Dataset: Development and survivorship of juvenile red abalone

 A gas-controlled aquarium (GCA) system housed at Monterey Bay Aquarium Research Institute was utilized, 64 tanks that are individually and randomly delivered water from each of 4 predefined treatments: (1) ambient pH with ambient temperature (control); (2) reduced pH with ambient temperature (OA individually); (3) ambient pH with heated temperature (OW individually); and (4) low pH with heated temperature (OA and OW). Ambient seawater was collected from an intake in Monterey Bay. Offset values from ambient were used as opposed to constant treatments to achieve fluctuation that matched the degree of natural daily/seasonal fluctuations in Monterey. Low pH was defined as a - 0.5 pH unit offset from ambient to represent potential OA conditions projected for the year 2100, exacerbated by upwelling. Erroneous system functioning caused unexpected spiking of temperature within temperature treated tanks, thus these treatments were not utilized in analysis. 256 juvenile H. rufescens (post-settlement, <1 yr) of 2 size classes were weighed and photographed for later measurement of initial shell length and surface area using ImageJ. Individuals were randomly distributed into GCA system tanks in groups of 4, 2 of each size class. After 28 days, abalone were once again photographed and weighed. Shells and tissue were separated, and shells were dried and measured for final dry shell weight. There was a significant interaction between pH and size class, F(1,124) = 4.31, p = 0.04. The small size class in low pH was significantly different in change in surface area from the other group means, with a mean change of -0.006 ± 0.039 cm2 (mean ± SD) while all others had positive average changes. Final dry shell weight varied with size class and pH, F(1,124) = 422.9, p < 0.001, and F(1,124) = 6.61, p = 0.01, respectively. The small size class in high pH had a significantly higher average final dry shell weight, 0.138 ± 0.052 g (mean ± SD), than that of the small size class in low pH, 0.104 ± 0.034 g (mean ± SD), p = 0.027. Size class significantly predicted mortality, z = 2.515, p = 0.012.