The corvina reina (Cynoscion albus) is an important part of the artisanal fishery in the Gulf of Nicoya, Costa Rica. Stock assessment on this sciaenid species has been restricted to the use of length-based methods because of the lack of age data. Direct age determination methodologies for tropical species often encounter serious difficulties such as poorly defined hyaline and opaque zones and lack of adequate techniques of ageing. This thesis presents the results of an age-determination study of Cynoscion albus based on otolith surface readings and microincrement analysis. Age estimates were obtained from counts of hyaline zones from surface readings using the light microscope and from microincrement readings from cross sections of the otolith using the scanning electron microscope. Validation of age estimates from surface readings was based on a linear regression of the age estimates from surface readings on age estimates from integrated daily increment readings. Growth of the otolith was studied using linear and multivariate regression methods and the results were used to construct multivariate models for prediction of age. Consistent estimates of age and fish growth parameters were obtained from surface and microincrement analysis. This study showed that Cynoscion albus is a slow-growing fish (K = 0.121) and reaches a large size (L∞ = 127.5 cm) and therefore is likely to suffer overfishing in the Gulf of Nicoya fishery. / Graduation date: 1993

During the 1960´s and 1970´s the number of grey seals in the Baltic Sea was decreasing rapidly, mostly due to hunting and toxic substances like DDT and PCB. When hunting became less intense and toxic substances decreased in the environment the grey seal population started to increase. Today grey seals are found common in the Baltic Sea and have started to become a big treat and a problem to the fishing industry. The grey seal destroys and enters fishing traps and consumes large quantities of the fish that have been caught. The knowledge of the grey seal, like abundance and food preferences, is today limited. It is also important to define the position of the grey seal in the ecosystem in the Baltic Sea and to be able to predict changes that could occur if the population would rapidly decrease or increase. This project was therefore started in an attempt to increase the knowledge about the grey seals food preferences. The study was made in tree separate parts. Part one contained analyses of prey remains from stomachs and digestive tract from fourteen individuals put down in two geographically separate areas. The collected material from the seal digestive tract was cleaned and otoliths (hearing stones from fish), scales and back vertebra from fish eaten by the grey seal were sorted out. With the help of hard parts collected from the intestines the food preferences of the seals could be estimated. Eight different species of prey was found. The species were herring (Clupea harengus membras), sprat (Sprattus sprattus), common whitefish (Coregonus spp), perch (Perca fluviatilis), salmon (Salmo salar), trout (Salmo trutta) and roach (Rutilus rutilus). In two of the digestive tracts several individuals of the isopod Saduria entomon were found. No earlier studies describe the isopod as a food source for the grey seals in the Baltic Sea. The findings are therefore unique information. The results showed that during summer the main part of the grey seal diet in the gulf of Sundsvall and in the surrounding coastal area of Hårte was herring and sprat. No significant difference in food preferences was shown between the investigated seals from the gulf of Sundsvall and seals from the surrounding coastal area of Hårte. The second part was made to investigate if it was possible to build a floating platform that would work as a resting place for the grey seal. The surface of the platform was covered by a layer that keeps the seal scats on the platform so that it could be collected. Otoliths from herring and common whitefish were found on the floating platform. Because the platform could not be under surveillance during the whole study some uncertainties about whether the otoliths found came from grey seal or from resting cormorants or other fish eating birds. However, the otolit size is linearly related to the fish size and this relationship can be used to track the predator. Otoliths from herring taken by grey seals and otoliths found on the platform were significantly bigger than the otoliths originating from the prey of cormorants. The results indicated that the common whitefish size was too big for a full grown cormorant bird to consume. The common whitefish size showed that it probably not had been cormorants that had deposited the otoliths on the platform. The platform method was concluded promising but it needs to be modified in order to work more effective in the future. In the third part scats were collected from the area of Österåsen to increase the amount of information about the grey seals food preferences. The knowledge of the grey seals diet in the Baltic Sea is today limited and few similar study’s have earlier been made. The collected scats and otoliths in this project are therefore unique. 2008:Bi 2

Thesis (M.S.)--Missouri State University, 2009. / "May 2009." Includes bibliographical references (leaves 35-37). Also available online.

Although mammals are the most commonly utilized laboratory animal, laboratory animal medicine continually seeks to replace them with animals of lower phylogenic classification. Fish are becoming increasingly important as investigators seek alternative animal models for research. Fish can provide an economical and feasible alternative to typical mammalian models; moreover, many fish, which have comparatively short life spans, can easily reproduce in the laboratory. One key area of animal health research in which fish have been underutilized is the field of advanced imaging. Although many images of fish have been captured through the use of computed tomography (CT), radiography, and ultrasonography, these images have been primarily utilized for anatomical study. In addition, fish have never before been studied with positron emission tomography/ computed tomography (PET/CT). My objectives were to determine if these imaging techniques can be used to obtain physiological information from fish, therefore making it more likely that fish can be utilized as replacement animals using these new imaging techniques (CT, PET/CT). I performed two different types of studies to assess the potential application of advanced imaging techniques to fish. In the first experiment, microCT was used to characterize otolith deformity in vitamin C deficient captive-raised red drum and relate the deformity to behavioral and physiological changes. I found that the normal and abnormal fish had statistically significant differences in behavior, cortisol levels, and otolith volume and density. MicroCT assessment of abnormal fish revealed operculum abnormalities, malocclusions, and several types of otolith malformations. Therefore, the affected fish had not only an abnormal skeletal appearance but also significantly abnormal behavior and cortisol responses. In the second experiment, fluorodeoxyglucose-positron emission tomography/ computed tomography (FDG-PET/CT) was used to quantify glucose uptake in select organs prior to carcinogenesis studies in fish. The quantified glucose uptake was compared to published data on humans, mice, and dogs. Rapid, quantifiable glucose uptake was demonstrated, particularly in brain, kidneys, and liver in all imaged fish species. Glucose uptake in the major organ systems of fish was closer to that in humans than uptake in mice or dogs, indicating that fish may serve as an effective alternative animal model for tumor studies using this technology. Other applications for this technique in fish may include metabolism studies and screening for environmental carcinogenesis. I found that both microCT and PET/CT imaging provided useful and meaningful results. In addition, the use of non-invasive scanning allows for re-use of fish, thus reducing the number of animal models used in experiments. These experiments suggest that fish will be good replacement models for mammals using these advanced imaging techniques.

Estuarine residence and growth of juvenile chum salmon (Oncorhynchus keta) from Netarts Bay, Oregon were estimated from daily-formed growth increments of sagittal otoliths which are distinguishable from accretion patterns formed during freshwater residence. Estuarine residence time was inversely related to the average size at which juvenile chum salmon entered Netarts Bay. Among fin-clipped, hatchery fish, large individuals disappeared from Netarts Bay more rapidly than smaller members of the same release group during the first 9 days of estuarine residence. This selective removal was not evident among creek-reared chum which were smaller than the fin-clipped fish. Size-related emigration explains this variation in residence time. Growth rates were estimated from back-calculations of fork length from otoliths. The growth rates of juvenile chum salmon in Netarts Bay (0.6 mm FL/d; 3.5% bw/d) were lower than growth rates in other estuaries where harpacticoid copepods were a major prey item. Juvenile chum salmon that entered the estuary early in the spring grew faster than those which entered later in the year, possibly because of lower water temperature and lower density of small (50 mm FL) chum during the early period. High water temperature reduced apparent growth rates by slowing growth and causing emigration of larger, faster-growing individuals. / Graduation date: 1990

Thesis (Ph. D.)--Montana State University--Bozeman, 2004. / Title from PDF t.p. (viewed on June 12, 2006). Chairperson, Graduate Committee: Thomas McMahon. Includes bibliographical references.

<p>During the 1960´s and 1970´s the number of grey seals in the Baltic Sea was decreasing rapidly, mostly due to hunting and toxic substances like DDT and PCB. When hunting became less intense and toxic substances decreased in the environment the grey seal population started to increase. Today grey seals are found common in the Baltic Sea and have started to become a big treat and a problem to the fishing industry. The grey seal destroys and enters fishing traps and consumes large quantities of the fish that have been caught.</p><p>The knowledge of the grey seal, like abundance and food preferences, is today limited. It is also important to define the position of the grey seal in the ecosystem in the Baltic Sea and to be able to predict changes that could occur if the population would rapidly decrease or increase. This project was therefore started in an attempt to increase the knowledge about the grey seals food preferences. The study was made in tree separate parts. Part one contained analyses of prey remains from stomachs and digestive tract from fourteen individuals put down in two geographically separate areas. The collected material from the seal digestive tract was cleaned and otoliths (hearing stones from fish), scales and back vertebra from fish eaten by the grey seal were sorted out. With the help of hard parts collected from the intestines the food preferences of the seals could be estimated. Eight different species of prey was found. The species were herring (Clupea harengus membras), sprat (Sprattus sprattus), common whitefish (Coregonus spp), perch (Perca fluviatilis), salmon (Salmo salar), trout (Salmo trutta) and roach (Rutilus rutilus). In two of the digestive tracts several individuals of the isopod Saduria entomon were found. No earlier studies describe the isopod as a food source for the grey seals in the Baltic Sea. The findings are therefore unique information. The results showed that during summer the main part of the grey seal diet in the gulf of Sundsvall and in the surrounding coastal area of Hårte was herring and sprat. No significant difference in food preferences was shown between the investigated seals from the gulf of Sundsvall and seals from the surrounding coastal area of Hårte.</p><p>The second part was made to investigate if it was possible to build a floating platform that would work as a resting place for the grey seal. The surface of the platform was covered by a layer that keeps the seal scats on the platform so that it could be collected. Otoliths from herring and common whitefish were found on the floating platform. Because the platform could not be under surveillance during the whole study some uncertainties about whether the otoliths found came from grey seal or from resting cormorants or other fish eating birds. However, the otolit size is linearly related to the fish size and this relationship can be used to track the predator. Otoliths from herring taken by grey seals and otoliths found on the platform were significantly bigger than the otoliths originating from the prey of cormorants. The results indicated that the common whitefish size was too big for a full grown cormorant bird to consume. The common whitefish size showed that it probably not had been cormorants that had deposited the otoliths on the platform. The platform method was concluded promising but it needs to be modified in order to work more effective in the future.</p><p>In the third part scats were collected from the area of Österåsen to increase the amount of information about the grey seals food preferences.</p><p>The knowledge of the grey seals diet in the Baltic Sea is today limited and few similar study’s have earlier been made. The collected scats and otoliths in this project are therefore unique.</p><p>2008:Bi 2</p>

Dissertação(mestrado) - Universidade Federal do Rio Grande, Programa de Pós-Graduação em Oceanografia Biológica, Instituto de Oceanografia, 2011. / Submitted by Cristiane Gomides (cristiane_gomides@hotmail.com) on 2013-10-14T11:15:53Z No. of bitstreams: 1 Luis.pdf: 935570 bytes, checksum: 7d5daa83c8296317d26a8027f9980e53 (MD5) / Approved for entry into archive by Sabrina Andrade (sabrinabeatriz@ibest.com.br) on 2013-10-17T02:53:42Z (GMT) No. of bitstreams: 1 Luis.pdf: 935570 bytes, checksum: 7d5daa83c8296317d26a8027f9980e53 (MD5) / Made available in DSpace on 2013-10-17T02:53:42Z (GMT). No. of bitstreams: 1 Luis.pdf: 935570 bytes, checksum: 7d5daa83c8296317d26a8027f9980e53 (MD5) Previous issue date: 2011 / O cienídeo demersal costeiro Macrodon atricauda (Günther, 1880), anteriormente M. ancylodon (Bloch & Schneider, 1801) foi amostrado para determinação de idades em quatro períodos (1976-79, 1884-86, 1995-97 e 2006-09) a partir da pesca comercial e de cruzeiros científicos ao longo do Sul do Brazil (Lat. 30°S e 34°40’S). A análise de incrementos marginais em seções finas de otólitos validou a determinação de idades e mostrou que bandas opacas e translúcidas são depositadas em todas as idades a cada primavera-verão e outono-inverno, respectivamente. A determinação de idades em M. atricauda em seções de otólitos é altamente recomendável, pois comparações com leituras feitas em otólitos inteiros mostraram que as últimas superestimaram as idades em um ou mais anos em 56,5% dos espécimes que tiveram suas idades determinadas. O crescimento de M. atricauda aumentou nas últimas quatro décadas, mais notavelmente em machos adultos acima de 2 anos e fêmeas adultas acima de 3 anos. Um decréscimo de três vezes na sua densidade e da comunidade de peixes demersais como um todo é a causa mais provável do aumento no crescimento. / The coastal demersal sciaenid Macrodon atricauda (Günther, 1880), formerly M. ancylodon (Bloch and Shneider, 1801) was sampled for ageing in four periods (1976-79, 1984-86, 1995-97 and 2006-09) from commercial fishing and scientific surveys along Southern Brazil (Lat. 30°S to 34°40’S). Maximum observed age was seven but no fish older than five years was sampled in the last period. Marginal increment analysis on thin sections validated ageing and showed that opaque and translucent bands were laid down at all ages in spring-summer and autumn-winter, respectively. Ageing M. atricauda on sectioned otoliths is highly recommended because comparisons with readings on whole otoliths showed that the last overestimated in one or more years in 56.5% of the aged specimens. The growth of M. atricauda increased in the last four decades, most noticeably for adult males over 2 years old and females over 3 years old. A three fold decrease in its density and the demersal fish community as a whole are the likely cause of the growth increase.

Many marine fishes use the mangrove ecosystem for foraging, protection, spawning, and as a nursery habitat. To develop a better understanding of energy flow between the coastal mangrove and coral reef ecosystems, the ontogentic migration and trophic connectivity of reef fishes were examined through the use of carbon (C), nitrogen (N), and oxygen (O) stable isotope ratios. Juvenile and adult gray snapper Lutjanus griseus, lane snapper L. synagris, bluestriped grunt Haemulon sciurus, French grunt H. flavolineatum, sailor’s choice H. parra, yellowfin mojarra Gerres cinereus, and great barracuda Sphyraena barracuda were collected from both mangrove and coral reef sites located near Port Everglades, Broward County, Florida. All species were analyzed for δ13C and δ15N of muscle tissues and δ 18O and δ 13C of otoliths to evaluate ontogenetic migrations, foraging, and occupation within both the mangrove and reef sites. The δ13C and δ15N in muscle tissue were more depleted in juvenile fish from the mangroves than their adult forms caught on the adjacent reef. The δ18O and δ13C otolith data were significantly different between species, age class, and habitat, with lower δ18O values for juvenile fish caught in the mangroves. A general trend of increasing δ13C in otoliths corresponded to increasing total length, also suggesting juvenile movements from mangrove to nearshore reefs with age. Overall, the findings of this study further confirm that several commercially and recreationally important reef-associated fishes utilize mangrove ecosystems during juvenile life stages.

La gravité terrestre est une contrainte mécanique fondamentale exercée sur les organismes vivants et contre laquelle nous avons adapté nos stratégies de posture et de locomotion ainsi que toutes les régulations métaboliques et cardiovasculaires. Outre le stimulus mécanique direct, la gravité est mesurée par l'organe vestibulaire, premier système sensoriel à émerger chez les protochordés il y a environ 500 millions d'années, aussi précocement que le système visuel. Le système vestibulaire a alors été asservi aux fonctions d'équilibre et de stabilisation du regard, par des réflexes posturaux et oculaires, fonctions récemment enrichies d’un rôle clé dans la cognition spatiale et sociale chez l’adulte. Ses capacités d’encodage des mouvements de la tête, des accélérations du corps et de la gravité terrestre font de ce système un acteur majeur dans la perception de la verticalité, la navigation, l’orientation et la mémorisation spatiale. Nous avons émis l'hypothèse que la perception sensorielle vestibulaire de la gravité via les otolithes pourrait jouer un rôle crucial non seulement chez l’adulte mais également dans les premières étapes du développement des fonctions sensorimotrices et cognitives. Pour la première fois, nous avons étudié un modèle de souris original (souris Head-tilt, B6Ei.GL-Nox3Het / J) présentant une absence congénitale sélective de gravisenseurs vestibulaires. Les souris présentaient un retard dans l'acquisition des réflexes sensorimoteurs, des capacités d’orientation spatiale par guidage olfactif, d'une communication mère-petits par ultrasons alors que les soins maternels étaient normaux. Un retard dans la locomotion et des troubles hyperactifs avec stéréotypies ont également été montré. Nous démontrons ainsi que le développement des individus sur Terre possède une période critique dépendante de la perception sensorielle vestibulaire de la gravité, au moins entre les jours post-nataux 6 à 10 chez les rongeurs. Les informations otolithiques jouent également un rôle clé chez l’adulte dans les fonctions motrices, les processus mnésiques spatiaux et non spatiaux et dans la régulation émotionnelle. Une corrélation entre ces troubles et le retard développemental a été mis en évidence. Nous travaillons actuellement sur les effets de stimulations sensorielles précoces sur le développement et les fonctions adultes chez la souris Het ainsi que sur la caractérisation structurale et fonctionnelle au niveau cérébral des atteintes développementales et comportementales observées. Les observations chez les souris Het corroborent les symptômes rapportés chez les enfants vestibulo-déficients, soutenant le besoin d'un meilleur dépistage des maladies vestibulaires pendant l'enfance. De manière intéressante, les symptômes de ces souris correspondent à ceux présentés par des modèles murins validés d'autisme et réactualiseraient l’importance de la graviception vestibulaire dans la physiopathologie et la thérapie des troubles du spectre autistique (TSA) et autres maladies neurodégénératives au cours du développement. / Earth’s gravity is a fundamental mechanical constraint for living organisms against which we have adapted our strategies of posture and locomotion as well as all metabolic and cardiovascular regulations. Beyond the mechanical stimulus, the vestibular organ is the first sensory system to emerge in protochordates about 500 million years ago, as early as the visual system, encoding the gravity strength into the brain. The vestibular system has since then been devoted to balance and gaze stabilization supported by postural and ocular reflexes, recently fortified with a key role in spatial and social cognition in adults. Its encoding abilities of head movements, body accelerations and Earth's gravity make this system a major player in the perception of verticality, navigation, orientation and spatial memorization. We have hypothesized that vestibular sensory perception of gravity might play a crucial role not only in adults, but also during the first stages of development in both sensorimotor and cognitive functions. For the first time, we have investigated an original mouse model (Head-Tilt mice, B6Ei.GL-Nox3Het/J) with selective congenital absence of vestibular gravisensors. Our data highlights that mouse pups suffered from a delay in the acquisition of sensorimotor reflexes, spatial olfactive guidance, path integration and ultrasonic communication while maternal care remained normal. In addition, a delay in locomotor development and the appearance of were observed during the late stage of development. We demonstrate that development on Earth has a critical period dependent on the vestibular sensory perception of gravity, at least between postnatal days 6 to 10 in rodents. We have shown that otolithic information plays a key role in the adult motor functions, spatial and non-spatial memory processes, reference frames choice but also in emotional regulation. These disorders have been correlated with early developmental delay. We are currently working on the effects of early sensory stimulation on development and adult functions in our Het mouse model as well as on the structural and functional characterization at the cerebral level of observed developmental and behavioral impairments. Observations in Het mice corroborate with symptoms reported in vestibulo-deficient children, supporting the need for better screening of vestibular diseases during childhood. Remarkably, the symptoms of our vestibulo-congenital deficient mice investigated here matched with the profile of validated mouse models of autism and re-update the significance of vestibular graviception in the physiopathology and therapy of autism spectrum disorders during its development.