Table 1

Temporal changes in the frequency at which the dominant species of pelagic fish were caught with jellyfish, expressed as monthly variation in total number of catches of each fish species together with jellyfish, divided by the total number of catches of the same species when jellyfish were not present. Data were collected from randomly selected samples of the landings of the pelagic fleet in Walvis Bay, Namibia, for the period 1990–2007. Only months where the total number of samples (N) was greater than 100 are shown. Information for juvenile hake (M. capensis) was not available, as this species is not a routine part of the pelagic fishery.

MonthTotal NSardinops sagaxEngraulis encrasicolusTrachurus trachurus capensisEtrumeus whitheadiSufflogobius bibarbatus
January10661823132275
February175717261019151
March198219281420508
April174918181014130
May20883827133580
June11134912448103182
July10387313195147175
August31848404470233
Average35523154192