We conducted 4 experiments to study the effects of salinity and temperature on the barnacle Balanus amphitrite amphitrite Darwin, with particular focus on the effects of stress experienced in one life-stage on the performance of the next life-stage. At 15°C, typical winter water temperature in Hong Kong, larvae exhibited low survivorship, adults molted infrequently, and only a low percentage of individuals had developing ovaries and embryos. However, at 30°C, typical summertime temperature in Hong Kong, larvae developed rapidly, survivorship was high, adults molted frequently, and a high percentage of individuals had developing ovaries and embryos. These results suggest that low winter temperature may be a limiting factor responsible for cessation of recruitment, whereas high summer temperature is unlikely to be the cause for the decline in recruitment. Salinity produced significant detrimental effects on both survival and development at ≤10 ‰. In the 15 to 35 ‰ S range, however, none of the stages tested exhibited signs of stress. Salinity is a limiting factor for the survival and development of B. a. amphitrite in Hong Kong only during mid-summer when salinity in the surface water can drop to below 10‰. Exposing embryos to different salinities produced differential effects on larvae. For larvae cultured at 10‰ S, both survivorship and time of development were independent of the salinity that the embryos had experienced; for larvae cultured at 15 and 35‰ S, exposing embryos to 10 ‰ S led to lower larval survivorship and longer larval development times. Exposing cypris larvae to 10‰ S did not alter juvenile growth but did result in lower survivorship. Osmotic stress experienced in one life-stage can be passed over to the next life-stage. In bioassays involving the use of B. a. amphitrite, results of the tested life-stage may be affected by stress experienced in a previous life-stage.
Scopus Subject Areas
- Ecology, Evolution, Behavior and Systematics
- Aquatic Science