الفهرس 
Acknowledgment
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Abstract
Lutjanidae fishes are considered with high food value as well as their
economic value. This study aims to gain field, scientific and practical
experience and to study some aspects of biological and marine fisheries
through studying the biological characteristics of two species of Lutjanid
fishes, including age estimation, growth rates in length and weight as well as
total length relationship with weight, in addition to the breeding and estimation
of fish stocks, as well as the analysis of the statistical results of this type in the
fisheries, this study could be summarized as follows:
I: Knowledge of the common species of the Lutjanidae family
• The common species of Lutjanidae family were found in Hurghada, Red
Sea, Egypt, and eight species were recorded as following: Lutjanus
ehrenbergii, L. quinquelineatus, L. bohar, L. argentimaculatus, L. gibbus, L.
fulviamma, L. Lutjanus, and L. monostigmus.
Identification of Fish Stocks
Fish stocks of Lutjanidae fishes were identified by morphometric,
numerical and protein content.
Morphometric and Meristic characteristics
The morphometric characteristics of two species of Lutjanidae fishes, as
well as the alumetric (isometric, negative alomoteric, and positive alometric)
parameters were studied. The distinction between qualitative Lutjanus
quinquelineus and Lutjanus ehrenbergii was made using some morphometric
parameters of 18 morphometric measurements. In addition, the study included
some numerical characteristics and their relationship to growth, and it was
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proved from the study that the number of rays in the dorsal fin, Pectoral and
anal fin is fixed in both types subject to study.
• SDS-Polyacrylamide Gel Electrophoresis
In the present study, muscle proteins were measured in the types of
Lutjanus quinquelineus and Lutjanus ehernbergii using the
electrophysiological system, which showed the same number of protein tapes
(20 protein tapes). Also, the muscle proteins of the same types were classified
into several tapes. These tapes showed a difference in quantitative parameters,
where Lutjanus quinquelineus have unique bands of molecular weights as
following (266.43, 215, 119.82, 30.51, and 27.18), while the Lutjanus
ehernbergii type has the following molecular weight proteins (75.97, 50.81,
30.86, 30.07, 27.18 and 16.6).
The present study is the first attempt to study the genetic relationships of
two species using general muscle proteins. Based on the protein band pattern
shows that the species analyzed are more or less closely related to each other.
Future studies using biochemical-genetic markers and DNA barcoding
hopefully will establish new ventures in the field of stock management and
conservation of snappers.
II: Fishery Statistics
Data for catch were collected from 2004 to 2015 for the purpose of
assessing fish stocks and determining the status of current Red Sea fisheries
with a focus on Lutjanidae fisheries. The present study showed that the catch in
the fishing areas around Hurghada area during the last 10 years from 2004 to
2015 included the following types of fish: Gropper, Emperor, Jack, Soldier
Fishes , Spanish Mackerel, , Needle Fish, Seabream, and Porgy in addition to
snapper, all these types were caught by the strings. Other fishes are also more
commonly caught by gill nets and tributaries nets such as: Goat, Rabbit, Parrot,
Soldier Fish and Caranx respectively, according to the statistics of the General
Authority for Fisheries in Hurghada. Also, the study showed that the total catch
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111
of whole bone fishes and Lutjanidae fishes in particular in the landing area of
Hurghada , Red Sea, Egypt during the period from 2004 to 2015 were different.
III. Biological characteristics and assessment of fish stocks
A( Biological characteristics:
The age of two species (L. quinquelineatus and L. ehrenbergii ) was
estimated using scales. The annual rings were clearly shown. The annual rings
began to appear on the scales in December for L. quinquelineatus and
November for L. ehrenbergii
The total length - the total weight relationship of the two species was
studied by linear regression analysis using the statistical methods, which can
be represented by the following equations:
L.quinquelineatus W = 0.0118 L= 3.098 R
2 = 0.95 TL in cm
L. ehrenbergii W = 0.0194 L= 2.911 R2=0.96 TL in cm
The relation between the standard length-scale radius was first
determined, this relation was found to be linear. The linear regression does not
pass through the origin, the equation representing this relationship was:
L.quinquelineatus TL = 0.628 + 0.4778 R2 = 0.952
L. ehrenbergii TL = 0.5626 + 1.9181 R2 = 0.929
B: Stock Assessment
The fishery biology, including growth, mortality and reproduction of the
Lutjanidae species were used to determine ages and estimate the backcalculated
lengths-at-ages, growth rates and then the von Bertallanfy growth
parameters (VBGPs; K, Land to). The maximum age was found to be 4 years
for hoth sexes males and females. The von Bertallanfy equation for the
mathematical description of the growth in length could be written as follows:
Lutjanus quinquelineatus
For growth in length Lt = 35.5 [1 - e
-0.35(t + 1.3)]
For growth in weight Wt = 750.62 [1 - e
-0.35(t + 1.3)]
3.0986.
For growth in length Lt = 32.4 [1 - e
-0.32(t + 1.3)]
For growth in weight Wt = 545.50 [1 - e
-0.32(t + 1.3)]
3.0986
The total mortality coefficient ’Z’, natural mortality coefficient ’M’, and
fishing mortality coefficient ’F’ were estimated to be 2.16 ,0.78, and 1.38 year
-1
,
in L. quinquelineatus, 2.45 , 097 , and 1.47 year
-1
in L. ehrenbergii,
respectively. The current exploitation rate ’Ecur’ was 0.8 year-1
. The spawning
season was found to extend from March to July, and the maximum absolute
fecundity was estimated to be 088883 eggs in L. quinquelineatus. and 083333
eggs in L. ehrenbergii. The yield and biomass per recruit were estimated using
the Beverton and Holt’s yield per recruit Model (1957). Results indicated that
the stock of Lutjanidae in Hurghada fisheries is currently overexploited where
both Emax = 0.71 year-1
and E0.1 =0.61 year
-1
are lower than Ecur = 0.8 year-1
. It is
recommended that the current exploitation rate be reduced to the level of E0.1,
in addition to protecting the spawning stock biomass during the spawning
season and reducing the natural mortality rates.
Species L∞ K To Ø’
Lutjanus quinquelineatus 35.5 0.354 -1.310 2.65
Lutjanus ehrenbergii 32.4 0.474 -1.0185 2.69
In the study of the length -age distribution of the lutajanidae fish, the
maximum age of both species was 4 years. The first age group is
predominant in the catch of both species of lutajanid fish in the study
area.
yield per recruit was calculated for lutajanidae fish using the Beverton
and Holt model (1957). To obtain the highest yield per recruit, the
mortality rate of the fishing process should be reduced by L.
quinquelineatus 58.%. and 54 % L. ehrenbergii.
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IV: Fisheries Management
In the light of the above findings and with the fact that all target species in
the Egyptian Red Sea fisheries are in a situation of overexploitation, L.
quinquelineatus and L. ehrenbergii, snapper fishery in Hurghada fishing area
can become more profitable and can achieve more economic returns if it given
more attention and care. So, a detailed knowledge on behavior, biology and
population dynamics of the all fish stocks in the area is a vital step and should
be done to put a full concept for how to exploit and expand this promising
resource that will achieve the desired sustainable development of the
Lutjanidae fishery in Hurghada.