Effects of near-future-predicted ocean temperatures on early development and calcification of the queen conch Strombus gigas

Abstract

The queen conch, Strombus (Lobatus) gigas, is one of six species of conch distributed throughout the Caribbean of significant commercial importance. The Caribbean region is adversely impacted by climate change, which affects the marine ecosystems and the calcification process of organisms with calcareous structures, such as mollusks. We tested the influence of global warming predicted in 2100 on queen conch, Strombus gigas larval development, growth, survival rate, and calcification by exposing egg masses and larvae to increased temperatures (28, 28.5, 29, 29.5, and 30 °C) for 30 days. For analysis of calcification, imaging and chemical mapping (proportion, wt) were performed on 30-day-old larvae using a high-resolution scanning electron microscopy (HR-SEM) and X-ray photoelectron spectroscopy (XPS). A temperature of 30 °C resulted in the highest larval growth rate (mean ± SD 27.33 ± 2.96 μm day−1), significantly among treatments (p ≤ 0.05). Development was fastest at 30 °C, where the first larvae settled by day 27 (49%) and the mortality rate was 76%. At 28 °C, day 29 was the first day where settlement was observed for 20% of the larvae. There are significant differences among treatments on larval growth and development. The calcification process of S. gigas larvae was not affected by the experimental temperatures tested. Percent Ca content of shelled larvae showed no significant differences among treatments (mean ± SD 25.44 ± 4.74 and 24.99 ± 0.74% w for larvae grown at 30 and 28 °C, respectively).