Knowledge of fish habitat use and connectivity is critical for understanding the structure and dynamics of fish populations and, therefore, necessary for the implementation of successful fisheries management strategies. Tagging is an effective means of providing such information, and the elemental composition contained within fish otoliths is increasingly being used as a natural tag. The chemical composition of otoliths reflects the incorporation of elements from different water bodies and can thus be used to understand the habitat use, movements, and life history patterns of fishes. To assess the applicability of otolith elemental composition as a tagging technique within the Tampa Bay estuary, Florida, laser ablation-inductively coupled-plasma mass spectrometry (LA-ICP-MS) was used to analyze the elemental composition of otoliths from two estuarine-dependent fish species, Snook (Centropomus undecimalis) and Red Drum (Sciaenops ocellatus). Otolith elemental fingerprints can be used to quantify the proportion of juveniles from different nurseries that survive to join the sub-adult and adult fisheries, thus, providing resource managers with quantitative criteria to prioritize the most productive areas for conservation and restoration. To evaluate the use of otolith elemental fingerprinting in the Tampa Bay estuary, the spatial and temporal scales of chemical variation in otoliths collected from throughout Tampa Bay were examined by performing permutation-based multivariate analyses of variance (MANOVA) on the elemental data at several spatial (individual tributary, two-region, and three-region) and temporal (annual and seasonal) scales. Canonical Analysis of Principal Coordinates (CAP) was used to generate classifiers based on the otolith elemental fingerprints of juvenile fish, and `leave-one-out' cross-validation procedures indicated that the greatest classification accuracy was obtained by using the two-region model (upper vs. lower Tampa Bay) for both species (for Snook F=45.8, p=0.001, CAP cross-validation success=76%; for Red Drum F=9.7, p=0.001, CAP cross-validation success=87%). For both species, all temporal analyses at the inter-annual scale indicated that otolith elemental fingerprints were significantly different across years (two-way MANOVA; p Several environmental factors which may have contributed to the regional differences in otolith chemistry were examined, including physico-chemical parameters (surface measurements of salinity, dissolved oxygen, pH, and temperature taken at the time of sample collection), surficial geologic stratigraphy, and land development. Weak, but significant correlations were identified between some elements and physico-chemical parameters; however, instantaneous measurements taken at the time of fish collection may not have provided an accurate representation of the overall conditions experienced by the fish during the period in which the otolith material used in analyses had been deposited (2 - 4 weeks). A significant correlation between latitude and otolith Sr/Ca was found, likely corresponding to an increasing ambient gradient that occurs from the upper to lower bay (for Red Drum F=77.1, p=0.001; for Snook F=69.2, p=0.001). The Land Development Intensity metric was negatively correlated with otolith Li/Ca and Sr/Ca. While surficial geologic inputs may have also contributed to the elemental composition of otoliths, the relationships revealed by redundancy analyses (RDA) were somewhat unclear or contradictory. Once the appropriate chemical characterization of the study area was identified (the two-region models for both species), elemental fingerprints from the core portions of sub-adult and adult otoliths were assigned to their most probable juvenile habitat region using a maximum likelihood estimator based on the posterior probabilities generated by CAP analyses (CAP-MLE). Application of the two-region model revealed that the majority of Red Drum (83%) was determined to have originated from juvenile habitats in the upper Tampa Bay region, while most Snook (60%) originated from juvenile habitats in the lower Tampa Bay region. The majority of sub-adult/adult Snook and Red Drum were collected from the same region in which they were determined to have originated (for Snook, 36 out of 55 = 65%; for Red Drum, 58 out of 78 = 74%), indicating some level of site fidelity to juvenile habitat areas. The use of otolith elemental profiling to reconstruct specific environmental and physiological experiences has the potential to provide unique insights regarding the life histories of Snook, a species with unpredictable spawning and movement characteristics. Otoliths from Snook maintained in captivity at the Mote Aquaculture Park (MAP) were analyzed to elucidate the degree to which various factors, including otolith growth (macrostructure features), spawning events, handling stress, and salinity influence otolith chemistry. Cross-correlation analyses of otolith elemental profiles and quantified macrostructure features (including annuli and checks) demonstrated that interpretations of elemental patterns should not be confounded by changes associated with otolith crystallography. An elemental marker for known spawning events was not identified (ANOVA spawners vs. non-spawners, p>0.05); however, because the physiological costs and alterations in blood chemistry associated with gonadal maturation (rather than the singular act of spawning) could affect otolith chemistry, additional studies which more thoroughly track maturation stages may be able to identify a suite of elements that can be used to discern the reproductive histories of Snook. Significantly elevated Zn:Ca (ANOVA: F=5.64, p=0.012) and decreased Fe:Ca (ANOVA: F=25.02, p Continuous life history Ba:Ca and Sr:Ca profiles of 56 wild Snook collected from throughout Tampa Bay revealed significant plasticity in the types of juvenile habitats settled, as well as in the timing of ontogenetic movements from these habitats. Of the profiles examined, 55% exhibited otolith core signatures characterized by an opposing Sr:Ca and Ba:Ca pattern, followed by an inverted pattern, providing an indicator of the movement of larvae from high salinity, pre-settlement environments into mesohaline, tidally-influenced juvenile habitats. In contrast, nearly half (45%) the Sr:Ca and Ba:Ca profiles indicated settlement in higher salinity environments, suggesting a high degree of habitat plasticity for juveniles of this species. For fish that settled into mesohaline habitats, decreases in Ba:Ca and/or increases in Sr:Ca over the first several years of life signaled the ontogenetic transition out of the juvenile habitat, with the timing of emergence ranging from within the first year to age-3. Because conditions during early life may propagate into divergent behaviors in subsequent life stages, information on the experiences of early life and juvenile stages could help to inform whether the occupation of different juvenile habitat types, or the precocious or delayed emergence from those habitats, explain the peculiar spawning and movement habits that occur in this species.

Increased knowledge of stock mixing and migration patterns of Atlantic bluefin tuna (Thunnus thynnus) is required to appropriately manage and conserve declining populations. The nursery origin of giant bluefin tuna present in the Gulf of St. Lawrence was identified using stable carbon (δ13C) and oxygen (δ18O) isotopes in sagittal otoliths. Anthropogenic and natural processes are capable of impacting atmospheric and oceanic concentrations of δ13C and δ18O, affecting otolith concentrations. Therefore, inter-decadal variation of δ13C and δ18O in the otolith cores (corresponding to the first year of life) of bluefin tuna was examined prior to stock predictions and temporal variability was detected in both isotope ratios. Significant changes in both δ13C and δ18O were recorded in the otolith cores of individuals with birthdates between 1947 and 2003. Both δ13C and δ18O varied significantly as a function of year of birth, with δ13C decreasing and δ18O increasing over the time period investigated (-2.39×10-2 and 5.78×10-3 per year, respectively). The rate of change in otolith δ13C was nearly identical to the reported rates of atmospheric δ13C depletion, recently attributed to the burning of fossil fuels (referred to as the Suess effect). Observed shifts in otolith δ18O were less pronounced and likely linked to changing physicochemical conditions (i.e. salinity) in oceanic reservoirs over the time period investigated. The results show that otolith cores of bluefin tuna effectively track inter-decadal trends and record past oceanic δ13C and δ18O levels. After adjusting for inter-decadal trends, the isotopic composition of milled otolith cores of giants from three decades (1970s, 1980s, 2000s) and three regions were compared to otolith δ13C and δ18O values of yearling bluefin tuna collected from eastern and western nurseries. Maximum likelihood estimates indicated that 99% of bluefin tuna caught in the Gulf of St. Lawrence fishery originated from the western nursery, with no significant differences among the decades and regions examined. Results suggest that little to no mixing of eastern and western populations of adult bluefin tuna occurs in the Gulf of St. Lawrence, making it important for the management and conservation of the declining western population.

Increased knowledge of stock mixing and migration patterns of Atlantic bluefin tuna (Thunnus thynnus) is required to appropriately manage and conserve declining populations. The nursery origin of giant bluefin tuna present in the Gulf of St. Lawrence was identified using stable carbon (δ13C) and oxygen (δ18O) isotopes in sagittal otoliths. Anthropogenic and natural processes are capable of impacting atmospheric and oceanic concentrations of δ13C and δ18O, affecting otolith concentrations. Therefore, inter-decadal variation of δ13C and δ18O in the otolith cores (corresponding to the first year of life) of bluefin tuna was examined prior to stock predictions and temporal variability was detected in both isotope ratios. Significant changes in both δ13C and δ18O were recorded in the otolith cores of individuals with birthdates between 1947 and 2003. Both δ13C and δ18O varied significantly as a function of year of birth, with δ13C decreasing and δ18O increasing over the time period investigated (-2.39×10-2 and 5.78×10-3 per year, respectively). The rate of change in otolith δ13C was nearly identical to the reported rates of atmospheric δ13C depletion, recently attributed to the burning of fossil fuels (referred to as the Suess effect). Observed shifts in otolith δ18O were less pronounced and likely linked to changing physicochemical conditions (i.e. salinity) in oceanic reservoirs over the time period investigated. The results show that otolith cores of bluefin tuna effectively track inter-decadal trends and record past oceanic δ13C and δ18O levels. After adjusting for inter-decadal trends, the isotopic composition of milled otolith cores of giants from three decades (1970s, 1980s, 2000s) and three regions were compared to otolith δ13C and δ18O values of yearling bluefin tuna collected from eastern and western nurseries. Maximum likelihood estimates indicated that 99% of bluefin tuna caught in the Gulf of St. Lawrence fishery originated from the western nursery, with no significant differences among the decades and regions examined. Results suggest that little to no mixing of eastern and western populations of adult bluefin tuna occurs in the Gulf of St. Lawrence, making it important for the management and conservation of the declining western population.

The condition of juvenile fish relates to their overall health and is a strong predictor of survival and eventual recruitment. Condition can be quantified and interpreted in a variety of ways covering different time scales and levels of biological organization. Here I (i) quantify interannual variability in the condition in Young-of-Year (YOY) Pacific herring (Clupea pallasi) in the Strait of Georgia, BC, from 2013-2016, and (ii) examine the extent to which the condition of an individual fish varies depending on which condition metric is used. Chapter 1 provides a general background on the concept of measuring condition in fish, as well as the basic biology of Pacific herring and their importance in Strait of Georgia ecosystem. In Chapter 2, I report the condition of YOY herring from 2013-2016 using six metrics: (i) Fulton’s K, (ii) the residuals from a length:weight regression, (iii) the RNA:DNA ratio, (iv) recent growth estimated via otolith microstructure analysis, (v) lipid content, and (vi) the ratio of two essential acids DHA:EPA. Four of these metrics (Fulton’s K, length:weight residuals, and growth from RNA:DNA and otolith increments) indicate a decrease in condition over the four years. In contrast, lipid content suggests an increase across the four years, while DHA:EPA suggests a decrease in 2015 but no change over the other three years. The observed interannual variability in condition can be partly linked to unfavourable changes in temperature and zooplankton community composition in 2015 and 2016, and to the propensity of juvenile fish to prioritize energy storage over somatic growth before a period of prey scarcity, such as their first winter. This dataset is further examined in Chapter 3, wherein I examine variability in condition of individual fish based on the different metrics used. Individual herring are ranked based on their scores from the six different metrics of condition, and the distribution of these rankings are examined to assess the degree of intercorrelation among the metrics. Based on this model, as well as pairwise Spearman rank correlations between the six metrics, I conclude that there is little intercorrelation between metrics, and that a fish that scores highly in terms of condition in any one metric will not necessarily score highly for the other metrics. These findings underscore the importance of choosing condition metrics carefully, based on the nature of the question being asked. / Graduate / 2019-07-04

Asian carp have rapidly expanded their range through much of the Mississippi River Drainage over the past 10 to 15 years. Silver and bighead carp are now the dominant fish species present along several reaches of the Illinois River. The upper Illinois River and shipping canals entering Lake Michigan are of great concern as pathways for Asian carp to enter the Great Lakes. Knowledge of reproductive habitats and dispersal pathways for these species may be valuable for ongoing and future efforts to control these exotic invasives. Previous studies have successfully identified spawning areas of native riverine species via otolith microchemistry, but this technique has not yet been applied to Asian carps. Both stable isotope and trace element ratios have been found to differ significantly among the large rivers of the Mississippi River drainage, enabling identification of natal environment for individual fish. The primary objective of this study was to identify differences in natal river origin and floodplain habitat use through the incorporation of trace elements (Sr:Ca) and stable isotopes (δ18O and δ13C). Silver and bighead carp were collected via electrofishing and trammel netting along four reaches of the Illinois River from the Mississippi-Illinois River confluence at Grafton, IL to the upper segment of the Illinois River upstream of Starved Rock State Park. Sagittal otoliths were removed from both silver and bighead carp collected from each of the four reaches of the Illinois River for analysis of stable isotope ratios and trace element concentrations. Water samples were collected seasonally from the four reaches of the Illinois River and several of its associated floodplain lakes in addition to the Missouri, Upper Mississippi and Middle Mississippi Rivers to validate water signatures of the various river reaches. Results indicated the majority of adult Asian carp caught in the Illinois River originated from the Illinois. However, there was strong evidence indicating roughly twenty percent of captured adults were in fact immigrants from other sources; primarily the Middle Mississippi river and, to a lesser extent, the Missouri River. Stable isotope results indicated that Asian carps primarily used river channel rather than floodplain lake habitats during early life. The findings of this study suggest current Asian carp removal efforts should continue to be primarily directed within the Illinois River, however, the evidence of immigrant silver carp indicate expanding the control efforts into other rivers (Middle Mississippi River and Missouri River) will further support the control of Asian carp within the Illinois River.

Submitted by (ana.araujo@ufrpe.br) on 2016-08-10T12:06:43Z No. of bitstreams: 1 Paulo Jose Duarte Neto.pdf: 927067 bytes, checksum: 6f9466ce92dc195b6b58522421427737 (MD5) / Made available in DSpace on 2016-08-10T12:06:43Z (GMT). No. of bitstreams: 1 Paulo Jose Duarte Neto.pdf: 927067 bytes, checksum: 6f9466ce92dc195b6b58522421427737 (MD5) Previous issue date: 2005-02-28 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / The otolith shape of dolphinfish, C. Hippurus, was studied to verify the hypotheses of two stocks in the northeastern Brazilian coast. Eighty two sagittal otoliths were collected from specimens caught by the artisanal fleet in two regions of northestern Brazil (Maranhão – MA and Rio Grande do Norte – RN coasts), in December of 2003 and April to May of 2004, respectively. Several types of shape descriptors were taken (area, perimeter, rectangularity, circularity, eccentricity, fractal dimension and Fourier coeficients) to evaluate the similarity level between regions. Differences between left and rigth otoliths and by sex were not found in the sample. Cluster and principal components (PC) analyses, based in the Fourier coeficients of 30th harmonics, revealed a three morfotypes pattern, concerning general differences of otolith shape. This pattern is supposed to be influenced by genetic factors, according to ANOVA results among the six signicant PC, regardless clinal variation between samples. When the two geographical regions were compared, significants differences were found in the otolith structure using both MANOVA and ANOVA, for all shape descriptors. Canonical discriminant analysis suggested the separation of the two regions samples, with a sucess classification of 57,1% for MA and 69,6% for RN, despite the high variability among otoliths shapes. The fractal dimension was a powerful descriptor to discriminate the two samples in this work, since the significance in all cases and high DSC value. Differencesin sagittal otoliths shape, possibly are due to different growth rates, added evidences to confirm the two stocks hypotheses of C. hippurus along the Brazilian coast. / A forma do otólito sagita do dourado, C. hippurus, foi estudada para verificar a hipótese de dois estoques na costa nordeste do Brasil. Oitenta e dois otólitos foram coletados de espécimes desembarcados pela frota artesanal na costa do estado do Maranhão (MA), em dezembro 2003, e na costa do Rio Grande do Norte (RN), de abril a maio de 2004. A partir da imagem do otólito, foram obtidos vários descritores da forma (área, perímetro, retangularidade, circularidade, excentricidade, dimensão fractal e coeficientes de Fourier) para avaliar, sobre vários aspectos, qual o nível de similaridade entre os otólitos das duas amostras. Nenhuma diferença significativa, na amostra, foi observada entre os otólitos direitos e esquerdos e entre sexos. As análises de agrupamento e de componentes principais, baseadas nos coeficientes de Fourier das 30 primeiras harmônicas, estabeleceram um padrão de 3 morfotipos do otóltio de dourado, os quais estão correlacionados a diferenças gerais da forma. A ANOVA entre os CPs sugeriu que este padrão esteja relacionado a características genéticas, pois nenhuma evidência de seleção clinal foi encontrada. Na comparação das amostras do MA e do RN, foram encontradas diferenças significativas na estrutura do otólito entre as duas regiões estudadas, tanto nas análises de variância uni e multivariada, como também na análise discriminante canônica. O sucesso de classificação foi de 57,1% para a amostra do MA e 69,6% para a do RN. A dimensão fractal demonstrou ser um eficiente descritor, pois foi significativamente diferente em todas as análises e apresentou um dos maiores valores de DSC. Os resultados sobre diferenças das características da forma do otólito sagita, que aparentam estar relacionadas a taxas de crescimento, adicionou evidências indicativas para a confirmação da hipótese de 2 circuitos migratórios do C. hippurus ao longo da costa brasileira mesmo havendo uma grande variabilidade individual.

Oil from the Deepwater Horizon blowout reached the Gulf of Mexico coast in the summer of 2010 and potentially exposed species living in those areas to toxic chemicals. The purpose of this study is to examine otoliths from Red Drum (Sciaenops ocellatus) for evidence of oil exposure that could be related to reduced growth rates. Because otolith growth and somatic growth are directly related, differences in annulus measurements can indicate differences in annual somatic growth, which is a good indicator of overall fish condition, and translates into changes in survival and lifetime reproductive potential. This study assessed variation in otolith elemental composition in years before, during, and after the oil spill using laser-ablation inductively-coupled plasma mass spectrometry, with emphasis on trace metals previously found in MC252 oil. Relative annual growth rates were estimated by calculating mean increment measurements for each age, and calculating a percentile for each observation. Growth was then compared with otolith elemental profiles. These two analyses were used to investigate associations between any observed growth variation and the temporal profiles of oil-indicator and stress-indicator elements. Otoliths obtained from Florida archaeological sites were used as a baseline for pre-industrial elemental compositions. Fish taken from 12 sampling sites in Florida and Louisiana with varying degrees of oil intrusion were analyzed for otolith element composition. Individual measurements were classified using Similarity Profile Analysis (SIMPROF, Clarke et al. 2008) and resulting SIMPROF groups were plotted on a seriated heat map to visualize elemental abundance groups. The largest group with the lowest elemental abundances was used as a reference group. This group was compared to higher-element abundance groups and to fossil otoliths found in Native American middens on Weedon Island, FL using nonparametric multivariate analysis of variance (NP-MANOVA) and Canonical Analysis of Principal Coordinates (CAP) to determine similarities of modern fish groups and an ancient baseline. Growth rates were then compared to the microchemistry groups to determine if there are any correlations with growth rates and otolith trace metal compositions. This study did not find any correlation between the Deepwater Horizon oil spill event and either Red Drum otolith microchemistry or growth. Otolith oil-metal concentrations did not vary significantly among study years, and there was no relationship between microchemistry and otolith-based growth rate. While there was decreased growth in 2010, the decreased growth appeared to be due to unusually cold winters during that year. Oil metal concentrations measured in the otoliths indicated continuous metal exposure rather than exposure to an episodic oil-spill event. This study also verified the use of archaeological otoliths as a viable microchemical baseline for pre-industrial otoliths. Preserved otolith material had very low hydrocarbon-associated metal concentrations, which is expected in otoliths that were formed before the period of heavy anthropogenic influence on coastal waters. This study represents a novel effort to compare pre-industrial-age microchemistry to the microchemistry of fish collected from impacted areas following a large oil spill.

Northern pike or pike Esox lucius is total piscivorous fish species found in the brackish and freshwater ecosystems of the Northern hemisphere. It is a top predator and keystone species that causes cascading effects in these ecosystems. Otoliths have been used to estimate age and growth rates in most fishes. Cleithra have generally have been used in Pike due to opaque nature of the otoliths. The aim of this study was to develop a method for age and growth estimation of pike using sagittal otoliths and carry out age and growth rates estimation of four sub populations; Dunöbäcken, Kårehamn, Oknebäcken and Väderön that represent freshwater and brackish water spawning sites. Determination of growth rates differences between sub populations was done for the first 2 years of their life. The methods included burning of the otoliths, fixing the otoliths in the epoxy resin, polishing of otoliths and staining with Alizarin red, Silver nitrate solution, Tetracycline and alkaline Lugol's solution with observation under light, dissecting and epifluorescence microscopes. Four methods tested based on staining with Alizarin red, Silver nitrate, alkaline Lugol's solution and burning otoliths. Provided useful results and not the method with Tetracycline. Alkaline Lugol's solution staining method was chosen and further developed. There was a significant difference in the relative growth rates between the sub population from brackish water spawning site of Väderön and the sub population from freshwater spawning site of Kårehamn in the first year (One-way ANOVA:F value 3.18, p value 0.0356) and after Tukey post hoc test (p value 0.0362). No difference among sub populations from the freshwater spawning sites. There was no difference in growth rates between any other sub populations in the second year. The importance of the study is successful application of Lugol's solution staining method for age and relative growth estimation studies with otoliths in pike. / EcoChange

Animal migrations are often associated with high mortality due to increased energy expenditure, reduced foraging opportunities, and increased predation risk. Migratory traits such as body size, phenology, or use of stopover habitats may moderate individual risk to mortality mechanisms and influence patterns of survival. However, variability in migratory traits is rarely quantified in detail because tracking many individuals over large areas is logistically challenging. In this dissertation, I used otoliths to examine migratory variability among and within sockeye salmon (Oncorhynchus nerka) populations, a species that has recently experienced declines associated with poor survival during juvenile marine migrations. Broadly, I examined the individual and environmental drivers of migratory patterns, as well as how variation across ecological scales (individuals, populations, and years) contributed to migratory diversity. First, I conducted a laboratory study to validate the use of otolith microstructure techniques in sockeye salmon post-smolts. Next, I assessed how a suite of ecological processes could interact to create a latitudinal gradient in sockeye salmon body size. By reconstructing individual growth and migration histories I determined that variation in size was correlated with ocean entry size and phenology, rather than differential marine growth or size-selective mortality. I then used estimates of migratory rate from otoliths to demonstrate that juvenile sockeye salmon exhibited distinct migratory phenotypes associated with ocean entry traits. Larger individuals migrated rapidly offshore, while smaller fish reared for several weeks in nearshore regions. Furthermore, a subset of the smallest individuals entered the ocean late in the year, migrated particularly slowly, and may have overwintered on the continental shelf. These linkages between ocean entry and migratory traits suggest juvenile sockeye salmon exhibit substantial migratory plasticity associated with carry-over effects from freshwater residence; however juvenile salmon may also respond strongly to variable conditions in marine habitats. In my fifth chapter, I compared marine growth and migration phenology in years with low and high competitor densities. After accounting for freshwater density-dependent effects, growth rates were similar in both years, but mean migration rates were nearly 50% faster in the high-density year. Migratory behavior may be used to buffer individuals from the effect of competitive interactions. In my final chapter, I sampled 16 Fraser River sockeye salmon populations to explore variation in the timing and duration of early marine migrations. Although populations differed in downstream migration timing, as well as their duration of residence within nearshore habitats, there was substantial variation within each population and between sampling years. These findings suggest individual characteristics and stochastic processes interact with population-specific strategies to shape migratory phenologies in this metapopulation. Management actions should account for and preserve migratory diversity at multiple ecological scales to maintain resilient salmon populations into the future. / Graduate / 2018-10-17

Although otolith organ testing is becoming more widely used in vestibular clinics throughout the world, the clinical significance of otolith organ dysfunction is unclear. The purpose of this study was to determine the impact of otolith dysfunction on postural stability and quality of life. A prospective case-controlled study of Veterans was completed. The findings of this study have important implications for developing effective clinical protocols for the diagnosis and management of individuals with dizziness related to otolith organ dysfunction.