caa a22 4500 477115594 CHVBK 20180405111621.0 cr unu---uuuuu 170330e19960701xx s 000 0 eng 10.1007/BF00005005 doi (NATIONALLICENCE)springer-10.1007/BF00005005 The effect of group size on space use and aggression at a concentrated food source in blue gouramis, Trichogaster trichopterus (Pisces: Belontiidae) [Elektronische Daten] [S. Syarifuddin, Donald Kramer] Synopsis: We examined how spatial distribution and the use of aggressive behavior by blue gouramis, Trichogaster trichopterus (Belontiidae), in the presence of a concentrated food source were affected by group size and by the short-term presence and absence of food. Gouramis aggregated in the area of the food source, and the frequency of aggressive acts per fish was higher for fish near the food source than for fish away from it. The frequency of aggressive acts per fish near the food source decreased with group size and was about 50 times higher in groups of 2 and 4 than it was in groups of 16 and 32. In group sizes 2 and 4, the frequency of aggression was unaffected by the presence and absence of food, but in larger group sizes aggression increased during short intervals without food. The mean proportion of time spent near the food source increased from group size 2 to group size 8 and decreased from group size 8 to group size 32 and was greater during intervals of food availability than during intervals in which food was not available. We suggest that gouramis adjust their relative use of contest and scramble competition according to the costs and benefits of aggression as determined by the number of competitors and by the potential for missed feeding opportunities. The average proportion of time spent in the vicinity of the food source appears to be influenced by both the rate of aggression and by the net rate of gain available. Kluwer Academic Publishers, 1996 Aggression nationallicence Population density nationallicence Resource defense nationallicence Syarifuddin S. Department of Biology, McGill University, 1205 Docteur Penfield Ave., H3A 1B1, Montreal, Quebec, Canada aut Kramer Donald Department of Biology, McGill University, 1205 Docteur Penfield Ave., H3A 1B1, Montreal, Quebec, Canada aut Environmental Biology of Fishes Kluwer Academic Publishers 46/3(1996-07-01), 289-296 0378-1909 46:3<289 1996 46 10641 https://doi.org/10.1007/BF00005005 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00005005 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Syarifuddin S. Department of Biology, McGill University, 1205 Docteur Penfield Ave., H3A 1B1, Montreal, Quebec, Canada aut NATIONALLICENCE 700 1- Kramer Donald Department of Biology, McGill University, 1205 Docteur Penfield Ave., H3A 1B1, Montreal, Quebec, Canada aut NATIONALLICENCE 773 0- Environmental Biology of Fishes Kluwer Academic Publishers 46/3(1996-07-01), 289-296 0378-1909 46:3<289 1996 46 10641 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer