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Living in Groups

Resource Competition

It has long been recognized that damselfish aggressively defend their territory against outsiders. By doing this they maximize the biomass of the turf algae they cultivate and feed on (Brawley and Adey 1977). On many tropical reefs, territorial damselfish can occupy more than 80% of the benthos (Robertson et al. 1980). The aggressive behavior of such territorial fish is effective in warding off solitary and small group herbivores. However, large schooling groups of non-territorial herbivores have been observed overwhelming the defenses of territorial damselfish to gain access to their algal patches (Robertson et al. 1976). For example, in a patch reef habitat in Panama the foraging rate of schooling fish was higher, and attack rates by damselfish were lower compared to solitary fish of the same species (Foster 1985).
Credits 
Cinematography: Dr. Stuart Sandin
Edited by: Neilan Kuntz
Written by: Neilan Kuntz
Location: Palmyra Island, Line Islands, Central Pacific (2004)

Brawley, S. H. and W. H. Adey (1977) Territorial behavior of threespot damselfish (Eupomacentrus planifrons) increases reef algal biomass and productivity. Environmental Biology of Fishes 2(1): 45-51.

Foster S.A. (1985) Group foraging by a coral reef fish: a mechanism for gaining access to defended resources. Animal Behavior. 33:782-792.

Robertson D.R. and B. Lassig (1980) Spatial distribution patterns and coexistence of a group of territorial damselfishes from the Great Barrier Reef. Bulletin of Marine Science 30:187-203. Robertson D.R., H.P.A.

Sweatman, E.A. Fletcher, M.G. Cleland (1976) Schooling as a mechanism for circumventing the territoriality of competitors. Ecology 57: 1208-1220.



Nuclear Hunting

Nuclear hunting or inter-specific fish foraging is a type of association where two or more species forage together. In this association a fish species, the attendant, follows another species, the nuclear. This well documented behavior provides unique feeding opportunities for following individuals (Strand 1988). However, the benefits to the nuclear and attendant vary depending on which type of scheme is employed (review by Ormond 1980). The most common type is "Following and scavenging": a large predator followed by an opportunistic carnivore. Other schemes include: "Interspecific joint hunting" when two predatory species hunt together, and "Hunting by riding" when a predatory attendee swims alongside or above non-predatory nuclear. These associations are not exclusive as behavioral overlap can be observed between categories (Lukoschek & McCormick 2002). The advantage of these social groups allows a broader range of prey categories compared to single-species associations and can increase an individual's ability to catch otherwise unobtainable prey (Silvano 2001). 

Credits 
Cinematography: Dr. Forest Rohwer & Dr. Stuart Sandin Edited by: Neilan Kuntz
Written by: Neilan Kuntz
Location: Palmyra Island, Line Islands, Central Pacific (2004) & Borneo, Malaysia (Sipadan) (2003)

Lukoschek V., M.I. McCormick (2002) A review of multi-species foraging associations in fish and their ecological significance. Proceedings of the 9th International Coral Reef Symposium 1: 467-474.

Ormond R.F.G. (1980) Aggressive mimicry and other interspecific feeding associations among Red Sea coral reef predators. Journal of Zoology of London 191: 247-262.

Silvano R.A.M. (2001) Feeding habitats and interspecific feeding associations of Caranx latus (Carangidae) in a subtropical reef. Environmental Biology of Fishes 60: 465-470.

Strand S. (1988) Following behavior: Interspecific foraging associations among Gulf of California reef fishes. Copeia 2:351-357.



Foraging Efficiency

It is generally accepted with a few exceptions, that fish foraging in large shoals find food faster than those in small shoals. As expected, the probability of locating a food source increases with more members and is therefore directly related to group size. The result is that less time is spent foraging as shoal size increases (Pitcher et al. 1982). To increase foraging efficiency, shoaling fish must be able to quickly recognize group members that have successfully located food (Pitcher and House 1987, Brown and Laland 2003). Changes in foraging behavior such as the termination of searching and concentration of fish in an area acts as a cue to other fish to exploit the resource in that area. This behavior is demonstrated by the Convict Surgeon fish (Reinthal and Lewis 1986.

Credits 
Cinematography: Dr. Stuart Sandin
Edited by: Neilan Kuntz
Written by: Neilan Kuntz Location: Palmyra Island, Line Islands, Central Pacific (2004)

Brown C and Laland K.N. (2003) Social learning in fishes: a review. Fish and Fisheries 4: 280-288.

Pitcher T.J., A.E. Magurran and I.J. Winfield (1982) Fish in larger shoals find food faster. Behaviorial Ecology & Sociobiology 10: 149-151.

Pitcher T.J. and A. House (1987) Foraging rules for group feeders: area copying depends upon density in shoaling goldfish. Ethology 76: 161-167.

Reinthal P.N. and S.M. Lewis (1986) Social behavior, foraging efficiency and habitat utilization in a group of tropical herbivorous fish. Animal Behavior 34: 1687-1693.



Circular Search Strategy

It has long been recognized that damselfish aggressively defend their territory against outsiders. By doing this they maximize the biomass of the turf algae they cultivate and feed on (Brawley and Adey 1977). On many tropical reefs, territorial damselfish can occupy more than 80% of the benthos (Robertson et al. 1980). The aggressive behavior of such territorial fish is effective in warding off solitary and small group herbivores. However, large schooling groups of non-territorial herbivores have been observed overwhelming the defenses of territorial damselfish to gain access to their algal patches (Robertson et al. 1976). For example, in a patch reef habitat in Panama the foraging rate of schooling fish was higher, and attack rates by damselfish were lower compared to solitary fish of the same species (Foster 1985). 
Credits 
Cinematography: Dr. Stuart Sandin
Edited by: Neilan Kuntz
Written by: Neilan Kuntz Location: Palmyra Island, Line Islands, Central Pacific (2004)

Brawley, S. H. and W. H. Adey (1977) Territorial behavior of threespot damselfish (Eupomacentrus planifrons) increases reef algal biomass and productivity. Environmental Biology of Fishes 2(1): 45-51.

Foster S.A. (1985) Group foraging by a coral reef fish: a mechanism for gaining access to defended resources. Animal Behavior. 33:782-792.

Robertson D.R. and B. Lassig (1980) Spatial distribution patterns and coexistence of a group of territorial damselfishes from the Great Barrier Reef. Bulletin of Marine Science 30:187-203.

Robertson D.R., H.P.A. Sweatman, E.A. Fletcher, M.G. Cleland (1976) Schooling as a mechanism for circumventing the territoriality of competitors. Ecology 57: 1208-1220.