Stable carbon and nitrogen isotope values in teeth of Steller sea lions: age of weaning and the impact of the 1975–1976 regime shift in the North Pacific Ocean

2008 ◽  
Vol 86 (1) ◽  
pp. 33-44 ◽  
Author(s):  
A. E. York ◽  
J. R. Thomason ◽  
E. H. Sinclair ◽  
K. A. Hobson
Keyword(s):  
Regime Shift ◽  
North Pacific Ocean ◽  
Large Population ◽  
Nitrogen Isotope ◽  
Steller Sea Lions ◽  
Linear Discriminant ◽  
Sea Lions ◽  
The North ◽  
Tooth Width ◽  
The Impact

We measured δ15N and δ13C values and tooth width from the first 4 years’ dentinal growth layer groups (GLGs) in the teeth of 113 female Steller sea lions ( Eumetopias jubatus (Schreber, 1776)) born between 1960 and 1983, a period that included a large population decrease and a climate regime shift. A linear discriminant analysis on the δ13C and δ15N values estimated 60% of Steller sea lions were weaned in their 1st year, 30% in their 2nd year, and 8% in their 3rd year. GLG-1 was wider in “weaned” animals than those still “nursing” in their 2nd year, suggesting that faster growing pups weaned earlier. Except during the regime shift, the average age at weaning increased and the size of GLG-1 in weaned animals decreased. We suggest that during the regime shift a greater proportion of pups which survived (to have their teeth sampled for this study) grew faster and were weaned by the end of their 1st year. We hypothesize that the long-term weaning age increase and growth rate decrease are consistent with a change in relative mortality of weaned pups and those that continued to nurse, possibly caused by a reduction in available resources, characterized as a switch from a “live-fast” to a “live-slow” life history.

Availability to Steller sea lions (Eumetopias jubatus) of a seasonal prey resource: a prespawning aggregation of eulachon (Thaleichthys pacificus)

2004 ◽  
Vol 61 (8) ◽  
pp. 1475-1484 ◽  
Author(s):  
Michael F Sigler ◽  
Jamie N Womble ◽  
Johanna J Vollenweider
Keyword(s):  
North Pacific Ocean ◽  
Eumetopias Jubatus ◽  
Steller Sea Lions ◽  
Sea Lion ◽  
Southeast Alaska ◽  
Sea Lions ◽  
The North ◽  
Large Numbers ◽  
Spawning Run ◽  
The North Pacific

The availability of seasonally abundant energy-rich prey can be a significant factor for the survival and reproductive success of predator populations. Large numbers of Steller sea lions (Eumetopias jubatus) were attracted to a prespawning aggregation of eulachon (Thaleichthys pacificus) in Berners Bay in southeast Alaska during April–May in 2002 and 2003. Sea lion abundance increased as eulachon gathered in Berners Bay, peaked as eulachon abundance peaked, and decreased as the eulachon moved up-river. As sea lion abundance increased in Berners Bay, sea lion abundance decreased at Benjamin Island, a sea lion haulout located 22 km away. The eulachon provided an abundant, energy-rich, predictable prey source for the Steller sea lions: (i) eulachon energy density was 9.70 ± 0.24 kJ·g–1, much higher than that of any forage species reported in the North Pacific Ocean except northern lampfish (Stenobrachius leucopsarus); (ii) a large surplus of prey was available per sea lion while the eulachon aggregation was present; and (iii) the spawning run usually begins between late April and early May. The eulachon pulse may be critical to Steller sea lions during a period of high energetic demands.

An ensemble analysis to predict future habitats of striped marlin (Kajikia audax) in the North Pacific Ocean

2013 ◽  
Vol 70 (5) ◽  
pp. 1013-1022 ◽  
Author(s):  
Nan-Jay Su ◽  
Chi-Lu Sun ◽  
André E. Punt ◽  
Su-Zan Yeh ◽  
Gerard DiNardo ◽  
...  
Keyword(s):  
Climate Change ◽  
Pacific Ocean ◽  
Water Temperature ◽  
North Pacific ◽  
North Pacific Ocean ◽  
Additive Models ◽  
The North ◽  
The Impact ◽  
The North Pacific ◽  
Ensemble Analysis

Abstract Su, N.-J., Sun, C.-L., Punt, A. E., Yeh, S.-Z., DiNardo, G., and Chang, Y.-J. 2013. An ensemble analysis to predict future habitats of striped marlin (Kajikia audax) in the North Pacific Ocean. – ICES Journal of Marine Science, 70: 1013–1022. Striped marlin is a highly migratory species distributed throughout the North Pacific Ocean, which shows considerable variation in spatial distribution as a consequence of habitat preference. This species may therefore shift its range in response to future changes in the marine environment driven by climate change. It is important to understand the factors determining the distribution of striped marlin and the influence of climate change on these factors, to develop effective fisheries management policies given the economic importance of the species and the impact of fishing. We examined the spatial patterns and habitat preferences of striped marlin using generalized additive models fitted to data from longline fisheries. Future distributions were predicted using an ensemble analysis, which represents the uncertainty due to several global climate models and greenhouse gas emission scenarios. The increase in water temperature driven by climate change is predicted to lead to a northward displacement of striped marlin in the North Pacific Ocean. Use of a simple predictor of water temperature to describe future distribution, as in several previous studies, may not be robust, which emphasizes that variables other than sea surface temperatures from bioclimatic models are needed to understand future changes in the distribution of large pelagic species.

scholarly journals A Case Study of Downstream Baroclinic Development over the North Pacific Ocean. Part I: Dynamical Impacts

2006 ◽  
Vol 134 (5) ◽  
pp. 1534-1548 ◽  
Author(s):  
Richard E. Danielson ◽  
John R. Gyakum ◽  
David N. Straub
Keyword(s):  
North Pacific ◽  
Initial Conditions ◽  
North Pacific Ocean ◽  
The North ◽  
Potential Vorticity Inversion ◽  
Surface Cyclone ◽  
Upper Level ◽  
The Impact ◽  
The North Pacific

Abstract The impact of eddy energy growth and radiation from a western North Pacific cyclone on the intensity of an eastern North Pacific cyclone a few days later is examined. Associated with the western cyclone is an upstream ridge and trough couplet, initially over Siberia on 8 March 1977. The amplitude of this couplet is perturbed in 5-day numerical simulations of the two marine cyclones. Balanced initial conditions are created by potential vorticity inversion. The magnitude of the upper-level couplet governs much of the subsequent growth of eddy energy in the western cyclone as well as the propagation of eddy energy between the two cyclones. This culminates in measurable changes in the maximum intensity of the eastern surface cyclone. The broader question of the sensitivity of this cyclone to upstream perturbations is also briefly addressed.

ARCO Tanker Slamming Study

1993 ◽  
Vol 30 (03) ◽  
pp. 135-147
Author(s):  
Peter Lacey ◽  
Rod Edwards
Keyword(s):  
Structural Damage ◽  
North Pacific Ocean ◽  
Warning System ◽  
Weather Conditions ◽  
The United States ◽  
Ship Motions ◽  
The North ◽  
Data Acquisition Program ◽  
Impact Characteristics ◽  
The Impact

ARCO Marine currently operates ten tankers which move crude oil from Valdez, Alaska to West Coast ports of the United States. These tankers range in size from 70 000 to 265 000 dwt and operate throughout the year in the harsh environment of the North Pacific Ocean. Some of these ships have experienced bow structural damage, presumably due to slamming in heavy weather conditions. In late 1990 ARCO initiated a program with Arctec Offshore Inc. and Ocean Systems Inc. to investigate slamming of ARCO tankers. This ongoing effort focuses on three issues: the frequency of occurrence and intensity of impacts; the relationship between the impact characteristics, sea conditions, and ship motions; and the development of an onboard slam monitoring and warning system. During the winter of 1991 data were collected aboard two ARCO 190 000 dwt San Diego Class tankers. This paper describes the data acquisition program, including the problems encountered, the preliminary interpretation of the collected data, and plans for continuation of the program.

scholarly journals The Impact of Analysis Error on Medium-Range Weather Forecasts

2008 ◽  
Vol 136 (9) ◽  
pp. 3425-3431 ◽  
Author(s):  
Kyle L. Swanson ◽  
Paul J. Roebber
Keyword(s):  
North Pacific Ocean ◽  
Forecast Skill ◽  
Ensemble Spread ◽  
Weather Forecasts ◽  
The North ◽  
Medium Range ◽  
Difference Fields ◽  
Height Fields ◽  
Analysis Error ◽  
The Impact

Abstract All meteorological analyzed fields contain errors, the magnitude of which ultimately determines the point at which a given forecast will fail. Here, the authors explore the extent to which analysis difference fields capture certain aspects of the actual but unknowable flow-dependent analysis error. The analysis difference fields considered here are obtained by subtracting the NCEP and ECMWF reanalysis 500-hPa height fields. It is shown that the magnitude of this 500-hPa analysis difference averaged over the North Pacific Ocean has a statistically significant impact on forecast skill over the continental United States well into the medium range (5 days). Further, it is shown that the impact of this analysis difference on forecast skill is similar to that of ensemble spread well into the medium range, a measure of forecast uncertainty currently used in the operational setting. Finally, the analysis difference and ensemble spread are shown to be independent; hence, the impact of these two quantities upon forecast skill is additive.

scholarly journals Decadal variability of the Kuroshio Extension: the response of the jet to increased atmospheric resolution in a coupled ocean–atmosphere model

2020 ◽  
Author(s):  
Giusy Fedele ◽  
Alessio Bellucci ◽  
Simona Masina ◽  
Stefano Pierini
Keyword(s):  
Large Scale ◽  
Decadal Variability ◽  
North Pacific Ocean ◽  
Kuroshio Extension ◽  
Low Frequency ◽  
Small Scale ◽  
The North ◽  
Ocean Atmosphere ◽  
The Impact ◽  
The Kuroshio

AbstractThe Kuroshio Extension (KE) shifts between elongated and convoluted states on interannual to decadal time scales. The nature of this low frequency variability (LFV) is still under debate since it is known to be driven by intrinsic oceanic mechanisms, but it is also synchronized with the Pacific Decadal Oscillation (PDO). In this analysis we present the results from two present-climate coupled simulations performed with the CMCC-CM2 model under the CMIP6 HighResMIP protocol and differing only by their atmospheric component resolution. The impact of increased atmospheric resolution on the KE LFV is assessed inspecting several aspects: the KE bimodality, the large-scale variability and the air–sea interactions. The KE LFV and the teleconnection mechanism that connects the KE and the PDO are well captured by both configurations. However, higher atmospheric resolution favors the occurrence of the elongated state and leads to a more realistic PDO representation. Moreover, both simulations qualitatively capture the signatures of atmosphere-driven and ocean-driven regimes over the North Pacific Ocean, even if the higher resolution induces an excessively strong ocean–atmosphere coupling that leads to an overestimation of the air–sea feedbacks. This work highlights that the small scale atmospheric variability (resolution lower than 1°) does not substantially contribute to improve the realism of the KE LFV, but causes significant differences in the air–sea interaction over the KE region likely related to the strengthening of the coupling. The eddy-permitting ocean resolution shared by both configurations is likely responsible for the degree of realism exhibited by the simulated KE LFV in the two analyzed simulations.

scholarly journals A modelling study of the 1976 climate regime shift in the North Pacific Ocean

1999 ◽  
Vol 56 (12) ◽  
pp. 2450-2462 ◽  
Author(s):  
Julia Qiuying Wu ◽  
William W Hsieh
Keyword(s):  
Pacific Ocean ◽  
North Pacific ◽  
General Circulation ◽  
Regime Shift ◽  
North Pacific Ocean ◽  
Circulation Model ◽  
Climate Regime ◽  
Climate Regime Shift ◽  
The North ◽  
The North Pacific

Around 1976, the North Pacific Ocean underwent a climate regime shift, with significant biological consequences. To model the changes in the ocean, an ocean general circulation model was forced by the wind stress and sea surface temperature monthly climatology of the 1952-1975 period in one numerical experiment and the 1976-1988 period in another. Changes in the ocean model between the two experiments revealed how the ocean might have changed under the 1976 climate regime shift. In winter, the intensified post-1976 Aleutian Low spun up the subarctic gyre and the subtropical gyre, except in the Gulf of Alaska, where the circulation weakened. Upwelling was generally enhanced in the subarctic and downwelling enhanced in the subtropical region, with temperature changes down to 600 m. In the post-1976 period, the meridional heat transports were also enhanced: poleward in the low latitudes, equatorward in the midlatitudes, and poleward in the high latitudes.

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