The Determination of Some Biological Characteristics of Horse Mackerel (Trachurus Trachurus L., 1758) Caught in Samsun Bay

Abstract

In the present research, which was carried out during the period of Noverber 2004 to March 2005 in order to determine some population parameters of the Horse mackerel (Trachurus trachurus L., 1758) in the Samsun Bay that one of the most important fisheries area in the Black Sea, a total of 1290 individuals (591 female, 647 male) were investigated according to age, length, weight and sex composition, the relationship of length-weight, condition factor, Von Bertalanffy growth formula and mortality rates. The female-male ratio was 1: 1.1. In the specimens consisted of 0-V age groups and the age-group II was dominant (37.60%). In the research, the relationship of length-weight was found for general, male and female determined as W=0.0063 L-3.0931 (r=0.98), W=0.0056 L-3.1378 (r=0.96), W=0.0055 L-3.1423 (r=0.97) and the Von Bertalanffy growth formula was found for general, male and female as Lt=26.74(1-e(-0.138) ((t+2.824))), Lt=26.88(1-e(-0.132) ((t+3.075))), Lt=26.59(1-e(-0.131 (t+3.229))), respectively. The growth of horse mackerel was determined as positive allometric. It was determined that the average condition value of population was 0.6299 +/- 0.00151 0.5628 +/- 0.002 for females, 0.5519 +/- 0.0018 for males. Total (Z), natural (M) and fishing (F) mortalities were Z=1.26 year(-1), M=0.27 year(-1) and F=0.99 year(-1), respectively. The exploitation ratio E=0.79 indicates that the population is being heavily exploited.