Iraqi Journal of Aquaculture

This study was conducted to study the response of
Blue Tilapia Oreochromis aureus to increasing
salinity. Abrupt and gradual transfer to higher salinity
was done to determine salinity tolerance and survival
rates and was found that this fish tolerate the abrupt
increasing in salinity between 1.5 – 20 g/l with Lc50
(20.44 g/l). Salinity tolerance increased with gradual
increase in salinity as survival rate increased to 90%
in salinity 30 g/l. Muscle and gut were used to
investigate their role in water and ionic balance and
was found that the water content in the muscle
decrease with increasing salinity while it increase in
the gut. The ionic content (Na+ and K+) increased in
both muscle and gut with increasing salinity. This
study showed the ability of this fish to change its
osmoregulatory ability from hyperosmotic in fresh
water to hyposmotic in salt water.

This study was conducted to determine the effect of
various feeding levels (3%, 5% and 7% body weight/
day) on final weight, weight gain, specific and daily
growth rates as well as food conversion rate of
Arabian yellowfin seabream Acanthopagrus arabicus.
The experiment were executed in three concrete tanks
(1m3) and extended 60 days. Results reveal significant
differences (P>0.05) of final weight, weight gain,
specific and daily growth rates at different feeding
levels. Final weight attain 61.9, 63.25 and 61.65gm in
feeding levels 3, 5, 7% body weight, respectively. The
best food conversion rate showed that feed conversion
rate value (4.677) was encountered at the feeding level
3% body weight followed by feeding ratio 5% (7.654)
where as the lower food conversion rate (11.018) was
found at the feeding level 7% body weight, Statistical
analysis proved significant differences (P<0.05) in
food conversion rates among selected feeding levels.

Current study estimates Chlorophyll – a and
Phaeophytin - aand their vertical distributed to a depth
ten centimeters in the sediments of Shatt Al-Arab
riverfor five stations from Al-Maakal to Fao city for the
period from February to November 2013.The upper
centimeters, especially the first centimeterwas marked by
the highest concentrations of the chlorophyll - apigment
in all stations for most of the study period, while the
lower values have been recorded in the lower centimeters
except for a few exceptions. The highest concentrations
of both pigments was in the first station, the highest
concentrations of chlorophyll - a 79.833 µg/g during
April for the first centimeter, while the highest
concentrations of phaeophytin - a 51.706 µg/g during
October at first centimeter. The lowest concentrations of
chlorophyll –awas in the second station, reaching 0.101
µg/g in April, while the lowest concentrations of
Phaeophytin - a0.026 µg/gwas at sixth centimeter during
May atfourth station.In general, the first stationwas
marked bythe highest concentrations of Chlorophyll –
arecorded during whole the study period, while the fifth
station had recorded the lowest concentrations.

Propagation of Alternanthera Sessiels in vitro by callus induction
through the culture of adventitious bud on MS medium supplemented
with 2.4-D and NAA in 1.5mg/L, primary callus where transferred on
MS medium supplemented with 0.5mg/L Benzyl Adenine (BA) and
0.5mg/L Kinetin (Kin) for induction Adventitious shoot, somatic
embryos appeared when primary callus transferred to free hormones
MS medium, Effects of cytokinins in direct organogenesis with various
concentration was also examined, the fourth treatment 1mg /L
Kin+1mg/L BA give significant Increase , and scored the highest mean
of shoot number 12 shoot. Also fourth treatment caused significant
increase and gave highest mean of shoot length 5.33cm, while no
significant different was appeared between the fourth treatment and
1mg/L Kin in the number of vegetative bud. Fourth treatment also
scored significant increased in the number of flower and give 5.33
flower/node, Direct and indirect regenerated shoot were transferred
to half strength MS medium supplemented with 0.5 mg /L NAA+ 0.5
mg/L IBA for root induction, plantlet were transferred to water field
after successful acclimatization.

The study included extracting of gelatin from the
fish`s skin Cynoglossus bilineatus using acid and
alkaline pretreatment the chemical analysis of the
experiment fishes skin shows that the extracted gelatin
was 11.7% for yield, 85.7% for protein, 0.84% for fat ,
0.65% for ash and 12.81% moisture. The physical
properties of extracted gelatin such as melting point was
25.3 °C, setting points 21.8°C and 112 Sc. While the
relatively viscosity was 2.5 cP, the result shows that the
extracted gelatin have an ability to gelation in all
concentrations, the emulsifying property increased with
increasing of the concentration of the sample, the
extracted gelatin have a good sensory properties with a
pale Yellow color and less fish smell acceptable.

Seasonal study was done for the distribution and composition of
benthic invertebrate community in three selected sites (S1, S2 and S3)
near a fish floating cages in Tigris river before Al-Kut Barrier south
Baghdad, during the period from January to December 2014. Some of
water quality parameters were measured as following: temperature
ranged from 14°C in winter to 32 °C in summer, dissolved oxygen from
5.2 in summer and 9.8 mg/l in winter, pH values from 7.5 to 7.8,
salinity from 0.5 in winter to 0.73 mlg/l in summer and water turbidity
from 250 in spring to 900 NTU in autumn. The river bottom of study
area was clay loan, silt clay, clay loan and clay for sites S1, S2 and S3
respectively. A total of 19 benthic fauna species were identified. Of these
8, 6, 3, and 2 species belonged to Arthropod, Oligochaet, Mollusca and
Nematode respectively. There were significant differences shown at S2
(inside cages) for the organic matter 4.7%, and for organic carbon
2.74%, 19 species, the abundance was 813.4 ind/ m2 and benthic
biodiversity was 2.86, compared with S1 and S3. Also, S2 was shown the
dominance for Arthropod: Insect (46.6%), followed by Oligochate,
Mollusca and Nematode (32.9%, 16.5% and 4%) respectively of the total
benthic invertebrate density. The results shown increment in benthic
invertebrate density and biodiversity inside cages (site S2) compared
with the other two sites before and after cages respectively.