Growth Rates of Leiostomus xanthurus as an Indicator of Habitat Quality Among Estuarine Creeks

Otoliths are calcareous and vestibular structures found within the inner ear of bony fish. They primarily function as balance, gravity, and movement indicators. Otoliths can also be used as estimators of age. Rings develop on the otolith as a fish matures, which can then be counted to estimate age. From measuring these rings, the growth rates of fish can be estimated. This data is helpful for determining things such as habitat quality, spawning patterns, and population age structure. This purpose of this study was to test whether there were differences in nursery habitat quality between closely related intertidal creeks within North Inlet Estuary, SC, based on the growth rates of Leiostomus xanthurus. Samples of juvenile Leiostomus xanthurus, or spot, were collected from Oyster Landing, Bly Creek, Old Man, Town Creek, and Clam Bank, five creeks within the estuary that are geographically close in range. The otoliths, specifi cally the lapilli and sagittae, of each collected fish were isolated through dissection. From the otoliths obtained, this study utilized the left lapillus for estimating age and growth. The number and width of the rings were measured and age was estimated through otolith analysis software. The determined growth rates were used as an indicator of nursery quality, with the assumption that a better habitat would support faster growth. Results demonstrated that growth rates vary among creeks, indicating fine-scale differences in nursery habitat quality within the estuary