engleski

Mediterranean moray eel, Muraena helena (Pisces: Muraenidae): biological indices for life history

This paper presents the first published data on age, growth and reproduction of Muraena helena in the Mediterranean Sea. A total of 193 individuals of M. helena were sampled by longlines at depths from 5 to 80 m in the southern Adriatic Sea. Mediterranean moray eel’s length and weight ranged from 27.5 to 121.0 cm and from 116.1 to 3680.0 g, respectively. The age reading by annual zones of M. helena otoliths revealed the presence of age groups 2-12. The von Bertalanffy growth function (VBGF) for sampled population had the following parameters: L∞ = 162.70 cm, k = 0.089 and t0 = -0.660. Females dominated the total male-female ratio (0.35:1.00) and, together with immatures, were more frequent in the costal shallow waters. The greatest increase in gonadosomatic index occurred in summer, while condition factor was the lowest in winter. The ovaries of moray eels mostly contained oocytes in a pre-vitellogenic or vitellogenic stage and males with testes at their maturation stage were observed at the beginning of July. The absence of males and ripe or spent females in the inshore costal waters suggests that moray eels leave this region to spawn most likely in the south Adriatic Pit on depth bellow 600 m, in summer.

Moray eel; Muraena helena; age; growth; reproduction; Adriatic Sea

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