Scientists have studied the diet of a Brazilian brackish water puffer fish, revealing new information on the feeding ecology of the species.
Experts at the Center for Tropical Marine Ecology at Bremen, Germany, caught 102 Colomesus psittacus in intertidal mangrove creeks near Braganca, northern Brazil and analysed their gut contents.
Their findings, which were published recently in the Brazilian Journal of Biology, show that the species is a specialised predator of barnacles and fiddler crabs.
Analyses showed that the guts of C. psittacus contained on average 58% Balanus barnacles and 38% Pachygrapsus gracilis fiddler crabs; the two foods dominated gut contents in puffers of all ages.
The study also determined how much food each fish consumed: "The mean daily consumption of Cirripedia and Brachyura was 6.2% body weight of C. psittacus. On average C. psittacus consumed 100.3 g x ha(-1) x d(-1) of Cirripedia and 178.7 g x ha(-1) x d(-1) of Brachyura (wet weight).
"The predation on Brachyuran crabs--a significant driver of fluxes of organic matter and energy in the system--provides C. psittacus with an important ecological function in the mangrove food web.
"A plant-animal interaction is proposed where C. psittacus exerts a mutually beneficial cleaning function on the Aufwuchs (Cirripedia and associated epibiota) of Rhizophora mangle stilt roots.
"Our results and those of other studies suggest that C. psittacus encounter optimum foraging conditions in the mangrove at high inundations at daylight (spring tide-day) whereas darkness and low inundations are linked to poor foraging conditions (neap tide-night).
"The C. psittacus resource could be used as an alternative income in the region in terms of i) sustainable catch and filet processing for exports to East Asia, ii) developing certified aquaculture methods for breeding puffers for the aquarium trade."
Colomesus puffers are kept in aquariums but commonly suffer from over-growing teeth, which may require veterinary attention to allow the fish to feed normally.
Krumme U, Keuthen H, Saint-Paul U, Villwock W (2007) - Contribution to the feeding ecology of the banded puffer fish Colomesus psittacus (Tetraodontidae) in north Brazilian mangrove creeks. Braz J Biol. 2007 Aug ; 67(3): 383-92