PECULIARITIES OF LAGIS NEAPOLITANA (CLAPAREDE, 1869) (ANNELIDA, POLYCHAETA) DEVELOPMENT IN THE SHAGANY LAGOON (NORTHERN BLACK SEA REGION)

Abstract

The results of the study of quantitative parameters of development and the character of allometry of polychaete Lagis neapolitana in the conditions of the Shagany estuary (Tuzlovska group of estuaries, northern Black Sea region) were presented. Sampling was carried out at a depth of 1,3 m using a metal frame 1×1 m in size, fixed on the sediment surface. The polychaetes that were found inside the frame were selected by hand by a diver. The average parameters of the abundance and biomass of these invertebrates were determined, which amounted to 113±36 ind.·m-2 and 137,86±44,02 g·m-2, respectively. It was revealed that the length of the protective tubes of polychaetes ranged from 44,0 to 75,2 mm. The outer diameter of their anterior end was 6,4–8,3 mm, and the posterior end was 2,1–3,8 mm. The highest frequency of occurrence (36,9 %) was in specimens with a tube length of 52–57 mm. For the parameters of the outer diameter of the anterior end of the polychaete tube, which ranged from 6,9 to 7,3 mm, the frequency of occurrence was 31,5 %. An analysis of the age-related variability of the ratio of the diameter of the posterior end of the tube to the diameter of its anterior end during the growth of the polychaete and the increase in the length of its tube was carried out. Using correlation-regression analysis, it was found that the relationship between these parameters was inversely proportional. It was shown that the relationship between the parameters of the diameter of the anterior end of the polychaete tube and the parameters of the total mass, body mass and tube mass has the character of negative allometry. The received regression equations make it possible to pass from the size parameters of polychaetes to their weight characteristics with a sufficient degree of accuracy. It was shown that the wet body weight is on average 52,9±1,18 % of the total mass of the polychaete, and the weight of the tube is 47,4±1,51 %. The dry body weight of L. neapolitana averages 15,3±1,07 % of the wet weight. It was noted that the regression equations relating the parameters of the outer diameter of the anterior end of the L. neapolitana tube with the parameters of its mass can be used for studying the productivity of this species in specific habitat conditions.