesis (doctoral)--Ludwig-Maximilians-Universitat zu Munchen, 1906.
4

Embryology, larval ecology, and recruitment of "Bathymodiolus" childressi, a cold-seep mussel from the Gulf of Mexico. /

Arellano, Shawn Michelle, January 2008 (has links)
Thesis (Ph. D.)--University of Oregon, 2008. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 171-198). Also available online in Scholars' Bank; and in ProQuest, free to University of Oregon users.
5

Mortality of larval capelin (Mallotus villosus Muller) : environmental and density correlates during post-emergent dispersal

Taggart, Christopher Thomas. January 1986 (has links)
No description available.
6

Growth, development and mortality in metazoan early life histories with particular reference to marine flatfish

Bertram, Douglas F. January 1993 (has links)
Patterns of variability in growth, development and mortality in early life histories were examined at two levels--general and specific. At the general level, I examined the functional significance of larvae in metazoan life cycles. This was achieved by surveying the metazoa at the class level and categorizing mode of development by habitat. Three long-standing hypotheses for the paucity of larval development in fresh water were rejected. I argue that viewing metazoan larvae as a means for feeding and growth provides a unifying framework for evaluating the features of habitats which correlate with the range of variation expressed in development modes. I offer a modelling framework to investigate variation in developmental modes within and between habitats. The suggested model requires input on larval growth rates, larval period duration (development time), and size-specific mortality rates. These variables, and the interactions between them, are also central to the specific analysis which addresses the ecological processes and mechanisms which affect survival and hence recruitment during the early life histories periods of marine fishes. Winter flounder (Pleuronectes americanus) was used as a model species to investigate phenotypic variability in patterns of growth and development and their survival consequences. Using laboratory-reared fish, I demonstrate that size-at-age does not diverge continuously during the larval and juvenile periods. The results show that fish which grow slowly as larvae, compensate for their slow growth by growing rapidly as juveniles. This compensation in growth rate causes juvenile size-at-age to converge, or at least, prevents divergence in juvenile size-at-age. In addition, I provide some of the first estimates of individual variability in larval growth trajectories for a marine fish. I conducted the first experiment which separates the effects of both size and age on the vulnerability to predation in recently metamorphosed fishes. Th
7

The influence of small-scale turbulence and upwelling on the ecology of larval fishes /

MacKenzie, Brian R. (Brian Royce) January 1991 (has links)
Environmental control of interactions between larval fish and their prey, and the potential influence of this relationship on fish feeding and recruitment, were assessed using empirical models developed using data drawn from the literature and developed in field studies. Ingestion rates of larval fish in laboratory and natural environments were found to differ in relation to food density. In laboratory studies, larvae show a strong functional response to prey density. Larvae situated in situ consume food at much higher races than would be predicted from laboratory studies and these rates are independent of prey density at known in situ densities. This discrepancy between laboratory and field feeding rate-food density relationships can be partly explained by the in situ contribution of small-scale turbulence to predator-prey encounter rates. Field studies of the influence of wind on nearshore hydrography showed that wind-induced upwelling generated favorable combinations of nutrients, light, and small-scale turbulence for production by phyto- and zooplankton. The distribution of microplankton $(<$80 $ mu$m) that resulted from these upwelling episodes was quantitatively described by the cumulative longshore wind velocity during the summer months. Microplankton abundance was greatest within 4 km of a major spawning site for capelin, Mallotus villosus, an economically and ecologically important forage species in the north Atlantic Ocean. Interannual variability in the intensity and frequency of upwelling-favorable winds was positively and significantly correlated with recruitment levels in the NAFO 2J3K capelin population. A new recruitment forecasting model, using an upwelling-related wind index as an input, explained more of the variance in capelin recruitment than did a previously published model. These results suggest that larval capelin are more likely to be food-limited in years when wind conditions are unfavorable for upwelling, and that recruitment in this fi
8

Effects of body size and particle size on feeding rates and morphology of the larvae of three congeneric barnacles (class cirripedia : genus balanus)

Smart, Tracey Irene, 1978- 12 1900 (has links)
ix, 84 leaves : ill. ; 29 cm Notes Typescript Thesis (M.S.)--University of Oregon, 2003 Includes vita and abstract Includes bibliographical references (leaves 73-84) Another copy on microfilm is located in Archives
9

Composition and distribution of Ichthyoplankton in the waters off Southwestern Taiwan

Liao, Chen-Hen 01 September 2000 (has links)
Abstract: There were 75 families, 119 genera and 182 species of ichthyoplankton found in the adjacent areas of Kaohsiung and Liuchiu Yu Island. Fifty families, 82 genera and 111 species were collected in the surface waters, and 37 families, 54 genera and 68 species were collected in oblique tows to 100m with an open 1 m net, while 41 families, 48 genera and 73 species were collected by a multiple opening-closing net. Engraulis japonicus was the most dominant species, and was found all year round; other dominant species included coastal fish species (Apogonidae and Pomacentridae), anadromous species (Scombridae), oceanic species (Engraulidae and Myctophidae), and demersal species (Gobiidae). There were only 3 species of ichthyoplankton belonging to 3 genera and 2 families found in the Tapong Bay, all these species are benthic species. The coastal waters of Kaohsiung and Liuchiu Yu Island might be influenced both by the river and the topography of Kaping Trench, and thus the hydrological conditions of this area were more complex, and the ichthyoplankton was more diverse. On the other hand, the hydrological conditions of the semi-closed Tapong Bay changed less than that of the estuary of Kaoping river, thus the species composition of larval fish was simple and less diverse. Overall, the highest abundance of the ichthyoplankton in the adjacent areas of Kaohsiung and Liuchiu Yu Island was found in the wet season(June), with an average of 108¡Ó 116 ind./100 m3. E. japonicus was the most abundant in February, revealed that might be the breeding season of this species. Other dominant species (eg. Bregmaceros japonica and Tridentiger sp.) also showed significant seasonal variation. Higher abundance of ichthyoplankton was usually found in the entrance of Kaohsiung first harbor(St.1) and the estuary of Kaoping river(ie. St.4~6). No significant diel vertical migration of the ichthyoplankton was observed in this study. Most ichthyoplankton were found in the water column above 100 m during both day and night.
10

A simple design of automatic counting system for fish larvae

Huang, Chien-hua 14 July 2002 (has links)
A simple design of automatic counting system for fish larvae Chien-hua Huang Advisor: Dr. Sun-chio Fong Institute of Marine Biology, National Sun Yat-sen University, Kaohsiung 804,Taiwan, R.O.C. The purpose of this study is to develop a portable-computer system for automatic counting of fish larvae. It was intended as an economical, fast and accurate tool for the general fish farmers. The basic principle of the system is to use gray level value of the three prime colors (red, green and blue) as an indicator to separate and estimate fish larvae within the CCTV image. The hardware part includes a CCTV camera which hooks up to an IBM compatible laptop computer. Images of fish in a tank were captured and stored for future counting process. Program was written in True Basic language for taking the average number of pixel for individual fish, and system optimization for estimating the total number of fishes within tank. Regression analytical methods were also employed for estimating and correction of bias and errors. In an experiment using the present system to estimate known numbers (100, 300, 500, 700 and 900) of larval Paracheirodon innesi in a 60-liter tank as the testing material, the estimated fish numbers were 132, 259, 495, 799 and 1054 respectively. The group of 500 fishes (standard deviation equals to 88) gave the best result. The total percentage of error ranged between 0.9% and 32%. Application of this system on other species of fishes is yet to be tested. It was safe to suggest that the current version of the system works only onto the same species of fishes under similar conditions (less than 1000 fishes of similar sizes, water depth of 25 cm etc.). For different target fishes under different type of container, a new set of error-correcting formula would be needed. However, the present results when compared with published reports of other system, are no less accurate. This system however is more economical and works more conveniently than do most others.

Page generated in 0.0392 seconds