Pteropods are marine pelagic calcifies mollusks dive to chemical changes in seawater due to their highly soluble aragonite shells, Increased acidity (reduced pH) of seawater causes difficulties in precipitating their shells and/or results in their dissolution, which is related to increased atmospheric CO2 concentrations and warming of seawater. They are therefore indicators of environmental changes. In this paper, we present the first record of the straight-needle pteropod Creseis acicula Rang, 1828 bloom in the surface waters of the canakkale Strait, Turkey (NE Aegean Sea), encountered in July 2020, when the highest sea surface temperatures and pH levels since 2007 were recorded. In coastal zones, such as the canakkale Strait, anthropogenic activity contributes significantly to environmental changes. Consequently the increase in pH at elevated temperatures indicates an auxiliary factor (i.e. anthropogenic activity) that triggered the C. acicuin bloom, rather than globs atmospheric CO2 levels.