Transoceanic migration rates of young North Pacific albacore, Thunnus alalunga, from conventional tagging data

2008 ◽  
Vol 65 (8) ◽  
pp. 1681-1691 ◽  
Author(s):  
Momoko Ichinokawa ◽  
Atilio L. Coan, ◽  
Yukio Takeuchi
Keyword(s):  
North Pacific ◽  
Seasonal Migration ◽  
Western Pacific ◽  
Migration Routes ◽  
Migration Rates ◽  
The North ◽  
Maximum Likelihood Methods ◽  
Westward Movement ◽  
Thunnus Alalunga ◽  
The North Pacific

This study summarizes US and Japanese historical North Pacific albacore ( Thunnus alalunga) tagging data and uses maximum likelihood methods to estimate seasonal migration rates of young North Pacific albacore. Previous studies related to North Pacific albacore migration have found that the frequency of albacore migrations is difficult to quantify because of inadequate amounts of tags released by the US tagging program in the western Pacific. Use of the combined Japan and US tagging data solves this problem. This study also incorporates specific seasonal migration routes, hypothesized in past qualitative analyses, to avoid overparameterization problems. The estimated migration patterns qualitatively correspond to those from previous studies and suggest the possibility of frequent westward movements and infrequent eastward movements in the North Pacific. This frequent westward movement of young albacore in the North Pacific would correspond to a part of albacore life history in which immature fish recruit into fisheries in the western and eastern Pacific and then gradually move near to their spawning grounds in the central and western Pacific before maturing.

Age and growth of albacore Thunnus alalunga in the North Pacific Ocean

2012 ◽  
Vol 80 (6) ◽  
pp. 2328-2344 ◽  
Author(s):  
K.-S. Chen ◽  
T. Shimose ◽  
T. Tanabe ◽  
C.-Y. Chen ◽  
C.-C. Hsu
Keyword(s):  
Pacific Ocean ◽  
North Pacific ◽  
North Pacific Ocean ◽  
Age And Growth ◽  
The North ◽  
Thunnus Alalunga ◽  
The North Pacific

scholarly journals Geolocator tagging links distributions in the non-breeding season to population genetic structure in a sentinel North Pacific seabird

PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0240056
Author(s):  
J. Mark Hipfner ◽  
Marie M. Prill ◽  
Katharine R. Studholme ◽  
Alice D. Domalik ◽  
Strahan Tucker ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Pacific Ocean ◽  
Genetic Differentiation ◽  
Breeding Season ◽  
North Pacific ◽  
Western Pacific ◽  
The North ◽  
Wintering Areas ◽  
The North Pacific ◽  
Rhinoceros Auklet

We tested the hypothesis that segregation in wintering areas is associated with population differentiation in a sentinel North Pacific seabird, the rhinoceros auklet (Cerorhinca monocerata). We collected tissue samples for genetic analyses on five breeding colonies in the western Pacific Ocean (Japan) and on 13 colonies in the eastern Pacific Ocean (California to Alaska), and deployed light-level geolocator tags on 12 eastern Pacific colonies to delineate wintering areas. Geolocator tags were deployed previously on one colony in Japan. There was strong genetic differentiation between populations in the eastern vs. western Pacific Ocean, likely due to two factors. First, glaciation over the North Pacific in the late Pleistocene might have forced a southward range shift that historically isolated the eastern and western populations. And second, deep-ocean habitat along the northern continental shelf appears to act as a barrier to movement; abundant on both sides of the North Pacific, the rhinoceros auklet is virtually absent as a breeder in the Aleutian Islands and Bering Sea, and no tagged birds crossed the North Pacific in the non-breeding season. While genetic differentiation was strongest between the eastern vs. western Pacific, there was also extensive differentiation within both regional groups. In pairwise comparisons among the eastern Pacific colonies, the standardized measure of genetic differentiation (FꞌST) was negatively correlated with the extent of spatial overlap in wintering areas. That result supports the hypothesis that segregation in the non-breeding season is linked to genetic structure. Philopatry and a neritic foraging habit probably also contribute to the structuring. Widely distributed, vulnerable to anthropogenic stressors, and exhibiting extensive genetic structure, the rhinoceros auklet is fully indicative of the scope of the conservation challenges posed by seabirds.

Influence of the North Pacific Victoria mode on the Madden–Julian Oscillation

2020 ◽  
Author(s):  
Tao Wen ◽  
Quanliang Chen ◽  
Jianping Li ◽  
Ruiqiang Ding ◽  
Yu-heng Tseng ◽  
...  
Keyword(s):  
Significant Influence ◽  
North Pacific ◽  
Western Pacific ◽  
Kelvin Wave ◽  
Central Pacific ◽  
Low Level ◽  
The North ◽  
The North Pacific ◽  
Sst Gradient ◽  
Sst Anomalies

<p>The influence of the North Pacific Victoria mode (VM) on the Madden–Julian Oscillation (MJO) are examined in this analysis. The results show that the February–April (FMA) VM had a significant influence on the development and propagation of the MJO over the equatorial central–western Pacific (ECWP) during spring (March–May) between 1979 and 2017. Specifically, MJO development was favored more by positive VM events than negative VM events. One probably description for these complicated connections is that the SST gradient anomalies associated with positive VM events enhance the convergence of low-level over the ECWP, which, combined with the warm SST anomalies (SSTAs) in the equatorial central Pacific that lead to a boost in the Kelvin wave anomalies, results in the enhanced MJO activity over the ECWP. These conclusions indicate that the VM is an important factor in MJO diversity.</p>

Short communication: New data support phylogeographic patterns in a marine parasite Tristriata anatis (Digenea: Notocotylidae)

2019 ◽  
Vol 94 ◽  
Author(s):  
Anna Gonchar ◽  
Kirill V. Galaktionov
Keyword(s):  
North Pacific ◽  
Barents Sea ◽  
Life Cycles ◽  
Intraspecific Diversity ◽  
Migration Routes ◽  
Arctic Ecosystems ◽  
Reproduction Mode ◽  
North East ◽  
The North ◽  
The North Pacific

Abstract Intraspecific diversity in parasites with heteroxenous life cycles is guided by reproduction mode, host vagility and dispersal, transmission features and many other factors. Studies of these factors in Digenea have highlighted several important patterns. However, little is known about intraspecific variation for digeneans in the marine Arctic ecosystems. Here we analyse an extended dataset of partial cox1 and nadh1 sequences for Tristriata anatis (Notocotylidae) and confirm the preliminary findings on its distribution across Eurasia. Haplotypes are not shared between Europe and the North Pacific, suggesting a lack of current connection between these populations. Periwinkle distribution and anatid migration routes are consistent with such a structure of haplotype network. The North Pacific population appears ancestral, with later expansion of T. anatis to the North Atlantic. Here the parasite circulates widely, but the direction of haplotype transfer from the north-east to the south-west is more likely than the opposite. In the eastern Barents Sea, the local transmission hotspot is favoured.

The Impact of ENSO on Atmospheric Intraseasonal Variability as Inferred from Observations and GCM Simulations

2005 ◽  
Vol 18 (12) ◽  
pp. 1902-1924 ◽  
Author(s):  
Chi-Yung Tam ◽  
Ngar-Cheung Lau
Keyword(s):  
North Pacific ◽  
Intraseasonal Variability ◽  
Wave Activity ◽  
Western Pacific ◽  
Incoming Wave ◽  
Enso Events ◽  
The North ◽  
The Tropics ◽  
The Impact ◽  
The North Pacific

Abstract The impact of the El Niño–Southern Oscillation (ENSO) on the atmospheric intraseasonal variability in the North Pacific is assessed, with emphasis on how ENSO modulates midlatitude circulation anomalies associated with the Madden–Julian oscillation (MJO) in the Tropics and the westward-traveling patterns (WTP) in high latitudes. The database for this study consists of the output of a general circulation model (GCM) experiment subjected to temporally varying sea surface temperature (SST) forcing in the tropical Pacific, and observational reanalysis products. Diagnosis of the GCM experiment indicates a key region in the North Pacific over which the year-to-year variation of intraseasonal activity is sensitive to the SST conditions in the Tropics. In both the simulated and observed atmospheres, the development phase of the dominant circulation anomaly in this region is characterized by incoming wave activity from northeast Asia and the subtropical western Pacific. Southeastward dispersion from the North Pacific to North America can be found in later phases of the life cycle of the anomaly. The spatial pattern of this recurrent extratropical anomaly contains regional features that are similar to those appearing in composite charts for prominent episodes of the MJO and the WTP. Both the GCM and reanalysis data indicate that the amplitude of intraseasonal variability near the key region, as well as incoming wave activity in the western Pacific and dispersion to the western United States, are enhanced in cold ENSO events as compared to warm events. Similar modulations of the MJO-related circulation patterns in the extratropics by ENSO forcing are discernible in the model simulation. It is inferred from these findings that ENSO can influence the North Pacific intraseasonal activity through its effects on the evolution of convective anomalies in the tropical western Pacific. On the other hand, there is little modification by ENSO of the circulation features associated with the WTP. The combined effect of the MJO and WTP on the intraseasonal circulation in the North Pacific is studied. Based on multiple regression analysis, it is found that the MJO and WTP make comparable contributions to the variability in the midlatitude North Pacific. These contributions may be treated as a linear combination of the anomalies attributed to the MJO and WTP separately.

Frequency of Increment Formation on Sagittae of North Pacific Albacore (Thunnus alalunga)

1985 ◽  
Vol 42 (9) ◽  
pp. 1552-1555 ◽  
Author(s):  
R. M. Laurs ◽  
R. Nishimoto ◽  
J. A. Wetherall
Keyword(s):  
North Pacific ◽  
Average Rate ◽  
Commercial Fisheries ◽  
Systematic Bias ◽  
Otolith Growth ◽  
The North ◽  
Daily Increments ◽  
Increment Formation ◽  
Thunnus Alalunga ◽  
The North Pacific

An examination of sagittae from 116 albacore (Thunnus alalunga) caught in the North Pacific, injected with tetracycline, tagged, released, and subsequently recaptured in sport and commercial fisheries showed that detectable increments are formed on these otoliths at an average rate of 0.954 per day. We take this as a confirmation of daily increment formation in North Pacific albacore sagittae. The slight departure of observed mean increment counts from the expected rate of one per day may be due to an occasional interruption of otolith growth, or to a systematic bias in detecting daily increments or interpreting otolith microstructure. The estimated rate of detectable increment formation applies explicitly to albacore of fork lengths between about 50 and 100 cm. If the same rate holds for fish smaller than 50 cm, as is likely, most albacore taken in sport or commercial catches can be aged accurately by applying our methods and expanding the increment count by 5%.

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