The amphipod Melita longidactyla occurs in great abundance and serves important roles in the trop... more The amphipod Melita longidactyla occurs in great abundance and serves important roles in the trophic transfer and nutrient recycling in marine systems along the Chinese coast. This study investigated the lethal dose (48 h LC 50 ), as well as sub-lethal effects of a common xenobiotic, 1,2-dichlorobenzene (1,2-DCB), on the bioenergetics, growth and reproduction of this important species. The 48 h LC 50 for M. longidactyla exposed to 1,2-DCB was 780 lg L À1 . Exposure to 20 lg L À1 1,2-DCB for 3 weeks resulted in 22% reduction in the growth (dry weight) and 57% reduction in the number of progeny, respectively. Furthermore, a significant reduction in RNA:DNA ratio was observed in amphipods exposed to 1,2-DCB at concentration as low as 5 lg L À1 , whereas significant reductions in scope for growth occurred upon exposure to higher concentrations of 1,2-DCB (10 and 20 lg L À1 ) for 3 and 5 weeks. Our results showed that environmentally relevant concentrations of 1,2-DCB can affect the bioenergetics and more importantly, growth and reproduction of M. longidactyla, implicating that 1,2-DCB may affect the recruitment and sustainability of natural populations of this ecologically important species.
Chattonella marina, a red tide or harmful algal bloom species, has caused mass fish kills and ser... more Chattonella marina, a red tide or harmful algal bloom species, has caused mass fish kills and serious economic loss worldwide, and yet its toxic actions remain highly controversial. Previous studies have shown that this species is able to produce reactive oxygen species (ROS), and therefore postulated that ROS are the causative agents of fish kills. The present study investigates antioxidant responses and lipid peroxidation in gills and erythrocytes of fish (Rhabdosarga sarba) upon exposure to C. marina, compared with responses exposed to equivalent and higher levels of ROS exposure. Even though C. marina can produce a high level of ROS, gills and erythrocytes of sea bream exposed to C. marina for 1 to 6 h showed neither significant induction of antioxidant enzymes nor lipid peroxidation. Antioxidant responses and oxidative damage did not occur as fish mortality began to occur, yet could be induced upon exposure to artificially supplied ROS levels an order of magnitude higher. The result of this study implies that ROS produced by C. marina is not the principal cause of fish kills.
Journal of Experimental Marine Biology and Ecology, 2011
This study investigated whether a mussel predator (the swimming crab Thalamita danae) and a scave... more This study investigated whether a mussel predator (the swimming crab Thalamita danae) and a scavenger (the gastropod Babylonia lutosa) could induce anti-predator response in the green-lipped mussel Perna viridis by chemical means. The crabs and gastropods had been either starved or recently fed with the mussels. We examined the number, diameter, length and volume of byssus threads produced by the mussels in order to compare the intensity of anti-predator responses when they were exposed to different stimuli. Our results showed that the mussels produced a significantly larger volume of byssus threads when they were exposed to a crab that had recently consumed conspecifics than the mussels in the control group. The starved crab had a weak effect on increasing the number, length, diameter and volume of byssus threads. Furthermore, the scavenging gastropods failed to increase byssus thread production in the mussels, no matter they had been starved or consumed conspecifics. Indeed, byssus thread production is energetically costly. It would be maladaptive for the mussels to increase byssus thread production in response to a low predation risk presented by a scavenger.
The effects of hypoxia on the larvae of two sub-tidal nassariid gastropods, Nassarius siquijorens... more The effects of hypoxia on the larvae of two sub-tidal nassariid gastropods, Nassarius siquijorensis and N. conoidalis were compared so as to understand how the species-specific tolerance to hypoxia might have resulted in changes in the abundance and distribution of these two species in the hypoxic Tolo Harbour, Hong Kong, since the 1980s. Respiration rates of N. siquijorensis and N. conoidalis larvae were reduced at 4.5 mg O 2 l À1 , or below, as compared with the normoxic control. Significant reduction in swimming velocity was also observed for 10-day old larvae which were exposed to <2.0 mg O 2 l À1 for N. siquijorensis and <1.0 mg O 2 l À1 for N. conoidalis. The 48 h LC 50 values of N. siquijorensis and N. conoidalis larvae were 0.7 and 1.7 mg O 2 l À1 , respectively. The results suggested that N. siquijorensis are more tolerant to hypoxia than N. conoidalis.
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Papers by Jill Chiu