The influence of macrophytes on the feeding of fish larvae in a shallow brackish sea

Abstract

Abstract We studied the impact of the macrophyte stands on the feeding of fish larvae, paying special attention to feeding on ciliates. Generally, the importance of ciliates as larval food has been overlooked or underestimated. Based on our earlier observations we hypothesized that the consumption of ciliates by fish larvae is higher in vegetated areas. Studies were carried out in a shallow Vainameri Sea (semi-enclosed Baltic Sea basin). Fish were sampled over 3 years (2011−2013). We examined larval diet by gut segmentation and epifluorescence microscopy. The study revealed that: (1) larval food intake and condition factors were generally higher in vegetated areas; (2) ciliates represented a very important food source for larval fish; (3) in vegetated areas larval fish consumed more ciliates than in open water areas; (4) larvae of piscivorous fish species tended to catch larger prey items. In general our study suggests that larval growth may be better secured in vegetated areas.