Diet Niche Relationships among Early Life Stages of Fish in German Estuaries.

Abstract

Diet composition, selectivity, food niche width and food niche overlap of early life stages of fishes were studied in the Barther Bodden system and in the Weser and Elbe estuaries during spring and summer from 1987 to 1991 and from 1993 to 1994. Larvae of perch (Perca fluviatilis) and roach (Rutilus rutilus) dominated in the Barther Bodden. Herring (Clupea harengus) and perch were the dominant species in the Barther Strom. Smelt (Osmerus eperlanus) was the most common species in the Elbe estuary. Sprat (Sprattus sprattus) was of most importance in the Weser estuary. The dominant prey of fish larvae were copepodids, nauplii and eggs of Eurytemora afinis. The highest food niche width was observed for nine-spined stickleback (Pungitius pungitius), ruffe (Gymnocephalus cernuus), three-spined stickleback (Gasterosteus aculeatus) and perch in the Barther Bodden. Negative selectivity indices indicated that populations of rotifers were scarcely influenced by predation by fish larvae. In contrast, E. affinis was preferred by early life stages of fish. Positive relationships were estimated between maximum prey lengths and predator lengths of different fish species. Key species with regard to niche overlap were nine-spined stickleback, roach, three-spined stickleback and perch in the Barther Bodden, perch and herring in the Barther Strom, herring and three-spined stickleback in the Elbe estuary, and sprat and common goby (Pomatoschisrus microps) in the Weser estuary. High geographical overlap between fish species occurred in the Elbe estuary and Barther Bodden, whereas high diet overlap was estimated for both the Weser estuary and Barther Strom.

Spring diet and feeding strategy of the European sprat Sprattus sprattus (L., 1758) from the Black Sea coast of Turkey

“…According to several studies on the diet composition of the species, sprat is planktivore and feeds particularly on planktonic copepods, which is similar to our findings (Sirotenko and Sorokalit, 1979;Last, 1987;Thiel et al, 1996;Oven et al, 1997). For example, copepods were found to be among the most important prey of sprat in Hardangerfjord.…”

Diel and habitat-dependent resource utilisation of deep-sea fishes at the Great Meteor seamount (subtropical NE Atlantic): niche overlap and support for the sound-scattering layer-interception hypothesis

“…This stresses the prominent role of dietary resource partitioning in structuring the bentho-pelagic community, which was also emphasised by Piet et al (1999). However, this cannot be generally extended, since data in the literature (Hopkins & Gartner 1992, Thiel et al 1996, Sala & Ballesteros 1997) suggest a rather ambivalent relationship, i.e. in cases of closely related pairs of species, either dietary or spatial overlap may be pronounced, but not simultaneously.…”

“…The data fit well into the theoretically determined bounds. Compared to reference data from estuarine and limnetic habitats (Naesje et al 1991, Thiel et al 1996, the isogram of 1.44 is a good approximation of maximum allowable overlap and minimum necessary distance in the fish communities considered.…”

Use of stable isotope ratios of fish larvae as indicators to assess diets and patterns of anthropogenic nitrogen pollution in estuarine ecosystems

“…Fish larvae are typically zooplanktivorous, feeding on a variety of micro-and meso-zooplankton, often dominated by copepods, with a shift from smaller to larger prey through larval ontogeny (Llopiz, 2013). The common goby Pomatoschistus microps (Krøyer, 1838) is among the most abundant species in estuaries, lagoons and along the shores of Europe, and despite its high abundance and importance in estuarine trophic webs (Maes et al, 2003;Parmanne and Lindstrom, 2003;Salgado et al, 2004;Leitão et al, 2006;Dolbeth et al, 2008), to the best of our knowledge, only one study, Thiel et al (1996), based on gut content analysis, has examined the diet of P. microps larvae.…”