Trade-off between reproductive effort and adult survival in oviparous and viviparous fishes

An interspecific analysis of life history characteristics for 28 stocks of fish showed that age at maturity (alpha), natural mortality (M), and reproductive effort (gonadosomatic index, GSI) were weakly (r(2)= 0.18-0.33) but significantly correlated with body size. Viviparity was associated with reduced reproductive effort, reduced age at maturity, and low M relative to oviparous species of a corresponding size. The allometric relationships of alpha, M, and GSI with L-infinity showed a high degree of scatter but were in agreement with predictions from models based on metabolic and ecological constraints on assimilation rate. In addition, however, residuals around the GSI-L-infinity and M-L-infinity relationships showed a strong positive correlation (r(2) = 0.64), consistent with previous intraspecific manipulation experiments that indicated that reproductive effort and Mare genetically linked. A strong positive correlation (r(2) = 0.75) was found between GSI and M, and this relationship did not differ significantly between oviparous and viviparous species.