التنوع السمكي وبعض الخصائص الحياتية في الجزء الشمالي لشط العرب وبعض مقترباته == Fish biodiversity and some biological characteristics in the Northern part of Shatt Al - Arab River and some of its reaches
Author name:
عبد المحسن جعفر عبد الله
Supervisor name:
ساجد سعد حسن النور
General topic:
Agricultural sciences
Specific topic:
Zoology - Fish And Marine Wealth
Degree:
Master
University:
University Of Basrah - Faculty Of Agriculture - Department Of Fish And Marine Wealth
Language:
Arabic
University location:
Basrah
First pages:
31T1824 - p.pdf
Abstract:
The aimed of the present study to find out the nature of the qualitative compositionand some biological aspects in the North part of Shatt Al - Arab River and some of its reaches after emergence of many changes in the region and habitats segmenting by Dam construction on Euphrates River in the area between Chibyish and Mudina town and establishment of Qlat - Salih Regulator, reduction of water discharge to minimum limits, entry of alien species on an ongoing basis, so it is necessary to conduct a study to find out the nature of the diversity of fish in the region, and it has shown that the composition of community differs from previous studies revealed that introduced alien small size species and some of uneconomic species were dominate. The samples were caught monthly from the river from December 2013 to May 2015 North of Basrah Province. Several fishing tools were used to collect fishes seine, fixed, draft, cast net and electrofishing. Three stations were selected; the station 1 was in the North of Qurna town about five kilometers North the point which the Tigris and Euphrates River confluence, station 2 at the place of Seweeb River is meeting the Shatt Al - Arab Rive and station 3 at the point that Al - Shafii River which meet Shatt Al - Arab river. Some environmental parameters were measured, namely air temperature ranged from 15ºC in December 2014 in station 3 to 43ºC in the August 2014 at station 2 and 3, while the water temperature from 11ºC in January 2015 for station 1 to 36 ºC in July at station 2. Light penetration revealed 33 cm in April and May 2014 and 132 cm in January 2015 for station 3. Current speed ranged between 0.03 m/s in January 2015 in station 3 and 0.29 m/s in October 2014 for station 1. Salinity ranged from 0.66 g/L in January 2014 for station 1 to 1.46 g/L in February and March 2015 in station 1 and October 2014 for station 2. The pH values tend toward the alkaline, the lowest 7.30 in May 2014 for station 2 and 8.90 measured in February 2014 in station 1. Monthly discharges, average incoming from the Tigris River recorded 35.20 ± 8.47 m3/s in November 2014 to 73.85 ± 17.55 m3/s on February 2014. Lower values of reactive nitrate were recorded 0.69 μ g at. N/L in March 2015 at station 3 and highest 24.32 μ g at. N/L in May for station 2, however the values of reactive phosphate recorded, the lowest 0.0037 μ g at. N/L in March 2015 at station 2, the highest was 0.589 μ g at. N/L in November 2014 for station 1. A total of 29405 individuals was collected during the study period represented 916521g included 33 species eight of them were marine species contain 29 genera belong to 14 families of Osteichthyes, Cyprinids family occupied first degree in the number of species (13) and genera (12), the numerical relative abundance of marine species in the study area was 3.38% and the relative abundance gravimetric was 8.45%. A significant positive correlation was found between number of species and water temperature (r=0. 506). Liza abu, Carassius auratus and Coptodon zillii were the most total numerical relative abundance 30.89, 29.30 and 15.64 % respectively, C. auratus, S. triostegus and C. zillii were the most total weight relative abundance and composing 27.58, 14.27 and 11.64% respectively in the study area. Discharges rates flowing from the Tigris River revealed negative effect with the number of species and the insignificant negative correlation was recorded (r= - 0.109) with discharge monthly rates, and fluctuation relationship was noticed between discharges and ecological indices. However, native species included 15 seasonal species 4 and 14 for rare species. Diversity index (H) ranged between 0.91 in January 2015 at station 3 to 2.05 in March 2015 for station 2, richness index (D) 0.83 in February 2014 at station 3 and 2.79 in March 2015 at station 1, evenness index (J) recorded 0.38 in January 2015 and the highest 0.78 in September 2014 for station 1. The percentage of similarity among stations by Jaccard similarity index (Ss%) showed variation uneven during study months. Cluster analysis of species similarity pointed to clumping in groups controlled by temperature. The Multivariate analysis was (CCA) adopted to clarify the impact of a biotic factors on the distribution of species. Total catches were ranged between 16380 g in December 2013 to 80309g in December 2014. The total average catch per unit of effort was 24.953 kg/hr for seine nets ranged from 0.928 kg/hr in December 2014 at station 2 to 30.271 Kg/hr during January 2015 for station 3. The number of fishing boats in the study area 143 their length between 5 - 7m most of them without an engine. The impact of alien species direct effects during the destruction of nests and reproductive ground, especially eggs which lie on a plant for native species and hybridization between alien and native species, and indirect effects of competition on food, ecological space, environment destruction and aggressive behavior. The length groups of all fish species were recorded, the lowest values were for Alburnus mossulensis, Acanthobrama marmid, Hemiculter leucisculus and Garra rufa, they were 7.3 - 18, 6.3 - 17, 7 - 17 and 7.2 - 17.8 cm respectively, whereas the highest were for Silurus triostegus, Leuciscus vorax and Mastacembelus mastacembelus, they were 10.8 - 72.4, 9.5 - 57.3 and 14 - 55 cm respectively. Faben method used for estimating growth parameters (L∞,K) by applying FiSAT program for C. auratus, Carasobarbus luteus and L. abu, the values of L∞ for three species 38.97, 35.69 and 22.19 cm respectively, and for K 0.29 to the C. auratus and C. luteus and 0.41 for L. abu, the results revealed five years age for C. auratus and C. luteus whereas four years age for L. abu. The present study showed high values of diet overlap between L. abu and Cheon subviridis 09% also high values 90% Oreochromis aureus and Oreochromis niloticus S. triostegus and L. vorax 89%, but it did not reach the competition limit, also high diet overlap 86% and competition was found between C. auratus and C. luteus Absolute fecundity for C. auratus females ranged from 1303 for 8.8 cm total length and 10g weight to51245 egg for 30.1 cm total length and 557g weight, and for C. luteus from 2098 for 13.1 cm total length to 14147 egg for 20.9 cm total length and 131g weight, while in L. abu from 6247 for 9.7 cm total length and 11g weight to 41219 egg for 17.5 cm total length and 63g weight.
