26 research outputs found
Use of Otolith Morphology for Separation of King Mackerel (Scomberomorus cavalla) and Spanish Mackerel (Scomberomorus maculatus)
Shapes of otoliths (sagittae) of king and Spanish mackerel (Scomberomorus cavalla and S. maculatus) were compared using theta-rho analysis aided by digitized computer methods. Otoliths from three king mackerel groups [Yucatan (Mexico), northwest Florida, and North Carolina] and one Spanish mackerel group were examined. Seven analytical combinations of measurements were tested. Intraspecific separation was highest using two truss systems (66.7-70.0% and 57.7-77.5%) and interspecific separation was highest using length and width radii (91.7%)
Age-Size Structure of Red Grouper, (Epinephelus morlo), from the Eastern Gulf of Mexico
Sagittal otoliths from 534 red grouper, Eplnephelus morlo, were collected from recreational and commercial fisheries of the eastern Gulf of Mexico in 1979-1981 (236 fish) and 1991-1992 (298 fish). Age estimations for the two collections were made In 1991-1992 from the surface and transverse sections of these otoliths. Also, estimates of back-calculated size at age (using the final annulus present at time of capture following Lea\u27s (1910) method were made for these collections. Red grouper were larger in size at capture at age and back-calculated size at age in 1991-1992 than in 1979-1981. The respective von Bertalanffy growth parameters were:
1979·81 L∞ = 78.9, K = 0.1778, t0 = 0.82591991·92 L∞ = 92.6, K = 0.1588, t0 = 0.9323 where L∞ Is mean maximum attainable total length In centimeters, K Is growth coefficient, and t0 Is hypothetical age in years at which fish would have zero length
Age, Growth, and Mortality of Blue Runner, Caranx crysos, from the Northern Gulf of Mexico
Estimates of age, growth, and mortality for blue runner obtained from commercial fisheries in northwest Florida and the Mississippi delta were developed using otolith sections. The oldest fish was 11 years old, the largest was 460 mm fork length. Mean back-calculated fork lengths varied from 212 mm at age 1 to 422 mm at age 11. The von Bertalanffy equation for combined sexes was FLt = (1-e-0.35(t + 1.07)) where FL = fork length (mm) and t = age (years). Regression equations for the interconversion of fork length (FL), standard length (SL), and total length (TL) were:
TL = -7.4792 + FL (1.1938), (r = 1.00, α = 0.01), FL = 1.9453 + SL (1.0596), (r = 1.00, α = 0.01), and TL = -5.1694 + SL (1.2651), (r = 0.99, α = 0.01).
The weight·length relationship for combined sexes was W = 0.0000251355 FL 2.94593 (N = 193, r = 0.98, α = 0.01) where W = whole body weight in grams and FL = fork length in millimeters. Estimates of annual mortality, determined by four methods, ranged from 0.41 to 0.53
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Biology of the ratfish, Hydrolagus colliei (Lay and Bennett)
In the fall and winter of 1965, 1966, and 1967, 298 ratfish (180 males, 118 females) were collected off the Pacific coast of
Oregon and Washington and examined for food habits , parasites, growth relationships and a method of age determination. The following
food organisms were found to be the most important in the collection; Pandalus, Crag o, Musculus, Amphissa, Pecten, and Brisaster.
Two occurrences of cannibalism were found in ratfish collected off Cape Arago, Oregon. The parasite Gyrocotyle occurred in from 29. 2% to 65. 8% of the ratfish from the four collections made off Oregon. The copepod,
Acanthochondria sp. , was found attached to the pelvic claspers of seven male ratfish from Cape Arago, Oregon. Age appears to be related to body length, with females growing
faster and to a larger size than the males.
The eye lens weights (wet and dry), vertebral radii, and body weights were compared to body lengths (S-V). General equations for body weight-body length (S-V) relationships (metric system) are Log weight = Log -4. 3217 + 3. 0546 Log length for the males and Log
weight = Log -4. 1692 + 2. 9720 Log length for the females. No accurate method of determining age of the ratfish was found,
although the body parts examined showed an increase in size with increase in body length. Ridges on the posterior side of the upper dental plate offer a promising indicator of age, but the relationship could
not be confirmed
It's about time: A synthesis of changing phenology in the Gulf of Maine ecosystem
© The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Staudinger, M. D., Mills, K. E., Stamieszkin, K., Record, N. R., Hudak, C. A., Allyn, A., Diamond, A., Friedland, K. D., Golet, W., Henderson, M. E., Hernandez, C. M., Huntington, T. G., Ji, R., Johnson, C. L., Johnson, D. S., Jordaan, A., Kocik, J., Li, Y., Liebman, M., Nichols, O. C., Pendleton, D., Richards, R. A., Robben, T., Thomas, A. C., Walsh, H. J., & Yakola, K. It's about time: A synthesis of changing phenology in the Gulf of Maine ecosystem. Fisheries Oceanography, 28(5), (2019): 532-566, doi: 10.1111/fog.12429.The timing of recurring biological and seasonal environmental events is changing on a global scale relative to temperature and other climate drivers. This study considers the Gulf of Maine ecosystem, a region of high social and ecological importance in the Northwest Atlantic Ocean and synthesizes current knowledge of (a) key seasonal processes, patterns, and events; (b) direct evidence for shifts in timing; (c) implications of phenological responses for linked ecological‐human systems; and (d) potential phenology‐focused adaptation strategies and actions. Twenty studies demonstrated shifts in timing of regional marine organisms and seasonal environmental events. The most common response was earlier timing, observed in spring onset, spring and winter hydrology, zooplankton abundance, occurrence of several larval fishes, and diadromous fish migrations. Later timing was documented for fall onset, reproduction and fledging in Atlantic puffins, spring and fall phytoplankton blooms, and occurrence of additional larval fishes. Changes in event duration generally increased and were detected in zooplankton peak abundance, early life history periods of macro‐invertebrates, and lobster fishery landings. Reduced duration was observed in winter–spring ice‐affected stream flows. Two studies projected phenological changes, both finding diapause duration would decrease in zooplankton under future climate scenarios. Phenological responses were species‐specific and varied depending on the environmental driver, spatial, and temporal scales evaluated. Overall, a wide range of baseline phenology and relevant modeling studies exist, yet surprisingly few document long‐term shifts. Results reveal a need for increased emphasis on phenological shifts in the Gulf of Maine and identify opportunities for future research and consideration of phenological changes in adaptation efforts.This work was supported by the Department of the Interior Northeast Climate Adaptation Science Center (G14AC00441) for MDS, AJ, and KY; the National Science Foundation's Coastal SEES Program (OCE‐1325484) for KEM, ACT, MEH, and AA; the National Aeronautics and Space Administration (NNX16 AG59G) for ACT, KEM, NRR, and KSS; the USGS Climate Research and Development Program for TGH; National Science & Engineering Research Council of Canada, University of New Brunswick, Environment Canada, Sir James Dunn Wildlife Research Centre, and New Brunswick Wildlife Trust Fund for AD. We also thank the Regional Association for Research on the Gulf of Maine for support, and the Gulf of Maine Research Institute for hosting and providing in kind resources for a two day in‐person workshop in August 2016. We greatly appreciate contributions from K. Alexander, G. Calandrino, C. Feurt, I. Mlsna, N. Rebuck, J. Seavey, and J. Sun for helping shape the initial scope of the manuscript. We thank J. Weltzin and two anonymous reviewers for their constructive comments. The contents of this paper are solely the responsibility of the authors and do not necessarily represent the views of the Northeast Climate Adaptation Science Center, U.S. Geological Survey, National Oceanographic and Atmospheric Administration, Fisheries and Oceans Canada or the US Environmental Protection Agency. This manuscript is submitted for publication with the understanding that the United States Government is authorized to reproduce and distribute reprints for Governmental purposes. None of the authors have conflicts of interest to declare in association with the contents of this manuscript
The Static and Dynamic Lattice Changes Induced by Hydrogen Adsorption on NiAl(110)
Static and dynamic changes induced by adsorption of atomic hydrogen on the
NiAl(110) lattice at 130 K have been examined as a function of adsorbate
coverage. Adsorbed hydrogen exists in three distinct phases. At low coverages
the hydrogen is itinerant because of quantum tunneling between sites and
exhibits no observable vibrational modes. Between 0.4 ML and 0.6 ML, substrate
mediated interactions produce an ordered superstructure with c(2x2) symmetry,
and at higher coverages, hydrogen exists as a disordered lattice gas. This
picture of how hydrogen interacts with NiAl(110) is developed from our data and
compared to current theoretical predictions.Comment: 36 pages, including 12 figures, 2 tables and 58 reference
The Seventh Data Release of the Sloan Digital Sky Survey
This paper describes the Seventh Data Release of the Sloan Digital Sky Survey
(SDSS), marking the completion of the original goals of the SDSS and the end of
the phase known as SDSS-II. It includes 11663 deg^2 of imaging data, with most
of the roughly 2000 deg^2 increment over the previous data release lying in
regions of low Galactic latitude. The catalog contains five-band photometry for
357 million distinct objects. The survey also includes repeat photometry over
250 deg^2 along the Celestial Equator in the Southern Galactic Cap. A
coaddition of these data goes roughly two magnitudes fainter than the main
survey. The spectroscopy is now complete over a contiguous area of 7500 deg^2
in the Northern Galactic Cap, closing the gap that was present in previous data
releases. There are over 1.6 million spectra in total, including 930,000
galaxies, 120,000 quasars, and 460,000 stars. The data release includes
improved stellar photometry at low Galactic latitude. The astrometry has all
been recalibrated with the second version of the USNO CCD Astrograph Catalog
(UCAC-2), reducing the rms statistical errors at the bright end to 45
milli-arcseconds per coordinate. A systematic error in bright galaxy photometr
is less severe than previously reported for the majority of galaxies. Finally,
we describe a series of improvements to the spectroscopic reductions, including
better flat-fielding and improved wavelength calibration at the blue end,
better processing of objects with extremely strong narrow emission lines, and
an improved determination of stellar metallicities. (Abridged)Comment: 20 pages, 10 embedded figures. Accepted to ApJS after minor
correction
Dark Energy Survey year 1 results: cosmological constraints from cluster abundances and weak lensing
We perform a joint analysis of the counts and weak lensing signal of redMaPPer clusters selected from the Dark Energy Survey (DES) Year 1 dataset. Our analysis uses the same shear and source photometric redshifts estimates as were used in the DES combined probes analysis. Our analysis results in surprisingly low values for S8=σ8(Ωm/0.3)0.5=0.65±0.04, driven by a low matter density parameter, Ωm=0.179+0.031−0.038, with σ8−Ωm posteriors in 2.4σ tension with the DES Y1 3x2pt results, and in 5.6σ with the Planck CMB analysis. These results include the impact of post-unblinding changes to the analysis, which did not improve the level of consistency with other data sets compared to the results obtained at the unblinding. The fact that multiple cosmological probes (supernovae, baryon acoustic oscillations, cosmic shear, galaxy clustering and CMB anisotropies), and other galaxy cluster analyses all favor significantly higher matter densities suggests the presence of systematic errors in the data or an incomplete modeling of the relevant physics. Cross checks with x-ray and microwave data, as well as independent constraints on the observable-mass relation from Sunyaev-Zeldovich selected clusters, suggest that the discrepancy resides in our modeling of the weak lensing signal rather than the cluster abundance. Repeating our analysis using a higher richness threshold (λ≥30) significantly reduces the tension with other probes, and points to one or more richness-dependent effects not captured by our model