The present study aimed to establish spatiotemporal food and feeding habits of the crab Pachygrapsus marmoratus inhabiting the rocky shores of the southern Mediterranean Sea coast, exemplified by Al-Haniyah, Al-Hamamah, and Susah sites in eastern Libya, and relate them to crab morphometric traits, and abundance of food organisms in the habitat. A total of 425 crabs collected during 2019 were used in the study. The minimum and maxim carapace length (CL), and total weight (TW) were: 8.5-35.1mm, and 0.4-31.0g in order, the means were 26.79mm and 12.37g. P. marmoratus is an omnivore facultative feeder, i.e. feeds on what is available in its habitat. Stomach fullness was established and discussed in terms of season, site, crab sex and growth, and availability of food in the habitat. The abundance of food in the stomach by taxa vary according to the site, and crab sex and size, but the overall trend was cnidaria and algae > crustacea > mollusca > seaweed, by season it was fall > spring > winter > summer. Cnidaria and mollusca were more abundant in stomachs of P. marmoratus of Al-Haniyah, Crustacea in Al-Hamamah, and mollusca and crustacea in Susah crab’s stomachs.

Marine gastropods are known to accumulate high metal concentrations in their tissues especially in the digestive glands. In this study, the accumulation of Cu, Zn, Cd, Cr and Pb in the gastropod Gibbula sp. (Family: Trochidae) has been assessed using Atomic absorption, spectrophotometry graphite Furnace. Animals were collected from rocky shores at Al-Hanyaa region on the northeast coast of Libya. Two groups of animals were studied; one from an area adjacent to a sewage outlet and the second was collected from a relatively clean site. Concentrations of metals in the viscera, of both adults and juveniles, of Gibbula collected from the polluted site were higher than that recorded in the clean site. Thus, there is a tendency for Gibbula tissues in the polluted area to have higher concentrations of metals although the differences are not always statistically significant. The values recorded for adult specimens collected from the polluted and non polluted locations were 0.51±0.

A total of 207 specimens of Epinephelus guaza (Family: Serranidae) were collected from Catches by long line and spear fishing operating on Susa Coast on the Mediterranean sea , Libya were studied monthly from April 2010 to March 2011. hepatosomatic index (HSI), condition factor (K) and length-weight relationship (LWR) were evaluated. Monthly variations of GSI in both sexes showed the higher values during the period from June to September when HSI values were lower. Based on the values of GSI and HSI, the reproductive cycle of E. guaza is designated into prespawning period (April–May), spawning period (June-September), and posts pawning period (October-November). The correlation coefficient for length weight relationship was 0.99. The value of regression coefficient for both sexes was isometric (b = 2.969). The highest values of condition factors were recorded in summer (K 1.75) and autumn (K 1.63). The data revealed that E. guaza is a seasonal breeder and reproduction took a longer duration of time.

Age and growth characteristics of the thin-lipped Grey Mullet (Liza ramada) were investigated in Eastern coast of Libya. Aging was done by two methods: counting annuli on scales and by length frequency distribution, a total of 218 scales were studied for age determination, in addition of 334 fishes specimen for length frequency distribution reading. Four age groups were determined from scale reading, and five age groups from length frequency distribution methods, the parameters of the Von Bertalanffy growth equation for both sex of all individuals were estimated at 35.4 cm, 0.187 per year, -1.14 years and 2.4, for male were estimated at 35.7 cm, 0.17 per year, -1.367 and 2.3, for female were 38.6 cm, 0.156 per year, -1.383 and 2.4, for L∞, k and t0, and φ′, respectively.

The aim of this work was to establish morphological traits of P. marmoratus inhabiting the rocky intertidal zone of the southern Mediterranean Sea coast. 457 P. marmoratus collected randomly from the AL-Haniyah, Al-Hamamah, and Susah sites, eastern Libya, during 2019 were used in the study. The largest carapace length (CL) and weight (WW) were 35.1cm and 31.0g, respectively, while the minimums were 8.50cm and 0.40g. The means were 24.5cm and 10.2g. The order of WW by season was: winter and spring > fall > summer; by site: Al-Haniyah > Susah > Al-Hamamah; males being heavier than females. The WW-CL relationship was WW=0.001*CL**2.817; R2=0.909. The condition factor of P. marmoratus was highest in spring and lowest in summer, highest in Al-Haniyah and Susah and lowest in Al-Hamamah, and similar for both sexes, it increased in a negative allometric manner as the crab grew. The morphometrical parameters of male P. marmoratus were higher than those of females. Most morphometrical parameters scored higher values in winter and spring, followed by fall, and summer, with Al-Haniyah and Susah parameters being higher than the Al-Hamamah ones. Temporal and spatial variations of the morphometric parameters were discussed in terms of the availability of food and prevailing environmental conditions. Regressions of females and males P. marmoratus morphometric parameters with CL were strong and positive. Bilateral dimorphism was not observed. Four-year age groups, +1 (11-12mm), +2 (16-18mm), +3 (25-26mm) and +4 (32-33mm), comprised the P. marmoratus population.