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Ecosystem-based fisheries management must consider many elements of a complex marine community and, to accurately model the abundance of a particular target species, it is necessary to determine the most important out of many possible ecological dynamics. Here we consider three potential drivers: temporal heterogeneity, non-target effects, and species interactions. Firstly, we investigated how the assumption of equal recruitment and mortality timing, common to many fishery production models, affects stock estimates for data-poor species. Adjusting models to include no mortality delay and a recruitment time lag equal to age-at-maturity eliminated a 14-40% over-estimation of overfishing limits. Estimation error increases with age-at-maturity and natural mortality rate, indicating that time lag separation is most important for long-lived species. Secondly, we analyzed the balance within a multi-species fishery between non-target bycatch and positive indirect interactions between species. If the species involved interact strongly, the release from competition or predation can counteract or exceed the negative effects of bycatch. In particular, in communities where a shared predator forms a strong link between the target and non-target species, the positive effects of release from apparent competition can be larger than those of direct competitive release. Finally, we explored how the presence of an obligate predator affects recovery trajectories in the post-harvest period of a target species with a truncated size distribution. Compared to generalist predation, obligate predation delays the recovery of large prey individuals to pre-harvest abundance, even for sizes not targeted by the predator. In addition, the obligate predator lowered the relative abundance of smaller vulnerable individuals, delayed the shift to pre-harvest size distribution, and complicated post-harvest monitoring through population cycling. We conclude that the use of appropriate life-history time scales and the inclusion of strong species interactions are both important aspects of fisheries management, and their omission can cause over-estimation of initial stock size, damage from bycatch, and species recovery potential. Keywords Fisheries management; time lags; delayed recruitment; mortality; density dependence; stock assessment; Depletion-Based Stock Reduction Analysis.

Binary expression systems like the LexA-LexAop system provide a powerful experimental tool kit to study gene and tissue function in developmental biology, neurobiology and physiology. However, the number of well-defined LexA enhancer trap insertions remains limited. In this study, we present the molecular characterization and initial tissue expression analysis of nearly 100 novel StanEx LexA enhancer traps, derived from the StanEx1 index line. This includes 76 insertions into novel, distinct gene loci not previously associated with enhancer traps or targeted LexA constructs. Additionally, our studies revealed evidence for selective transposase-dependent replacement of a previously-undetected KP element on chromosome III within the StanEx1 genetic background during hybrid dysgenesis, suggesting a molecular basis for the over-representation of LexA insertions at the NK7.1 locus in our screen. Production and characterization of novel fly lines were performed by students and teachers in experiment-based genetics classes within a geographically diverse network of public and independent high schools. Thus, unique partnerships between secondary schools and university-based programs have produced and characterized novel genetic and molecular resources in Drosophila for open-source distribution, and provide paradigms for development of science education through experience-based pedagogy.

It is the object of this thesis to study the Delaware River with a view to its development for water power purposes. The study will include an analysis of the sites available for power and storage purposes, tentative design of dams and cost estimates for the project. An economic investigation will be made of the power installation, the additional value of a storage reservoir, the comparison in cost between the hydro generated power and equivalent steam power and the size of installation necessary to reduce the power cost to a minimum on a combined project. While the project is designed primarily to carry base loads, costs will be calculated for a wide range of load factors to suggest the possibilities for peak load operation.