Understanding the factors influencing the invasion success of round goby (Neogobius melanostomus) is important to managing the dynamic food web of Lake Michigan. Growth is one aspect of fish biology commonly measured to identify ecological factors influencing the success of a species in a particular habitat. Growth is often measured using back-calculation in order to compare varying influences over the lifetime of a fish. This study compares the use of multiple otolith radii and back-calculation methods for round goby using artificial annuli created by immersion in an oxytetracycline (OTC) solution. Back-calculated length (BCL) was estimated using three otolith radii (rostrum, ventral, and post-rostrum) and two back-calculation methods (direct proportion, Fraser-Lee) and assessed for accuracy compared to the measured length at the time of OTC marking. In general, post-rostrum BCLs were the most accurate of the three radii and the Fraser-Lee method outperformed the direct proportion method. All but two BCLs (among all fish and radius x method combinations) underestimated length at marking. Growth rate was negatively correlated with the absolute value of percent error, indicating that faster growth leads to more accurate back-calculated lengths. Future work utilizing back-calculation to understand round goby growth should utilize a radius from the core to the post-rostrum point as well as the Fraser-Lee method with an appropriate biologic intercept in order to estimate the most accurate BCLs.
|Original language||English (US)|
|State||Published - 2015|