Are hatchery-reared abalone naive of predators? Comparing the behaviours of wild and hatchery-reared northern abalone, Haliotis kamtschatkana (Jonas, 1845)

摘要

Abalone populations have declined worldwide, generating interest in enhancement using hatchery-reared individuals. In many cases, such restoration efforts have met with limited success due to high predator-induced mortality rates. Furthermore, the mortality rates of outplanted hatchery abalone are often considerably higher than for wild individuals. This study uses northern abalone (Haliotis kamtschatkana) as a case study to determine whether hatchery-reared abalone behave differently than their wild counterparts. In the field, outplanted hatchery-reared abalone were significantly less responsive than wild abalone, in terms of number of abalone responding and intensity of response, to nearby movement and to physical contact with an inert probe. Also, when encountering a cue to which all abalone responded (a seastar predator), hatchery-reared individuals remained subdued. Anti-predator behavioural deficits in hatchery-reared abalone were more pronounced in 4-year-old individuals than in 1-year-old individuals, suggesting an influence of either age or amount of time spent in the hatchery environment. These behavioural differences are expected to increase the vulnerability of hatchery-reared abalone to predators, and are likely a major cause of their elevated predator-induced mortality when outplanted.