Did sturgeon ever breed in Britain? Evaluating historical evidence and conservation implications

Abstract

Historical archives can provide unique perspectives on past biodiversity and have the potential to reconstruct life-history cycles for lost populations. Two sturgeon species (Acipenser sturio and A. oxyrinchus) are historically documented from Britain, but evidence for whether sturgeon formerly bred in British rivers has not been systematically evaluated. British sturgeon records mainly sourced from nineteenth- and twentieth-century newspapers contain >10 records from 24 rivers and >50 records from nine rivers, with 196 records from the Severn. River records show strong spring–summer seasonality matching the timing of spawning migrations in extant populations, with multiple individuals often reported together and numerous records of fish in spawning condition. Historical accounts and historical and archaeological specimens document individuals below the size at which young sturgeon leave natal estuaries, and indicate small individuals remained in estuaries outside the spawning period. The species identity of sturgeon mentioned in historical accounts is hard to determine, although most juvenile British specimens probably represent A. oxyrinchus. Assessment of multiple archives provides strong evidence of past sturgeon breeding in many British rivers throughout the nineteenth century and into the twentieth century, establishing a new baseline for interpreting sturgeon as native British species with important implications for their potential reintroduction.