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.

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.

Thesis (M. Agr. Sc.)--University of Queensland, 2002. / Includes bibliographical references.

Thesis (Ph. D.)--University of Queensland, 2002. / Includes bibliographical references.

The occunence of temperature acclimation was investigated in a range of caddis species. A closed bottle method was used for the majority of the respiration experiments, a flow-through respirometer being designed for the remaining experiments. Temperature acclimation was demonstrated in eight out of twelve species studied. Increased ability to compensate was associated with increased ecological distribution. The hydropsychids were shown to have a greater ability to acclimate than polycentropodids with similar distributions. No relationship was apparent between the interspecific differences in the respiration rate and the distribution of the species. For some species maintenance at a warmer temperature for 4-5 weeks caused a decrease in the undulatory activity of the larvae when compared, at a constant temperature, with larvae maintained at a cooler temperature. For eight of the ten species for which both sets of data were obtained the metabolic and undulatory data were compatible. A relationship between undulatory activity and distribution was suggested. For two cased caddis species a positive correlation was demonstrated between the number of gills and the body weight. Maintenance at the warmer of two temperatures over a period including a moult caused an increase in the number of gills on larvae and pupae. Intraspecific differences were found in the number of gills on larvae from different field sites, the number increasing with increased stream temperature. No relationship was demonstrated between the oxygen consumption of the larvae and the number of gills. No evidence was obtained for a difference in metabolism following maintenance of larvae at fluctuating temperatures of differing amplitudes.Decreased undulatory activity was demonstrated in larvae of Hydropsyche contuberna7is maintained under conditions of greater temperature fluctuations. Field acclimatisation was demonstrated in two species, Sericostoma personatum and Potamophy7ax cingu7atus, larvae from the warmer sites having a lower respiration rate than larvae of the same species from cooler sites, when both were measured at the same temperature.

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