Otolith Age Validation and Microchemical Investigation of the Northern Stock f Atlantic Black Sea Bass (Centropristis Striata)

Black sea bass (Centropristis striata) is a demersal marine species that supports extensive commercial and recreational fisheries along the Atlantic coast. A recent expansion into the Gulf of Maine raises questions about this species’ movement and population dynamics in the region. Additionally, the 2016 catch-at-age stock assessment model for the northern stock incorporated a population split at the Hudson Canyon. Though this model better accounts for differences in populations, several issues remain. First, validation of the otolith ageing technique for this stock is incomplete; and, second, the origin of fish that moved into the northern ranges of the Gulf of Maine (GOM) remains unclear. Error stemming from inaccurate age determinations can have serious effects on age-structured calculations (e.g. growth rate) leading to stock assessments that do not correctly reflect the population. In this study, I validated the black sea bass otolith ageing method using marginal increment analysis and young-of-year annulus measurements. Samples spanned the spatial distribution and age range of the northern stock. Results indicated black sea bass otoliths complete an annual increment, one translucent and one opaque band, in the late spring or early summer. Additionally, the first annulus was validated, an important step in verifying total age that is not present in the current literature for this species. The natal origin of black sea bass caught in the northern ranges of the GOM was assessed by otolith core trace element and stable isotope microchemistry. Analysis of spawning adult otoliths identified unique chemical fingerprints for the regions north and south of the Hudson Canyon: Southern New England (SNE) and the Mid-Atlantic Bight (MAB), respectively. Black sea bass caught in Maine waters were assigned to a spawning region by matching chemical fingerprints. Overall, 87% were assigned to SNE and 13% to MAB. This project helps to improve the accuracy and precision of black sea bass otolith ageing practices by validating the method used by agencies and organizations across its distribution. Additionally, this project confirms hypotheses that SNE spawned fish moved north, and further elucidates population composition of the GOM, an area where little is known about this species

Otolith Age Validation and Microchemical Investigation of the Northern Stock of Atlantic Black Sea Bass (Centropristis striata)

Black sea bass (Centropristis striata) is a demersal marine species that supports extensive commercial and recreational fisheries along the Atlantic coast. A recent expansion into the Gulf of Maine raises questions about this species’ movement and population dynamics in the region. Additionally, the 2016 catch-at-age stock assessment model for the northern stock incorporated a population split at the Hudson Canyon. Though this model better accounts for differences in populations, several issues remain. First, validation of the otolith ageing technique for this stock is incomplete; and, second, the origin of fish that moved into the northern ranges of the Gulf of Maine (GOM) remains unclear. Error stemming from inaccurate age determinations can have serious effects on age-structured calculations (e.g. growth rate) leading to stock assessments that do not correctly reflect the population. In this study, I validated the black sea bass otolith ageing method using marginal increment analysis and young-of-year annulus measurements. Samples spanned the spatial distribution and age range of the northern stock. Results indicated black sea bass otoliths complete an annual increment, one translucent and one opaque band, in the late spring or early summer. Additionally, the first annulus was validated, an important step in verifying total age that is not present in the current literature for this species. The natal origin of black sea bass caught in the northern ranges of the GOM was assessed by otolith core trace element and stable isotope microchemistry. Analysis of spawning adult otoliths identified unique chemical fingerprints for the regions north and south of the Hudson Canyon: Southern New England (SNE) and the Mid-Atlantic Bight (MAB), respectively. Black sea bass caught in Maine waters were assigned to a spawning region by matching chemical fingerprints. Overall, 87% were assigned to SNE and 13% to MAB. This project helps to improve the accuracy and precision of black sea bass otolith ageing practices by validating the method used by agencies and organizations across its distribution. Additionally, this project confirms hypotheses that SNE spawned fish moved north, and further elucidates population composition of the GOM, an area where little is known about this species

White Matter Integrity is Associated with Treatment Outcome Measures in Cocaine Dependence

Cocaine dependence is associated with white matter impairments that may compromise cognitive function and hence drug users' abilities to engage in and benefit from treatment. The main aim of this study was to assess whether white matter integrity correlates with treatment outcome measures in cocaine dependence. Diffusion tensor imaging (DTI) was used to assess the white matter (WM) of 16 treatment-seeking cocaine-dependent patients before 8 weeks of therapy. The measures for treatment outcome were longest self-reported duration of continuous cocaine abstinence, percent of urine screens negative for cocaine, and duration (weeks) of treatment retention. Correlations between treatment outcome measures and DTI parameters (fractional anisotropy (FA), longitudinal eigenvalue (λ1), perpendicular eigenvalue (λT), and mean diffusivity (MD)) were analyzed. Longest self-reported abstinence from cocaine and percent of cocaine-negative urine samples during treatment positively correlated with FA values and negatively correlated with λ1, λT, and MD values across extensive brain regions including the corpus callosum, frontal, parietal, temporal, and occipital lobes, and cerebellum. The findings of an association between better WM integrity at treatment onset and longer abstinence suggest that strategies for improving WM integrity warrant consideration in developing new interventions for cocaine dependence