Ingestion rates of Artemia
nauplii for different larval stages of Macrobrachium rosenbergii
H.P. Barros, W.C. Valenti-2002
Aquaculture, 217(1-4): 223-233
Abstract:
The functional response between ingestion rate and
food concentration was determined for each larval stage of Macrobrachium
rosenbergii. Artemia franciscana nauplii were supplied at 2, 4,
6, 8, 10 and 12 per milliliter. The nauplii were counted by sight using a
Pasteur pipette and transferred to Petri dishes containing 40 ml of brackish
water (12 ppt) lying on the top of black plastic. One larva at each stage
was individually placed into each Petri dish containing different food
density. After 24 h, each larva was removed from the Petri dish and the
leftover nauplii were counted. The amount consumed was determined by the
difference between the initial and final number of nauplii. Ingestion rate (I)
increased as food density (P) increased and was defined by the model I=Im(1-e-kP).
The results suggest four levels of ingestion during larval development. The
first level includes stages II, III and IV, with average maximum consumption
of about 40 nauplii/day; the second level includes stages V and VI, with
consumption of approximately 55 nauplii/day; the third level includes stages
VII and VIII, with consumption of 80–100 nauplii/day. The fourth level
includes stages IX, X and XI, in which the high values for maximum ingestion
(Im) exceed the load capacity of the medium. The low
values for constant k (that may correspond to the adaptability of the
food to prey characteristics, such as, size, mobility, etc.) obtained for
stages IX, X and XI indicated that Artemia is not an adequate prey
and there is necessity of a supplementary diet. The best relationship
between predator and prey seemed to occur during stage IV. Results obtained
in the present work may subsidize future researches and serve as a guideline
for practical considerations of feeding rates.
(Avenida Cipriano Rodrigues, 492, bloco 1, apto 2,
Vila Formosa, São Paulo SP 03361-010, Brazil, e-mail of H.P. Barros: helenice_hpb@ig.com.br,
e-mail of W.C. Valenti: valenti@caunesp.unesp.br)