ANALYZING TECHNICAL AND ECONOMIC INTERRELATIONSHIPS IN HAWAII'S LONGLINE FISHERY

This paper provides an analysis of technical and economic interrelationships among species harvested in Hawaii's pelagic longline fishery. The results indicate that this multispecies fishery is characterized by a joint production process, meaning that the regulation of one species would affect the harvest of other species. It implies that a single species regulation may not be appropriate in managing the longline fishery. Estimates of own-price output supply elasticities suggest that fisher's decisions on the amounts of each species harvested are independent of own expected prices. However, as evidenced by the estimates of cross-price elasticities, there are a number of significant technical-economic interactions among species. Failing to reject the null hypothesis of input-output separability suggests that management of the entire fishery as a whole by partial area/seasonal closure or by a 'limited entry' system as in the past is justified instead of regulating a few key species.Resource /Energy Economics and Policy,

Search for eccentric black hole coalescences during the third observing run of LIGO and Virgo

Despite the growing number of confident binary black hole coalescences observed through gravitational waves so far, the astrophysical origin of these binaries remains uncertain. Orbital eccentricity is one of the clearest tracers of binary formation channels. Identifying binary eccentricity, however, remains challenging due to the limited availability of gravitational waveforms that include effects of eccentricity. Here, we present observational results for a waveform-independent search sensitive to eccentric black hole coalescences, covering the third observing run (O3) of the LIGO and Virgo detectors. We identified no new high-significance candidates beyond those that were already identified with searches focusing on quasi-circular binaries. We determine the sensitivity of our search to high-mass (total mass M>70 M⊙) binaries covering eccentricities up to 0.3 at 15 Hz orbital frequency, and use this to compare model predictions to search results. Assuming all detections are indeed quasi-circular, for our fiducial population model, we place an upper limit for the merger rate density of high-mass binaries with eccentricities 0<e≤0.3 at 0.33 Gpc−3 yr−1 at 90\% confidence level

Ultralight vector dark matter search using data from the KAGRA O3GK run

Among the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through the measurement of oscillating length changes in the arm cavities. In this context, KAGRA has a unique feature due to differing compositions of its mirrors, enhancing the signal of vector DM in the length change in the auxiliary channels. Here we present the result of a search for U(1)B−L gauge boson DM using the KAGRA data from auxiliary length channels during the first joint observation run together with GEO600. By applying our search pipeline, which takes into account the stochastic nature of ultralight DM, upper bounds on the coupling strength between the U(1)B−L gauge boson and ordinary matter are obtained for a range of DM masses. While our constraints are less stringent than those derived from previous experiments, this study demonstrates the applicability of our method to the lower-mass vector DM search, which is made difficult in this measurement by the short observation time compared to the auto-correlation time scale of DM

Modeling entry, stay, and exit decisions of the longline fishers in Hawaii

A behavioral study on the entry, stay and exit decisions of the fishers in Hawaii's longline fishery was undertaken in a random utility framework by applying the multinomial logit (unordered) model. Pooled annual cross-sectional and time-series (1991-1998) data were used. The empirical results confirm that the entry, stay, and exit decisions are significantly associated with the earning potential of fishers, crowding externality, resource abundance and some managerial factors. The probability of a vessel to stay (or exit) in the fishery increased (or decreased) for an increase in the earning potential of a fisher. A larger fleet size shows vessels were more inclined to exit from the fishery than stay in the fishery. The probability of vessel entry (or exit) was also positively (or negatively) associated with an increase in stock levels of major target species. Further, a vessel was more likely to stay in the fishery when the vessel owner was a Hawaii resident or a vessel captain. Simulation of the probability for a vessel to enter, stay, or exit for a change in fleet size or stock level was also carried out.Vessel entry-stay-exit Longline fishery Multinomial logit Choice Hawaii