The bounded-hybrid superiority hypothesis (BHSH) predicts stable hybrid zones are characterized by hybrids having the highest fitness within the zone. The dynamic-equilibrium hypothesis (DEH) predicts hybrids to have the lowest fitness and mating should be strongly assortative in the hybrid zone. I used phenotypic-based hybrid indices (HI) to assess mating patterns, reproductive success, and survival of hybridizing northern flickers (Colaptes auratus) within the hybrid zone at Riske Creek, British Columbia. Contrary to the BHSH, flickers showed significant assortative pairing (P = 0.038) which may result via passive mate choice if yellow and red flickers migrate from allopatric winter ranges. North American band recoveries show red-shafted and yellow-shafted flickers winter on different sides of the Rocky Mountains while red-orange hybrids from Riske Creek winter in the range of red-shafted flickers. Arrival dates of phenotypes did not support the idea that mating patterns are caused passively via different arrival schedules. However, assortative mating patterns did correlate with regional weather patterns along flicker migration routes as well as the North Atlantic Oscillation (NAO) a continental weather pattern that has been shown to influence various aspects of the annual cycle in other birds. If variable weather patterns result in different mating patterns by affecting migration, the geographic location of the northern portion of the zone may be variable due to the migratory behaviour of individuals.<p>There were no differences among yellow, orange and red flickers to win more agonistic contests or have earlier nest initiation dates, larger clutch sizes, greater hatching success, or produce more fledglings. No colour group had a higher likelihood of having a successful compared to a depredated nesting attempt. Aggression was similar between red (N = 21) and yellow flickers (N = 20) during taxidermy model presentations of pure red-shafted and yellow-shafted flickers. Using Akaikes information criterion (AIC) in Program MARK, I determined survival was best modeled as either constant between males and females or varying annually according to weather. Models incorporating HI had less support but suggested that survival is best modeled as a linear relationship where red-shafted flickers have the highest survival. Survival modeled in quadratic relationships found hybrid flickers to have the highest apparent survival estimates in support of the BHSH. Overall there was no support for reduced hybrid fitness, but survival appears to be influenced more by annual variation rather than strictly by an individuals HI. Overall, I failed to find reduced hybrid fitness in support of the DEH but also failed to find increased hybrid fitness as predicted by the BHSH. Annual changes in selection pressure could prevent introgression of hybrid genes throughout the zone if selection favours red-shafted genes in some years and yellow-shafted genes in other years.

The sexes have different life histories that can influence their parental care strategies. I studied northern flicker, Colaptes auratus, parents and simultaneously radio-tracked mates during the nestling and post-fledging periods. I tested hypotheses about sex differences in parental care strategies by examining foraging patterns, provisioning effort and habitat use. Males and females used the same microhabitats, but avoided overlap of their foraging areas on the home range consistent with the hypothesis that mates separate the home range to reduce competition. During temporary (i.e., 24 hr) brood size manipulations, both parents decreased provisioning to reduced broods, but did not increase provisioning to enlarged broods or alter their foraging pattern on the landscape. I suggest flickers were energy limited and were incapable or unwilling to respond to increased brood demands. During the post-fledging period, males spent more time near their fledglings, and cared for their fledglings longer than females (16 days versus 12 days, respectively). Approximately 36% of females abandoned their brood in the post-fledging period and females with high levels of feather corticosterone were more likely to abandon. Older males and those with high provisioning rates in the nestling period fed their fledglings longer. Nearly 45% of fledglings died within the first week after leaving the nest, but survival was higher for fledglings with intermediate body mass and those that occupied areas of dense cover. Families moved a greater distance from the nest during the first 4 days post-fledging when there was less tree cover within 250 m of the nest site. Parents brought fledglings to areas with dense vegetation within the first week post-fledging, but subsequently shifted to open grassland habitats. My results show that parents invest in their offspring indirectly by taking them to habitats that increase survival. This research stresses the importance of studying parental care during the post-fledging period to gain a more complete understanding of the total parental investment of males versus females and how each sex may react differently to trade-offs between investing in the current brood versus self-maintenance.

Dogbane beetle, Chrysochus auratus, was studied for its biological control potential against spreading dogbane, Apocynum androsaemifolium, a native perennial weed in lowbush blueberry (Vaccinium angustifolium). No-choice host range experiments were conducted with common milkweed (Asclepias syriaca), periwinkle (Vinca minor), wild raisin (Viburnum cassenoides), and lowbush blueberry. There was no significant feeding on these plant species by adult dogbane beetles. Significant decreases in foliar dry weight were achieved with 16 beetles per ramet. In Nova Scotia, beetles were present in the field for 8-12 weeks beginning in late June or early July (225-335 growing degree days). Peak beetle abundance occured at 357-577 growing degree days and varied from 4-7 beetles/m2. The fecundity and fertility, timing of pupation, and number of instars were also examined. Females deposited approximately 100 eggs over a 20 day period, with an egg viability of over 90%. Pupae were found on June 1st and June 15th. / A unique project exploring biological control of a native plant species using a native insect species

Worldwide, an increasing demand for fish and fisheries products, together with socioeconomic pressure for industry expansion, is placing considerable pressure on wild fish stocks – more than 80% of which are considered by the Food and Agriculture Organisation of the United Nations (FAO) to be either maximally- or over-exploited. Adding value to the existing catch and/or improving the sustainability of current wild capture methods may offer a means of providing industry growth while negating the need for increased landings. In particular, the peri-mortem condition of a fish plays an integral role in the condition of the tissues post-mortem and hence in product quality, with harvesting techniques that result in stress or fatigue yielding a lower quality product. An understanding of the physiology of the target species and its response to harvest is therefore essential to implementing targeted improvements in harvesting technologies. For species harvested using trawl-based technologies, this includes knowledge of their exercise physiology, in particular their swimming capacity, since this is a key determinant of the interaction between fish and trawl gears, and hence of the nature and severity of stress experienced and of the condition of fish at landing. This thesis describes a series of discrete studies relating to the exercise physiology of juvenile snapper, Pagrus auratus, an iconic New Zealand finfish that comprises important recreational and commercial fisheries. In particular, we sought to characterise the capacity of snapper for sustained swimming activity, including how performance may differ between fish of different size or with environmental temperature; to determine the consequences of exhaustive exercise for both subsequent swimming activity, an important determinant of survival in escaping or discarded catch, and for tissue biochemistry, which ultimately determines product quality in harvested fish; to validate the use of laboratory-based simulations for the study of capture-related stress by comparing the response of laboratory-exercised snapper with commercially caught fish; and to determine the tolerance of snapper to environmental hypoxia, and further, the possible consequences of hypoxia for swimming capacity and for recovery in fish retained for subsequent rested-type harvest. The capacity of snapper for sustained swimming activity was characterised through the use of incremental exercise tests to determine critical swimming speeds, Ucrit. Juvenile snapper (94-107 mm length, 16-157 g mass) demonstrated a strong swimming capacity, with individual fish attaining critical swimming speeds of up to 7.1 body lengths per second (bl s⁻¹). Swimming performance demonstrated an allometric association, with absolute critical speeds increasing with fish size, whilst relative performance favoured smaller fish. The relation was described by the function Ucrit (m s⁻¹) = 0.003412 [length (mm)] + 0.2669. Critical swimming performance also exhibited variation in response to environmental variables. Thermal performance curves were evident in snapper acclimated to 12, 18 and 24 °C, with the suggestion of optimal performance at acclimation temperatures between 18 and 24 °C. Critical swimming performance was also significantly reduced during exposure to ambient oxygen tensions below 80 mmHg; at 40 mmHg, snapper attained only 21% of the critical swimming speeds observed under normoxic (150 mmHg) conditions. In juvenile snapper (~75 g), exhaustive exercise resulted in severe metabolic, acid-base, haematological and hormonal perturbations, the nature of which were similar to those classically demonstrated in other strong-swimming fish species, especially salmonids. These included the depletion of glycogen from within the white muscle (WM) and the concomitant production of lactate, with a resultant lactacidosis of the plasma; recruitment of erythrocytes from the spleen; and the release of cortisol to the plasma. The recovery of these disturbances required 6 hours under laboratory conditions. As the stresses experienced by fish during commercial capture are often considered to be greater than those which can be induced during laboratory-based simulations, it was necessary to investigate whether the magnitude of the perturbations observed in laboratory-exercised snapper were an appropriate model of those of trawl-caught fish. In trawl-caught snapper (1100 g, 38 cm) obtained under commercially-relevant conditions (tow speed ~3.0 knots; duration 2.25-2.75 hours), the magnitude of the perturbations were greater than for laboratory-exercised fish. While the recovery of some metabolites was evident within the first 18 hours post-capture, their recovery was prolonged relative to laboratory-exercised fish; other metabolites, namely muscle glycogen and plasma cortisol, exhibited no signs of recovery. These observations suggest that the response of snapper to exhaustive exercise within the laboratory may underestimate the severity of the response induced by commercial harvest. This is further suggested by post-capture mortality rates of 14%, whereas no mortality was observed following fatigue at Ucrit. Exhaustive exercise also resulted in the impairment of subsequent critical swimming performance. Immediately following fatigue, snapper (85-160 g) were capable of sustained swimming activity at speeds of up to 60-70% Ucrit; however, critical swimming performance was reduced 30%, presumably due to limitations in WM function. There was no suggestion of the recovery of WM function within the first 30 minutes post-fatigue; thereafter, Ucrit was progressively restored, such that snapper were able to repeat their initial swimming performance in a second Ucrit test performed 2 hours after the conclusion of the first. Snapper were moderately tolerant of hypoxia, oxygen-regulating at reduced oxygen tensions (<100 mmHg) by virtue of increased ventilatory rate and stroke volume, with a distinct bradycardia developing at PO₂ below 60 mmHg. Larger snapper appeared to possess a greater hypoxia tolerance than did smaller fish, with Pcrit resolved to 77 in 20 g fish, and 50 mmHg in 150 and 230 g fish. Exposure to moderate hypoxia (60-80 mmHg) during recovery from an exhaustive exercise event constrained MO₂ max to 78% of that of normoxic fish, however did not appear to impede the return of MO₂ to routine levels. The present study is the first to examine in detail the swimming performance of snapper, and the consequences of exhaustive exercise for physiological condition. By understanding the swimming capacities of snapper, it may be possible to refine harvesting practices (i.e. tow speeds) or utilise technologies (i.e. net design) such that the water velocities through the trawl net are within the range at which the fish can swim sustainably, minimising the extent of stress and fatigue experienced by fish, and hence their effects on both quality and survival. The study also demonstrates that whilst snapper experience significant physiological disturbance during commercial harvesting, including significant mortality, some fish demonstrate the potential for metabolic recovery, which may permit their retention in an on-board tank facility for subsequent rested-type harvest. Finally, the present work highlights a number gaps in our understanding of the link between harvesting conditions and fish condition, and makes a number of suggestions for future studies or directions.

Made available in DSpace on 2014-06-11T19:28:21Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-07-08Bitstream added on 2014-06-13T18:57:25Z : No. of bitstreams: 1 kunii_emf_me_botfmvz.pdf: 301873 bytes, checksum: 4b8b58dc7e25c2545e98d937d27b4c8b (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Universidade Estadual Paulista (UNESP) / Com o trabalho, objetivou-se avaliar o desempenho do kinguio (Carassius auratus) em hapas providas com dispensadores automáticos de ração utilizando frequências alimentares de seis, 12 e 24 vezes ao dia e duas taxas de alimentação, 5% e 10% do peso vivo da biomassa, durante 75 dias. As hapas foram instaladas em tanques-rede submersos a um metro de profundidade em um viveiro escavado de 2.000m2. O delineamento experimental foi inteiramente casualizado em esquema fatorial com três frequências alimentares e duas taxas de alimentação. Cada tratamento teve três repetições e os peixes foram alimentados com ração comercial. Foram utilizadas 18 hapas de 0,42m³ onde foram distribuídos 75 peixes com peso médio inicial de 5,26± 1,52 gramas em cada unidade experimental. As frequências alimentares de seis, 12 e 24 vezes ao dia foram semelhantes com a taxa alimentar de 10% (P>0.05). Já com a taxa de 5% o desempenho produtivo foi superior naqueles alimentados de hora em hora em relação aos demais – P<0.05. Como esperado, observou-se maior ganho de peso nos kinguios submetidos à maior taxa de alimentação, apresentando o valor médio de 40,01 gramas, enquanto que na menor taxa o valor foi 32,07g. Em relação à frequência alimentar, os melhores resultados foram obtidos com maior parcelamento da ração. Com o fornecimento de ração de hora em hora o peso médio foi de 38,59g, quando os animais foram alimentados a cada duas horas apresentaram peso médio de 36,89g e quando receberam ração a cada quatro horas o peso médio de 33,75g. A conversão alimentar dos peixes que receberam 5% de seu peso em ração foi de 1,66, sendo que para os peixes que receberam 10% foi de 2,85. As conversões para os animais que foram alimentados a cada quatro horas, a cada duas horas e a cada hora foram 2,01; 2,32 e 2,44, respectivamente... / In the present work the performance of kinguio (Carassius auratus) in hapas with automatic feeder, fed with 5% and 10% level of body weight in frequencies of six, 12 and 24 times a day was studied during 75 days. The hapas of 0.42 m³ was distributed in 18 cages submerged one meter depth in a water reservoir of 2.000m². There were used kinguio with 5.26 ± 1.52g in each experimental unit in a density of 75 fishes/m³. The experimental design used was a completely randomized whit three replicates in outline factorial three frequencies and two level, a commercial ration used. In 10% level the times frequency of six, 12 and 24 times a day were similar (P> 0.05). However the performance was higher with 5% level in those fed hourly over the other - P <0.05. As expected, the higher level of body weight provided greater weight gain in kinguios with the average value of 40.01g, whereas the lowest level the value was 32.07g. The best results were obtained with greater fragmentation of the ration in relation of food frequency. The supply of food in each hour, the average weight was 38.59g, when the animals were fed every two hours the mean weight 36.89g and when fed every four hours the average weight of 33.75g. Fishes that received 5% level of body weight the feed conversion were 1.66, while for the fishes receiving 10% were 2.85. For animals that were fed every four hours every two hours and each hour the feed conversions were 2.01, 2.32 and 2.44, respectively. The increase of frequency of food associated a lower level of body weight improved utilization of the ration resulting in better performance

No description available.

Orientador: Claudio Angelo Agostinho / Banca: Margarida Maria Barros / Banca: Luiz Edivaldo Pezzato / Banca: João Batista Kochenborger Fernandes / Resumo: Com o trabalho, objetivou-se avaliar o desempenho do kinguio (Carassius auratus) em hapas providas com dispensadores automáticos de ração utilizando frequências alimentares de seis, 12 e 24 vezes ao dia e duas taxas de alimentação, 5% e 10% do peso vivo da biomassa, durante 75 dias. As hapas foram instaladas em tanques-rede submersos a um metro de profundidade em um viveiro escavado de 2.000m2. O delineamento experimental foi inteiramente casualizado em esquema fatorial com três frequências alimentares e duas taxas de alimentação. Cada tratamento teve três repetições e os peixes foram alimentados com ração comercial. Foram utilizadas 18 hapas de 0,42m³ onde foram distribuídos 75 peixes com peso médio inicial de 5,26± 1,52 gramas em cada unidade experimental. As frequências alimentares de seis, 12 e 24 vezes ao dia foram semelhantes com a taxa alimentar de 10% (P>0.05). Já com a taxa de 5% o desempenho produtivo foi superior naqueles alimentados de hora em hora em relação aos demais - P<0.05. Como esperado, observou-se maior ganho de peso nos kinguios submetidos à maior taxa de alimentação, apresentando o valor médio de 40,01 gramas, enquanto que na menor taxa o valor foi 32,07g. Em relação à frequência alimentar, os melhores resultados foram obtidos com maior parcelamento da ração. Com o fornecimento de ração de hora em hora o peso médio foi de 38,59g, quando os animais foram alimentados a cada duas horas apresentaram peso médio de 36,89g e quando receberam ração a cada quatro horas o peso médio de 33,75g. A conversão alimentar dos peixes que receberam 5% de seu peso em ração foi de 1,66, sendo que para os peixes que receberam 10% foi de 2,85. As conversões para os animais que foram alimentados a cada quatro horas, a cada duas horas e a cada hora foram 2,01; 2,32 e 2,44, respectivamente... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In the present work the performance of kinguio (Carassius auratus) in hapas with automatic feeder, fed with 5% and 10% level of body weight in frequencies of six, 12 and 24 times a day was studied during 75 days. The hapas of 0.42 m³ was distributed in 18 cages submerged one meter depth in a water reservoir of 2.000m². There were used kinguio with 5.26 ± 1.52g in each experimental unit in a density of 75 fishes/m³. The experimental design used was a completely randomized whit three replicates in outline factorial three frequencies and two level, a commercial ration used. In 10% level the times frequency of six, 12 and 24 times a day were similar (P> 0.05). However the performance was higher with 5% level in those fed hourly over the other - P <0.05. As expected, the higher level of body weight provided greater weight gain in kinguios with the average value of 40.01g, whereas the lowest level the value was 32.07g. The best results were obtained with greater fragmentation of the ration in relation of food frequency. The supply of food in each hour, the average weight was 38.59g, when the animals were fed every two hours the mean weight 36.89g and when fed every four hours the average weight of 33.75g. Fishes that received 5% level of body weight the feed conversion were 1.66, while for the fishes receiving 10% were 2.85. For animals that were fed every four hours every two hours and each hour the feed conversions were 2.01, 2.32 and 2.44, respectively. The increase of frequency of food associated a lower level of body weight improved utilization of the ration resulting in better performance / Mestre

Department of Ecology an Resource Management / MENVSC

"December 2003" / Includes bibliographical references (leaves 203-219) / xviii, 219 leaves : ill. (some col.), maps, plates ; 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, School of Earth and Environmental Sciences, Discipline of Environmental Biology, 2004

Caffeine is one of the most popular psychostimulant drugs worldwide. Its effects are exerted through a variety of complex mechanisms, apparently primarily via interactions with adenosine A1 and A2A receptors. This drug has also been proven to elicit neuroprotective responses in a number of different brain disorders of the Central Nervous System (CNS), as well as provide enhancement of cognitive abilities. Moreover, a biphasic set of functional and structural neurological changes are often found in these receptors among diverse vertebrates. I investigated the effects of chronic caffeine exposure on functional recovery of the dorsal light reflex (DLR) in hemilabyrinthectomized common goldfish, Carassius auratus. In this lesion model the unilateral removal of vestibular organs results in the temporary loss of gravitational regulated postural control, which over time corrects itself by a vestibular compensation (VC) mechanism and can be quantified via the DLR. We compared the functional recovery over 24 post -surgery days in goldfish continuously held in a caffeine solution of 2.5mg/L (n=10), 5.0mg/L (n=10), 10.0mg/L (n=11) or a control 0.0mg/L (n=9). Compared to a sham surgery group (n=11), statistically significant changes in the DLR of all hemilabyrinthectomized goldfish was observed on day 1. The control group recovered over the study period by approaching but not entirely reaching sham surgery DLR. The 2.5mg/L and 5.0mg/L groups initiated postural recovery similar to the controls, but then regressed to a stronger DLR. Beginning on day 10 the caffeine groups deviated from the control and all three experimental caffeine groups were statistically different from the control group on days 15-24. Results suggest early caffeine exposure may be innocuous; however, chronic exposure inhibits the functional recovery process.