Energy requirements of a Great white pelican (Pelecanus onocrotalus) population and its impact on fish stocks

Abstract

The Great white pelican Pelecanus onocrotalus is a major predator of some freshwater fish stocks in much of Africa. Detailed population time‐activity budgets allowed us to estimate that the south‐western Cape Province population consumed 184 tonnes offish annually. Of this, 69% was required for adult existence, 17% for chicks and 14% for flight. Per capita consumption averaged 840 g per day, or 8–8% of body weight; very much less than the figure of 17–6% used in some energy budget calculations. Our integrative bioenergetics approach lends some support for the use of 10% of body weight as the amount of food consumed per day by large piscivorous birds for initial estimates of their impact on stocks. Predation by Great white pelicans may account for some 10–25% offish production, a shortage of reliable data on fish production in African freshwater ecosystems makes a more precise estimate impossible. Food supplies and shoreline length may both be important factors for pelican populations.

Energy requirements of migrating Great White Pelicans Pelecanus onocrotalus

“…46% higher than eupecttd BMR although this difference mag ha\ e heen Jue to thc high stress I c \ d ot Lapturecl pelicans i n thc fiist IC'M hours In capti\it\ In an\ case, the higher thdn predii ted metabolic rate re\ ealtd in the prewnt itiictv dccorcls N ith the findings of Bennett and 13anex (108;) \\ho found in their large phylogenetic d i d > $IS that Pelecanids are i haracterized b\ a higher than predicted metabolic rate i n relation to body mass (a ile\iation tactor of 0 284) Some studies ha\e shou n The LJppar"nt m t~t a b o l i d energ\ (AhlE) of the captive pelicans (mean body mass of 7.8 kg) in the present study was 4494.4 kJ/day, 43% higher than that measured in a juvenile White Pelican (body mass of 8.9 kg) in South Africa (3143 kJ/day) (Cooper 1980). However, the ratio between AME and BMR revealed in the present study (2.2-2.8) is within the range of other birds like geese, pelicans, cormorants and various shorebirds (Drent et al 1978, Laugksch & Duffy 1984, Guillet & Furness 1985, Kersten & Piersma 1987, Glahn K: Brugger 1995, Robbins 1993.…”

“…Therefore, it is necessary to examine the ecophysiological needs and the food and energy demands of the pelicans, which are now common visitors to the fish-ponds in Israel. However, most previous studies of the energetic demands and food consumption of the Great White Pelican have dealt only with African populations (Brown & Urban 1969, Din & Eltringham 1974, Din 1979, Whitfield & Blaber 1979, Guillet & Furness 1985, while comparable information on the Palearctic migratory population is unavailable. Din (1979) examined fat deposits of the White Pelicans in Uganda but, until now, no equivalent information on the fat content of migratory pelicans of the European-Asian population has been available.…”

Nutrient Utilization and Diet Preference of American White Pelicans Consuming Either a Mono- or Multi-Species Diet

“…The energetic demands of wild pelicans have been reported to increase during times of breeding (Gremillet et al 1995) and migration (Shmueli et al 2000). Pelicans in the wild consume a variety of fish species, including Channel Catfish ( Ictalurus punctatus ) and Grass Carp ( Ctenopharyngodon idella ) (Guillet and Furness 1985;Johnsgard 1993;Shmueli et al 2000;King 2005;King et al . 2010).…”

“…Daily maintenance requirements of AWPE have been estimated to be 10% of body mass (800 to 1500 g of fish as-fed basis; Guillet and Furness 1985;Johnsgard 1993). The energetic demands of wild pelicans have been reported to increase during times of breeding (Gremillet et al 1995) and migration (Shmueli et al 2000).…”

Colonial nesting waterbirds as vectors of nutrients to Lake Lesser Prespa (Greece)

“…The defecation rates for the waterbirds were estimated per species. The average daily food intake for piscivorous waterbirds is ∼10% of their body mass (Table 3; Guillet andFurness 1985, Shmueli et al 2000). The fresh weight to dry weight (FW/DW) ratio for food and the food intake/excrement ratio were obtained from the literature (Marion et al 1994, Hahn et al 2007; Table 3).…”