Effects of non-spawning season (yolkless to early yolk formation stage) temperature on growth and reproductive characteristics in hatchery-reared, repeat-spawning walleye pollock Gadus chalcogrammus

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

“…In the case of walleye pollock JPS, there is a trade-off in the size of eggs because the water temperature decreases gradually before and during the spawning season (Figure 11). In JPS, however, the tendency for older fish to spawn early was greater, and these mature females laid large eggs early in the spawning season (Sakurai, 1989;Tanaka et al, 2019Tanaka et al, , 2020, and so large eggs appeared early in the spawning season. Furthermore, as the matured female individuals aged, the eggs became larger, so it is likely that the eggs gradually increased in size between the 2013 and 2015 classes.…”

“…Thus, clear‐cut phenotypic responses rather than genetic traits are considered as principal drivers in the maternal effects hypothesis (Bernardo, 1996; Johnston & Leggett, 2002). The maternal effects hypothesis has been verified in Atlantic cod ( Gadus morhua ; Chambers & Waiwood, 1996; Kjesbu et al, 1992; Marteinsdottir & Steinarsson, 1998; Vallin & Nissling, 2000), haddock ( Melanogrammus aeglefinus ; Hislop, 1988; Trippel & Neil, 2004), European sardine ( Sardina pilchardus ; Riveiro et al, 2004), Pacific herring ( Clupea pallasii ; Takayanagi & Ishida, 2002), black rockfish ( Sebastes melanops ; Berkeley et al, 2004), marbled sole ( Pseudopleuronectes yokohamae ; Higashitani et al, 2007), and walleye pollock ( G. chalcogrammus ; Tanaka et al, 2020). Tanaka et al (2020) showed that larger eggs of hatchery‐reared walleye pollock were spawned from fish that had greater increases in weight and condition during the non‐spawning season.…”

“…The maternal effects hypothesis has been verified in Atlantic cod ( Gadus morhua ; Chambers & Waiwood, 1996; Kjesbu et al, 1992; Marteinsdottir & Steinarsson, 1998; Vallin & Nissling, 2000), haddock ( Melanogrammus aeglefinus ; Hislop, 1988; Trippel & Neil, 2004), European sardine ( Sardina pilchardus ; Riveiro et al, 2004), Pacific herring ( Clupea pallasii ; Takayanagi & Ishida, 2002), black rockfish ( Sebastes melanops ; Berkeley et al, 2004), marbled sole ( Pseudopleuronectes yokohamae ; Higashitani et al, 2007), and walleye pollock ( G. chalcogrammus ; Tanaka et al, 2020). Tanaka et al (2020) showed that larger eggs of hatchery‐reared walleye pollock were spawned from fish that had greater increases in weight and condition during the non‐spawning season. Verification of the maternal effects hypothesis so far has been limited to laboratory experiments comparing the length, the number of days without feeding, the growth rate, and the survival rate of larvae obtained from female parent fish of various characteristics.…”