An experiment was carried to study the effect of a simulated heatwave on the survival of two intertidal invertebrates, Carcinus maenas and Hemigrapsus sanguineus. Animals where collected on Helgoland and larvae hatched in the laboratory; the experiment was restricted to the larval stages. Larvae were reared in 5 replicate groups of 10-11 individuals in filtered water and fed Artemia sp. nauplii (glasses of 60 ml). There were four thermal treatments: 1: low - constant temperature; 2: smooth increase in temperature; 3: high constant temperature; 4: sudden increase in temperature simulating a short heatwave. Treatment 1 and 2 had the same average temperature (16.5 °C) as well as treatments 3 and 4 (=17.5 °C). Treatment 2 started with temperature at 15 °C and it increased 0.5 °C every day; treatment 4 started also at 15 °C and increased to 18 °C on day 1 where it remained constant until the end of the experiment. The four thermal treatments were applied to groups of larvae under three different additional treatments: (A) Food provided 24 h a day - salinity = 32 PSU; (B) Food provided 6 h a day - salinity = 32 PSU;Food provided 24 h a day - salinity = 20 PSU. The experiment was repeated with larvae from 3 females of each of the above mentioned species. The response variable was the survival proportion to the second larval stage (Zoea II).

File containing two tables corresponding to survival rates of larvae of two species (Hemigrapsus sanguineus and Carcinus maenas) under different conditions of food availability, temperature and salinity.