Some aspects of the biology of Abu mullet Liza abu (Heckel, 1843) in the Orontes River, Turkey

Abstract

The age, growth and reproduction are described for 411 individuals of abu mullet from the Orontes River in Turkey between May 2011 and April 2012. The overall male to female ratio was 1:1.29. Fork length of all individuals ranged from 2.2 to 18.5 cm and total weight from 1.85 to 66.40 g. Isometric growth was observed for males (b=2.938) and all individuals (b=2.907); positive allometric growth was observed for females (b=3.246). The von Bertalanffy growth parameters based on data from otoliths were L ∞ = 19.48 cm, k=0.258 year -1 and t 0 =-1.738 years for males, L ∞ = 20.31 cm, k=0.313 year -1 and t 0 =-1.432 years for females. The growth performance index ( ) was found to be 1.99 for males, 2.11 for females and 2.18 for all individuals. The mean condition factor (K) was calculated as 0.792±0.027 for males and 0.835±0.030 for females. Length at maturity was 11.49 cm for males and 11.82 cm for females. The fecundity was 14413±1569 with an egg diameter of 0.44±0.07 mm. Spawning period was between April and August. Abu mullet has acclimated well in the Orontes River and is capable of successful reproduction. Its calculated age and size at maturity was smaller and younger than for other populations.

Reproductive Biology of Abu Mullet, Planiliza abu (Heckel, 1843), in Karun River, Southwestern Iran

“…The sex ratio in this study was equal (1M:1F), however, it differed in different seasons and length classes. In other studies, the sex ratio of P. abu was reported as 1M:2.7F in Khozestan Province, Iran (Chelemal et al, 2009), as equal in Atatürk Dam Lake (Doğu et al, 2013) and as 1M:1.3F in the Orontes River, Turkey (Ay and Özcan, 2016). These differences are most probably related to sexual differences in growth rate, natural mortality rate, and energetic cost of reproduction (Stergiou et al, 1996).…”

“…In this study, the maximum observed total length and weight of P. abu was 17.3 cm and 71.28 g, respectively. In other studies, the maximum reported fork length and weight is 22.1 cm and 136.6 g in Atatürk Dam Lake (Doğu et al, 2013), 22 cm and 66.1 g in East Hammar marsh of Iraq (Mohamed, 2014) and 18.5 cm and 66.40 g in the Orontes River, Turkey (Ay and Özcan, 2016), 65.0 cm (Garbin et al, 2014) in southeastern coastal regions of Brazil and 23.1 cm and 166.1 g in Ceyhan River Basin of Turkey (Birecikligil et al, 2017). In general, the differences in the length of the fish could be due to differences in the fishing methods and seasons, different geographic areas, biological and ecological conditions, or inter-species differences.…”

“…The highest mean egg diameter was observed in February. In the study of the reproductive biology of P. abu in Turkey, the mature egg diameter was in the range of 0.31 to 0.63 with a mean of 0.44 mm (Ay and Özcan, 2016). Egg diameter variations in fish are probably one of the important strategies in determining reproductive activities (Tomasini et al, 1996).…”

“…Fecundity is the most common criterion for determining the potential of reproduction in fishes (Nichol and Acuna, 2001). In the study of Ay and Özcan (2016), P. abu fecundity was calculated for 51 adult females in the spawning season, and the absolute fecundity ranged between 12000-25000 eggs with an average of 14400±1600 eggs. Several factors such as size and age of females, life history strategy, food supply, and water temperature affect the fecundity (Thrope et al, 1984).…”

“…It has three key components including sexual maturity, reproductive period, and fecundity, which are important demographic characteristics, essential for understanding a species life history (Mousavi-Sabet et al, 2017;Ghafori et al, 2019). There are some works on the biology of this fish in nearby countries (Mhaisen and Al-Jaffery, 1989;Doğu et al, 2013;Mohamed, 2014;Ay and Özcan, 2016;Birecikligil et al, 2017), but almost none in Iran. The main object of this study was to provide data on the reproductive biology of P. abu, including sex ratio, gonadosomatic index, fecundity, oocyte diameter, and spawning season which are necessary for conducting conservation and management programs in Karun River.…”