Annual and seasonal changes in the assemblage of planktonic copepods and appendicularians in Funka Bay before and after intrusion of Coastal Oyashio Water

Yamaoka, Hideyoshi; Takatsu, Tetsuya; Suzuki, Kota; Kobayashi, Naoto; Ooki, Atsushi; Nakaya, Mitsuhiro

doi:10.1007/s12562-019-01345-9

Cited by 4 publications

(1 citation statement)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Water temperature and salinity were measured at all stations from 2 m above the sea floor to the surface using a CTD (SBE‐19 plus; Seabird Electronics Inc., USA). Data of temperature and salinity from December 2013 to March 2014 and December 2014 to March 2015 in the 15 m depth layer of Stations 1–6 (Figure 1) were quoted from Yamaoka et al (2019). Ohtani (1971) defined the water masses that occur in Funka Bay as Tsugaru Warm Water (TWW; ≥33.6 in salinity and ≥6°C in temperature); Winter Funka Bay Water (FW; ≥33.8 and ≤6°C); and Coastal Oyashio Water (COW; ≤33.3 and ≤3°C).…”

Section: Methodsmentioning

confidence: 99%

Effect of egg size on the growth rate and survival of wild walleye pollock Gadus chalcogrammus larvae

Kajiwara

Nakaya

Suzuki

et al. 2022

Fisheries Oceanography

Self Cite

View full text Add to dashboard Cite

To clarify the survival process of walleye pollock larvae of the Japan Pacific stock in relation to the individual egg size, we estimated the original relative egg diameter from the diameter of the hatch check formed on larval sagittal otoliths. Significant positive correlations were obtained between egg diameter and embryonic body length, yolk sac volume, and lapillar otolith diameter in 3-year groups (2013-2015 year classes) collected with a plankton net in Funka Bay. Embryos before hatching were without a check; however, checks were observed on all larval otoliths just after hatching. The check diameters showed significant positive regressions to age at collection (days after hatching) in 2014 and 2015 year classes, however not in the 2013 year class. Diameters of eggs collected with a ring net in Funka Bay gradually increased from 2013 to 2015 year classes. During the 2013-2015 spawning seasons, the proportion of adult females of the 2007 and 2009 year classes, which had relatively high abundances, gradually increased to higher proportions with age (43%, 57%, and <73%, respectively), indicating that the mechanism by which the eggs gradually became larger. The low water temperature experienced by the spawners ca. 2 months earlier, advancement in spawner age, and increase of repeat spawners (at least twice in their life time) would contribute to the increase in egg size and growth and survival rate of walleye pollock larvae.

show abstract

Section: Methodsmentioning

confidence: 99%