The Importance of a Northern Gulf of Mexico Spring Transition As Inferred from Marine Fish Biochronologies

Multidecadal biochronologies were generated from the otolith growth-increment widths of reef-dwelling red snapper (Lutjanus campechanus) and gray snapper (L. griseus), migratory king mackerel (Scomberomorous cavalla), and estuarine black drum (Pogonia cromis), all collected from the Gulf of Mexico.  Synchronous growth patterns were evident within each species, which facilitated the development of exactly dated biochronologies, the longest of which spanned 46 years.  All species significantly (p < 0.05) and positively correlated to sea surface temperatures (SST) in the northern Gulf of Mexico, especially between March and June.  Red and gray snapper correlated with SST early in the springtime window (March and April), as did mackerel (March through May), while drum correlated from May through June.  The leading principal component (PC1_fish) of these four fish chronologies captured 68% of the variability in the dataset, underscoring the synchrony among these fish time series.  PC1_fish also positively correlated to sea level pressure in the Gulf of Mexico and western Atlantic in the area of the Bermuda High.  Thus, a strong springtime Bermuda High and associated warm temperatures are favorable for fish growth and may reflect a broader spring transition from a winter to summertime climate pattern in the northern Gulf.