Document of bibliographic reference 106736

BibliographicReference record

Type

Bibliographic resource

Type of document

Book chapters

BibLvlCode

AM

Title

Zonation and tidal stream migration of fishes on an estuarine mudflat

Abstract

Intertidal migration is relatively well-studied in marine fish biology. Most studies focused on marine sandy beaches and rocky shores. Comparatively little work, however, has been done on the distribution and migration patterns of fishes on estuarine mudflats. The seasonal composition of an intertidal estuarine fish community was studied with directional fyke nets at different heights on the mudflat. These fyke nets each sampled an opposite direction and as such could be used to analyze the migration patterns of fishes on the mudflat. The fish assemblage was dominated by juveniles of Clupea harengus, Dicentrarchus labrax, Platichthys flesus and Solea solea. The composition of the intertidal fish community reflected the cyclicity of seasonal recruitment of species into the estuary. Analysis of the directional data of the fyke nets showed that the flatfish species, flounder and sole, migrated actively onto the mudflat. In contrast, the distribution of herring and seabass in the fyke nets suggests that they were transported passively by the tidal currents. These (semi-)pelagic species can be considered opportunistic vagrants onto the mudflat. They might follow their migrating hyperbenthic and pelagic prey and may find a valuable supplement to their diet in the infauna that disperses into the water column. Because of the low predator abundance and high turbidity in this part of the Scheldt estuary, predation is probably not an important trigger for intertidal migration. Species didn’t show a clear zonation on the mudflat and, if observed, this was mainly the result of species-specific differences in mobility. The zonation of flatfishes tended to be affected by density-dependent processes. Whenfish densities were higher, relatively more flounder were caught on the upper shore. By doing so, they avoid competition for food or space with sole, which stays on the middle and lower reaches of the mudflat.

Bibliographic citation

Stevens, M.; Maes, J.; Van Asten, B.; Ollevier, F.P. (2006). Zonation and tidal stream migration of fishes on an estuarine mudflat, in: Stevens, M. Intertidal and basin-wide habitat use of fishes in the Scheldt estuary = Getij- en bekkengebonden habitatgebruik door vissen in het Schelde-estuarium. pp. 17-36

Topic

Marine

Fresh water