Premium
Ontogenetic allometric coefficient changes: implications of diet shift and morphometric traits in Hoplias malabaricus (Bloch) (Characiforme, Erythrinidae)
Author(s) -
Teixeirade Mello F.,
Iglesias C.,
Borthagaray A. I.,
Mazzeo N.,
Vilches J.,
Larrea D.,
Ballabio R.
Publication year - 2006
Publication title -
journal of fish biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.672
H-Index - 115
eISSN - 1095-8649
pISSN - 0022-1112
DOI - 10.1111/j.1095-8649.2006.01245.x
Subject(s) - allometry , biology , insectivore , piscivore , ontogeny , zoology , anatomy , ecology , predator , predation , endocrinology
This study evaluated the relationship between body size and digestive tract characteristics of the important predatory freshwater fish Hoplias malabaricus , which is widely distributed in South America. The allometric coefficients were calculated for the mass and standard length ( L S ) relationships for two different L S groups: (1) between 20 and 100 mm (characterized as insectivores) and (2) >100 mm (characterized as piscivores). Differential growth measured from the allometric coefficient, b , between the insectivore ( b < 3) and the piscivore ( b > 3) groups was detected. Anterior intestine length and pyloric caeca zone length showed significant differences between groups. Two complementary hypotheses were developed to explain the differential growth: (1) H. malabaricus has a digestive tract adapted to a piscivorous diet, which is independent of its ontogenetic stage of development, and (2) the negative allometry observed in group 1 individuals agrees with a general behavioural strategy, allowing individuals to grow in L S during a shorter period of time.