Population dynamics of an invasive species Carassius auratus in the Shatt Al-Arab River, Iraq

Abstract

The population dynamics of the crucian carp, Carassius auratus in the Shatt Al-Arab River, Iraq was studied from November 2015 to October 2016 with monthly samples collected by different fishing gears. The FAO-ICLARM Stock Assessment Tool (FiSAT II) software was used for the mathematical analysis. Length-weight relationship was calculated as W= 0.0149L3.065 for fish length 4.6 to 26.8 cm. Growth parameters L∞, K and Ø were computed as 29.1 cm, 0.51 and 2.635. The total (Z), natural (M) and fishing (F) mortalities were 2.69, 1.09 and 1.60, respectively. Exploitation rate (E) was 0.59. Length at first capture (Lc) was found to be 10.04 cm. C. auratus displayed one main pulse of annual recruitment. The relative yield per recruit analysis revealed that the exploitation rate (E) of C. auratus was higher than the biological target reference points E0.1 and equivalent to Emax. It could be concluded that the C. auratus stock in the Shatt Al-Arab River is operating nearby the exploited situation and needs some precautionary measures to avoid the overexploitation by activating the national law of fishing, exploiting and protecting aquatic resources, in particular preventing illegal fishing methods and follow up the execution of the closed season to prevent the decline of our fish resources.

Stock Assessment and Virtual Population Analysis of Carassius auratus (Linnaeus, 1758) in the Al-Diwaniya River, Middle of Iraq

“…this type of growth indicates that the fish becomes relatively stouter or deeper-bodied as it increases in length" [40]. This growth shape was found to be similar to those recorded by several authors in various waters [18,41,[21][22][23]. Conversely, some authors stated a negative allometric growth for this species in other waters [19,20,42].…”

“…The growth rate (K) and the growth performance index (Ǿ) for the species estimated in the present study were lower than estimates from other studies in Table 2. Abood and Mohamed [23] recorded the highest value of K in the Shatt Al-Arab River, Iraq, while the maximum value of Ǿ was observed by Mohamed et al [12] in the East Hammar Marsh, Iraq (Table 2). The variations in the growth parameters of the same species in different locations observed would be due to the [17,[48][49][50][51].…”

“…The growth parameters of fish population dynamics (asymptotic length L∞ and growth coefficient (K) are critical for stock assessment and fisheries management. Some studies reported that L∞ for C. auratus in Wanghu Lake [18], Euphrates River, Iraq [19], Yellow River, China [22], and Shatt Al-Arab River, Iraq [23] were shorter than the present findings, while was lower than those recorded for the species in the Lake Trasimeno, Italy [2], East Hammar marsh, Iraq [12] and Shadegan Wetland, Iran [21]. However, an L∞ of 33.0 cm obtained in this study agreed with the value previously estimated for the Shadegan Wetland, Iran by Hashemi et al [21] through (34.6 cm).…”

“…Yin et al [22] considered "the growth characteristics and resource evaluation of crucian carp (C. auratus) in the Yellow River, China". Abood and Mohamed [23] studied "the population dynamics of C. auratus in the Shatt Al-Arab River, Iraq".…”

Determination of Most Reliable Bony Structure For Ageing of Carassius carassius (Linnaeus, 1758) Inhabiting In Duhok River (Iraq)

“…In Iraq some researches about Carassius species have been made as population status of gold fish Carassius auratus [7,8].…”