Selected aspects of the life history of desert suckers were examined in four southeastern Arizona streams. Diet, age class structure, reproduction, and habitat use were analyzed from field data obtained from April 1987 through October 1988. Adults fed primarily on plant matter, while fry fed almost exclusively on diatoms. Aging of suckers by scales was not possible and length frequencies were too evenly distributed to determine age class structure. In 1988, ovary and teste development occurred from late January through April, with spawning commencing in May. Suckers primarily used pools with high water flow and significant (∼80%) cover formed by tree limbs, branches, leaves, and other debris. Deterioration or loss of suitable habitat is reducing the range of the sucker due to reductions in and manipulations of surface waters.

The spotted grunter, Pomodasys commersonnii, has been identified as a candidate species for mariculture in South Africa due to its high market demand and apparent biological suitability for culture. In common with most other potential mariculture species the spotted grunter has an estuarine juvenile phase. In this respect, the difficulties encountered in determining the optimum environmental requirements of spotted grunter are applicable to the majority of other potential mariculture species. Due the variability of estuarine habitats determination of the optimum environmental requirements of estuarine species under laboratory conditions are a prerequisite to subsequent evaluation of aquaculture potential. Therefore, using the spotted grunter as a representative of a typical potent ial mariculture species, the aim of this study was to contribute to the protocol for evaluating the environmental requirements of potential aquaculture species. The growth of fish is dependent on the relationship between food intake, metabolism and environmental factors. In this relationship, environmental factors do not act on growth per se, but rather act through metabolism on growth. Consequently, the environmental factors affecting the growth of a fish species can be classified into functional categories according to their respective influence on metabolic processes. Five functional categories are recognised, namely: controlling, limiting, masking, directive and lethal factors. In this study, the functional categories were sequenced to develop a theoretical protocol for determining the optimum environmental requirements of potential mariculture species under artificial conditions. It was hypothesised that the correct sequence for experimentally determining the optimum environmental requirements of a species should correspond to theoretical protocol. The hypothesis was tested from the experimental investigation into the individual effects of temperature, salinity, light intensity, photoperiod and food intake on growth performance of juvenile spotted grunter. The investigations quantified the relative effects of controlling, masking, directive and limiting factors on growth performance. The results of the studies were statistically compared to obtain a ranking of the effects of the environmental factors (e.g. temperature, salinity, etc.) on growth performance of juvenile spotted grunter. The statistical ranking facilitated the formulation of a second protocol for sequentially determining the optimum environmental requirements of a species. The second protocol was derived purely from the experimental data. Based on the corroboration between the theoretical protocol and that formulated from the experimental investigations, the hypothesis was accepted. Confirmation of the protocol for examining the effects of controlling, limiting, masking and directive factors provided a basis for the development of a preliminary experimental sequence for determining the optimum environmental requirements of juvenile marine fish. In the development of the experimental sequence, the protocol was interpreted in conjunction with the experimental methods used to determine the effects of environmental factors on the growth of juvenile spotted grunter. The experimental sequence provides a logical frame work within which the optimum environmental requirements of other marine fish species can be determined. In addition, evaluation of growth performance by this method provides a basis for comparison of the mariculture potential between species.

The Deepwater Horizon oil spill in 2010 prompted an enormous survey effort to assess the under-studied, deep-ocean ecosystems of the Gulf of Mexico. The resulting samples and datasets afforded a unique opportunity to study the ecology of a poorly known group of mesopelagic fishes, the barracudinas (Aulopiformes: Paralepididae). Here we address several important data gaps regarding the ecology of the Paralepididae. Our results indicate that a majority of barracudina species are efficient at avoiding research-sized nets, suggesting that their overall abundance has been historically underestimated. Notable differences in vertical distribution, seasonal abundances of sizes classes, and diets were observed among the three major sub-groups of the family, with potential implications to ecosystem-based management of deep-pelagic fisheries. This thesis is dedicated to all the fish, squids, and shrimps that gave their lives to make these data and to those that endured the hardship of the Deepwater Horizon oil spill. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2018. / FAU Electronic Theses and Dissertations Collection

published_or_final_version / Ecology and Biodiversity / Doctoral / Doctor of Philosophy

This work was performed as part of a major research project into the evaluation of the ecology of lake dwelling Brown Trout, Salmo trutta L. using ultrasonic biotelemetry techniques. The supplementary research results. leading up to and after the execution of a program of experiments involving the telemetry of feeding and ventilatory rhythms are described: 1. The presence of red (slow) fibres in the adductor mandibulae muscle of Brown Trout was confirmed to be as previously described in the Rainbow Trout, Sälmo gairdneri Richardson and other salmonids. 2. By electromyographic (EMG) and pharmacological means, the red fibres in the a. mandibulae were shown to be active during ventilation and the mosaic fibres comprising the bulk of the muscle were recruited during more dynamic events such as feeding and coughing. Observations were made on the innervation of the red fibres. 3. Comparative investigations made at sea on large deep sea Squaloid and Galeoid sharks (which have a simple adductor muscle like the Trout) showed an identical functional differentiation as obtained in the Trout. 4. The presence of a migratory 'pace setter potential' was found for the first time in Fish. Its use as an indicator of feeding activity by telemetry was rejected on practical grounds. ýýY NO 5. An ultrasonic transmitter was developed to telemeter an analogue of the adductor mandibulae EMG from wild Brown Trout, using a novel electrode design. Four fish were so equipped and released into Airthrey Loch, University of Stirling and tracked for up to 24 hours (following a 24 hr allowance for post-anaesthetic recovery). Feeding and ventilatory periodicity, linear and angular movement patterns and photoperiod were intercorrelated. Angle of turn and subsequent step length were positively correlated and feeding activity was marked by a preference for dextral turning. 'Area restricted searching' and 'area avoided searching' were the probable causes of the movement patterns seen in this and previous investigations at Airthrey Loch. A depth preference and orientation of the fish to topography was demonstrated. Following analysis of the angle of turn and step length data, it was concluded that the larger transmitter package and more severe surgery materially affected the fishes' behaviour relative to data previously obtained at Airthrey Loch using smaller transmitters. 6. Due to difficulties experienced in 5 above due to an unsuspected effect on the a. mandibulae EMG detectable up to 24 hrs post-anaesthesia, a frequency analysis was made of the a. mandibulae EMG of the Brown Trout and several other species. This disclosed that the EMG from red fibres has a frequency spectrum considerably lower than that of 'standard' mammalian muscle. The progressive failure of the EMG transmitter with time was due to a combination of the anaesthetic effect and the frequency spectrum relative to certain design features. In the light of these observations, subsequent designs of the EMG transmitter were able to take this into account.

Thesis (M.S.)--San Diego State University, 1994. / Includes bibliographical references (leaves 69-75).

Nip Hin Ming. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 132-150). / Abstracts in English and Chinese. / Declaration --- p.i / Abstract --- p.ii / Acknowledgements --- p.vi / Table of Contents --- p.vii / List of Tables --- p.ix / List of Figures --- p.xi / Chapter Chapter 1 --- General introduction --- p.1 / Chapter Chapter 2 --- Fish communities in the shallow soft shores of eastern Hong Kong / Introduction --- p.4 / Materials and methods --- p.7 / Results --- p.11 / Discussion --- p.21 / Chapter Chapter 3 --- Mangroves as fish nurseries: a case study in subtropical southeastern China / Introduction --- p.33 / Materials and methods --- p.37 / Results --- p.41 / Discussion --- p.113 / Conclusion --- p.124 / Chapter Chapter 4 --- General discussion --- p.126 / Chapter Chapter 5 --- General conclusions --- p.131 / References --- p.132

Waldo Lake, located in the Oregon Cascades, is considered to be one of the most dilute lakes in the world. Even with very low nutrient concentrations and sparse populations of zooplankton, introduced fish in the lake are large in size and in good condition when compared to fish from other lakes. Fish were originally stocked in Waldo Lake in the late 1800's. The Oregon Department of Fish and Wildlife began stocking in the late 1930's and continued stocking until 1991. Species existing in Waldo Lake today include brook trout, rainbow trout, and kokanee salmon. The overall objective of this thesis was to increase the understanding of the interrelationships that affect the age, growth, and diet of fish in Waldo Lake. The specific objectives were to summarize and synthesize available information on the substrate, climate, water, and biota of the Waldo Lake Basin; describe the cultural history and current cultural values of the Waldo Lake Basin; determine the age, growth, length, weight, condition, diet, and reproduction of introduced fish species in Waldo Lake; interrelate the above information to show how these components of the natural-cultural system are related. Fish were collected one week per month from early June through mid-October in 1992 and 1993. Variable mesh experimental gillnets set in nearshore areas were used to capture fish in 1992. During the 1993 sampling period, experimental gillnets and trapnets were set in the nearshore areas of the lake. Relative age specific growth rates of brook trout in Waldo Lake are comparable to brook trout growth rates in other lakes. Brook trout growth rates generally decreased with age, however, there were no significant differences in the growth rate of each age class between 1991 and 1993. The condition of brook trout in Waldo Lake is also comparable to brook trout in other lakes. The same is true for rainbow trout and kokanee salmon. Fish in Waldo Lake are large in size and in good condition due, in part, to the availability of benthic macroinvertebrates. Taxa found in stomach contents of fish captured in Waldo Lake consisted primarily of aquatic benthic macroinvertebrates, but terrestrial vertebrates and vertebrates, although infrequently consumed, were also part of the total diet. Rainbow trout in Waldo Lake consumed primarily chironomidae larvae and pupae although odonata larvae, ephemeroptera larvae, and amphipods were also consumed. Kokanee salmon fed almost exclusively on chironomid larvae although small numbers of ephemeroptera larvae, odonata larvae, and coleoptera were also consumed. The most important macroinvertebrate taxon consumed by Waldo Lake brook trout was chironomid larvae and pupae, although other species also were important. The diet of Waldo Lake brook trout varied in a complex way that appeared to be related to the relative abundance of macroinvertebrate taxa, feeding location in the lake, and time of year. Brook trout diet also varied by size class. The components of the Waldo Lake natural-cultural system are complexly interrelated and the nature of these relationships are constantly changing. Each component in some way affects and is, in turn, affected by each of the other components. Changes in some components, such as substrate, affect other components along geologic time scales. Other components, such human culture and biota, may change rapidly within a decade. The capacity of natural-cultural systems, such as Waldo Lake, to change over time makes it possible to view the present state of the system only as a snapshot in time. This dynamic nature of the Waldo Lake natural-cultural system is not unique to Waldo Lake, but is expressed in all natural- cultural systems. / Graduation date: 1997

No description available.

The feeding of the cichlid fish Sarotherodon mossambicus in Lake Sibaya, KwaZulu, was studied in relation to various biotic and abiotic features of the l ake environment from January, 1973 to July, 1975. The primary goal of the study was to determine the cause of stunting and poor condition of adults in this population. Juvenile and adult S. mossambicus feed on a mixture of detritus, bacteria and diatoms that occurs as a flocculent layer on sand substrates throughout the lake. Concentrated gastric acid, commonly at pH values of 1.5 and lower, lyses diatoms and bacteria which are subsequently digested in the intestine. This is the first report of digestion of bacteria by a fish, and the nutritional significance of the finding is discussed. Juveniles feed predominantly on shallow sand terraces found along the margin of much of the lake, while adults usually feed in offshore waters at depths of 3 m and greater. Benthic floc from feeding areas of juveniles and adults have similar concentrations of organic matter, total carbohydrate, soluble carbohydrate and calories, but differ markedly in respect to diatom and protein concentration. Diatom concentrations are generally high in terrace floc but are consistently low in floc from deep water. Protein concentration of benthic floc decreases with increasing depth from 0 - 5 m. Partial correlation analysis shows that protein and diatom concentrations have no correlation independent. of their common relationship to depth, and the evidence implicates detrital bacteria as the primary source of protein in benthic floc. Probable causes of the observed distributions of diatoms and protein are discussed. The protein content of benthic floc profoundly influences its nutritional value. A comparison with available data on animal nutrition shows that the ratio of digestible protein to digestible energy in floc in the shallows is high enough that this food resource would be expected to support good growth, but the ratio for deep water floc is so low that it would be expected to result in conspicuous malnutrition. Thus, inadequate dietary protein is identified as the principal cause of stunting and poor condition of adult S· mossambicus in Lake Sibaya; It is argued that the ratio of digestible protein to digestible calories can be expected to determine the food value of particulate organic matter that includes amorphous detritus in other ecosystems. Despite stunting and poor condition of adults, S. mossambicus are abundant in Lake Sibaya. The precocious breeding of this population is discussed as an adaptation that allows it to maximize reproductive output given the limited resources available to adults. Juvenile S. mossambicus perform daily movements from deep water onto the terraces where they feed and then back into deep water. During periods of relatively low lake level when terrace waters were usually less than 1.5 m deep (1-73 to 1-74), juveniles were present on the terrace throughout daylight hours. At relatively high lake levels (7-74 to 8-75), juveniles were present on the terraces for only about five hours following sunset. Periods of heavy wave action interrupt feeding activity and result in reduced numbers of fish in terrace waters. The possible roles of predator avoidance and temperature in determination of daily feeding behavior are discussed. Daily energy assimilation by juveniles, estimated by a field technique, is approximately 115 cal per g fish dry weight.