Call number: LD2668 .T4 1986 N445 / Master of Science / Grain Science and Industry

Thesis (Ph. D. (Zoology)) -- University of Limpopo, 2009. / Aspects of the ecology and biology of the Lowveld largescale yellowfish (Labeobarbus marequensis) were studied in the Luvuvhu River over a period of three years. In this study the origin of the species, its phylogenetic relation to the other South African yellowfish species, its distribution and gross morphology are discussed and the lack of knowledge regarding aspects of the species is pointed out. The study area is identified and its geology, hydrology, climate and water quality as well as the historic distribution of the species is discussed. Adapted “truss” techniques were applied to measure and calculate the morphometric features related to feeding and habitat preference of the species. From this data the habitat preferences and requirements were inferred after which it was compared to data obtained during field surveys. The study of the breeding biology and ecology of the species included investigations of gonad and egg structure and development as well as seasonal surveys of selected breeding sites. The diet of the species was established through stomach content analyses and related to the digestive tract morphology. Data obtained from the Xikundu fishway was used to establish the migratory behaviour. Results show that nine distinct stanzas or growth phases, each with its own morphometric characteristics, were identified. The body form, and some morphological aspects, of the species make it suitable to cope with flowing water. Ontogenetic changes in body form and the identified morphological aspects were observed and related to the habitat preferences of the stanzas. A distinct ontogenetic shift in preferred habitat was illustrated. The species was shown to be fractional spawner with two spawning events per annum. A major extended spawning event occurred during spring or early summer and coincided with a temperature increase and in particular with an increase in flow. Breeding occurred at sites with fast flowing water over cobble or boulder beds and it was observed that the presence of nursery areas related to breeding biotopes was extremely important. Although the diet of the species was dominated by plant and algal matter, juvenile stanzas ingested large amounts of animal material. It was found that the spatial movements of the species could be characterised as migrations and that breeding and dispersal migrations occurred.

I tested if spatial variation of Ohio River drainage basin fish assemblages, current habitat, water quality, and hydrology were concordant with historic glaciation boundaries. Assemblage analyses were organized using taxonomic and functional groups. Multivariate analyses, principal components analysis (PCA) and indicator species analyses, were used to test whether taxonomic and functional assemblages were distinct among regions with varying glacial histories. Principal components analysis was used to identify habitat and water quality as well as hydrologic gradients that could be discerned by glacial region. I identified significant differences in both taxonomic and functional fish assemblage structure and habitat variation among regions that had different glaciation histories. Recently glaciated Wisconsinan sites were characterized by assemblages of Cyprinidae and Catostomidae families, with high abundances of tolerant fishes that tended to occur in habitats with reduced current velocity. Sites in the Pre- Wisconsinan region were characterized by Cyprinidae, Catostomidae, Centrarchidae, and Percidae families, with increased abundances of intolerant fishes that tended to occur in habitats with coarser substrates and increased water velocity in streams of varying size. Sites in the unglaciated region were dominated by Cyprinidae and Percidae families but were not closely associated with any habitat-based functional group. Taxonomic and functional analyses explained 25% and 40%, respectively, of the variance in assemblage structure. Mean habitat PCA component scores in the unglaciated and Pre-Wisconsinan sites were significantly different than Wisconsinan sites, which were characterized by increased channel structure and reduced stream size. While a multitude of factors impact the distribution of fishes, these results suggest that historical influences such as glaciation may be used to further explain underlying mechanisms of spatial variation in fish assemblages. / Department of Biology

In response to anthropogenic pressures that have degraded habitat and put marine resources at risk (Leslie et al., 2003; Mumby et al., 2001; Puniwai et al., 2003), there has been a growing interest in the use of marine protected areas (MPAs) as a management tool to help slow, prevent or reverse negative anthropogenic changes. Recent studies have shown that the most effective MPAs are those which represent a full range of habitat types (Leslie et al., 2003; Carr et al., 2003). Yet, available scientific research has not evaluated the near-shore marine habitat utilization along the West Coast of Hawaii at the large-scales utilized by resource managers. Thus, this study focused on identifying the regional habitat utilization patterns for selected Hawaiian reef fish species to determine the most effective combination of habitat types. In addition, the habitat utilization analysis was used as one of several case studies to test the ArcGIS Marine Data Model���s (MDM) (Wright et al., 2001) adaptability to work with real-world data and perform real-world analyses, as well as meet the five goals outlined by the MDM Working Group (Wright et al., 2001). Created in 2001, by researchers from Oregon State University, Duke University, NOAA, the Danish Hydrologic Institute and ESRI, the MDM is a geodatabase template tailored to meet the needs of the marine GIS user community. Ultimately, this analysis will aid marine managers as it establishes correlations between small and large-scale habitat information, which provides a regional look at habitat utilization. Also, by testing the functionality of the MDM, its strengths and weaknesses will be identified so that it can be improved to better serve the marine GIS user community. / Presentation date: 2004-06-08 / Graduation date: 2005

I assessed fish community data collected by the Oklahoma Conservation Commission from 82 minimally impaired wadeable reference streams in eastern Oklahoma to determine whether existing aquatic ecoregions provide the best framework for spatial classification for the development of biological assessment methods and biocriteria. I used indirect ordination and classification to identify groups of sites that support similar fish communities. Although correspondence was observed between fish assemblages and three montane ecoregions, the classification system must be refined and expanded to include major drainage basins and physical habitat attributes for some areas to adequately partition variance in key measures of biological integrity. Results from canonical correspondence analysis indicated that substrate size and habitat type were the primary physical habitat variables that influenced the fish species composition and community structure.

Bibliography : leaves 293-304. / xii, 304 leaves : ill., maps ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Zoology, 1994

Many communities are currently seeking to balance urban water needs with preservation of sensitive fish habitat. As part of that effort, CE-QUAL-W2, a hydrodynamic and temperature model, was developed for Chester Morse Lake and the lower Cedar River, WA. Chester Morse Lake is approximately 10 km long with a maximum depth at full pool of 40 m. The Cedar River model started immediately downstream of the Chester Morse dam and ended 21 km downstream at Landsburg, where drinking water is diverted for the City of Seattle. This water quality model was coupled with a fish habitat and bioenergetics model for bull trout and was calibrated to temperature data between 2005 and 2008. Bull trout fish bioenergetics parameters were provided by the USGS. The CE-QUAL-W2 model was found to be highly accurate in modeling temperature variation in the lake - at most locations having an average absolute mean error of between 0.5 and 0.8 oC. The Cedar River model had an average absolute mean error of 0.7oC. This tool is designed to allow managers and operators to estimate the impact to fish habitat and growth potential from various management decisions including extent of drawdown, timing/volume of flows, and various pumping operations. Future studies could include incorporating further water quality parameters such as nutrients, algae, and zooplankton as they relate to fish productivity.

M.Sc. (Aquatic Health) / Yellowfish and specifically Labeobarbus marequensis are a charismatic species targeted by anglers throughout South Africa. Their population are limited to the north-western parts of the country including the lower reaches of the Crocodile River that flows through the Kruger National Park (KNP). Despite conservation efforts the Crocodile River in the KNP is still highly impacted. The effect of these impacts on the ecosystem is largely unknown. The main aim of the study was to determine the influence of changing water quantity and quality in the Crocodile River on adult L. marequensis. This was achieved by evaluating altered flows (discharge) on the behaviour of adult L. marequensis in the Crocodile River using biotelemetry over a two year period. The influence of altered water quality was assessed using metal bioaccumulation as an indicator of metal exposure in L. marequensis, Clarias gariepinus and Hydrocynus vittatus in the Crocodile and Sabie Rivers during a high and low flow season. Biotelemetry was used on 16 L. marequensis and 12 H. vittatus to determine the habitat use and movement responses of the species. Fish were tagged with Advanced Telemetry Systems (ATS) and Wireless Wildlife (WW) tags and tracked remotely and manually. Home ranges were determined using Arc GIS ®, Habitat uses were analyzed using Windows Excel (© 2011, Microsoft inc.). Environment variables recorded were scored as primary and secondary and then combined with a weighting variable 2:1 ratio (primary variable: secondary variable). A mixed-model analysis of variance (ANOVA) approach with a random co-efficients model and Akaike’s information criteria (AIC) were used to test for significance. Analyses were conducted using SAS version 9 (SAS institute, Cary, NC)...

The ichthyofaunal community structure, population dynamics and movement patterns in the small temporarily open/closed (TOCE) Grant’s Valley estuary, situated along the Eastern Cape coastline, were investigated over the period May 2004 to April 2005. Community structure in the littoral zone was assessed, while growth of selected ichthyofaunal species was investigated using the MULTIFAN model. Population size was assessed using mark recapture models and movement within the estuary using the Hilborn (1990) model. Total ichthyofaunal densities and biomass within the littoral zone ranged between 0.31 to 21.45 fish m⁻² and 0.20 to 4.67 g wwt m⁻², with the highest values typically recorded during the summer. Results of the study indicated that the ichthyofaunal community structure within the estuary was closely linked to the mouth phase and the establishment of a link to the marine environment via overtopping events. In the absence of any link to the sea, the ichthyofaunal community was numerically dominated by estuarine resident species, mainly Gilchristella aestuaria and to a lesser extent, by the river goby, Glossogobius callidus which collectively comprised ca. 88% of all fish sampled. The establishment of the link to the marine environment contributed to an increased contribution of marine breeding species (e.g. Rhabdosargus holubi, Myxus capensis and Atherina breviceps) to the total ichthyofaunal abundances. In contrast, total ichthyofaunal biomass was almost always dominated by marine breeding species by virtue of their larger sizes. Results of hierarchical cluster analyses did not identify any spatial patterns in the ichthyofaunal community within the littoral zone. Results of MULTIFAN analysis indicated estuarine resident fish species bred over an extended period with peaks occurring in the summer months. Conversely, marine breeding fish were shown to recruit into the estuary following overtopping and breaching events. Results of the mark-recapture experiment indicated a population of ca. 12 000 (11 219 – 13 311) individuals greater than 50mm SL. Marine-breeding species (R. holubi, Monodactylus falciformis, and two mullet species) numerically dominated the ichthyofauna, possibly as a result of their effective use of overtopping events. The two mullet species, M. capensis and Liza richardsonii, and the Cape stumpnose, R. holubi moved extensively throughout the estuary, while the remaining species exhibited restricted movement patterns possibly due to the preference for refuge and foraging areas associated with reed beds. The observed movement patterns of individual fish species appeared to be associated with both foraging behaviour and habitat selection.

The spotted grunter (Pomadasys commersonnii) is an important, estuarine-dependent, fishery species in southern Africa. Since estuaries are essential habitats in the life history of this species, the quantification of area use patterns and movements is important for fisheries management. In this study, acoustic telemetry was used to investigate movements, use of habitat and home range dynamics of spotted grunter in the small intermittently open East Kleinemonde Estuary on the Eastern Cape coast of South Africa. Nine spotted grunter (range: 326-489mm TL) were surgically equipped with uniquely coded acoustic transmitters. Positional fixes were obtained by manual tracking tagged individuals on six days and six nights during five tracking sessions from March to November 2004. In addition, five stationary data-logging receivers, moored at specific locations from the mouth to the top of the estuary provided additional long-term monitoring. Kernel home ranges (95% UD) varied in size (26 296-165 321m²) but were all located in a common high use area situated between 300-1 300m from the estuary mouth, which coincided with the highest abundance of prey items. There was no significant variation in home range size [C² (N = 9, df = 4) = 4.18; p = 0.38] between the temporally segregated tracking sessions (over nine months). The persistence of these home range estimates were confirmed by the long-term data-logging receivers. There was no significant diel variation in home range size [F(4, 64) = 0.05, p = 0.99] or core area size [F(4, 64) = 1.40, p = 0.25]. Fish length showed negative, although not significant, relationships between home range size (p = 0.225); number of home range areas (p = 0.065); core area size (p = 0.512) and home range length (p = 0.320). Use of habitat and home range dynamics of spotted grunter in the East Kleinemonde Estuary were consistent over the nine month study period, and they appeared to be influenced more by biotic than abiotic factors. However, when the mouth opened at the end of the study, most tagged fish vacated their home ranges and emigrated to sea.