Cryptic corals: Coral polyp size and biometry are indicators of feeding mechanisms

Reef-building coral species are found in relatively stable environments with specific environmental conditions such as water temperatures ranging from 25◦C-29◦C. However, two cryptic coral species (non-reef building), Astrangia poculata, and Oculina diffusa were recently documented in a shipping channel in Corpus Christi, TX. However, there is little information regarding these coral colonies in Corpus Christi, TX. Therefore, this study aims to investigate the primary feeding mechanism of the cryptic coral species to understand the survival strategies. To do this polyp sizes and abundance were compared per colony, seasonally over a 100-meter transect. Coral colony samples were collected from Packery Channel, Texas seasonally over a year, and each of the polyps was counted and sized for area. Polyps were significantly smaller during the Fall season compared to the Winter colonies. The change in the average polyp size over the year suggests that these corals adjust their feeding mechanisms in response to their fluctuating environmental conditions. In addition, there was also a significant difference in the mean area of the polyps between the two locations of the colonies on the shipping channel (bay side or gulf side), with the bay side being larger overall. The significantly larger size of the bay side suggests that cryptic coral species adjust their feeding mechanisms based on location within the shipping channel. These findings provide insight into how the cryptic coral species survive in the dynamic conditions present in Corpus Christi, TX.