An investigation of personality in non-reserve and reserve snapper (Pagrus auratus)

Abstract

Previous studies at the Leigh Marine Laboratory demonstrate that snapper (Pagrus auratus) show consistent individual differences (CIDs), otherwise known as ‘personality’, with respect to their behaviour and physiology. Snapper are a commercially and recreationally valuable species, but the implication of personality differences for fisheries management and marine reserves is not entirely understood. However, empirical evidence suggests that variations in personality, specifically boldness, may be significant to the exploitation and dynamics of species abundance as a result of selective fishing. Additionally, evidence suggests that variations in physiology may drive variations in behaviour. To investigate this, the behaviour and physiology of legal-sized snapper were observed in fish from both CROP marine reserve, and the surrounding, non fished areas. Individuals were tested for their willingness to take risk in the presence of a novel object and food, and their activity was monitored to provide measurements of individual behaviour. Additionally, the standard metabolic rate (SMR) and cortisol concentrations of snapper were investigated under laboratory conditions, to provide measurements of individual physiology. Some evidence for significant differences in the behaviour of non-reserve and reserve snapper was determined under laboratory conditions. A significant correlation between risk taking and hormonal stress responsiveness was observed (p<0.01), although due to the absence of supporting significant differences in the metabolic rates and hormonal stress responses of the fish, this cannot be attributed to differing personalities between the two groups. Snapper personality was then investigated in a field setting. Boldness and hormonal stress response were once again observed in both non-reserve and reserve snapper. Evidence of personality differences between non-reserve and reserve snapper were found in a limited number of snapper under field conditions. Fish from the marine reserve were significantly bolder than non-reserve fish (p<0.05) and displayed significantly lower stress responsiveness (p<0.05). Additionally, stress response was significantly correlated to boldness in both reserve (p<0.001) and non-reserve (p=0.001) fish. Understanding personality differences in snapper may be the next stage in addressing the influence of animal behaviour on fisheries management.