scholarly journals Spatiotemporal spawning patterns and early growth of Japanese sardine in the western North Pacific during the recent stock increase

2021 ◽  
Author(s):  
Yohei Niino ◽  
Sho Furuichi ◽  
Yasuhiro Kamimura ◽  
Ryuji Yukami
Keyword(s):  
North Pacific ◽  
Western North Pacific ◽  
Early Growth ◽  
Japanese Sardine

scholarly journals Spatio-temporal spawning patterns and early growth of Japanese sardine in the western North Pacific during the recent stock increase

2020 ◽  
Author(s):  
Yohei Niino ◽  
Sho Furuichi ◽  
Yasuhiro Kamimura ◽  
Ryuji Yukami
Keyword(s):  
North Pacific ◽  
Western North Pacific ◽  
Early Growth ◽  
Transitional Region ◽  
Initial Growth ◽  
Japanese Sardine ◽  
Growth And Survival ◽  
Successful Recruitment ◽  
Spatio Temporal ◽  
Spawning Periods

Spatio-temporal patterns in spawning influence growth and survival by affecting the environment experienced by offspring during their early life stages. Therefore, identifying changes in spawning patterns can help researchers understand population dynamics and recruitment fluctuations. The Japanese sardine Sardinops melanostictus is a small pelagic fish that undergoes large stock fluctuations. Although spawning patterns are known to change spatially and temporally with stock abundance, little information is available on the processes underlying stock increases. This study aimed to describe changes in spawning pattern and early growth of Japanese sardine during the recent period of stock increase, and to clarify the effects of different spawning periods on offspring growth. We examined trends in egg abundance in the western North Pacific in 2004-2018 and analyzed hatch dates and growth trajectories by otolith microstructure analysis of juveniles from the Kuroshio-Oyashio transitional region (the species' main nursery area). During the study period, the main spawning area shifted from the western to the eastern part of this region off Japan, and spawning in the eastern part roughly coincided with juvenile hatch dates. Hatch dates also shifted from mid-March at the earliest to February and early March from 2013 onwards. Although early-hatched cohorts (which originate offshore of eastern Japan) experienced slower initial growth, they likely played an important role in the recent stock increase. Successful recruitment of these cohorts may have been facilitated by factors such as early hatching and transport to the nursery, which reduces the frequency of predator encounters.

A simulation model for Japanese sardine (Sardinops melanostictus) migrations in the western North Pacific

2009 ◽  
Vol 220 (4) ◽  
pp. 462-479 ◽  
Author(s):  
Takeshi Okunishi ◽  
Yasuhiro Yamanaka ◽  
Shin-ichi Ito
Keyword(s):  
Simulation Model ◽  
North Pacific ◽  
Western North Pacific ◽  
Japanese Sardine

scholarly journals Stronger density-dependent growth of Japanese sardine with lower food availability: Comparison of growth and zooplankton biomass between a historical and current stock-increase period in the western North Pacific

2021 ◽  
Author(s):  
Yasuhiro Kamimura ◽  
Kazuaki Tadokoro ◽  
Sho Furuichi ◽  
Ryuji Yukami
Keyword(s):  
Density Dependence ◽  
Food Availability ◽  
North Pacific ◽  
Western North Pacific ◽  
Fish Population ◽  
Japanese Sardine ◽  
Density Dependent ◽  
Mesozooplankton Biomass ◽  
Current Period ◽  
Dependent Growth

Density dependence is a fundamental concept for fish population dynamics. Although density-dependent growth and maturity among older juveniles and adults is important for regulating fish population size and for fisheries management, the mechanism of density dependence for marine fishes remains unclear. Here, we examined changes in Japanese sardine growth with increasing abundance beginning in the 2010s and how the current pattern of density-dependent growth differs from that of a previous stock-increase period from the 1970s to early 1980s. During the current period of increasing abundance, mean standard length has already dropped to the lowest level yet observed and growth has declined more sharply with increased abundance than in the 1970s and 1980s. Mesozooplankton biomass in July in the summer feeding grounds was also lower during the current period. Therefore, our results suggest that summer food availability in the western North Pacific controls the strength of density-dependent growth. A lower carrying capacity for Japanese sardine could account for the stronger density dependence of growth observed in the 2010s; this indicates that future Japanese sardine abundance might not increase as much as in the 1980s unless food availability improves.

Impacts of climate change on growth, migration and recruitment success of Japanese sardine (Sardinops melanostictus) in the western North Pacific

2012 ◽  
Vol 115 (3-4) ◽  
pp. 485-503 ◽  
Author(s):  
Takeshi Okunishi ◽  
Shin-ichi Ito ◽  
Taketo Hashioka ◽  
Takashi T. Sakamoto ◽  
Naoki Yoshie ◽  
...  
Keyword(s):  
Climate Change ◽  
North Pacific ◽  
Western North Pacific ◽  
Japanese Sardine ◽  
Recruitment Success ◽  
Impacts Of Climate Change

Western North Pacific Tropical Cyclone Formation and Structure Change in TCS08

2013 ◽  
Author(s):  
Patrick A. Harr ◽  
Russell L. Elsberry
Keyword(s):  
Tropical Cyclone ◽  
North Pacific ◽  
Western North Pacific ◽  
Structure Change ◽  
Tropical Cyclone Formation

scholarly journals Is the Number of Tropical Cyclone Rapid Intensification Events in the Western North Pacific Increasing?

SOLA ◽  
2020 ◽  
Vol 16 (0) ◽  
pp. 1-5 ◽  
Author(s):  
Udai Shimada ◽  
Munehiko Yamaguchi ◽  
Shuuji Nishimura
Keyword(s):  
Tropical Cyclone ◽  
North Pacific ◽  
Western North Pacific ◽  
Rapid Intensification
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