الفهرس 
Introduction
Classification Ingle (1993)Only 14 pages are availabe for public view
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Abstract
Hermit crabs are decapod crustaceans, most of which have non calcified abdomens requiring protection from predation. For this protection, they mostly inhabit empty shells of gastropods. On reviewing literature, the study of hermit crabs morphology, ecology and behavior attracted the attention of many authors around the world. In relation to Mediterranean hermit crabs, this subject did not attract much attention of the authors, despite the greater width and length of the Mediterranean Sea especially in Libya.
To the best of the present authors` knowledge and as far as can be ascertained, no previous studies on the hermit crabs inhabiting Libyan coast were carried out. So the present study was designed to through the light on the hermit crabs inhabiting the Mediterranean Sea coast of Libya. It was designed to carry out the following aims:
1- Survey and re-describe the hermit crab species inhabiting the intertidal and shallow subtidal regions along the Mediterranean Sea coast of Libya, with special focusing on the most common recorded species Clibanarius erythropus,
2- Design an identification key to the recorded species of hermit crabs..
3- Study population ecology of the most common recorded species Clibanarius erythropus in Misrata city.
4- Study the effects of some ecological factors including water temperature, pH, conductivity, dissolved oxygen concentration, and total dissolved solids on the density of the recorded species in the chosen main site.
5- Examine shell occupancy by the hermit crab Clibanarius erythropus; the most common hermit crab along the Mediterranean Sea coast of Libya.
To carry out the above mentioned goals, qualitative sampling of the hermit crab specimens was performed during the period extended for 6th months from January 2013 till June 2013. Collection was performed from the intertidal and shallow subtidal waters from 12 cities (25 sites) along the Mediterranean Sea coast of Libya which covered about 1100km. One of the above mentioned sites was taken as the main site to study the ecology of the investigated hermit crab species (Misrata city). Quantitative sampling from the main site was performed seasonally along one year from Summer 2013 till Spring 2014. During sampling, different five ecological factors were measured which included water temperature, pH, dissolved oxygen concentration, conductivity and total dissolved solids.
Scanning electron microscope was used to examine and describe the most common species Clibanarius erythropus. Measurements of morphological characteristics of the hermit crab C.erythropus were measured by an ocular micrometer. Pleopods with attached eggs were removed to estimate female fecundity.
For studying shell occupancy by the most common species of hermit crabs namely Clibanarius erythropus, a sample of 260 specimens were collected, on June 2014, from the shallow intertidal water from the public beach region of Misrata city.
Statistical analyses were used to test the collected data to investigate the significant results.
The most important results of the study are:
1- The horizontal survey recorded three hermit crab species:
Clibanarius erythropus (Latreille, 1818) (F%=24%)
Calcinus tubularis (Linnaeus, 1767) (F%= 12%)
Diogenes pugilator (Roux, 1829) (F%= 8%)
2- The common species recorded during survey was Clibanarius erythropus since it was recorded at six sites in considerable numbers while the other two species namely Calcinus tubularis and Diogenes pugilator were collected in few numbers from few sites (2-3 sites; respectively).
3- The total number of the hermit crab Clibanarius erythropus specimens collected from the investigated main site during the whole period of investigation was 166 specimens (Non-ovigerous females= 81, Males=62, Ovigerous females= 23). Its maximal value was in Summer (85 specimens, constituting 51.2% of the total catch in this season) whereas the minimal value was recorded in Autumn (12 specimens, constituting 7.2% of the total catch in this season).
4- A detailed description of the common species Clibanarius erythropus and brief descriptions of the taxonomically important characters of the other two species Calcinus tubularis and Diogenes pugilator were done . Also a key for the identification of the three recorded species was prepared.
5- The population of Clibanarius erythropus showed differences between the size (Shield length) of males (ranged between 3.5-6.5 mm) and females (the size of ovigerous females ranged between 3.5-5.5 mm, and the size of non-ovigerous females ranged between 3-6 mm).
6- The size of Clibanarius erythropus showed seasonal differences in size (Shield length), the size during summer ranged between 3.5-6.5 mm, autumn ranged between 3.5-5.5 mm, winter ranged between 4.5-6.5 mm, and spring ranged between 3.5-6.5 mm.
7- The sex ratio of Clibanarius erythropus showed that females are numerous than males.
8 - The high proportion of Clibanarius erythropus ovigerous females were observed in summer and spring while in autumn and winter not observed.
9- The size (shield length) of ovigerous females was negatively correlated with number of eggs.
10- The relationship between body size (shield length) and both of left cheliped and left third pereopod development decreasing with increasing the size of Clibanarius erythropus in both sexes.
11- The density of the common hermit crab Clibanarius erythropus is negatively correlated with the dissolved oxygen (DO2) and positively correlated with conductivity (Cond.).
The model equation is:
The density of Clibanarius erythropus in 0.025 m2 = -43.908-0.665 DO2+0.0465 Cond.
12- Applying stepwise multiple regression to conclude a model equation showing the relation between shield length and carapace length of the crab Clibanarius erythropus and some morphometric characters of the occupied gastropod shell, it was concluded that:
The model equation of the carapace length is:
The carapace length = 2.294+ 0.660 shell aperture width + 0.187 shell length + 0.141 shell aperture length.
So, the above model equation indicates that the carapace length of the hermit carb is positively correlated with the aperture width of the shell, shell length and shell aperture length (R= 0.801, p>0.01).
The model equation of the shield length is:
The shield length = 2.333 + 0.533 shell aperture width + 0.279 shell weight + 0.107 shell length.
So, the above model equation indicates that the shield length of the hermit carb is positively correlated with the aperture width of the shell, shell weight and shell length (R= 0.808, p>0.01).