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.

The aims of this study were firstly to observe the breeding behaviour and embryo ology. and then to identify factors affecting the reproductive biology of the Australian native pseudomtlgilid Pseudomugil signifer (pacific blue-eye) and the impact upon it of the presence of the exotic species Gambusia holbrooki (eastern gambusia). Six species of the genus Pseudomugil, and the related Scaturiginichthys venneilipinnis, are found on the Australian continent. The normal breeding behaviour, egg surface morphology and embryology of four species of Pseudomugil (P. signijer, P. genrudae, P. tenellus and P. mellis) were first investigated, using aquarium and microscopic (light and S.E.M.) studies. The four species were divided into two groups: P. signifer and P. mellis; and P. tenellus and P. gertrudae. The study provided further evidence for the view that the embryology of the genus Pseudomugil differs markedly from that of members of the family Melanotaeniidae, with which the pseudomugilids have previously been grouped. The seasonal pattern of gonadal function in P. signifer, both in the field and in aquariums, was then investigated for populations of P. signifer from the Sydney region. It was found that P. signifer bred over the spring and summer months, commencing breeding as the temperature and daylength increased, and declining in breeding activity as daylength and temperature declined. There was no substantial difference in the pattern of reproductive activity between wild and captive stocks of P. signifer in the populations used. The impact of the presence of the introduced G. holbrooki on P. signifer was then examined, first in open-air tank experiments , and then in the field. In the tank experiments the exotic species profoundly affected the breeding of the native species. When G. holbrooki were in the tanks P. signifer did not gain weight or grow in total length (except for females given supplementary feed); ovarian weight and fecundity was greatly reduced and the ovaries were morphologically undeveloped. No eggs from P. signifer were observed in tanks which also housed G. holbrooki. G. holbrooki were observed to actively hunt and eat young P. signifer and to nip the caudal fins of adult P. signifer. The results indicate clearly, that at least in a captive situation, the presence of the exotic species has a very deleterious effect on breeding and hence possible survival, of a native population. A pilot study conducted at the same time as the harvest of the second tank study did not reveal such drastic consequences. However, even in the less confined field situation, some evidence of an interrelation between water quality, numbers of P. signifer and numbers of G. holbrooki were seen in one disturbed site (Home bush Bay). These findings suggest that a newly designed field experiment based on data collected from the power analysis of the pilot study could clarify whether G. holbrooki adversely affects P. signifer in the wild. The information gained from these studies can be used in the management of P. signifer in the wild, and serve as a model of the possible effects upon other native species.

The aims of this study were firstly to observe the breeding behaviour and embryo ology. and then to identify factors affecting the reproductive biology of the Australian native pseudomtlgilid Pseudomugil signifer (pacific blue-eye) and the impact upon it of the presence of the exotic species Gambusia holbrooki (eastern gambusia). Six species of the genus Pseudomugil, and the related Scaturiginichthys venneilipinnis, are found on the Australian continent. The normal breeding behaviour, egg surface morphology and embryology of four species of Pseudomugil (P. signijer, P. genrudae, P. tenellus and P. mellis) were first investigated, using aquarium and microscopic (light and S.E.M.) studies. The four species were divided into two groups: P. signifer and P. mellis; and P. tenellus and P. gertrudae. The study provided further evidence for the view that the embryology of the genus Pseudomugil differs markedly from that of members of the family Melanotaeniidae, with which the pseudomugilids have previously been grouped. The seasonal pattern of gonadal function in P. signifer, both in the field and in aquariums, was then investigated for populations of P. signifer from the Sydney region. It was found that P. signifer bred over the spring and summer months, commencing breeding as the temperature and daylength increased, and declining in breeding activity as daylength and temperature declined. There was no substantial difference in the pattern of reproductive activity between wild and captive stocks of P. signifer in the populations used. The impact of the presence of the introduced G. holbrooki on P. signifer was then examined, first in open-air tank experiments , and then in the field. In the tank experiments the exotic species profoundly affected the breeding of the native species. When G. holbrooki were in the tanks P. signifer did not gain weight or grow in total length (except for females given supplementary feed); ovarian weight and fecundity was greatly reduced and the ovaries were morphologically undeveloped. No eggs from P. signifer were observed in tanks which also housed G. holbrooki. G. holbrooki were observed to actively hunt and eat young P. signifer and to nip the caudal fins of adult P. signifer. The results indicate clearly, that at least in a captive situation, the presence of the exotic species has a very deleterious effect on breeding and hence possible survival, of a native population. A pilot study conducted at the same time as the harvest of the second tank study did not reveal such drastic consequences. However, even in the less confined field situation, some evidence of an interrelation between water quality, numbers of P. signifer and numbers of G. holbrooki were seen in one disturbed site (Home bush Bay). These findings suggest that a newly designed field experiment based on data collected from the power analysis of the pilot study could clarify whether G. holbrooki adversely affects P. signifer in the wild. The information gained from these studies can be used in the management of P. signifer in the wild, and serve as a model of the possible effects upon other native species.

The aims of this study were firstly to observe the breeding behaviour and embryo ology. and then to identify factors affecting the reproductive biology of the Australian native pseudomtlgilid Pseudomugil signifer (pacific blue-eye) and the impact upon it of the presence of the exotic species Gambusia holbrooki (eastern gambusia). Six species of the genus Pseudomugil, and the related Scaturiginichthys venneilipinnis, are found on the Australian continent. The normal breeding behaviour, egg surface morphology and embryology of four species of Pseudomugil (P. signijer, P. genrudae, P. tenellus and P. mellis) were first investigated, using aquarium and microscopic (light and S.E.M.) studies. The four species were divided into two groups: P. signifer and P. mellis; and P. tenellus and P. gertrudae. The study provided further evidence for the view that the embryology of the genus Pseudomugil differs markedly from that of members of the family Melanotaeniidae, with which the pseudomugilids have previously been grouped. The seasonal pattern of gonadal function in P. signifer, both in the field and in aquariums, was then investigated for populations of P. signifer from the Sydney region. It was found that P. signifer bred over the spring and summer months, commencing breeding as the temperature and daylength increased, and declining in breeding activity as daylength and temperature declined. There was no substantial difference in the pattern of reproductive activity between wild and captive stocks of P. signifer in the populations used. The impact of the presence of the introduced G. holbrooki on P. signifer was then examined, first in open-air tank experiments , and then in the field. In the tank experiments the exotic species profoundly affected the breeding of the native species. When G. holbrooki were in the tanks P. signifer did not gain weight or grow in total length (except for females given supplementary feed); ovarian weight and fecundity was greatly reduced and the ovaries were morphologically undeveloped. No eggs from P. signifer were observed in tanks which also housed G. holbrooki. G. holbrooki were observed to actively hunt and eat young P. signifer and to nip the caudal fins of adult P. signifer. The results indicate clearly, that at least in a captive situation, the presence of the exotic species has a very deleterious effect on breeding and hence possible survival, of a native population. A pilot study conducted at the same time as the harvest of the second tank study did not reveal such drastic consequences. However, even in the less confined field situation, some evidence of an interrelation between water quality, numbers of P. signifer and numbers of G. holbrooki were seen in one disturbed site (Home bush Bay). These findings suggest that a newly designed field experiment based on data collected from the power analysis of the pilot study could clarify whether G. holbrooki adversely affects P. signifer in the wild. The information gained from these studies can be used in the management of P. signifer in the wild, and serve as a model of the possible effects upon other native species.

Thesis (M.S.)--Oregon State College, 1952. / Typescript. Includes bibliographical references (leaves 120-121). Also available online.

Thesis (Honors)--Liberty University Honors Program, 2007. / Includes bibliographical references. Also available through Liberty University's Digital Commons.

Thesis (M. Sc.)--Memorial University of Newfoundland, 1997. / Bibliography: leaves 114-125.

Thesis (M. Med. Sc.)--University of Hong Kong, 2005.

D.Sc. (Zoology) / Please refer to full text to view abstract

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