In this study, we investigated the behavioural, morphological and physiological responses of the sea urchin (Strongylocentrotus intermedius) after subacute exposure to stranded heavy fuel oil (HFO) at oil loadings of 600, 1200, 2400 and 4800 μg oil g−1 gravel for 21 days. No significant differences in the survival rate and body size of S. intermedius were found following subacute exposure to stranded HFO at various oil loadings. Differently, the food consumption, covering behaviour, righting response and gonadosomatic index (GSI) showed obvious adverse effects at higher oil loadings, manifested as a low level of food consumption, reduced covering ability, slower righting speed and decreased GSI compared with the control. This study indicated that subacute exposure to the stranded HFO could cause an adverse effect on the fitness-related traits of sea urchins and provide new insights into the impact of oil spill pollution on benthic organisms.

The purpose of this study was to explore and compare the sex-specific differences in the toxic effects of water-accommodated fractions of 380# heavy fuel oil (HFO WAF) on the sea urchin Strongylocentrotus intermedius. Sea urchins were acutely exposed to HFO WAF at different nominal concentrations (0%, 10% and 20%) for seven days. The results showed that females had a higher polycyclic aromatic hydrocarbons (PAHs) bioaccumulation in gonad tissues and that both the total antioxidant capacity (TAC) and lipid peroxidation (LPO) levels in the gonad tissues of females were much higher than those of males. The PAHs bioaccumulation in gametes indicated that parents’ exposure could lead to a transfer of PAHs to their offspring, and eggs had higher TAC and LPO than sperms. After maternal and paternal exposure to HFO WAF, the frequency of morphological abnormalities of the offspring was increased when compared to the control. Overall, these results indicated that maternal exposure to HFO WAF could cause more significantly toxic effects on sea urchins than paternal exposure could, which could lead to more significantly negative effects on their offspring.

The sensitivity of female and male individuals of the same species to environmental stress is often different. The present study investigated sea urchins (Strongylocentrotus intermedius) of both sexes that were exposed to water-accommodated fractions of heavy fuel oil (HFO-WAF) for 7 d. Polycyclic aromatic hydrocarbons (PAHs) bioaccumulation in sea urchin gonad tissue was significantly increased following the exposure to HFO-WAF. However, PAHs bioaccumulation significantly differed between females and males, which may be related to the lipid content of gonad tissue. We found a significant increase in the percentage of anomalies in their larvae 24 h post fertilization. This indicates that parental exposure to HFO-WAF can have an adverse effect on the offspring, which may consequently affect population recovery and maintenance.