Investigating prehistoric fisheries: growth-band and stable isotope analyses on otoliths of a critically endangered species (Totoaba macdonaldi) in the upper Gulf of California, Mexico.

Summary

Over 700 fish otoliths were recovered during archaeological excavations at the Rancho Punta Estrella sites on the northern Gulf coast of the Baja Peninsula of Mexico; over 120 of these have been identified as totoaba (Totoaba macdonaldi, Sciaenidae), a critically endangered species due to pressures from commercial fishing and human alterations of the Colorado River. AMS radiocarbon dates on seven totoaba otoliths suggest two primary occupations at ~4900-5400 cal BP and ~800-1150 cal BP. This study incorporates several analytical techniques for totoaba otoliths including: growth-band analysis, stable isotopes, and morphometric measurements; which are used to establish age and size estimates, and reconstruct local environmental conditions (SST). Oxygen (δ18O) and carbon (δ13C) isotope ratios have been used to generate inferences on the local habitats and life histories of totoaba, determine the season of capture, and investigate seasonal shifts in water temperature and salinity in the upper Gulf of California. Comparisons of archaeological and modern specimens revealed that pre-dam juveniles grew faster and matured earlier than post-dam totoaba. Our study contributes to the prehistoric record for this species, expanding our knowledge of indigenous fishing practices in the region and species-specific impacts related to the divergence of major waterways like the Colorado River.

This Resource is Part of the Following Collections

• Society for American Archaeology 82nd Annual Meeting, Vancouver, BC (2017)

Keywords

Record Identifiers

Abstract Id(s): 15986