Designing marine fishery reserves using passive acoustic telemetry

Marine Fishery Reserves (MFRs) are being adopted, in part, as a strategy to replenish depleted fish stocks and serve as a source for recruits to adjacent fisheries. By necessity, their design must consider the biological parameters of the species under consideration to ensure that the spawning stock is conserved while simultaneously providing propagules for dispersal. We describe how acoustic telemetry can be employed to design effective MFRs by elucidating important life-history parameters of the species under consideration, including home range, and ecological preferences, including habitat utilization. We then designed a reserve based on these parameters using data from two acoustic telemetry studies that examined two closely-linked subpopulations of queen conch (Strombus gigas) at Conch Reef in the Florida Keys. The union of the home ranges of the individual conch (aggregation home range: AgHR) within each subpopulation was used to construct a shape delineating the area within which a conch would be located with a high probability. Together with habitat utilization information acquired during both the spawning and non-spawning seasons, as well as landscape features (i.e., corridors), we designed a 66.5 ha MFR to conserve the conch population. Consideration was also given for further expansion of the population into suitable habitats

The preferences of voters over road tolls and road capacity.

We consider a congestible road, where the cost of travel increases with the number of users on the road and decreases with capacity. Those persons who do not use the road favor a toll which would maximize revenue, and they oppose spending on road capacity. Users of the road prefer a low toll and a large capacity financed by general revenues. We describe conditions that make majority voting lead to a toll and capacity level that equals the socially optimal toll and capacity, that is smaller, or that is larger. This model can also explain the decrease over time of user fees for road use.Investment; Pricing; Decisions; Decision; Transport; Preference;

An authentic approach to facilitating transfer of teacher's pedagogical knowledge

The pedagogical knowledge learned by pre-service teachers often fails to transfer to teaching practice. Instead, new teachers revert to instructional strategies they observed as children. This chapter describes design research conducted over four years, where pre-service teachers were immersed in an authentic learning environment using multimedia to learn mathematics assessment strategies. The first study was conducted with pre-service teachers in the second year of their degree, and then the second study followed up with the same people in their second year as practising teachers. The first study revealed several constraints for the participants on professional practice, including limited time and the influence of the supervising teacher. Later, as practising teachers, they faced cultural and practical constraints within the school environment that prevented them from fully operationalising the pedagogical principles they learned as pre-service teachers

Estimating Queen Conch (Strombus gigas) home ranges using acoustic telemetry: implications for the design of marine fishery reserves

Marine reserves (MRs) may function as a vital tool in the conservation and management of marine resources if source populations are managed for the benefit of those downstream. Consequently, it is critical to evaluate the home range of marine animals to ensure that MRs are large enough to protect source populations. We used acoustic telemetry to study movements of adult queen conch (Strombus gigas) within aggregations at two sites in the Florida Keys from June 1997 through July 1998. A total of 68 conch were tagged and tracked for up to one year. Latitude and longitude of each conch were recorded biweekly and data used to estimate the minimum speed, degree of site fidelity, and home range of each animal. Conch showed significantly greater displacement/ time during the summer. There were no significant differences in movement rate, site fidelity, or size of home range between males and females. Mean home range was 5.98 ha. Based on estimated home ranges of the aggregations, the size and location of the existing reserves at these two sites were inadequate to protect the conch aggregations should the fishery reopen

A statistical model approximation for perovskite solid-solutions: a Raman study of lead-zirconate-titanate single crystal

Lead titanate (PbTiO3) is a classical example of a ferroelectric perovskite oxide illustrating a displacive phase transition accompanied by a softening of a symmetry-breaking mode. The underlying assumption justifying the soft-mode theory is that the crystal is macroscopically sufficiently uniform so that a meaningful free energy function can be formed. In contrast to PbTiO3, experimental studies show that the phase transition behaviour of lead-zirconate-titanate solid solution (PZT) is far more subtle. Most of the studies on the PZT system have been dedicated to ceramic or powder samples, in which case an unambiguous soft-mode study is not possible, as modes with different symmetries appear together. Our Raman scattering study on titanium-rich PZT single crystal shows that the phase transitions in PZT cannot be described by a simple soft-mode theory. In strong contrast to PbTiO3, splitting of transverse E-symmetry modes reveals that there are different locally-ordered regions. The role of crystal defects, random distribution of Ti and Zr at the B-cation site and Pb ions shifted away from their ideal positions, dictates the phase transition mechanism. A statistical model explaining the observed peak splitting and phase transformation to a complex state with spatially varying local order in the vicinity of the morphotropic phase boundary is given.Comment: Article contains four black-and-white figures, one colour figure and one Table. Symmetry analysis and details of the model are given in Appendices I and II, respectivel

Structures of K0.05Na0.95NbO3 (50–300 K) and K0.30Na0.70NbO3 (100–200 K)

Rietveld refinement using neutron powder diffraction data is reported for the potential lead-free piezoelectric material KxNa1 - xNbO3 (x = 0.05, x = 0.3) at low temperatures. The structures were determined to be of rhombohedral symmetry, space group R3c, with the tilt system a-a-a- for both compositions. It was found that some of the structural parameters differ significantly in the two structures, and particularly the NbO6 octahedral strains as a function of temperature. The 300 K profile for K0.05Na0.95NbO3 shows the coexistence of rhombohedral and monoclinic phases, which indicates that the phase boundary is close to room temperature; the phase boundary for K0.30Na0.70NbO3 is found to be at approximately 180 K