Reproductive Biology of the Bunni Mesopotamichthys sharpeyi (Günther, 1874) from Southern Missan Province Marshes, Southern Iraq

Due to the lack of the Bunni Mesopotamichthys sharpeyi stock, some biological aspects of highly exploitable species were investigated to highlight fecundity, gonads developments, relationships between morphometric and reproductive features, in addition to relative condition factors. The study was conducted from June 2020 to May 2021 in the southern Missan Province marshes, southern Iraq to investigate the reasons that resulted in the decline of the current species stock. Hence, 496 specimens (312 females and 184 males) were caught each month from the study area. The total length of fish ranged from 18 cm to 46cm, collected in June and January, respectively, while the weight fluctuated from 143 to 1400g. The values of the gonadosomatic index varied from 0.02 for females in June 2020 and 0.01 for males in May, to the highest of 17.55 and 8.39 in March for females and males, respectively. Absolute fecundity ranged from 34371 eggs at a total length of 40.8cm and an 889.60 g weight to 224495 eggs at a total length of 44.1cm and a 1171.30g of weight. Strong relationships were noticed between morphometric and reproductive characteristics, except that between absolute fecundity and egg diameter, which was weak. The relative condition factors ranged from 0.93 in March to 1.13 in May, with a mean of 1.01±0.06. The present study confirmed that the spawning season for M. sharpeyi prolonging from March to April in the southern Missan Province Marshes occurs in two batches, but all individuals have a spent stage during May. An increase was recorded in fecundity aligned with the increase in length, weight, gonad weight, suitable condition factors and food availability.
The current study concluded no changes in species fecundity, but the shrinking of the reproductive ground area, the overfishing, the absence of stock support for the current species and fishing during the spawning season caused the lack of population stock of the species under study.