Does Daily Growth Affect the Rate of Manganese Uptake in Juvenile River Herring Otoliths?

• Published in: Transactions of the American Fisheries Society (1900) 2015-09, Vol.144 (5), p.873-881
• Main Authors: Turner, S. M, Limburg, K. E
• Format: Article
• Language: English
• Subjects: Alosa aestivalis; Alosa pseudoharengus; animal growth; herring; hypoxia; juveniles; manganese; otoliths; rivers
• ISSN: 1548-8659; 0002-8487; 1548-8659
• DOI: 10.1080/00028487.2015.1059888

Manganese is a commonly found constituent in fish otoliths, yet a direct correlation with ambient water concentrations as observed for other elements has proven elusive. There is compelling evidence that Mn uptake is related to the availability of reduced Mn (Mn ²⁺) resulting from hypoxia (Limburg et al. 2015) but that fish growth rate also plays a role. We tested the latter possibility by examining otoliths from anadromous river herring (Alewife Alosa pseudoharengus and Blueback Herring A. aestivalis) in New York waters. A significant correlation was found between the ages at which shifts in otolith daily growth increments (assumed proportional to somatic growth) and shifts in otolith Mn:Ca ratios were detected. Furthermore, significant positive Spearman's rank correlations were observed between mean otolith daily growth and otolith Mn:Ca. Species- and site-specific differences were evident, but significant positive correlations were found for these relationships within each species and at most sampling sites. Ambient water concentrations were weakly correlated with otolith Mn:Ca, suggesting that both exogenous and endogenous factors influence Mn:Ca in otoliths. Thus, while endogenous mechanisms (i.e., growth rate) likely influence Mn uptake, exogenous availability is the ultimate control. Received March 12, 2015; accepted June 2, 2015