Understanding the timing of oyster spawning in Delaware Bay is critical for effective oyster restoration, enhancement, and management. This knowledge is essential for optimizing shell planting, shellfish transfers, and harvest strategies. A deeper insight into local spawning patterns and their interaction with environmental factors can improve both the conservation of oyster populations and support the shellfish industry while benefiting ecosystem health.
Oyster spawning in Delaware Bay occurs from late spring to early summer. Timing is largely influenced by the seasonal temperature cycle and food availability. Like other regions, the Delaware Bay is warming, which could alter the timing of oyster reproduction.
This study examined the use of gross observations of oyster condition to provide real-time feedback to the industry stakeholders and resource managers, followed by histological analysis to gain detailed insights into gonadal tissue development and the timing of spawning. Weekly samples of ten to fifteen oysters were collected from commercial landings during the 2024 season and compared to archived monthly samples from 2014. Histological gonad ratings were correlated with gross observations and used to determine the timeline of gonad development and spawning during 2024, then compared with a histological timeline from 2014 to assess change over the last decade. Corresponding temperature and salinity data were analyzed to understand environmental influence on the observed spawning periods.
Despite an average annual temperature increase of 0.91°C since 2014, our findings indicate that the spawning period remained mid to late June, but was shorter in 2024. This pattern indicates later season shellplants may fail to obtain set, informing management strategies in the face of climate change.