The purpose of this paper is to present the first results obtained on the length/frequency distribution, age and growth, and the relations length/weight, length/girth, and girth/weight, of Corvina (Micropogon furnieri = M. opercularis), a fish of the family Sciaenidae caught off the Brazilian coast. This work is part of a long term programme designed to assess the size of the fishable stocks, to suggest the proper management of these stocks, and to aid the fishing industry in their rational exploitation. The data were obtained at the fish market of Santos in the period from August 1958 to August 1959. They were obtained from an area which extends between the parallels 23º S and 34º S and a few miles off the Brazilian coast; the area exploited by the Santos fishing fleet (Fig. 1). The data, however, are insufficient to define all the biological parameters of the fish under consideration. Nevertheless, they are a beginning towards assessment of the marine resources of Brazil. The author does not try to draw final conclusions, but only to present the first results of the research under way. Corvina is landed at the fish market in two forms: 1) Corvina as such, and sold under that name, and this comprises the bulk of the landing; and 2) Corvina included in "mistura" (a market category composed of a number of different species). These fish are of a small size and may be up to 12.93% of the total landed by numbers. The Corvina landed as "mistura" suffers from a selection made by the fishermen and therefore it was difficult to obtain good sampling of the numbers of Corvina landed of the lower lenghts. For this reason little use has been made of the data referring to Corvina landed as "mistura". For the period of thirteen months the length range was from 16 to 70 cm, with a modal value of 30.4 cm for corvina. For corvina included in "mistura" the range was 12 to 38 cm, with a modal value of 20.4 cm (Tables IV and V, and Fig. 2). The monthly length distributions (Table IV and Fig. 3) show the main modal values shifting to the right. This shifting is more visible from April to August. From March on, the curves show two clear modes; they also show a class of small fish, with low modal values. By examining the values of Table V it can be seen that small fish included in "mistura" appear in the catches in great quantity at that period. The monthly mean lengths (Table VI and Fig. 4) fluctuate from month to month, in the period from the end of winter, spring and almost all summer (Southern Hemisphere), but there is an overall trend towards a lower mean length during this period. It is suggested that this period is a period of reduced growth. In the period which includes all autumn and part of the winter months the mean lengths show, at the beginning of the period, a sharp fall followed by rapid increase, and this is the period of growth. This, together with the results from the modal values, suggests that in March small fish are recruited to the fishery. The modal values in Table V show that the period of growth is from the end of summer through autumn and part of winter, or from the end of March until August, a similar result is obtained using mean length values. The examination of scales showed rings (Fig. 6) which, it was thought, could be used for age determination. After two independent readings of the scales of the corvina samples and the corvina included in "mistura", the mean length per group of rings and the standard error of the mean for each group was calculated (Tables VII and VIII). The standard error was low for all groups with 0 to 5 rings. The method of back calculation was used and the assumption made that the relation between scale size and total length was linear. No correaction factor was applied. Using these data a growth curve (Fig. 9, curve A) was constructed and von Bertalanffy's formula was used to express the results. Lt = 50.7 (1 - e -0.25 t - 0.14) It can be seen that there is rapid growth until the 3rd ring after which growth is less marked. Using the mean length per ring group (Tables VIII and IXb) and the modal values from the length distribution of all fish (p. 74) growth curves were also drawn (Fig. 9, curve B) and the equation of von Bertalanffy applied. In this manner two sets of curves were obtained. Curve A is based on the size of the fish at the formation of the ring (without correction for non linearity in the scale/length relationship) and curve B based on the total length for each ring group. The modal lengths are similar to the mean lengths per ring group and it can therefore be assumed that the modes represent ring groups or age groups. The mean lengths per ring group (Table X) for each month are shown in Figure 8 for the 2, 3 and 4 ring groups. It can be seen that there appears to be only one maximum and minimum during the period August to October of the following year, and the maximum in one group approximates to the minimum in the following group. The minimum occurs in April. The rings are therefore assumed to be formed annually sometime before April, in summer or beginning of autumn. Using the age sampling in the form of an age?length key, together with the total number of fish of each length landed, the number of fish at each age was calculated (Tables X and XI, and Fig. 10). It can be seen that the fish landed as "mistura" belong to the 0 ring group. The dominant ring group are the 2 and 3 ring group and after these the fish with 1 or 4 rings on the scales. The monthly age distribution (Fig. 11) shows one period when the 2 and 3 ring group predominate, either one or the other being dominant. This lasts from August 1958 to March 1959. The other period from April to August 1959 has a higher frequency of fish with 0 and 1 ring on the scale. This later period is the period of recruitment into the fishery. The same can be seen from the data taken from "mistura" (Table XI). The equations used to express the relation between age and weight, age and girth of the fish, length and weight, length and girth, and girth and weight are as follows: Age/weight: W = 3,304.8 (1 - e -0.12 t - 0.37) 3.12 (Fig. 12) Age/girth: P = 39.28 (1 - e -0.12 t - 0.37) - 1.00 (Fig. 13) Length/weight: W = 0.008 L 3.12 (Fig. 14) Length/girth: P = 0.62 L - 1.00 (Fig. 15) Girth/weight: W = 0.008 <img width=32 height=32 id="_x0000_i1027" src="../../../../../../img/revistas/bioce/v12n1/a04form01.jpg" align=absmiddle> (Fig. 16)