Table 1. Natural food fluctuations (percent of total food intake)
Location	New Zealand - Lake Waahi (seasonal variations)					New Zealand - Waikato River	Spain - Cabanes Lake	Spain - Albufera Lake	Black Sea
Life stage	Juveniles/adults					Juveniles/adults (a)	Juveniles/adults (b)	Juveniles/adults (b)	Larvae (c)
Period	Jan/Feb (a)	Mar/Apr (a)	Jun/Jul/Aug (a)	Sept/Oct (a)	Nov/Dec (a)
Plants/algae	48	34	59	54	41	63	25	12.5
Detritus	35	29	34	29	53	6	37.5	30.7
Zoobenthos							37.5	18.2
Benthic copepod (Harpacticoida)									3.7				1.5
Benthic copepod (Monstrilla)													0.8
Zooplankton								38.6
Plankton copepods (Acartia clausi)										3		6.4	1.2
Plankton copepods (Anomalocera patersoni)										1.3		3.6
Plankton copepods (Centropages kr�yeri)									3.7	2.7		3.1	2.1
Plankton copepods (Labidocera brunescens)										0.7		3.1	3.1
Plankton copepods (Oithona nana)									92.6	56.9	85.7	23.8	61.3
Plankton copepods (Paracalanus parvus)										16.9		39.5	6.6
Plankton copepods (Pontenella mediterranea)												7.1
Plankton copepods (Pseudocalanus elongatus)										11.8		4.9
Plankton crustacea (Penilia avirostris)										5.4		5.9
Plankton crustacea (Evadne sp.)										1	9.5	2.3	23.4
Crustacean nauplii											4.8
Bivalvia larvae										0.3		0.3
Snails						7
Inorganic matter	17	37	7	17	6	24
*Define size class in terms of weight and age (if applicable)
Data source: (a) Wells (1984) in fishbase.org, (b) Blanco et al. (2003) in fishbase.org, (c) Pisarevskaya and Aksenova (1991) in fishbase.org