|Grazing preferences of marine isopods and amphipods on three prominent algal species of the Baltic Sea|Goecker, M.E.; Kåll, S.E. (2003). Grazing preferences of marine isopods and amphipods on three prominent algal species of the Baltic Sea. J. Sea Res. 50(4): 309-314. dx.doi.org/10.1016/j.seares.2003.04.003
In: Journal of Sea Research. Elsevier/Netherlands Institute for Sea Research: Amsterdam; Den Burg. ISSN 1385-1101, more
Algae; Food preferences; Grazing; Cladophora Kützing, 1843 [WoRMS]; Enteromorpha intestinalis (Linnaeus) Nees, 1820 [WoRMS]; Fucus vesiculosus Linnaeus, 1753 [WoRMS]; Gammarus oceanicus Segerstråle, 1947 [WoRMS]; Idotea balthica (Pallas, 1772) [WoRMS]; ANE, Baltic [Marine Regions]; Marine
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Preference tests were performed over a two-week period in September 2001 in which isopods (Idotea baltica) and amphipods (Gammarus oceanicus) were offered choices of three common species of algae from the Baltic Sea: Enteromorpha intestinalis, Cladophora spp., and Fucus vesiculosus. After a 48-hour starvation period, 20 individuals of each grazer species were placed in aquaria containing approximately 1.0 g of each algal species. Fifteen trials for each grazer species were run for 20 hours. We found that G. oceanicus ate significantly more Cladophora spp. and E. intestinalis than F. vesiculosus (p<0.001), with a preference order of: Cladophora spp.>E. intestinalis>F. vesiculosus. Similarly, I. baltica ate significantly more of both the filamentous green algae than F. vesiculosus (p<0.001), with a preference order of: E. intestinalis>Cladophora spp.>F. vesiculosus. Given the preference of isopods and amphipods for filamentous green algae, we might expect these algae to be maintained at low biomass levels. However, this is clearly not the case in the Baltic Sea. Nutrient enrichment (bottom-up effects) is the accepted dominant reason for the non-controlling impact of algal grazers, but other reasons may include cascading trophic effects resulting from the removal of large piscivorous fish (top-down effects).