Mean daily growth of herring larvae in relation to temperature over a range of 5-20°C, based on weekly repeated cruises in the Greifswalder Bodden

Reported estimates of mean daily growth of herring larvae generally cover the temperature range 1-12 degrees C and few estimates are available for temperatures >15 degrees C. We use larval surveys on Rugen spring-spawning herring in the Strelasund and the Greifswalder Bodden to estimate larval growth over a wider temperature range because the water temperature in that area normally increases from 5 to 20 degrees C during the larval growth period (i.e. from spring to summer). This large temperature increase has a significant influence on the mean daily growth of herring larvae. Growth estimates were based on the modes of length frequencies observed at individual stations or accumulated over strata from consecutive surveys. Mean daily growth (G; mm d(-1)) of larvae was primarily determined by the ambient temperature (T) during the growth interval (5-7 d), resulting in the following relationship: G = 0.011 + 0.037 T. A non-linear function is also described. Growth rate was not length-dependent over the size range studied (5-20 mm). The study also showed that herring larvae were growing and surviving in temperatures up to 17.5 degrees C.