The specimens of tambaqui, Colossoma macropomum, analyzed in this thesis
were obtained from the following sources: 1) cornrnercial fisheries, 2) floodplain
areas nearby Manaus, 3) captive specimens of known age from the INPA Fish
Culture Station, and 4) marked and recaptured specimens at the Marnirauá
Ecological Station. Food index, condition index, hepatosomatic index gonadosomatic
index, and cavity fat were analyzed. The tarnbaqui spawns from Septernber until
February with spawning occuring synchronously with the rise rise of the waters. This
specie reaches sexual maturity at 60.69 cm standard length which occurs at
aproxirnately 5 years of age. From the analysis of scales, vertebrae, fin rays and
otoliths it was concluded that the most appropriate bony structures for age
determination of tambaqui are scales and otoliths. The analysis of microstructures
from otoliths showed that there are daily growth rings. The lapilus showed betier
microstructural pattern than sagita and asteriscus. The daily rings are deposited in
layers starting on the fourth day after hatching the larvae. The seasonal rings were
validated using: 1) relative marginal increment analysis, 2) analysis of structures in
fishes of known age and 3) analysis of scales in marked and recaptured fishes. An
annual ring is formed on the scales and otoliths of C. macropomum during the low
water season. On scales and otoliths a maxirnum of 12 and 13 year rings were
observed, respectively. Growth curves in length and weight were adjusted based on
age determinations using the von Bertallanfy model, and growth pararneters for all
analyzed specimens were obtained based on (1) otolith (Lco = 923,16; K = 0,157; To
= -1,344), and (2) scale (Lco = 923,16; K = 0,167; To = 0,711).
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