Metaschistura cristata is a small nemacheilid loach species found at a few localities only in Turkmenistan and Iran. The present study reports, for the first time, data on its biology, based on 747 specimens collected from the River Zanglanlou in north-eastern Iran. Specimens were collected at monthly intervals over two reproductive seasons from February to June 2007 and 2008. Maximum age, based on opercula readings, was 4+ years for both sexes. Specimens ranged in size from 25 to 87 mm total length and weighed from 0.09 to 4.91 g. Length-weight relationships implied positive allometric growth for both sexes and the sex ratio was 1 : 1.2 in favour of females. The Gonadosomatic indicated that peak reproduction occurred during April and May, with highest average values of 1.473 ± 0.99 for males and 12.9 ± 7.14 for females in April. Oocyte diameter ranged from 0.53 to 1.46 mm, with a mean value of 0.943 mm. Absolute and relative fecundity ranged between 114-1246 eggs and 79.47-1285.71 eggs/g, respectively. Absolute fecundity and oocyte diameter to fish size (length and weight) were directly correlated, while the relationship between relative fecundity and fish size (length and weight) showed an inverse power function.
The trout barb Capoeta trutta is native to the Middle East only and little is known of its life-history in Iranian waters. Life history characteristics were examined in 366 specimens collected from the River Meymeh (western Iran) monthly during the reproductive seasons (March-May) of 2008 and 2009. Observed maximum age was 6+ years in both sexes, sex ratio (male : female) was 1 : 1.35, and length-weight relationships were TL = 0.0266TW2.7134 (males), TL = 0.0258TW2.7251 (females), and TL = 0.026TW2.7217 (entire population). Mean egg diameter (ED) was 1.61 (± 0.03 SE), ranging from 1.6 to 1.9 mm. Mean absolute (AF) and relative fecundity (RF) were 7594 (± 283.04 SE) eggs/female, and 70 (± 241.86 SE) eggs·g–1 body weight, respectively. AF and ED were found to increase significantly with increasing fish size, whereas RF decreased significantly with both fish TL and weight. Simplified von Bertalanffy growth estimates were also calculated.
Little is known of the life history of Cobitiscf. satunini, a loach species native to the Caucasus and southern Caspian Basin. Life history characteristics of this species were examined in 568 specimens collected from the Siahroud stream (northern Iran) between February and June 2010. The specimens ranged in size from 27 to 103 mm total length and weighed from 0.13 to 8.93 g total weight. The overall sex ratio was unbalanced as females dominated, with 342 females and 226 males being caught (sex ratio 1.5 : 1). Length-weight relationships implied that growth was positively allometric for both sexes. The von Bertalanffy growth function was estimated to be Lt = 94.95 (1 – e– 0.49 (t + 0.34)) for males and Lt = 121.65 (1 – e–0.39(t + 0.43)) for females. Egg diameter ranged from 0.44 to 1.02 mm, with a mean value of 0.77 mm. Absolute fecundity varied from 212 to 4666 eggs. Fecundity relative to total weight fluctuated from 383 to 268 eggs g–1. These growth and reproduction traits may be interpreted as species life history capacity and/or adaptation to environmental conditions caused by the southern Caspian climate.
A study was conducted from 2007 to 2010 to determine the status of the endemic loach species of Iran. So far 27 loach species belonging to two families (Nemacheilidae and Cobitidae) and eight genera have been recorded from 19 water basins of Iran. Eleven loach species are endemic to Iran. Oxynoemacheilus farsicus is considered as junior synonym of Oxynoemacheilus persus. The species Ilamnemacheilus longipinnis is known from a single specimen collected in the Tigris basin in 1978 and has to be considered as endemic but extinct in Iran. While some species like Paracobitis smithi are vulnerable due to their restricted and isolated habitat but drought, habitat alteration, extensive water extraction for irrigation and water pollution seems to be the major threatening factors to the loach survival in Iran. The Iran Department of Environment with the cooperation of Iranian Fisheries Research Organization must implement conservation programs to safeguard survival of Iran endemic loaches.