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A checklist of Moroccan marine Rhodophyceae excluding the members of the Ceramiales, the largest order, based on both literature records and some original data, is presented. The distribution of each taxon for this region (12 Mediterranean and 26 Atlantic localities) is given. Using present-day taxonomy, 218 species, infraspecific taxa and life-history phases are accepted for the Moroccan coasts. Six new combinations are proposed: Phymatolithon calcareum (Pallas) W. H. Adey et McKibbin f. compressum (M'Calla ex Harvey) Benhissoune, Boudouresque, Perret-Boudouresque et Verlaque comb. nov., Phymatolithon calcareum (Pallas) W. H. Adey et McKibbin f. squarrulosum (Foslie) Benhissoune, Boudouresque, Perret­Boudouresque et Verlaque comb. nov., Plocamium cartilagineum (Linnaeus) P. S. Dixon var. uncinatum (C. Agardh) Guiry ex Benhissoune, Boudouresque, Perret­Boudouresque etVerlaque comb. nov., Rhodophyllis divaricata (Stackhouse) Papenfuss var. werneri (P. Dangeard) Benhissoune, Boudouresque, Perret­Boudouresque et Verlaque comb. nov., Rhodymenia pseudopalmata (J. V. Lamouroux) P. C. Silva var. fuscopurpurea (P. Dangeard) Benhissoune, Boudouresque, Perret­Boudouresque et Verlaque comb. nov. and Titanoderma trochanter (Bory) Benhissoune, Boudouresque, Perret-Boudouresque etVerlaque comb. nov. [ABSTRACT FROM AUTHOR]

A checklist of Moroccan Ceramiales (Rhodophyceae), based on both literature records and some original data, is presented. The distribution of each taxon for this region (12 Mediterranean and 26 Atlantic localities) is given. Using present-day taxonomy, 161 species and infraspecific taxa of this order are accepted for the Moroccan coasts. [ABSTRACT FROM AUTHOR]

A checklist of Moroccan marine brown algae, based on both literature records and some original data, is given. The distribution of each taxon for this region (12 Mediterranean and 27 Atlantic localities) is reported. Using present-day taxonomy, 131 species, infraspecific taxa and life-history phases are accepted for the Moroccan coasts. [ABSTRACT FROM AUTHOR]

Morphological data has provided a basis for the hypothesis that three taxa belonging to the Caulerpa racemosa complex occur in the Mediterranean Sea: var. turbinata–uvifera , var. lamourouxi , and the `invasive variety'. In order to test this hypothesis and to determine the origin of the `invasive variety', the transcribed spacer ITS1–ITS2 and an 18S ribosomal DNA (rDNA) intron were analysed from 16 isolates of Caulerpa racemosa . The `invasive variety' shows intraindividual polymorphism for both types of sequences. The ITS1–ITS2 data confirm that the three morphological varieties of C. racemosa from the Mediterranean Sea are distinct taxonomic units. The 18S intron data suggest that the new `invasive variety' could be a recent hybrid between var. turbinata–uvifera and an unknown tropical strain. Incongruence between the phylogenetic tree computed from ITS1–ITS2 regions and the 18S intron indicates that homogenization processes of concerted evolution have run at different rates. [ABSTRACT FROM AUTHOR]

An annotated checklist of the Ceramiales (Rhodophyceae; red algae) of the Mediterranean, based on literature records, is given. The distribution of each taxon in the area (which is divided into 16 regions) is reported. The number of species and infraspecific taxa of this group accepted for the Mediterranean Sea as currently recognised taxonomically is 271. This list has benefited from the suggestions on taxonomy, nomenclature and regional distribution made by phycological advisers for each region. [ABSTRACT FROM AUTHOR]

A check-list of Moroccan marine Chlorophyceae, based on both literature records and some original data, is given. The distribution of each taxon for this region (13 Mediterranean and 25 Atlantic localities) is reported. Using present-day taxonomy, 102 species, infraspecific taxa and stadia are accepted for the Moroccan coasts. A new combination is proposed: Blidingia tuberculosa (P. Dangeard) Benhissoune, Boudouresque et Verlaque. [ABSTRACT FROM AUTHOR]

The compendium of literature citations for Caulerpa racemosa (Forsskål) J. Agardh in the Mediterranean Sea, together with available fresh and preserved material from both known and new localities, were critically examined. This analysis suggests that three distinct taxa of C. racemosa co-exist in the Mediterranean Sea. (i) C. racemosa var. turbinata - uvifera, known since 1926 and 1931 in Tunisia and in the Levantine basin (ii) var. larnourouxii f. requienii, known since the 1950s in the Levantine basin and (iii) an invasive variety which has been quickly spreading, since the early 1990s, throughout most of the Mediterranean Sea (Balearic Islands, France, Western and Southern Italy, Sardinia, Sicily, Greece, Crete, Turkey, Cyprus, Libya and Lampedusa Island, off Tunisia). The last variety differs mainly from the two first varieties by its upright axes with clavate, more or less inflated branchlets, which are uncrowded and radially to distichously disposed. Within the C. racemosa complex, several taxa are known to bear uncrowded, radially and/or distichously arranged branchlets. Among them, C. racemosa var. occidentalis, a tropical taxon widely distributed through- out the tropical seas, appears to be closest to the invasive Mediterranean variety of C racemosa. Various criteria (taxonomy, kinetics of spread, tendancy to pullulate) suggest that C. racemosa aff. var. occidentalis could be a taxon recently introduced to the Mediterranean Sea. [ABSTRACT FROM AUTHOR]

The compendium of literature citations for Caulerpa racemosa (Forsskål) J. Agardh in the Mediterranean Sea, together with available fresh and preserved material from both known and new localities, were critically examined. This analysis suggests that three distinct taxa of C. racemosa co-exist in the Mediterranean Sea. (i) C. racemosa var. turbinate—uvifera, known since 1926 and 1931 in Tunisia and in the Levantine basin (ii) var. lamourouxii f. requienii, known since the 1950s in the Levantine basin and (iii) an invasive variety which has been quickly spreading, since the early 1990s, throughout most of the Mediterranean Sea (Balearic Islands, France, Western and Southern Italy, Sardinia, Sicily, Greece, Crete, Turkey, Cyprus, Libya and Lampedusa Island, off Tunisia). The last variety differs mainly from the two first varieties by its upright axes with clavate, more or less inflated branchlets, which are uncrowded and radially to distichously disposed. Within the C. racemosa complex, several taxa are known to bear uncrowded, radially and/or distichously arranged branchlets. Among them, C. racemosa var. occidentalis, a tropical taxon widely distributed throughout the tropical seas, appears to be closest to the invasive Mediterranean variety of C. racemosa. Various criteria (taxonomy, kinetics of spread, tendancy to pullulate) suggest that C. racemosa aff. var. occidentalis could be a taxon recently introduced to the Mediterranean Sea. [ABSTRACT FROM AUTHOR]

Removal of important predators by fishing can result in trophic cascades and indirect effects on marine benthic communities. Indirect effects are especially evident when prey populations released from predation by fishing have the ability to modify entire benthic communities, as do sea urchins. Sea urchins have been shown to dramatically alter the underwater landscape by grazing, by converting stands of large erect algae into coralline barrens. In the western Mediterranean, a recent extension of coralline barrens into areas formerly dominated byerect algal assemblages has been attributed to release of predation on sea urchins by overfishing. Most suggestions concerning the transition from erect algal assemblages to coralline barrens, however, havebeen speculative, and little descriptive and experimental work has been carried out to verify the hypothesis that fish predation on sea urchins (and its subsequent release by overfishing) drives this transition. Here we critically review the literature concerning the effect of fishing on sea urchin populations and its subsequent maintenance of different algal assemblages in the Mediterranean. The extant data can not refute the 'fishes as important predators' model, but we arguethat other processes (recruitment, pollution, disease, large-scale oceanographic events, sea urchin harvesting, food subsidies, and availability of shelters) may also be important in regulating the structure of Mediterranean algal assemblages. [ABSTRACT FROM AUTHOR]