Seasonal change in the relationship between otolith radius and body length in age-zero Pacific saury Cololabis saira

Abstract

We examined seasonal changes in the relationship between otolith radius and body length in age-zero Pacific saury Cololabis saira collected from June to December 2002-2004, based on 12,164 specimens. Results of the analysis using a generalized linear model indicated that there were differences in the intercepts among months, but no difference was seen in the slopes. In addition, post hoc analysis showed that the intercepts got larger as the month progressed from June to December. These results suggested that although the body length growth rate decreased, the growth of the otolith does not decrease to the same degree as the body after September, so the ratio of otolith radius to body length becomes larger as the months pass. Consequently, we consider that the seasonal change in relation between otolith radius and body length affects the back-calculation of body length based on otolith radius.

Seasonal changes in otolith and somatic growth in age-0 Pacific saury Cololabis saira

“…As a result, the ratio of otolith radius to body length increased between June and November. Suyama et al [16] noted a similar phenomenon, based on analysis of the correlation between body length and otolith radius, for samples collected in every month. From June to November, not only did the ratio of otolith radius to body length increase, but the morphological patterns of growth also changed.…”

“…During this period, several changes are known to occur in the otolith: the hyaline zone starts to be formed [8,9,14,15] and the ratio of the otolith radius/body length changes [16]. These seasonal changes are considered to appear in the morphology of the otolith and are important for revealing the past life history based on observations of otolith microstructures.…”

Bomb Radiocarbon, Otolith Daily Increments and Length Modes Validate Age Interpretations of Chilean Jack Mackerel (Trachurus murphyi)

“…It is important to note that many species form the translucent zone (annulus) during periods of slow growth, which in some species may be linked to winter (i.e., the cold season), and in other species is the result of energy cost associated with spawning (e.g., Pearson, 1996;Suyama et al, 2006). Therefore, it is reasonable to infer that when the spawning season coincides totally or partially with the cold season, a well-marked and consistent annulus would be formed.…”

Use of saggital otolith shape analysis to discriminate Northeast Atlantic and Western Mediterranean stocks of Atlantic saury, Scomberesox saurus saurus (Walbaum)

“…However environmental factors that affect somatic and therefore otolith growth also have an effect on the otolith's final shape. For example temperature is proven to change the rate and pattern of deposition during otolith growth producing changes in the otolith length and overall shape (Lombarte and Lleonart, 1993;Oozeki and Watanabe, 2000;Suyama et al, 2009); feeding also influences otolith shape, to the point that even recent feeding history creates discernable differences in otolith shape (Gagliano and McCormick, 2004).…”