Originally presented as the author's Thesis (Ph. D.--North Carolina State University, 1980). / Includes indexes. In Arabic. Includes bibliographical references (p. 315-336).

Island nesting seabirds are the most threatened group of avian fauna and are particularly vulnerable to habitat disturbance. The white-eyed gull nests exclusively on islands in the Red Sea and Gulf of Aden, many of which are facing anthropogenic pressure. The Al Wajh archipelago in the northern Red Sea hosts the largest population of the white-eyed gulls in Saudi Arabia and is currently undergoing tourism development for one of the country’s largest ongoing “Gigaprojects”. The habitat preferences and movement ecology of the white-eyed gull are understudied, and the species’ ability to respond to rapid habitat modification is unknown. In 2021, a ground census was conducted on all 92 islands of the Al Wajh lagoon to determine the distribution of white-eyed gull nests. In total, 55% of the white-eyed gull metapopulation were found on islands where development is either ongoing or upcoming, with the one of the largest and densest colonies occurring on an island already undergoing development. The baseline census presented here should be viewed as a first step in understanding the population dynamics of the white-eyed gull and predicting their response to enhanced anthropogenic change in the Al Wajh lagoon.

No description available.

No description available.

Plankton samples were taken at fortnightly intervals from January 1986 to June 1987 at six stations 20-50 km north of Jeddah, Saudia Arabia: three in a mangrove area ( Zahban village) , two outside the mangrove area ( Thuwal village) and one off Obhor Creek. Larvae of decapod Crustacea ( excluding the Brachyura ) were identified as far as possible and descriptions are given of the anomuran larvae encountered . Studies were made on seasonal variations in the numbers of larvae and on differences in occurrence and abundance between the stations. Eighty nine species of A/pileus larvae were distinguished , largely using differences in chromatophore pattern. Only two species of adult A/pfJeus are recorded from the central Red Sea. Thirty seven unnamed species of Anomura were distinguished on morphological characters and these are described and figured. The anomuran larvae belong to the fo1lowing families : Upogebi1dae ( 4 species ) , Callianassidae ( 7 species) , Laomedi1dae ( 2 species) , Galatheidae (7 species) , Porcellanidae ( 6 species) , Paguridae ( 4 species) , Diogenidae ( 7 species ) , and the Dlogenidae are made up of the fo1lowing genera: Oiogenes ( 2 species), Ca/cinus ( 2 species) , Dardanus ( 2 species ) , Clioanari(Js ( 1 species ) . Ten genera of Macrura, belonging to seven families, are also listed.Descriptions are g1ven of the complete larval development of Coenobita sceevole ( Forskal ) ( Coenob1tidae ) and Dardanus ttoctor ( Forskal ) ( Diogenidae ) I based on laboratory rearing. Comparisons are made with the larvae of related species . The presence of a central telson sptne in zoea III and all subsequent zoeal stages 1s a feature of all known coenootttd larvae, although 1t does not occur 1nother larvae of the Anomura ( sensu stricto) ( i. e. excluding the tnatasstntoae ) . The concentration of decapod larvae over the 18 months at the d1fferent stations was fairly strnttar I averaging about 1190/1000 m3 . The most common anomuran larvae were those of the Dtoqentdae , w1th Diogenes avarus Heller the most common 1n the mangrove area and the unnamed spec1es Ca/ein(Js A the most common off Obhor Creek. Larvae of A/pneus spp. and Harpil/us spp. made up a large percentage of the decapod larvae I especially at the stations outside the mangrove area and off Obhor Creek . Larvae of Galatheldae I Paguridae and Callianassidae were conspicuously more abundant 1n the night samples than 1nthe day samples. During the e1ghteen months of sampling at the six stations I decapod larvae tended to be more common 1n summer, particularly in June. More sampl1ng would be reoutrec to establ1sh whether th1s 1s a regular annual feature.

Not much is known about hawkfish worldwide including those that occur in the understudied Red Sea reef system. Hawkfishes are small reef predators that perch in ambush-ready positions and shelter within or on various substrates including live and dead coral. The aim of this study was to look at the distribution and abundance patterns of Red Sea hawkfishes across an inshore and offshore gradient and to investigate the use of benthic habitats. This study was conducted on three inshore, four midshore, and two offshore reefs with surveys at 8 meters and along the reef crest. In total, three species were documented: Paracirrhites forsteri, Cirrhitichthys oxycephalus, and Cirrhitus spilotoceps. We found clear distinctions between depth zones and between continental shelf positions. Cirrhitichthys oxycephalus only occurs at the reef slope and Cirrhitus spilotoceps is only found on reef crests. Paracirrhites forsteri was the most abundant species across all reefs and was found in four varying color morphs. Morph 1 showed the most evidence of being a generalist as it utilized the greatest number of substrates. All three species were more abundant on midshore and offshore reefs which have healthier, intact coral communities. Coral cover is a good indicator of hawkfish abundance even when the species in question does not utilize live coral directly.

Although the Red Sea presents a unique environment with high temperature and salinity, it remains an area that is understudied. This lack of information is reflected in many areas, one which is biodiversity. Despite increasing work on biodiversity throughout the Red Sea and an increase in Cephalopoda studies, Cephalopoda in the Red Sea remain underrepresented, which is especially pronounced in molecular analyses. Members of the class Cephalopoda are considered to be major contributors to coral reef ecosystems, serving as part of the food chain and exhibiting population increases due to targeted teleost fisheries and global climate change. In order to assess the biodiversity of Cephalopoda in the Saudi Arabian Red Sea, 87 specimens were collected from 25 reef locations between 17°N and 28°N latitude, as well as from the largest fish market in the Kingdom of Saudi Arabia. Taxonomic identification of specimens was determined using morphological comparisons with previously reported species in the Red Sea and the molecular barcoding region Cytochrome Oxidase I. 84 Red Sea sequences were compared with sequences from GenBank and analyzed using a complement of Neighbor-Joining, Maximum-Likelihood, and Bayesian inference trees. Species complexes were also investigated for Sepia pharaonis and Sepioteuthis lessoniana, which had been previously reported. From 17 cuttlefish, our study yielded three species, two of which matched previously reported species in GenBank. In addition, two distinct clades of Sepia pharaonis were identified. Of 35 squid collected, four species were identified, one of which did not match any other accepted species in literature, while Sepioteuthis lessoniana in the Red Sea formed a distinct clade. From 30 different specimens a total of five genera of Octopoda were present, forming six distinct species. Five Octopoda species collected did not match previously reported species, although many specimens were paralarvae or juveniles, so morphologically we could not compare to previously described species in the Red Sea. Cephalopoda fisheries in the Red Sea is low, and as their populations increase worldwide, this could be a viable fishery for Saudi Arabia. As such, further investigation into the role which cephalopods play in supporting biodiversity in the Red Sea is essential.

Seagrasses are key coastal ecosystems, providing many ecosystem services. Seagrasses increase biodiversity as they provide habitat for a large set of organisms. In addition, their structure provides hiding places to avoid predation. Seagrasses can grow in shallow marine coastal areas, but several factors regulate their growth and distribution. Seagrasses can uptake different kinds of organic and inorganic nutrients through their leaves and roots. Nitrogen and phosphorous are the most important nutrients for seagrass growth. Biological nitrogen fixation is the conversion of atmospheric nitrogen into ammonia by diazotrophic bacteria. This process provides a significant source of nitrogen for seagrass growth. The nitrogen fixation is controlled by the nif genes which are found in diazotrophs. The main goal of the project is to measure nitrogen fixation rates on seagrass sediments, in order to compare among various seagrass species from the Red Sea. Moreover, we will compare the fixing rates of the Vegetated areas with the bare sediments. This project will help to ascertain the role of nitrogen fixing bacteria in the development of seagrass meadows.

This study confirms the presence of Gambierdiscus sp., Ostreopsis sp. as well as other epiphytic benthic dinoflagellates associated with Ciguatera Fish Poisoning (CFP) in the Central Red Sea, highlighting the potential occurrence of CFP in this region. These species are reported for the first time in Saudi Arabian coastal waters. A total of 80 Turbinaria and Halimeda macroalgae samples were collected from coral reefs off the Saudi Arabian coast. Sample analyses indicated low average cell abundances (< 40 cells g-1 wet weight algae) of Gambierdiscus sp. and Ostreopsis sp. Subsequent statistical analyses indicated a significant difference in the cell abundances of both genera between sampling sites, between species and between inshore and offshore reefs. The presence of several potentially toxigenic dinoflagellate species in the Red Sea and the statistical differences in abundances between different sampling sites merits future study on possible impacts of these dinoflagellates on marine food webs and human health.

The Saudi Arabian government has announced an economic development plan (Vision 2030) to invest in a range of industries across the Kingdom, one of which is the development of aquaculture. In the face of a likely increase in Red Sea fish farming, we investigated the impacts of offshore fish farms on the coastal water quality of the Red Sea by a) measuring the environmental impacts of an operational Red Sea fish farm, and b) testing whether an existing aquaculture modeling software can be used as a meaningful planning tool in the development of Red Sea aquaculture. Water quality parameters such as dissolved oxygen, nutrients, particulate matter, chlorophyll, ammonium, and bacterial abundance were measured seasonally over the course of a year around an offshore fish farm along the south-central coast of Saudi Arabia to determine the impacts of fish farm effluent on the surrounding waters. Bacteria, phosphate, inorganic nitrogen, and suspended particulate matter showed patterns of enrichment close to the fish farm. Additionally, dissolved oxygen has slightly lower concentrations close to and down current from the fish farms. Benthic sediments from a nearby coral reef were also assessed for organic enrichment, but concentrations of total organic carbon and total nitrogen were not significantly different from those at an offshore reef. The data from these sampling efforts were then used as input parameters for an aquaculture modeling software (AquaModel.net), however many of the input parameters required to run the model were unavailable and meaningful conclusions could not be drawn from the results. Through field studies and modeling, we assessed the current impact of a Red Sea fish farm on water quality with the goal of predicting the potential impacts of future offshore aquaculture development in Saudi Arabia.