Feeding ecology of juvenile turbot Scophthalmus maximus and flounder Pleuronectes flesus at Gotland, Central Baltic Sea
2007 (English)In: Journal of Fish Biology, ISSN 0022-1112, Vol. 70, no 6, 1877-1897 p.Article in journal (Refereed) Published
Food and feeding of juvenile turbot Scophthalmus maximus and flounder Pleuronectes flesus were studied in five nursery areas at Gotland, Central Baltic Sea, ICES SD 27 and SD 28. Ontogeny involved partitioning of available food resources. The food choice of turbot <30 mm standard length (L sub(S)) included both planktonic-hyperbenthic prey (calanoid copepods and mysids) and epibenthic-endobenthic prey (chironomids and amphipods), whereas turbot greater than or equal to 30 mm L sub(S) fed mainly on hyperbenthic species (mysids and fishes). Conversely, for flounder, epibenthic-endobenthic prey were the most abundant prey items throughout development (harpactocoid copepods, oligochaetes and chironomids for fish <40 mm L sub(S) and oligochaetes, chironomids and amphipods for flounder greater than or equal to 40 mm L sub(S)). Thus, the highest degree of dietary overlap occurred between turbot <30 mm and flounder greater than or equal to 40 mm. Food composition for both turbot and flounder varied, however, according to exposure and predominant wind direction in the nursery area. For example, expressed as the ratio between the biomass of mysids and fishes consumed, the relative importance of mysids v. fishes as food source for turbot, varied from <1 in the most sheltered area to 16 and 27 in the more open areas. Considerable differences in feeding incidence were recorded; mean plus or minus s.d. 58 plus or minus 20% for turbot <30 mm L sub(S) and 83 plus or minus 8% for turbot greater than or equal to 30 mm L sub(S), as opposed to greater than or equal to 85-90% for flounder irrespective of size. The lower feeding success of turbot <30 mm L sub(S) was related to mysid abundance, shown to vary spatially and temporally, and to density of flounder, indicating that food availability, and potentially interspecific competition, influence feeding of early juvenile turbot with implications for survival following settlement. Regarding variability in abundance, hyperbenthic prey, as mysids, are considered more variable than epi- and endobenthic organisms. Hence, in addition to the 'nursery size hypothesis', i.e. the positive relationship between abundance of recruits and extension of nursery areas, variability in food availability may explain the average lower recruitment of turbot as compared to other flatfishes, e.g. flounder.
Place, publisher, year, edition, pages
London: Academic Press , 2007. Vol. 70, no 6, 1877-1897 p.
dietary overlap, feeding ecology, feeding incidence, flatfishes, food availability, sandy beach
Research subject Biology
IdentifiersURN: urn:nbn:se:hgo:diva-169DOI: 10.1111/j.1095-8649.2007.01463.xOAI: oai:DiVA.org:hgo-169DiVA: diva2:275930