Use this URL to cite or link to this record in EThOS:
Title: Multispecies effects in larval fish assemblages
Author: Rasmussen, J.
Awarding Body: University of Aberdeen
Current Institution: University of Aberdeen
Date of Award: 2004
Availability of Full Text:
Access from EThOS:
A drift study was conducted east of Shetland in May 1996 which collected a range of environmental and biological data on a 6-hourly basis while tracking a patch of fish larvae. The data analysed in this work identified hydrographic sub-domains in the water column before, during, and after the onset of spring bloom conditions. It became evident that the water body which was being tracked was subject to some exchange processes as concentrations of zooplankton concentrations fluctuated to a larger extent than could be accounted for by internal production. A detailed analysis of zooplankton composition and larval fish gut contents were performed for a range of stations throughout the study. Seven species of larval fish were examined to assess potential density dependent processes occurring in the larval fish assemblages. However, the concentrations of larval fish prey items were generally high throughout the study, and the feeding of the entire larval fish assemblage had a negligible potential impact on the standing stock of zooplankton. The individual species of larval fish displayed changes in food selected with increased sizes. Some of the apparent higher relative proportions of prey in larval fish guts were explained from turbulence enhanced encounter rates, but strong selectivity for certain types of prey were still apparent. Conclusively, no density dependent processes were apparent during this study, but there are strong indications of dietary overlap between commercially important species, which potentially could have significant effects during food limitation.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available