Evidence of lower age, fast growth, and shrinking habitat in critically endangered croaker fish Larimichthys crocea

Abstract

Overexploitation can impact the life history traits of fish significantly altering growth rates and habitat use. The large yellow croaker (Larimichthys crocea) in the Northwest Pacific has been heavily harvested for nearly half a century, pushing it to the brink of extinction. However, traditional methods have failed to capture historical baselines data on its age structure, growth patterns, and habitat use due to changes that occurred before systematic scientific surveys began. This study aimed to reconstruct these baseline data by analyzing otoliths from three distinct geological times representing varying levels of human disturbance: Early Pleistocene (fossil site dated 1.90–1.35 Ma), Middle to Late Holocene (archaeological sites dated 5000–1000 B.P.), and modern periods. Biological age was estimated from otoliths and verified using stable isotope (δ¹⁸O) analysis. Modern wild large yellow croakers are significantly younger (1.1 ± 0.8 years) compared to those from the Holocene (3.2 ± 1.8) and Pleistocene periods (5.3 ± 2.4). Additionally, modern otoliths exhibit a higher growth rate compared to archaeological and fossil otoliths. Many archaeological and fossil otoliths show δ¹⁸O values well below −4‰, indicating that historical populations of large yellow croaker inhabited a broader range of environments, including brackish water conditions not observed in modern populations. These findings highlight how human impact has acted as a selective pressure on fish, leading to significant changes in age, growth patterns, and habitat use.