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International audience

International audience

International audience

International audience; Porteuse aujourd’hui encore d’une forte identité culturelle, la pêche des éponges s’inscrit dans un passé très ancien en Méditerranée. On en repère la trace il y a plus de 2500 ans dans cette mer intérieure1. Stimulé par les besoins nouveaux de la révolution industrielle, ce secteur de l’économie halieutique connaît une croissance forte qui atteint son apogée au cours des dernières décennies du XIXe siècle2. Cette croissance apparaît cependant comme paradoxale. Elle s’inscrit sur le plan technique à contre-courant de l’évolution survenue dans les autres secteurs de l’économie halieutique en Méditerranée à l’époque contemporaine. Soumise à des processus d’homogénéisation impulsés par la découverte de nouveaux matériels, la pêche méditerranéenne, à l’image de celle du petit pélagique révolutionnée par l’avènement de la senne tournante, a connu dès l’entre-deux-guerres un resserrement de ses pratiques halieutiques. La marginalisation des procédés les plus anciens en est la conséquence la plus remarquable. Tel n’est pas le cas de la pêche des éponges, qui fait coexister au XXe siècle des pratiques plurimillénaires et des engins nouveaux issus de la mécanisation et de l’ingénierie. On s’interroge actuellement sur les origines de cette singularité. On cherche à souligner les limites du processus de mécanisation de cette pêcherie, que ces limites ressortissent à une dimension humaine ou écologique. Des fonds documentaires italiens de l’Administration générale du Dodécanèse (1912-1943), actuellement conservés par les archives publiques de Rhodes, fournissent une illustration concrète de l’organisation complexe et plurielle d’une campagne de pêche à traversl’exemple de la flottille de Kalymnos. Ces fonds apportent des connaissances sur les acteurs de son financement, de sa mise en œuvre technique et de son déroulement matériel.

International audience; The production of Mediterranean bath sponges collapsed during the past century, as is shown by Tunisian catches, which fell from 108 tons in 1920 to 9 tons in 1988. A further illustration is provided by the well-known sponge-fishing island of Kalymnos, which lost about 90% of its active sponge-fisher population over the century between 1858 and 1967. What are the reasons for this dramatic decline of a once prosperous Mediterranean traditional fishery? What part of the decline can be attributed to the progressive reduction of the bath sponge stock, and what to a decreasing number of fishermen? How might this sponge fishery collapse be related to changes in uses, overfishing, and disease outbreaks triggered by climate events? How did sponge fishermen adapt to Regional Changes in the past? What is the future of such a fishery? What kind of guidelines can we provide for this fishery facing ongoing Regional Change?

Farrea bowerbanki n. sp. Boury-Esnault, Vacelet & Chevaldonné Type-specimen. Sample VAL2-ACH-P15_ECH01. MNHN-HJV-03 Type-locality. Valinco Canyon, SW Corsica (Western Mediterranean), 383 m, 41.66148N / 8.7953E, 31/07/ 2014. Comparative material. Slides from specimens of the Ibero-Morrocan Gulf (BALGIM Cruise, 1984, Stn CP91-13, 34.3675N – 7.417W, 945 m). External morphology. Several specimens were observed on ROV pictures and videos or by direct observations from the manned submersible ‘Remora 2000’ (Comex) in 2009, 2010, 2014 and 2016 (Fig. 1, 2 and 4, Table 3). A complete specimen, designated as holotype, has been collected in 2014. The holotype (Fig. 2 A, 2C) is 15 cm high, with a diameter of about 20 cm at its widest part. The body is formed by a branching and anastomosing system of tubes attached to the rocky substrate by a small basal plate, 2 cm in diameter. Two main tubes, 2 cm in diameter, arising from the basal plate, divide and merge several times, with distally infundibular openings 5–8 cm wide. The shape of these openings is reminiscent of a flower corolla. The thickness of the tube wall is about 1–2 mm. Color in life is white, with the basal plate and a short common basal part of the tubes, deep grey. The sponge is very fragile, and several parts of the tubes are broken on the preserved holotype which was very difficult to collect in a good state of preservation by the ROV. The other specimens observed, such as shown in Figures 2 B, 4A, 4B and 4D, have the same general shape, varying in size from a few centimeters to 40 cm. Several observed specimens were composed of a white living part and of a dead skeleton, colored in grey due to the deposit of mud. Skeleton. The skeleton framework is a typical farreoid dictyonal type with smooth beams and spined spurs (Fig. 2 D, 2F). Dictyonalia are formed in more than one layer. The meshes are mostly rectangular, sometimes square or triangular (Fig. 2 E), with dictyonal beams 168–430/35–50 µm in size. The spurs are 90–210 µm in length, always spined and most often curved (Fig. 2 F).

Tretodictyum reiswigi n. sp. Boury-Esnault, Vacelet & Chevaldonné Type-specimen. Sample VAL2-ACH-P15-ECH02. MNHN-HJV-04, Type-locality. Valinco Canyon (Western Mediterranean) 41.662N / 8.795E, 397 m, 31/07/2014. Other material (available in SME collection): Sample CS-ACH-P03- ECH 06 b, a small fragment encrusting a brachiopod shell, Cassidaigne canyon (W Mediterranean) 43.047N / 5.397E, 370 m, 28/10/2009. Sample VAL- ACH-P12- ECH 01, small fragments, Valinco Canyon, Corsica, 41.663N / 8.795E, 444 m, 24/08/2010. Sample from CYLYCE cruise, dive 12 of Cyana submersible, fragments of two tubes, Ile Rousse Canyon, NW Corsica, 42.833N / 8.953E, 320 m, 25/05/1997, Slides from specimens of BALGIM Cruise, R / V Cryos, Alboran Sea, Station CP 135-168, 35.435N / -4.301W and DR152–257, 35.935N/-5.569W, 390–560m, May–June 1984. External morphology. The sponge is formed by several tubes more or less coalescent, expanding from a narrower base of attachment to the substrate. The tubes are most often arranged in a single or a double line (Fig. 3), with each line formed by up to 12 tubes. The maximum size estimated from ROV images is ca 15 x 7 x 5 cm, with tubes either entirely joined or free for up to 5 cm. The tubes are 1–2.2 cm in diameter with a central canal 0.55–0.65 cm in diameter. The wall of the tubes is ca 3 mm thick. The surface is pierced by numerous small depressions. The color is pure white in living or freshly dead specimens, grey in dead skeletons due to sediment deposits. Specimens with both living parts and dead skeletons have often been observed (Fig. 3 B). The consistency is hard, but the sponge is easily broken. Numerous observations of sponges with very similar external characters have been made between 199 and 632 m depth from submersible and ROV dives, for examples Fig. 3 A, 3B; Fig. 4 B, 4C, 4D (Table 3). Their identification to the same species is made with great confidence. Skeleton. The main skeleton is a dictyonal framework of square meshes with 200–300 µm sides and beams 30–60 µm thick, with tubercles arranged in rows. Megascleres are dermal and parenchymal hexactins. Strongyloscopules are present in dermal and atrial surfaces. Microscleres are oxyhexactins and two types of hexasters.

UNEP(DEPI)/MED WG. 431/Inf.12 Dark habitats1 are distributed throughout the Mediterranean basin from the sea surface (i.e. caves) to the deep-sea realm. Various habitats of unique scientific and conservation interest are included in this broad habitat category, such as dark caves, submarine canyons, seamounts and chemo-synthetic features supporting sensitive assemblages which require special protection. Therefore, dark habitats were considered under the Action Plan adopted in the Eighteenth Ordinary Meeting of the Contracting Parties to the Barcelona Convention (Turkey, December 2013). In the context of implementation schedule of the Dark Habitats Action Plan (UNEP-MAP-RAC/SPA, 2015a) a set of guidelines should be identified aiming to reduce the imminent pressures and threats affecting these vulnerable assemblages. This document aims to establish guidelines for inventorying and monitoring Mediterranean deep-sea habitats and marine caves in order to settle the basis for a regional-based assessment.

Dark habitats are distributed throughout the Mediterranean basin from the sea surface (i.e. caves) to the deep-sea realm. Various habitats of unique scientific and conservation interest are included in this broad habitat category, such as dark caves, submarine canyons, seamounts and chemo -synthetic features supporting sensitive assemblages which require special protection. A set of guidelines should be identified aiming to reduce the imminent pressures and threats affecting these vulnerable assemblages. This document aims to establish guidelines for inventorying and monitoring Mediterranean deep-sea habitats and marine caves in order to settle the basis for a regional-based assessment.

The production of Mediterranean bath sponges collapsed during the past century as it is shown by Tunisian catches which went from 108 tons in 1920 down to 9 tons in 1988. Another illustration is given by the well-known sponge fishing island of Kalymnos which lost about 90% of its active fishermen population in a century between 1858 and 1967. For what reasons a Mediterranean traditional fishery once prosperous did dramatically decline? What part of the decline can be attributed to the lessening of the bath sponge stock and what to a decreasing number of fishermen? How can this decline of the sponge fishery be related to changes in uses, overfishing, disease outbreaks triggered by climate events? How did sponge fishermen adapt to these Regional Changes in the past? What is the future of such a fishery? What kind of guidelines can we provide for this fishery facing the on-going Regional Change? To answer these questions, SACOLEVE looks through ecological and historical windows into past evolution of the sponge fishery, chosen here as a model of traditional fishery which suffered good number of upheavals over the last three centuries. The overreaching aim of this program is to propose a management strategy for traditional fisheries that will allow attaining eco-durable practices in the current environmental, socio-economic and geopolitical contexts., La production des éponges commerciales méditerranéennes s’est effondrée au cours du siècle dernier, à l’image de la production tunisienne qui est passée de 108 tonnes en 1920 à 9 tonnes en 1988. Un même phénomène peut être observable sur l’île de Kalymnos (Dodécanèse), où le nombre des actifs employés dans cette pêche a baissé de 90% entre 1858 et 1967. Pour quelle raison cette pêche traditionnelle méditerranéenne a-t-elle connu un déclin aussi dramatique ? Quelle est la part dans cette évolution de la surpêche et des changements globaux ? Ces pêcheries ont-elles encore un avenir ? Le programme SACOLEVE propose une approche intersectorielle de cette thématique, dans le cadre d’une étude socio-environnementale de cette ressource spécifique.

International audience