ISSN 2375-0723
African Journal of Food Science Research ISSN 2375-0723 Vol. 12 (3), pp. 001-007, March, 2024. Available online at www.internationalscholarsjournals.org © International Scholars Journals
Full Length Research paper
Predation patterns in heterobranchus longifilis Larvae: An analysis of their first exogenous feeding
P. O. Ajah
Institute of Oceanography, University of Calabar, Calabar, Cross Rivers State, Nigeria. E-mail: [email protected].
Accepted 4 October, 2023
Abstract
Two-day-old post hatch Heterobranchus longifilis larvae (4.06 ± 0.1 mm, 2.75 ± 0.06 mg and 0.35 ± 0.03 mm average standard length, weight and mouth width, respectively) were introduced into glasswares and exposed to a wide range of live zooplankton (prey size range: 42 to 876 µm) at a density of 2,944 individual/larva/day for 14 days. The 180 guts examined showed that food intake changed markedly with age and size. Larger preys were preferred as larvae increased in age and size. Chilodonella uncinata and Lepadella ovalis (size range: 42 - 125 µm) dominated the larval gut from day 2 - 4 post hatch. Brachionus quadridentatus, Alona monachanta and Chydorus sphaericus (225 - 346 µm) were predominant at days 5 and 6, while Asplanchna priodonta, Bosmina longirostris and Daphnia ambigua (485 - 876 µm) dominated from day 7 - 14 post hatch. Results from another 146 stomachs batch revealed that 2 to 4 day old post hatch fry preyed on larger prey (225 - 876 µm) at disproportionate mouth-width to prey ratio from 1: 1.2 to 2 when solely introduced and adequate. Initial recognition of prey by 2 - 4 day old larvae was longer but thereafter feeding became more voracious and intermittent with shorter resting periods compared with older larvae. Active feeding in H. longifilis larvae decreased with age while the length of feeding and rest period increased with age.
Key words: Prey selection, behaviour, Heterobranchus longiflis, exogenous.