Age Structure of Atlantic and Shortness Sturgeon in the Cooper River Using the Minimally Invasive Pectoral Fin Ray

The Cooper River in South Carolina is home to Atlantic Sturgeon, Acipenser oxyrinchus, and Shortnose Sturgeon, Acipenser brevirostrum, endangered anadromous fishes. Understanding the status of these populations is especially significant given recent approval for extensive dredging of the Charleston Harbor and a portion of the Cooper River to deepen shipping channels. The age structure of the population in the Cooper River is unknown, yet important to understand due to potential effects of the dredging on the current population. It also plays a role in identifying the current health of these populations and inform on recruitment into the system. Fish were caught between (03/2015-03/2016) along the Cooper River and within Charleston Harbor following SCDNR anadromous fish protocol. In an attempt to improve upon age estimates obtained from the more commonly used but more destructive to remove fin spine, second marginal pectoral fin ray samples were removed from both species. Average percent error (APE) between readers and coefficient of variation (CV) results suggest that the second marginal fin ray is a precise method of ageing both species, and may be preferable to the first fin spine. Age estimates from the second marginal fin rays suggest that recruitment to both populations is limited.