Figure 1.
Measurement taken for morphometric analysis.
A) red king crabs, and B) Tanner crabs. Measurement on red king crabs included carapace width (CW), carapace length (CL), rostrum base width (RW), orbital spine width (OW), and the first spine length (SL). Measurements on Tanner crab included carapace width (CW), carapace length (CL), carapace length to the rostrum (CLR), carapace length to the eye orbit (CLO), rostrum base width (RW), rostrum length (RL), orbital spine width (OW), and orbital spine length (OL). The scale bars are 0.5 mm.
Figure 2.
Temperatures in experimental treatments during experiment.
Mean daily temperature in individual holding cells for red king crabs and Tanner crabs throughout the experiment from June to December 2010. The average daily standard deviation (not shown) was 0.1 °C.
Table 1.
The mean and standard error (SE) of water chemistry parameters measured (DIC, and Alkalinity) and calculated (all others, see text for details) in the three treatments during the experiments.
Figure 3.
Survival of crabs in Control and Acidified water.
Red king crab (A), and Tanner crabs (B) in control and treatment tanks over the duration of the experiment. Maximum likelihood estimated mortality rates±standard error were Control −0.0023±0.00007 day−1, pH 7.8−0.0047±0.00011 day−1, pH 7.5−0.025±0.00066 day−1 for red king crab and Control -0.0010±0.00004 day−1, pH 7.8-0.0023±0.00007 day−1, pH 7.5-0.0050±0.00011 day−1 for Tanner crab. See text for model details.
Table 2.
Models of survival for red king crab and Tanner crab ranked using AICc.
Figure 4.
Changes in crab morphology in Control and Acidified water.
Mean PC1 scores (±SE) from principle component analysis of red king crab (A) and Tanner crab (B) morphometrics for each molt for crabs held in Control, pH 7.8, and pH 7.5 water. Symbols with different letters beside them differ significantly within that molt stage. Note that crab size is inversely proportional to PC1 for both species.
Table 3.
Principal component analysis of red king crab morphometrics.
Table 4.
Principal component analysis of Tanner crab morphometrics.
Figure 5.
Growth of red king crab in Control and pH 7.8 water.
A) Carapace length and B) Wet mass. Points represent individual measurements and lines the best fit models (see text for details. Equations for the lines are: Control-CL = 0.00737t+2.34, WM = 0.00667e0.000829t; pH 7.8-CL = 0.000506t+2.38, WM = 0.00667e0.000557t where CL is carapace length, WM is wet mass, and t is time in degree days.
Table 5.
Models of red king crab growth ranked using AICc.
Figure 6.
Growth of Tanner crab in Control and Acidified water.
A) carapace width and B) wet mass. Lines represent the average CW or wet mass after each molt and the distance between the vertical jumps indicates the average intermolt duration. The height of the final line represents the average CW or wet mass at the end of the experiment and the number indicates the percentage of crabs molting a third time in each of the treatments.
Figure 7.
Condition index and calcification in crabs held in Control and Acidified water.
Condition index of red king crabs (A) and Tanner crabs (B) and percent calcium (dry mass) in red king crabs (C) and Tanner crabs (D) at the end of the experiment. Bars are mean+SE. Bars with different letters above them differ significantly.