No description available.

The garibaldi, Hypsypops rubicundus, is a sexually monochromatic pomacentrid found in rocky subtidal areas of Southern and Baja California. During the spawning season, males attempt to attract females to a nest of red algae located within individually defended territories. Females were observed to enter the nests of several males before selecting one for spawning and were significantly more likely to spawn in nests that contained eggs in the early stages of development than nests with no eggs or with late stage embryos. Among empty nests, the density of red turf algae and the number of nesting males surrounding the nest were inversely related to the amount of time elapsed until a nesting male acquired the first clutch of a brood. The percentage of long algae in the nest was positively related to this measure. These results demonstrate active female choice of spawning site by female garibaldi and suggest that certain characteristics of the male-defended nest influence this choice. / Graduation date: 1991

The family Pegasidae is found composed of 5 species in two genera, Eurypegasus Bleeker and Pegasus Linnaeus. They contain two (E. draconis (Linnaeus) and E. papilio (Gilbert)) and. three species (P. laternarius Cuvier, P. volitans Linnaeus and P. Lancifer Kaup) , respectively these species are all small, benthic, and covered with plastron from head to tail. Three species have been recorded in Taiwan, but there are many differences between the species names and the specimen illustrations in other foreign publication studies. Recision on the records in Taiwan indicated that three species occur in this region , namely, E. draconis, P. laternarius and P. volitans. According to some osteological and external characters, a hypothesis on the phylogenetic relationship was arrived : P. laternarius is not the sister group of P. volitans and P. lancifer, but the sister group of Eurypegasus species. It is suggested that these five species should be classified in only genus, the Pegasus. Bottom-trawl samplings were made between April 2001 to April 2002 in area of the Kaohsiung coastal at depth around 30 meters. 32 specimens of P. volitans were captured. P. volitans captured its prey by means of oral suction. Guts of the majority of the preserved specimens, including those died right after landed, were empty. Besides some fine granules of sand, one specimen¡¦s gut included caprellideans (Crustacea, Amphoipoda). Skin-shedding was observed numerous times in the aquarium. Unlike other seamoths, only part of the skin was shedded at one time; no regular cycle of skin-sheding was noticed. No social pairing of the sexes and reproductive activity during this study was not noticed. Specimens collected in November tended to be largerin size. The smallest specimens with large ovary was 55mm in length, whereas the largest dry female specimens with a 1.2mm egg was 70mm.. Histological evidence (individual female had eggs in various developmental stages at the same time) indicates that this species is a multiple spawner.

No description available.

The family Siphonariidae is considered primitive amongst the basommatophorans although the ancestry and evolutionary relationships of these marine pulmonates are far from settled. This thesis investigates and compares different aspects of egg development and the female reproductive system in two sympatric species of Siphonaria with different developmental mode (S. capensis, a planktonic developer and S. serrata, a direct developer). The study on the seasonality of gametogenesis and spawning shows that they are both spring/summer spawners with continuous sperm production. The egg production is highest in spring and summer with a brief interruption in winter months. The gametogenic cycle when examinated, reveals that both species are simultaneous hermaphrodites once sexually mature. Amongst various factors that are investigated, density of animals has a positive effect on the number of spawn only during peak spawning. Larger individuals of S. capensis and S. serrata contains more mature oocytes in the gonad indicating that the shell length and fecundity of these two limpets are positively correlated. By contrast, parasitism by trematodes has a drastic effect on the reproductive output of these limpets leaving them completely castrated. Egg development in S. capensis and S. serrata shows that both produce yolk auto synthetically (with the help of organelles like RER, Golgi bodies) but S. serrata also incorporates some high molecular weight precursors via endocytotis. The structure as well as the biochemical composition of the egg ribbons is also different between these two species with higher carbohydrate and protein content of collar shaped spawn of S. serrata. S. capensis produces egg ribbons of less fibrous nature containing thinner egg capsules compared to the direct developer. A comparison of both the glandular complex and spermatheca between these two limpets shows no inter specific difference in the structure although the glandular complex of the siphonariids shows fine structural and histochemical similarities with the albumen gland and membrane gland of the opisthobranchs. The structure of the spermatheca suggests that in both species the organ most possibly receives sperm (for degradation only?) and may transport them via the spermathecal duct (for fertilization?). Finally, it is suggested that S. capensis and S. serrata exhibit primitive features (e.g., an autosynthetic mode of vitellogenesis in S. capensis and a single glandular complex composed of an albumen and a mucous gland) compared to other basommatophorans, which should be considered in future phylogenetic investigations.

No description available.

No description available.

Studies were conducted during late winter and spring of 1970 to establish the extent of spawning of Pacific herring (Clupea harengus pallasi Valenciennes) in the Yaquina estuary, and to define the degree of egg mortality on certain substrates. Routine surveillance of the north shore of the estuary provided information on the length of the spawning season, the number of separate spawnings which occurred, the extent of spawning into brackish water, and the types of substrates utilized for spawn deposition. Random sampling of egg deposits at specific locations within the estuary, and at frequent intervals following deposition provided estimates of spawn mortality on two commonly used plant substrates, Fucus sp. and Zostera sp. These included estimates of the amount of eggs removed from the substrates prior to commencement of hatching, and estimates of the mortality among eggs which remained attached to the substrates. One series of samplings of a deposit of eggs on Fucus was designed to establish the extent of bird predation on the eggs. Results from the spawn survey indicated that at least five separate spawnings occurred during the season. Initial spawning took place on February 5 in the lower estuary (from the south jetty to a point three miles upriver from the mouth). Subsequent spawnings occurred in the third, fifth, sixth, and seventh weeks following this initial deposition, and appeared to take place exclusively in the middle and upper estuary (from three and one half miles to ten miles upriver from the mouth). Among the substrates observed with eggs Fucus appeared to be the most extensively utilized, while localized deposits were noted on Zostera, bare rocks and pilings. Spawning was predominantly located on substrates lying above mean lower low water. Analysis of the samples collected from four populations of eggs deposited on Fucus, and one population deposited on Zostera revealed that egg removal was extreme during the period of incubation. Recorded losses from initially sampled populations of eggs on Fucus ranged from 78% to 1OO% based on sample means. A 9l% loss was recorded for the one Zostera population sampled. A comparison of a protected with an unprotected segment of a sampled population on Fucus indicated that birds contributed at least 80% to the removal of eggs from the unprotected segment. The observed presence of birds on all of the sampling areas when eggs were present suggests that predators accounted for the extensive losses from these areas. Analysis of the ratios of dead eggs to the total number of eggs in samples collected from Fucus substrates provided estimates of natural mortality. Low rates of mortality (about 20%) were recorded for two populations sampled during a period in which the weather was cool and moist, while considerably higher rates (about 50%) were observed in samples from a population exposed to a dry and relatively warm climate. Dessication of eggs was therefore indicated as a significant cause of mortality of eggs remaining attached to substrates exposed to drying conditions in the atmosphere. In addition to these field studies, a study was conducted in the laboratory to define the effects, on the survival of herring eggs to hatching, of combinations of three environmental parameters: temperature, salinity, and exposure to air. Groups of artificially fertilized eggs were incubated in the 18 test environments provided by the different combinations of three temperatures, three salinities, and exposure and non-exposure to air. Survival of eggs to hatching remained high (from 60% to 86% of total eggs in each environment) except for eggs incubated in the highest temperature ( 11 °C.) and subjected to eight hour exposure periods. Average survival in these environments was 5.2% and 24.2% (for two replicates). These observations lend support to the findings from the field sampling studies that survival of herrings eggs can be tenuous when subjected to exposure to air. / Graduation date: 1972

Mass coral spawning represents a nutrient input to coral reef systems that for Pacific reefs has been shown to stimulate pelagic and benthic processes. If phytoplankton in the water column over the reef are able to utilize this annual nutrient input, this could potentially alter phytoplankton biomass and community composition, in what is normally a very oligotrophic system. Sampling was performed at East Flower Garden Bank (EFGB), Gulf of Mexico during May, July, and August 2009. The annual coral spawning event occurred there August 11-14, 2009. Samples were collected morning and evening at three depths and analyzed for nutrients, chlorophyll a, accessory pigments, phytoplankton species composition, and carbon, hydrogen, and nitrogen (CHN). During spawning, only small changes in nutrient concentrations were detected. Dissolved inorganic nitrogen (DIN) peaked on the second day of spawning and N:P ratio was highest on 5/28, likely due to particularly phosphate concentration. Chl a biomass was significantly different between sample dates and the biomass increased steadily throughout the spawning period. The contribution of different phytoplankton classes to total chlorophyll a was determined using known pigment algorithms. Prokaryotes were the dominant class across the entire sampling period with 60-80 percent abundance. Trichodesmium spp. was the dominant genus throughout the study and genus specific changes per sample date were seen. On 8/11 and 8/13 two genera contributed the majority of chl a (Trichodesmium spp. and Ceratium spp.; Cylindrotheca spp. and Trichodesmium spp., respectively). Abundance showed variability during spawning with a peak at 11 cells/ml on 8/12. The high abundance of Trichodesmium spp. could indicate N limitation is alleviated at the Flower Garden Banks (FGB). Current literature on coral spawning is limited to studies performed in the Great Barrier Reef, with assessment areas close to a major shoreline. Genera found at EFGB were similar to those found in other reef systems. It cannot be determined if nutrient input increased diversity, as diversity was high prior to spawning as well. Greater increase in available forms of nitrogen would have likely been found several days post major spawning. The FGB were a unique system to study, as they are coral reefs, but are located 200 km offshore. This study provided a snapshot into phytoplankton dynamics as a result of spawning. Changes across the short time scale were seen in biomass and community composition.

No description available.