Diet of labrisomid blenny Auchenionchus variolosus (Valenciennes, 1836) (Labrisomidae) during its larval development off central Chile (2012–2013)

The diet, feeding success (prey number and total volume per gut, and maximum prey width) and trophic niche width of the labrisomid blenny Auchenionchus variolosus (Valenciennes, 1836) was studied during its larval development (3.93–17.26 mm standard length). Individuals were collected in October 2012 and October 2013 in nearshore waters (<500 m offshore) from Bahía Valparaíso, central Chile with Bongo nets. When compared to the same length range, larval A. variolosus collected during 2013 showed larger upper jaw-at-sizes than those from 2012. This coincided with a reduction in relative importance (%IRI) of the main prey item, copepod nauplii, from ~90 to ~73%. Feeding incidence (FI) was high throughout larval development, varying from 97.3 to 100%, being similar throughout the larval development. Prey items per gut (PIPG) ranged from 0 to 35 prey, showing no differences among years. Total volume per gut (TVPG) was positively correlated with larval length, and at given larval size, TVPG ingested by larval A. variolosus was larger during 2013 (0.0607 mm) than during 2012 (0.0301 mm). Prey width range was 47.47–700.94 μm and was positively correlated with standard length (SL). Niche breadth was independent of larval size and did not change during larval development in 2012 or 2013. The study helps to understand the trophic interactions occurring in nearshore waters off rocky reef environments from mid-latitudes of the Southeast Pacific coasts.