Currently, many cities are struggling with inner-urban blight and disjointed, divided communities due to high unemployment and lack of economic opportunity. Towns along the Mississippi River are prime examples of such distressed urban spaces, due to a combination of declining industry, lateral physical expansion away from the center and into suburbs, shifts in American revenue generators and today’s generally poor economic climate. The banks of the river are vacant with many Main Street storefronts unoccupied. Cities offer little to no waterfront commerce, entertainment or gathering – for locals and tourists alike – besides steamboat casinos. In addition, treatment of the Mississippi River is especially conservative, cautious and careful due to its strategic international importance and flood plain sensitivity; leading to the acceptance of early 20th century river control methods, with little room to engage or experience the waters. Visual and physical access to the river is denied due to levees and flood walls. However, the river embodies great potential for revitalization due to its quality resources; various fishery groups have stressed the value of aquaculture, especially for catfish cultivation, as a strong source of employment and revenue across the state of Mississippi. This thesis project seeks to investigate a sustainable model for large-scale redevelopment of decaying downtown spaces that respectfully links landscape and design while addressing problems tied to the current decline of American cities and towns. Mississippi River communities, especially in the state of Mississippi, require redevelopment with the three-fold intent of highlighting regional history, establishing an economy and providing space for the community to gather. The proposed means of re-urbanization – an urban catfish aquaculture and fishery center – prescribes an ecological, economic and productive cultural infrastructure that highlights the river and layers historical and social spaces to reinvigorate the relationship between city and its place on the water. / acase@tulane.edu

The occurrence of blooms of toxic cyanobacteria in freshwater environments is a global ecological and public health concern. Species of Microcystis are of particular importance because blooms occur in many freshwater environments throughout the world and microcystin toxin concentrations can exceed World Health Organization advisory levels. While microcystin has been associated with fish kills, sublethal effects of chronic exposure at environmentally relevant concentrations are relatively unknown. The objective of this research was to evaluate toxicity of microcystin and Microcystis in fish during all life history stages. We evaluated global gene expression response in larval zebrafish (Danio rerio), and a sub-set of biomarker genes indicative of microcystin exposure were identified. In addition, vitellogenin genes were highly up-regulated in zebrafish exposed to Microcystis but not the microcystin toxin, indicating potential endocrine disrupting effects of Microcystis blooms. Effects on reproduction were evaluated in adult zebrafish exposed to Microcystis. There was a significant decrease in the percentage of adults that spawned, however fecundity and larval survival were not affected. Laboratory mesocosm experiments with channel catfish (Ictalurus punctatus) were also conducted to determine the importance of dietary and aqueous exposure in microcystin bioaccumulation and assess histopathological lesions. Tissue toxin concentrations and histopathological lesions were also evaluated in channel catfish collected from Lake Erie and Waterville Reservoir, North Carolina to monitor fish living in environments affected by Microcystis blooms and relate responses to those observed in laboratory exposures.

According to earlier surveys, there were nine sound types in areas adjacent to the estuaries of nine major rivers in Taiwan, and the frequency range of the H-type sound was as high as 6 kHz. The producers of this sound type have not been defined yet. Sea catfish can make two kinds of sounds: stridulatory sound and drumming sound. The former is pulsed, broad-band and high-frequency, whereas the latter is harmonic, and low-frequency (less than 1 kHz). Spotted catfish (Arius maculates) is the most common demersal species in the west coast of Taiwan. The aims of the study were (1) to find out if H-type sound is presence in Cigu lagoon; (2) to describe the disturbance (hand-held) sounds emitted by A. maculates; (3) to find clues to support that the stridulatory sound of A. maculates is the H-type sound; (4) to find if there is sexual difference in the sounds of A. maculates; (5) to find the relationship between sound characteristics and intrinsic characters of the fish; (6) to define the reproductive season of A. maculates; (7) to find out if there is correlation between the spawning season of A. maculates in Cigu lagoon and presence of the high-frequency sounds in the lagoon. Bimonthly sound recordings were made in Cigu lagoon between February to December 2009. Pulsed, broad-band and high-frequency sounds were present in April, June, and August; number of sounds per minute was higher in August (mean: 52.9 sounds/ min). The sound were characterized by: sound duration: 160.6 ¡Ó 16.6 ms, dominant frequency: 2840 ¡Ó 867.3 Hz, pulse period 12.6 ¡Ó 0.45 ms, pulse duration: 6.0 ¡Ó 0.82 ms, inter-pulse-interval: 6.6 ¡Ó 0.84 ms. The stridulatory sounds of A. maculates are pulsed, broad-band and high-frequency - sound duration: 64.0 ¡Ó 16.74 ms, dominant frequency: 1251 ¡Ó 419.8 Hz, pulse period 7.7 ¡Ó 2.69 ms, pulse duration 5.3 ¡Ó 1.69 ms, inter-pulse-interval 2.4 ¡Ó 1.93 ms. Drumming sounds of A. maculates are harmonic, low frequency - sound duration: 58.5 ¡Ó 25.54 ms, dominant frequency: 442 ¡Ó 96.3 Hz fundamental frequency: 163 ¡Ó 30.98 Hz, pulse period: 6.3 ¡Ó 1.21 ms, pulse duration: 6.3 ¡Ó 1.19 ms. There was significant sexual difference in the stridulatory sound characters including pulse period, inter-pulse-interval, pulse number; females are higher than males in these parameters. There was significant sexual difference in the drumming sound (including dominant frequency) as well; males are higher than females in these parameter. Pulse period of the stridulatory sounds increased significantly with increasing standard body length. Pulse period and pulse duration of the drumming sounds both increased significantly with increasing standard body length, whereas dominant frequency and fundamental frequency both decreased significantly with size. GSI and oocyte diameters were higher in February, April, and June with a peak in April. Reproductive period was considered occurring from April to August (i.e. in spring and summer). This reproductive period coincides with the peak of vocalization. Result of ANOSIM indicates that, H-type sound is significant different from the stridulatory sound of A. maculates - they are in different groups. As the sound source might be at a distance from the recording site, energy in the high frequency range might decay with distance, whereas low frequency range might be cutoff as well. As A. maculates is the only soniferous spices in Cigu lagoon that can emit high-frequency sounds, possibility remains high that the high frequency sound, which resembles the H-type sound, in Cigu lagoon is actually produced by the spotted catfish despite of the difference in frequency-domain features of the sounds.

The darkbarbel catfish (Peltoebagrus vachelli) is a small bodied benthic fish that inhabits the Yangtze River in China and is commercially valued as food. The objectives of this project were to develop the first set of microsatellite primers specific to P. vachelli and use them to examine the levels of genetic variability and population structure of three populations collected at three sites (Yibin, Luzhou, and Song Ji) along an unfragmented stretch of the upper Yangtze River. Microsatellite primers were designed from an enriched library of genomic DNA and a total of eight primer pairs were optimized to produce reliable polymorphic PCR amplicons on a LI-COR 4200 IR2 platform. A high level of variability was detected amongst the isolated loci with the number of alleles per locus ranging from 14 – 29 and mean observed and expected heterozygosity values of 0.84 and 0.90 respectively across the entire sample set. Overall levels of genetic diversity were high within the three populations with mean observed and expected heterozygosities ranging from 0.823 – 0.869 and 0.864 – 0.921 respectively. Little evidence of genetic structure was detected (global FST = 0.0065, p < 0.05) within the sampled region and pairwise tests of differentiation were not significant (all FST p > 0.05). These results imply historically large populations of P. vachelli in the upper portion of the Yangtze River that, in the absence of artificial barriers, are part of a single panmictic unit. As plans have been put forth for construction of hydroelectric installations within the sampled region, this study provides a baseline estimate of the levels of genetic variation present in P. vachelli within the remaining undammed stretch of the Upper Yangtze River which will serve as a foundation for future analyses on the effects of river fragmentation within this region. Additionally the isolation and characterization of the microsatellites will provide useful molecular markers for a variety of other applications in this and closely related species such as parentage analysis, determination of stocks, and maintenance of genetic variation in stocking practices. / Thesis (Master, Biology) -- Queen's University, 2012-06-29 18:00:25.509

Thesis(M.S.)--Auburn University, 2007. / Abstract. Vita. Includes bibliographic references.

Thesis(M.S.)--Auburn University, 2006. / Abstract. Vita. Includes bibliographic references.

Thesis--Auburn University, 2009. / Abstract. Vita. Includes bibliographical references (p. 58-68).

Thesis (M.Sc. (Molecular genetics-genetic engineering )) -- Mahidol University, 1999.

In Sweden, the Wels catfish (Silurus glanis) is a protected species and exist in only three known water systems in the country. With spawning habitats being destroyed by human activities, it is important to know more about the Swedish catfish’s reproductive behaviour and habitat preferences in order to protect the species. In this report, catfishes tagged with transmitters was tracked using radio telemetry, day and night for two weeks in Lake Båven during the spawning period. Habitat data on the depth, bottom hardness and vegetation was collected in known and potential spawning areas in the lake using an echo sounder. Habitat preference analysis indicated depth and bottom hardness as important factors when catfishes chose spawning habitat.  The analysis did not indicate vegetation to be important. Habitat data from spawning positions of tagged catfishes was used to identify other sites suitable for reproduction in nearby areas. Home range during spawning was calculated for two catfishes and was found to be 1.05 and 1.35 ha. Based on this information and the identified sites suitable for spawning, the total available spawning habitat in the study area was found to be enough for 12 to 15 catfishes. This is relatively few, and indicates that additional spawning sites would benefit the population.

Orientador: José Senhorini / Abstract: The aim of this study was to describe a procedure for sampling, reproduction, and first feeding of the Neotropical catfish Pseudopimelodus mangurus. Wild adult P. mangurus specimens were collected in the Mogi Guassu river, and subsequently, were induced to spawn in laboratory conditions. After hand-stripping the females, the average weight of the oocytes was 143 ± 1.66 g, having an average of 718 ± 49.802 oocytes g-1. The diameter of zygotes was about 1226.354 ± 47.719 µm nonhydrated to 1761.256 ± 26.412 µm after hydration. The fertilization rates were 98.00 ± 0.63%, and the hatching rate were 68.94 ± 11.83%. Three days after hatching, the larvae started exogenous feeding. First feedings were made with 6 different treatments, in which the best results arose with sequential feeding with artemia nauplii, Astyanax altiparanae, and Prochilodus lineatus larvae. This condition resulted in a growth rate of 2012.795 ± 44.891 µm by the tenth day of experiment, higher survival rate (65 ± 0.09%), and a lower cannibalism rate 14 ± 0.03% on the tenth day after exogenous feed. The data obtained in this study is important for reproductive biotechniques and mass production of the endangered catfish P. mangurus. / Mestre