Several clutches of Haemulon chrysargyreum eggs were purchased and shipped from a supplier in Florida, USA, and inspected for quality and development. A clutch was selected, eggs hatched, and larvae distributed among the 20 experimental aquaria at a stocking density of 130 individuals per aquarium. Larvae in each aquarium were subjected to one of 4 seawater pH treatments (8.10, 7.80, 7.60, 7.30) randomly assigned and replicated 5x. Seawater temperature in all aquaria was held constant at 28 C. Aquaria were filled with sterilized natural seawater, and 25% water changes were completed every 48 hrs. Larvae were fed ad libitum with wild copepods from monoculture (Pseudodiaptomus spp.) in a background of live microalgae (Isochrysis spp.). Larvae were reared under experimental conditions for 30 days until the majority achieved settlement competency.
Upon completion of the experimental trial, all surviving fish were removed from each aquarium, euthanized with a lethal dose of tricaine mesylate (MS-222) in seawater, and counted. Survival counts were subtracted from the initial stocking density to calculate mortality counts (see Related Dataset).
Smallmouth grunt otoliths were sampled and quantified for morphological variables according to the methodology reported in Holmberg et al. 2019 (earlier project). Briefly, otoliths were extracted from each experimental fish using microsurgical dissection techniques and photographed using a polarizing dissection microscope for morphometric analysis. Then, otoliths were mounted to aluminum stubs, coated with gold, and imaged using a scanning electron microscope for mineralogical analysis. The attached file "images.tar.gz" contains the SEM images.
The experimental trial took place between November and December 2013. The otolith morphology, fish length, and fish mortality data were collected over a 5-year span between January 2014 and August 2019.
