Trends in Kemp\u27s Ridley Sea Turtle (Lepidochelys kempii) Relative Abundance, Distribution, and Size Composition in Nearshore Waters of the Northwestern Gulf of Mexico

Long-term monitoring of in-water life history stages of the critically endangered Kemp’s ridley sea turtle (Lepidochelys kempii) is essential for management because it generates information on the species’ at-sea abundance, size composition, distribution, and habitat requirements. We documented trends in Kemp’s ridley size, relative abundance, and distribution using entanglement netting surveys at three study areas adjacent to tidal passes in the northwestern Gulf of Mexico (NWGOM) during intermittent sampling periods from 1991 to 2013. A total of 656 Kemp’s ridley sea turtles were captured ranging in size from 19.5 to 66.3 cm straight carapace length (SCL) (mean = 35.0 cm SCL). The dominance of juveniles (25–40 cm SCL) captured during sampling suggests the nearshore waters of the NWGOM are an important developmental foraging ground for Kemp’s ridley. Characterization of Kemp’s ridley long-term relative abundance reveals a generally stable trend in catch-per-unit-effort (CPUE) across all study areas combined. Based on the increasing trend in the number of hatchlings released from the species’ primary nesting beach, Rancho Nuevo, Mexico, since the early 1990s, the lack of a corresponding overall increase in juvenile abundance at nearshore sampling locations is puzzling. This disparity is most likely an artifact of the present study’s sampling design, but could also indicate shifts in Kemp’s ridley recruitment away from the NWGOM. While conservation efforts have contributed to this species’ overall growth since the 1980s, as measured by the increasing number of nests, recent declines in this rate of increase are a concern and call for a more comprehensive approach to managing Kemp’s ridley recovery efforts

Multimessenger Search for Sources of Gravitational Waves and High-Energy Neutrinos: Results for Initial LIGO-Virgo and IceCube

We report the results of a multimessenger search for coincident signals from the LIGO and Virgo gravitational-wave observatories and the partially completed IceCube high-energy neutrino detector, including periods of joint operation between 2007-2010. These include parts of the 2005-2007 run and the 2009-2010 run for LIGO-Virgo, and IceCube's observation periods with 22, 59 and 79 strings. We find no significant coincident events, and use the search results to derive upper limits on the rate of joint sources for a range of source emission parameters. For the optimistic assumption of gravitational-wave emission energy of $10^{-2}$\,M$_\odot$c$^2$ at $\sim 150$\,Hz with $\sim 60$\,ms duration, and high-energy neutrino emission of $10^{51}$\,erg comparable to the isotropic gamma-ray energy of gamma-ray bursts, we limit the source rate below $1.6 \times 10^{-2}$\,Mpc$^{-3}$yr$^{-1}$. We also examine how combining information from gravitational waves and neutrinos will aid discovery in the advanced gravitational-wave detector era

Multi-messenger Observations of a Binary Neutron Star Merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ∼ 1.7 {{s}} with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of {40}-8+8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 {M}ȯ . An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ∼ 40 {{Mpc}}) less than 11 hours after the merger by the One-Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ∼10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ∼ 9 and ∼ 16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC 4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta.</p

Trends in Kemp's Ridley Sea Turtle (Lepidochelys kempii) Relative Abundance, Distribution, and Size Composition in Nearshore Waters of the Northwestern Gulf of Mexico

Long-term monitoring of in-water life history stages of the critically endangered Kemp’s ridley sea turtle (Lepidochelys kempii) is essential for management because it generates information on the species’ at-sea abundance, size composition, distribution, and habitat requirements. We documented trends in Kemp’s ridley size, relative abundance, and distribution using entanglement netting surveys at three study areas adjacent to tidal passes in the northwestern Gulf of Mexico (NWGOM) during intermittent sampling periods from 1991 to 2013. A total of 656 Kemp’s ridley sea turtles were captured ranging in size from 19.5 to 66.3 cm straight carapace length (SCL) (mean = 35.0 cm SCL). The dominance of juveniles (25–40 cm SCL) captured during sampling suggests the nearshore waters of the NWGOM are an important developmental foraging ground for Kemp’s ridley. Characterization of Kemp’s ridley long-term relative abundance reveals a generally stable trend in catch-per-unit-effort (CPUE) across all study areas combined. Based on the increasing trend in the number of hatchlings released from the species’ primary nesting beach, Rancho Nuevo, Mexico, since the early 1990s, the lack of a corresponding overall increase in juvenile abundance at nearshore sampling locations is puzzling. This disparity is most likely an artifact of the present study’s sampling design, but could also indicate shifts in Kemp’s ridley recruitment away from the NWGOM. While conservation efforts have contributed to this species’ overall growth since the 1980s, as measured by the increasing number of nests, recent declines in this rate of increase are a concern and call for a more comprehensive approach to managing Kemp’s ridley recovery efforts