Décembre 2014 Vol 35 No.2 editorial SS oo mm mm aa ii rr ee

EDITORIAL 2 VOYAGE PLONGEE : Requins marteaux à gogo… 3 ACTUALITE : Tian Xiang : 18e récif artificiel à 7 Maurice hers amis lecteurs, C ACTUALITE : Stranding of Dwarf Sperm Whale 9 (Kogia Sima) D’après la NOAA, ce mois de septembre 2014, la planète a connu un coup de chaud sans précédent depuis le début des ENVIRONNEMENT : Progress of the REMMOA 11 relevés de températures en 1880. En effet, La température aerial surveys conducted in the French EEZ and moyenne mesurée sur les terres émergées a été de 15,7°C, soit adjacent waters: contrasted cetacean habitats in the 0,72 °C au-dessus de la moyenne du XXe siècle (15 °C). Sans southwest Indian Ocean. (End) pouvant pour autant faire un lien direct avec le réchauffement climatique, le climat global, n’étant analysable que sur des ENVIRONNEMENT : Coral reefs are the most 15 échelles de temps très longues (par-delà les fluctuations locales diverse Earth ecosystem et momentanées), cette chaleur exceptionnelle s’inscrit dans la tendance à la hausse du XXe siècle : chacune des décennies BIOLOGIE : MOLLUSQUES ENDÉMIQUES DE 19 étant plus chaude que la précédente, sauf pour les années 1940. L’OCÉAN INDIEN Parallèlement, les dirigeants européens siégeant à Bruxelles Le Cône textile vaulbert, Conus (Cylinder) textile sont parvenus le 24 octobre à un accord sur l’ampleur de la vaulberti réduction des émissions de gaz à effet de serre : réduction de 40% d’ici 2030 par rapport aux niveaux de 1990. Mais quid des ACTUALITE : Expedition to Agalega 21 pays comme les Etats-Unis et la Chine ? Cet accord sera-t-il suffisant pour limiter la hausse de 2 degrés de la température MONDE : Culler whales keep a balance 23 mondiale qui se profile à l’horizon 2050? Rien n’est moins sûr. Depuis le dernier rapport du Giec en 2009 la situation s’est aggravée. En effet les émissions de gaz à effet de serre ne cessent de s’accélérer malgré les efforts engagés. Elles actions en date sont, entre autres, le coulage du Tiang Siang ont augmenté de plus de 30% entre 1990 et 2010. En cause: 137 comme 18e récif artificiel à Maurice ou encore l’exposition le retour en force du charbon, redevenu plus compétitif. Ce « Un point de vue sur les requins ». Vous pourrez avoir tous les réchauffement affecte aussi les océans bien sûr, causant des détails de ce sabordage, ainsi qu’un livret présentant l’exposition bouleversements incessants de nos écosystèmes. Ainsi : dans ce Diodon. - les espèces tropicales envahissent de plus en plus les mers tempérées comme en Méditerranée par exemple par le Vous pourrez aussi vous tenir au courant de certaines autres actions biais du Canal de Suez. En effet dans le sud de la France du MMCS comme l’expédition à Agaléga ou encore l’étude du ont été péchés en 2010 des poissons qui jusqu’à lors ne cachalot nain échoué à Bambous Virieux en mars. De nombreux se rencontraient que dans les eaux de la Mer Rouge ou autres articles à ne mas manquer non plus dont un sur la plongée même dans les eaux mauriciennes comme le barracuda ou avec les requins marteaux et les raies mantas en Mer Rouge… le poisson flûte Fistularia commersonii ! - le blanchiment des coraux s’étend de plus en plus vers les Ainsi, sans plus tarder, je vous laisse découvrir ce nouveau Diodon. zones hors tropicales, comme celui de grande amplitude survenu en juillet/août de cette année à Miami et en Floride Bonne lecture! en général, pourtant situé au dessus du tropique du cancer. - le corail se détériore de plus en plus. En effet les derniers N. von Arnim relevés de 2014 indiquent que la Grande Barrière de Corail en Australie est dans le pire état jamais connu et qu’elle est en train de perdre sa capacité à se régénérer. Sa couverture Photo page de garde corallienne a diminué de moitié depuis les années 1980 lorsque le récif a été répertorié comme un site du patrimoine mondial. - l’acidification des océans se poursuit : leur pH moyen étant passé de 8,16 au début du 19e siècle à 8,05 aujourd’hui. Or l’échelle de pH est « logarithmique » : une baisse de 1 unité reflète une concentration en ions H+ multipliée par 10 ! - etc…. les exemples sont trop nombreux pour tous les citer ici. Corail mou : Dendronephthya klunzingeri Nous, avec nos partenaires (MSDA en particulier) si petit Photo : Yann von Arnim que nous soyons à l’échelle de la planète, nous poursuivons Elphinstone, Mer Rouge. nos actions afin de lutter contre ce fléau. Les dernières

DIODON 2 voyage plongÉe Requins marteaux à gogo…

nous nous arrachons avec peine aux -40 mètres du bleu et la plongée se poursuit le long du tombant que nous remontons progressivement pour éviter les paliers de décompression, Paris, 21h, aérogare Charles de En attendant le sauf conduit des et là, c’est l’explosion de Gaule. autorités pour quitter le port, nous couleurs : les gorgones déballons le matériel de plongée, d’espèces variées (Melithaea Un brouhaha nous entoure. tandis que le soleil, tel un artificier sp., Supergorgia hicksoni) allant Attablés face à face, je sirote contrôlant à merveille sa pyrotechnie, du rouge au violet, disputent la un thé aux agrumes pendant que déverse ses derniers rayons dans place aux coraux durs de toutes mon mari, titille son sandwich un flamboiement de couleurs, formes et teintes comme le corail aseptisé déballé il y a quelque changeant progressivement de de feu (Millepora dichotoma) minutes du cellophane. Notre vol l’orange au violet …. étalant ses éventails de dentelle pour Dubaï embarque dans 50 brune bordée du rouge intense minutes. Cette ville où les hôtels Et c’est parti. Notre excursion sous- des éponges encroûtantes, ou le de luxe et les plages chaudes sont marine nous mènera au Nord de Port corail peau d’éléphant (Mycedium la destination de nos nombreux Soudan, dans les eaux limpides des elephantotus) formant de voisins, n’est pourtant pas ce qui atolls de Sanganeb et Shab Rumi véritables tables prêtes à recevoir nous attire. Pour nous ce ne sera avant de terminer sur l’incroyable la vaisselle fine, ou encore ces qu’une escale vers une destination épave de l’Umbria. coraux imitant des fils de fer beaucoup plus exotique : une tordus (Cirripathes anguina), croisière plongée en Mer Rouge Que ce soit à Sanganeb ou à Shab sans compter les patates de toutes au départ de Port-Soudan. Rumi, nous plongeons sur des sortes, comme des mamelles tombants descendant en escalier multiples, et j’en passe, ainsi Après avoir somnolé tant bien que de 5 à plus de 200 mètres où qu’aux coraux mous du genre mal pendant notre escale de 7h à patrouillent requins marteaux, Dendronephthya, flamboyants Dubaï, puis avoir été tour à tour requins gris de récif, barracudas en dans leurs couleurs chatoyantes frigorifiés et ébouillantés dans bancs serrés, caranges qui copinent allant du rose au rouge vif et l’avion qui nous menait à notre avec les licornes pour former de passant par tous les tons d’orangé destination finale, il est déjà 17 vastes bancs bicolores, bécunes, et de violet. Entre les dédales de heures quand nous nous préparons thons, napoléons… cette vie fixée, une kyrielle de à embarquer sur l’Océanos qui poissons de récifs colorés s’agite sera notre bateau de croisière. La A raison de 3 à 4 plongées par jour, en tous sens à notre approche. foule qui nous entoure s’affaire, débutons toujours dans le bleu où Une nuée de barbiers orange dans un embouteillage de zodiacs, de nombreux requins marteaux (Pseudoanthias squamipinnis), à diriger tous les plongeurs (Sphyrna lewini), timides, viennent typiques de la Mer Rouge, débarqués, du seul vol de la faire une brève apparition, avant de virevoltent au gré du courant et semaine, sur le bon bateau, ce qui déguerpir, effarouchés par le banc des mouvements des plongeurs, n’est pas une mince affaire chacun de plongeurs que nous formons, les poissons ange géographes s’interpellant avec animation surmonté de sa large colonne de attirent notre regard de leur robe dans une langue étrangère, qui bulles, mais curieux tout de même, magnifique imitant une ile d’or au en arabe, qui en italien, qui en ils pointent à nouveau leur nez, milieu d’une mer d’azur, quelques français, qui en russe, qui en s’éloignent à nouveau, reviennent pseudochromis de Fridman anglais, qui en espagnol, et j’en vérifier si nous sommes toujours (Pseudochromis fridmani), passe !! là etc…. Après une dizaine de endémiques de la Mer Rouge, minutes à contempler leur ballet, dansent un ballet en tutu violet. Mais mon préféré reste le poisson

DIODON 3 voyage plongÉe

DIODON 4 voyage plongÉe

DIODON 5 voyage plongÉe

en transport de troupes pendant la 2e guerre mondiale, transportait bombes, obus, détonateurs, véhicules etc… quand le 9 juin 1940, arrivant en vue de Port Soudan il mouille sur le Wingate Reef. Malheureusement, le lendemain, l’entrée en guerre de l’Italie amène le capitaine à organiser le sabordage du navire : les différentes plaques d’obturation des prises d’eau étant brisées et l’équipage évacué sous couvert d’un hypothétique exercice d’évacuation. Ainsi, sur un fond de 38 mètres, remontant jusqu’à 3 mètres de la surface où affleurent les bossoirs tribord, l’Umbria git sur le côté babord tel un mastodonte, intact, sans traces d’explosion ni brèche, avec sa cargaison complète. Les mats, grues de chargements et la cheminée, tels de grands tentacules tordus, rejoignent le fond. Les parois du château, peu abimées, donnent une bonne idée de cette partie de l’épave, avec les quatre paires de bossoirs des chaloupes de chaque côté, et le large trou cylindrique d’où sortait la cheminée. Suivant prudemment notre guide, nous nous faufilons à travers couloirs et coursives : des cales avec ses murs de bombes, de munitions, et de voitures aux toilettes du capitaine, en passant par la cuisine et son four à pizza jusqu’aux montagnes de bouteilles de chianti, sans oublier la salle des machines ! Exceptionnel, même pour les non-amateurs d’épaves comme moi !!!

Nathalie von Arnim papillon jaune (Chaetodon semilarvatus), toujours en couple et qui arbore une robe jaune fluo avec un œil maquillé de bleu. Bibliographie : Nous ne voulons plus sortir la tête de l’eau ! Et pourtant la magie continue une • Amar et Isabelle Guillen ; L’épave de l’Umbria en Mer fois remontés : dans les lagons de Sanganeb Rouge au large du Soudan et Shab Rumi s’ébattent des familles de dauphins qui, curieux, sont attirés par notre • http://greec.free.fr; l’Umbria zodiac sur le chemin du retour, et partagent • Helmut DEBELIUS : Guide du récif corallien, Mer avec nous des moments magiques en apnée. Rouge Le clou de la croisière restera l’épave de • Helmut Gothel : Guide de la faune sous-marine - l’Umbria : nos trois dernières plongées poissons, Mer Rouge – Océan Indien ; Editions Ulmer du séjour. Ce cargo italien, transformé

DIODON 6 ACTUALITES L’Épave du Tian Xiang, 18ème Récif Artificiel à Maurice Le 16 Juin 2014 le bateau de pêche Par ailleurs pour faciliter le sabordage, à 3 taches (Dascyllus trimaculatus), chinois, le Tian Xiang No137, a quatre trous rectangulaires de 25cm des chromis à 2 couleurs (Chromis été sabordé au large de Flic en par 35cm avaient été pratiqués de part dimidiata), des rougets roses Flac par 43 mètres de fond par la et autre de la coque et ceci à l’avant (Parupenaus rubescens), des Mauritius Marine Conservation et à l’arrière. Ces trous avaient été poissons de verre (Parapriacanthus Society (MMCS) et la Mauritian prédécoupés au port puis ouverts une ransonneti), des poissons papillons Scuba Diving Association (MSDA). fois sur le site. de Klein (Chaetodon kleinii), des Avec le Water Lili en 1980, le Tug poissons papillon de Blackburn No2 en 1981, les Pneus en 1986, D’un point de vu « timing » le bateau (Chaetodon blackburnii), des labres le St Gabriel en 1987, le Kei Sei a quitté le Port à 8h30 remorqué par nettoyeurs (Labroides dimidiatus), No113 en 1987, le Stella Maru en le Sir Seewoosagur, il est arrivé sur des poissons chirurgien à marque 1989, le Carp en 1989, le Silver le site à 11h00, le câble acier de la orange (Acanthurus auranticavus), Star en 1991, l’Orient en 1992, le remorque fut lâché à 11h34, le premier des balistes bleus (Odonus niger) Hassen Mian en 1996, le Jabeda en trou dans la coque fut ouvert à 12h26, et quelques poissons lion (Pterois 1996, le Star Hope en 1998, le Hoi le deuxième à 12h43, le troisième volitans). Siong No6 en 2003, le Long Teh en à 12h50 et le dernier à 12h56. On 2010, la Baignoire en 2011 et en s’apprêtait alors à ouvrir les vannes et Dorénavant le Tian Xiang prendra incluant les récifs crées par d’autres à évacuer le bateau quand tout à coup une retraite bien méritée et, telle organismes tel le patrouilleur Amar le Tian Xiang prend l’eau par l’un des une perle se formant lentement sabordé en 1998 et le Pasifoo sombré trous et commence à s’enfoncer. Ce autour d’un nucleus, servira de accidentellement en 2013, Maurice fut alors avec célérité que l’évacuation support au développement d’un riche compte maintenant 18 récif artificiels fut terminée, Yann quittant en dernier écosystème. dont deux sont situés au Nord de le futur récif artificiel à 13h07 tandis l’ile, douze dans l’Ouest, trois dans que celui-ci s’inclinait sur tribord Un grand merci à tous ceux qui nous l’Est et un au Sud. pour s’enfoncer par l’arrière pour ont aidés à faire de ce sabordage une toucher le fond à 13h18. Finalement belle réussite en particulier à l’équipe Le Tian Xiang 137 a longtemps au son des corps de brumes, celui-ci du MMCS et de la MSDA, à Nico Kux navigué dans le Pacifique et disparait complètement à 13h20. Ainsi, et à l’équipe des mécaniciens de la l’Océan Indien comme palangrier. le sabordage, à partir du moment où le MPA ainsi que le Bureau du Premier Enregistré sous pavillon chinois à dernier trou fut ouvert dans la coque, Ministre, le Ministère de la Pêche, la «Inter-American Tropical Tuna n’a duré 24 minutes, ce qui fut un le Ministère de l’Environnement, le Commission» sous le No8451 et à la record! Commissaire de Police, les National Commission des Thons de l’Océan Coast Guards, le Mauritus Ports Indien sous le NoIOTC00839 son Plusieurs plongées d’inspection en Authority, IBL Fishing Ltd, le indicatif d’appel radio fut BZYI. juin et en juillet 2014 ont montré que Mauritius Underwater Group, les Construit en 1980, il mesurait 45.3 l’épave du Tian Xiang s’est stabilisée Moulins de la Concorde sans oublier mètres de long par 8.5 mètres de sur un fond de sable à 44 mètres de les centres de plongée de la côte large et sa jauge brute était de profondeur et à environ 60 mètres à ouest, Abyss, Ticabo, Exploration 496 tonneaux. Les propriétaires l’ouest du site choisi ce qui peut être Sous-Marine, JP Appadu, Nemo, successifs furent la Seven Seas considéré comme étant parfait pour un Euro Divers, Ocean Divers, Sea Marine S.A. basé à Belize ainsi que navire de 44m de long. Urchin et Sun Divers. la Tianjin Deepsea Fishing Co., la Tixiang Fishing Co. et la Tianjin Dans la plupart des cas, les récifs Yann von Arnim Tianxiang Fishing Co. basés en artificiels sont colonisés en quelques Chine avec comme agent à Maurice mois, en attirant de nombreuses espèces Bibliographie IBL Fishing Co. Ltd.. de poissons et d’invertébrés. Ils sont d’abord colonisés par des espèces von Arnim Y., La Hausse de Lalouvière Pour le Tian Xiang, le remorquage pionnières, puis ils offrent un milieu P., 2000, Artificial reefs in Mauritius. depuis le port et le positionnement de substitution à une biodiversité plus Diodon Vol. 21. Special Issue. sur le site se sont déroulés sans importante. C’est aussi le cas du Tian von Arnim N., 2003, Un nouveau récif problèmes. Avant de quitter le port Xiang étant donné que des plongées artificiel, le Hoi Siong No6. Diodon le bateau avait été nettoyé de tout effectués 4 à 6 semaines après le Vol.24 :1 p.20. débris flottant, des ouvertures avaient sabordage ont montré que l’ensemble Lieske E., Myers R.F., 1995, Guide été pratiquées dans les caissons du navire est recouvert d’un duvet des poissons des récifs coralliens. étanches des cales, et les réservoirs algal et qu’il a été colonisé par de Delachaux et Niestlé. de fuel avaient été vidés pour être de nombreux jeunes poissons récifaux nouveau rempli avec de l’eau de mer. dont principalement : des demoiselles

DIODON 7 ACTUALITES

Le Tian Xiang

Les derniers instants du Tian Xiang

Un nouveau terrain pour la vie marine Un recif artificiel est né

DIODON 8 ACTUALITES Stranding of Dwarf Sperm Whale (Kogia Sima)

he Mauritius Marine Conservation society of the total length. (Plön, 2004). The animal had a Treceived phone calls from Albion Fisheries total length of 221cm and was male. As males of Research Centre and the Ferme Marine de this species are known to reach 260cm it is believed Mahebourg alerting us to a stranded cetacean farm this was a sub-adult between the ages of 2.9 and 15 near the village of Bambous Virieux, on the 24th years (3). of March 2014. The identity of the cetacean caused confusion as it was reported as both a dolphin and This whale is rarely encountered and is extremely a whale. The animal died that afternoon only 10 difficult to identify at sea. The Dwarf Sperm Whale minutes after our arrival on site. It was identified seems to live mainly over the continental shelf and easily on sight as a member of the Kogiidae family slope, off tropical and warm temperate coasts of all and Kogia genus. Determining which species, either oceans (4). Mauritius matches this description with a Pygmy Sperm Whale (Kogia breviceps) or a Dwarf its tropical waters and location on the Mascarene Sperm Whale (Kogia Sima) was more difficult as Plateau, a continental shelf which stretches from the they weren’t even considered as different species island of Reunion in the south to Saya de Malha in until the mid-1960’s. (1) the north (5).

Dwarf and Pygmy Sperm Whales share many The whale underwent a necropsy to determine the characteristics. Several of these, such as the cause for its stranding. The major organs (liver, presence of a single blow-hole slightly left of center kidneys and lungs) did not show obvious signs of and the appearance of a false gill and an under parasites or cysts; however the fore stomach and slung jaw, can also cause them to be mistaken for main stomach had large numbers of endo-parasites. sharks. (Plön, 2004). The whale that was stranded Plön (2004) reports that parasitism is prevalent in in Mahebourg Lagoon was identified as a Dwarf the Kogiidae family, and in particular there can be Sperm Whale because the length between its nose large amounts of nematodes in the stomach. and dorsal fin, 100c m, was less than 50% of the total length, 221 cm, and because of the dolphin- Photos of these parasites were sent to Dr. Nahiid like appearance of its dorsal fin located further to Stephens, a wildlife vet pathologist at Murdoch the posterior, at a distance back greater than 50% University, who suggested that the parasites

DIODON 9 ACTUALITES

were likely nematode worms known as Anisakids ƒƒ Dig shallow trenches under the flippers. (from the family Aniskidae, a member of genus ƒƒ If possible take a photograph of the animal or Contracaecum or Anisakis). These parasites were draw it. causing ulceration and swelling in the stomach wall. However, the level of infestation is unlikely to have contributed to the death of the animal. The Do not try to apply sunscreen, go too close to the tail heart was photographed as this species is known or attempt to move the animal until information has to be susceptible to heart failure (Bossart et al. been collected and authorities informed. It is illegal 1985; Credle, 1988). However, the photos proved to remove or kill any marine mammal in Mauritius. inconclusive. Alec Reade MMCS Volunteer (2014) Other reasons for the live stranding could include Imogen Webster Scientific Coordinator possibilities that changes in the Earth’s magnetic field caused the whale to lose its sense of direction; References earthquakes or storms caused the animal to panic; (1) http://www.iucnredlist.org/details/11048/0 loud underwater sound from activities such as sonar (2) http://eprints.ru.ac.za/2799/1/Pl%C3%B6n-PHD- or seismic activity caused its sonar system to fail; TR05-154.pdf (3) http://www.environment.gov.au/cgi-bin/sprat/public/ or the animal was simply lost or sick. (Carwadine, publicspecies.pl?taxon_id=58 2002). However, all of these are theoretical and very (4) http://www.cms.int/reports/small_cetaceans/data/K_ difficult to prove. sima/K_sima.htm (5) http://www.vliz.be/projects/marineworldheritage/ Should you see a sick or stranded marine mammal sites/2_Masc%20Plateau_S%20Malha.php?item=The%20 (whale, dolphin, seal) or turtle please contact Albion Indian%20Ocean Fisheries Research Centre 238 4100 and MMCS Bossart, G. D., Odell, D. K. and Altman, N. H. 1985. 483 7781. There are some basic things you can do Cardiomyopathy in stranded pygmy and dwarf sperm to assist the animal. Determine whether the animal whales. Journal of the American Veterinary Medical is alive by looking for breathing and eye movement. Association 187(11): 1137-1140. If the animal is on the shore, reef or shallow water Carwardine, M. 2002. Whales, Dolphins and Porpoises. you should: Credle, V. R. 1988. Magnetite and magnetoreception in stranded dwarf and pygmy sperm ƒƒ Try to keep it in the upright position, keep whales, Kogia simus and Kogia breviceps. M.Sc. Thesis. quiet and do not make sudden movements to Division of Biology and Living Resources, Rosenstiel avoid additional stress. School of Marine and Atmospheric Science, University of Miami, Miami, Florida, USA. 86 pp. ƒƒ Provide shade/ shelter if possible and cover Plön, S. 2004. The status and natural history of pygmy the animal in a wet towel or sheet but DO (Kogia breviceps) and dwarf (K. sima) sperm whales off NOT cover the blow hole. Southern Africa. PhD Thesis, Rhodes University, South Africa.

DIODON 10 SC/64/E14 ENVIRONNEMENt Progress of the REMMOA aerial surveys conducted in the French EEZ and adjacent waters: contrasted cetacean habitats in the southwest Indian Ocean. (End)

SOPHIE LARAN, GHISLAIN DORÉMUS, LAURA MANNOCCI, OLIVIER VAN CANNEYT, PIERRE WATREMEZ, ADÈLE CADINOUCHE, VIOLAINE DULAU-DROUOT, FRANÇOIS-XAVIER MAYER, DEVIS MONTHY, NORBERT ANDRIANARIVELO, YVETTE RAZAFINDRAKOTO, ANLI TOILIBOU & VINCENT RIDOUX

Habitat modeling The best model for density of small production and sea surface delphininae selected longitude, temperature (p=0.000), then Models of density surface were latitude, depth, distance to the 200 chlorophyll with a time lag of 2 obtained for seven groups of m contour, gradient of chlorophyll, months (p=0.01) as significant cetaceans: small delphininae sea surface temperature (p=0.000), covariates. This model explained (29% of the deviance explained), then slope and primary production 49% of the deviance (figure 7 large delphininae (19%), (p=0.001) as significant covariates. right). small globicephalinae (25%), It explained 29% of the deviance. Risso’s dolphin (49%), large Prediction was produced for the Predictions for the seven cetacean globicephalinae (29%), beaked whole region with the environmental taxa were then made for the whole whales (20%) and Physteroidea conditions as of December 2009 region and pooled together. This (Kogidae and Physeteridae; (figure 7 left). For the Risso’s prediction clearly highlighted the 33%). As examples, only the dolphin the best model selected importance of the Mozambique small delphininae and the Risso’s longitude, latitude, depth, slope, Channel and the Seychelles dolphin models are described distance to the 2 000 m contour, Plateau for cetaceans (Figure 8). below. gradient of chlorophyll, primary

Figure 7. Predicted density distributions and sightings for small delphininae (left) and Risso’s dolphin (right) with environmental conditions as of December 2009.

DIODON 11 SC/64/E14 ENVIRONNEMENt air are well known and include the heavier logistic constraints placed on survey design (aircrafts are ‘central-place’ survey platforms); higher number of sightings that cannot be identified to species; difficulty to implement the double platform methodology and hence to estimate detection probability on survey track. In the case of the REMMOA survey series, cost related issues were key elements of the decision because of the vast geographical span of the project, which made a series of ship surveys too expensive. Some of the aircraft-specific limitations can be mitigated. Figure 8: Pooled predicted density distribution pooled for seven cetacean taxa: small delphininae, large delphininae, small globicephalinae, Risso’s Distribution patterns in the SW dolphin, large globicephalinae, beaked whales and Physteroidea (Kogidae and Indian Ocean Physeteridae) with environmental conditions as of December 2009. The southwest Indian Ocean is an oceanographically contrasted DISCUSSION AND in a lower rate of platform usage region where three broad systems in optimal detection conditions; can be recognized: the Seychelles, PERSPECTIVES ships generate positive and negative the Mascarene Islands and the interaction biases with the survey Mozambique Channel, that belong General target species (either cetaceans to three distinct Large Marine Regarding the choice of the or birds) which imply species- Ecosystems (the Indian monsoon survey platform, aircrafts versus specific analyses; because of limited gyre, the East African coastal and ships, the advantages and steaming speed, several ships are the Indian south subtropical gyre limitations of both types are well needed to cover extended survey provinces respectively) as defined known. Vessels allow a higher areas if sufficient spatial resolution by Longhurst (1998) largely proportion of sightings to be is needed for modelling; finally on the basis on oceanographic identified at species level; thanks cost and carbon print per unit processes. Marine Ecoregions Of to their higher passenger capacity, effort (km surveyed in effort) are the World (MEOW) is another they also allow double platform higher. For aircrafts, the higher system of bioregionalization that methodology to be implemented flexibility of utilization allows incorporates more biological and therefore the detection an optimal rate of platform usage element and focus on shelf probability on track line to be under good detection conditions; habitats (Spalding et al., 2007). estimated; finally, because of their there is no evidence of survey In this latter context, the whole much longer autonomy, logistic target species reaction to survey study region of the present paper constraints on survey design are platform (this may be different with belongs to one single province lower. Their drawbacks include a helicopter); extended areas can called the Western Indian Ocean the limited flexibility of vessel be surveyed in a limited amount and our surveyed areas belong to utilization during survey period of time; costs and carbon print several of its marine ecoregions: which generally precludes quick are lower per unit effort flown Seychelles, Cargados Carajos- reaction to changing weather and (km surveyed in effort). Several Tromelin, Mascarene Islands and sea conditions, hence resulting limitations to surveying from the Western to Northern Madagascar.

DIODON 12 SC/64/E14 ENVIRONNEMENt The preliminary analyses oceanic ecosystems at various ACKNOWLEDGMENTS conducted on the REMMOA water depths and therefore has data set tend to fit well within the potential to provide additional The French Ministry in charge these bioregionalization systems. covariates of direct interest to top of the environment (Ministère de In particular encounter rates, predator ecology. l’Ecologie, du Développement Durable, du Logement et du relative densities and prediction Transport, MEDDLT) and the of preferred habitats all concur to Perspectives Agency for marine protected oppose areas of the Mozambique In the near future the immediate areas (Agence des aires Channel and the Seychelles priority is to complete the first marines protégées, AAMP) characterized by generally higher series of REMMOA surveys. The funded the project. The Indian values with areas of the Mascarenes next REMMOA aerial survey is Ocean Commission (IOC), the characterized by much lower planned in the southwest Pacific Governments of all Member values in general. A closer look Ocean between November 2012 States (Comoros, France- at the data would suggest that not and March 2013, and the eastern Réunion Island, Madagascar, all cetaceans, and by extension Caribbean/Guiana plateau region is Mauritius, Seychelles) and the pelagic megafauna, would planned to be surveyed regionally prefecture of the Terres Australes et Antarctiques Françaises respond similarly to differences later on (Table 1). Lessons drawn considerably facilitated the in oceanographic processes from the first steps are extremely regional approach conducted between areas. In particular, it useful for the continuation of the in the SW Indian Ocean. The appears that deep divers may project. In the southwest Pacific, the French Ministry of Foreign be more equally distributed French EEZ (2,040,000 km²) is split Affairs (Ministères des Affaires between areas suggesting that into two sub-units: the large New Etrangères et Européennes), the they would be less sensitive to Caledonia and the smaller Wallis French Embassies in Madagascar, the oceanographic parameters and Futuna area that are located Mauritius and the Seychelles classically used to describe some 15° longitude apart. offered their help in contacting surface marine productivity. To the appropriate authorities and develop further these analyses The long term objectives of the the French ONCFS in Mayotte. Civil Aviation authorities in and better interpret the causal REMMOA surveys is to establish Madagascar, Mauritius, the relationship underlying the an initial situation of cetacean and Seychelles and French Polynesia variety top predator distribution other pelagic megafauna diversity were extremely helpful with all patterns, data on the distribution and relative abundance and to aspects related with the flights. of their prey would be essential. build up a monitoring strategy Non-governmental organisations However, direct measurements to be implemented from this CetaMada in Madagascar, of prey field or prey densities point onwards. In 2013-2014 a Globice in Réunion, Mauritius in the different water layers of workshop is planned to be hold Marine Conservation Society interest to cetaceans are unlikely in order to examine the statistical in Mauritius, Megaptera in to be available in the southwest properties of the complete data Réunion, Naturalistes de Mayotte in Mayotte. All other observers: Indian Ocean in a near future. set and infer recommendations for Rebecca Guezel, Aurélie Hermans, SEAPODYM is a model initially monitoring strategies in the future. Morgane Perri, Claire Pusineri, developed for investigating In this exercise, expertise from the who were very professional in the spatial population dynamics marine mammal, seabird and fish air and friendly project mates on of tuna under the influence of scientific communities would be land. Finally, we are particularly both fishing and environmental most welcome and the outcomes indebted to all aircraft crew effects (Lehodey, 2004 a, b; of this work extremely useful for members of Aerosotravia, France Lehodey and Senina, 2009). This all stakeholders and managers in and Madagascar Trans Air, for model allows prediction of both charge of monitoring cetaceans their continuous high level of temporal and spatial distribution across the tropics. professionalism and enthusiasm of secondary consumers in despite hundreds of hours flying in strait lines over the ocean.

DIODON 13 SC/64/E14 environnement REFERENCES

Buckland, S.T., Anderson, D.R., 26 pp. http://www.spc.int/OceanFish/ Paper SC/62/E14 presented at the Burnham, K.P., Laake, J.L., Html/SCTB/SCTB17/ECO-1.pdf Scientific Committee meeting of the Borchers, D.L. and Thomas L. 2001. Lehodey, P. 2004b. A Spatial Ecosystem International Whaling Commission, Introduction to distance sampling: And Populations Dynamics Model May 31st –June 11th, 2010, Agadir, Estimating abundance of biological (SEAPODYM) for tuna and associated Maroc. populations. Oxford University Press, oceanic top-predator species: Part II Spalding, M.D., H.E. Fox, G.R. Oxford UK.vi+xv+432pp. Tuna populations and fisheries. 17th Allen, N. Davidson, Z.A. Ferdaña, Hiby, A.R. and Lovell, P. 1998. meeting of the Standing Committee on M. Finlayson, B.S. Halpern, M.A. Using aircraft in tandem formation Tuna and Bill fish, Majuro, Republic Jorge, A. Lombana, S.A. Lourie, K.D. to estimate abundance of harbour of Marshall Islands, 9-18 Aug. 2004, Martin, E. McManus, J. Molnar, C.A. porpoise. Biometrics 54: 1280-1289. Oceanic Fisheries Programme, Recchia and J. Robertson. 2007. A Kahru, M. 2010. Window Image Secretariat of the Pacific Community, bioregionalization of coastal and shelf Manager 1991-2010. Version 6.60 Noumea, New Caledonia, Working areas. Bioscience 57(7): 573-583. Build 0722. Paper: ECO-2: 36 pp. http://www.spc. Thomas, L., Buckland, S. T., Rexstad, Marques, F. F. C.; Buckland, S. T. int/OceanFish/Html/SCTB/SCTB17/ E., Laake, J. L., Strindberg, S., In Advanced Distance Sampling; ECO-2.pdf Hedley, S. L., Bishop, J. R. B., Buckland, S. T., Anderson, D. Lehodey P. and Senina, I. (2009) Marques, F. F. C. & Burnham, H. R., Burnham, H. P., Laake, J. L., A user manual for SEAPODYM P. 2010. Distance software: design Borchers, D. L., Thomas, L., Eds.; version 2.0: application with data and analysis of distance sampling Oxford: New York, 2004. assimilation. Available at http://www. surveys for estimating population Laran, S., Van Canneyt, O., Dorémus, wcpfc.int/system/files/documents/ size. Journal of Applied Ecology, G., Mannocci, L., Ridoux, V. and meetings/scientific-committee/5th- 47, 5-14. Watremez, P. 2012. Distribution et regular-session/ecosystem-and- Van Canneyt, O., Dorémus, G., abondance de la mégafaune marine bycatch-swg/information-pa/SC5-EB- Certain, G., Ridoux, V., Jérémie, dans le sud-ouest de l’océan Indien IP-13BSeapodym_user_manual.pdf S., Rinaldi, R. and Watremez, P. tropical. REMMOA- Océan Indien. Longhurst, A. 1998. Ecological 2009. Distribution et abondance des Final report for the French Marines Geography of the Sea. San Diego: Cetaces dans la Zone Economique Protected Area Agency [unpublish, Academic Press. Exclusive des Antilles françaises par in french]. 168p. Mannocci, L., Monestiez, P., Bolaños- observation aerienne. Final report for Lehodey, P. 2004a. A Spatial Jiménez, J., Dorémus, G., Jeremie, S., the French Marines Protected Area Ecosystem And Populations Laran, S., Rinaldi, R., Van Canneyt, O. Agency [unpublish, in french]. 44p. Dynamics Model (SEAPODYM) and Ridoux, V. (in review). Top predator Van Canneyt, O., Certain, G., for tuna and associated oceanic top- communities from two contrasting Dorémus, G., Laran, S., G., Ridoux, predator species: Part I Lower and ecosystems in the Western tropical V., Bolaños, J., Jéremie, S., and intermediate trophic components. Atlantic. Submitted to Journal of Marine Watremez, P. 2010. Distribution et 17th meeting of the Standing Systems. abondance de la mégafaune marine Committee on Tuna and Bill fish, Ridoux, V., Certain, G., Dorémus, G., en Guyane française. Campagne Majuro, Republic of Marshall Islands, Laran, S., Van Canneyt, O., Watremez, REMMOA. Final report for the 9-18 Aug. 2004, Oceanic Fisheries P. 2010. Mapping diversity and French Marines Protected Area Programme, Secretariat of the relative density of cetaceans and other Agency [unpublish, in french]. 41p. Pacific Community, Noumea, New pelagic megafauna across the tropics: Caledonia, Working Paper: ECO-1: general design and progress of the REMMOA aerial surveys conducted in the French EEZ and adjacent waters.

DIODON 14 environnement Coral reefs are the most diverse Earth ecosystem

Martin Pêcheux; Institut des at different time and spatial Of course, the oldest, the more Foraminifères Symbiotiques scales, i.e. of life invention. Of time for radiation and DNA - 16, rue de la Fontaine de course this is not quantifiable, divergence. Reefs are the oldest l’Espérance - 92160 Antony but a good measure is given biotope on the Earth since 3.4 - France; martin.pecheux@ by DNA divergence (although, billion years ago with reef free.fr with my Y chromosome – 1.61% stromatoliths (Allwood et al., length -, I am nearer to male 2007), and the prominent place Key-words: reef, coral, bonobos– 1.23% difference - than of life till planktonic appraisal biodiversity, tropic, forest, to woman). An approximation of (500 My at least, from isotope, symbiosis. this divergence is the number of Saltzman, 2011) and land phyla. For animals, reefs are the conquest (in Silurian, 425-475 Abstract: Comparisons are richest Earth ecosystem with 30 My by Rhynia, Cooksonia from made of biodiversity between represented phyla whereas there green algae). coral reefs and tropical rain is only 19 terrestrial ones (Paulay, forests. It is clear that coral 1997). I will not consider the case of reefs are the most diverse the bentic deep sea ecosystem, ecosystem of the Earth with The only animal phylum found said to be surprisingly rich, its spectrum of variability and on land and not in reefs is the with so wide an areal surface when ecological processes are anecdotal Onychophora (cousins extent. It is often quoted that considered, not just species of arthropods and tardigrades, reefs are the rain forests of the numbers. marine at first in the Precambrian, sea. No: rain forests are the actually 11 genera). Three other reefs of the land. Tropical rain Reefs are often quoted as one animal phyla are marine but not forests are the most diverse of the most diverse marine found in reefs; Orthonectida, land ecosystem, said to be the ecosystems (Reaka-Kudla, 24 species of parasitic worms one with 40%-70% of all biotic 1997). No. Reefs are the most of marine invertebrates, species, etc… diverse of all Earth ecosystems. Cycliophora, 3 microscopic species, one undescribed, cousin In fact, tropical rain forests are We do not have to count of rotifers, living on Atlantic said to be especially diverse biodiversity just in term of and Mediterranean crustacean primarily by the number of number of species, but in buccal pieces, and the famous arthropods species. Erwin term of processes/patterns, of Pogonophores, the big red (1982, in Strain, 2011) and original enzymatic pathways annelids living from H2S near his colleagues gassed 19 trees till innate comportments, rift events (of which half of in Panama, collecting about of fit to and evolving in a taxonomists make it a class 1000 unique beetle species. particular ecological niche, or put it in an other family) So, they extrapolate this with both abiotic (“Court (for all, source: Wikipedia). number to 30 million species. Jester”, Barnosky, 2001) and Hamilton et al. (2010) estimate biotic (“Red Queen”) factors, more reasonably that there are 2.5-3.7 million tropical

DIODON 15 environnement arthropod species. It is very perfect. Curiously, the number molluscs and above, numerous difficult to know exactly, of hermatypic coral species is fishes and few marine upper but insects would represent similar to the number of genera vertebrates (sea serpents, about 80% of all forest species of tropical trees: Hubbell et al. seven marine turtles of two (T. Bourgoin, specialist of (2008) report that 514 tree genera separated lineages, few tropical insects, Collection have been found in the Amazon in iguana and crocodiles, sea Director at National Museum over 300,00 samples. Symbioses birds, cetaceans), compared to of Natural History, Paris, com. of corals with zooxanthellae, freshwater fishes, amphibians, pers.). Why a so great number though, is less evolved by less reptiles, birds, and above, of species? They don’t seem intricated than endosymbioses of mammals. to play exceptional ecological trees with chloroplasts. Diversity roles: predation on plants, and of zooxanthellae clades appears Groups of the intermediate between them, decomposition, usual for dinoflagellates, but a levels seem of small size, which recently pollinisation, even if priori greater than chloroplasts could hypothetically explain each one is at its own place. It with their own short DNA. The their species number, as for appears that there are so man accessory groups of the primary example of micro-molluscs, beetles in part because they are trophic level in forests (small micro-arthropods, foraminifers, more or less specialized feeders plants, grasses, epiphytes, lichens, worms, compared to insects, on few tree species (cf. May, bryophytes and particularly arachnids, worms. Molluscs and 2010). vines) are somewhat like trees, arthropods are protostomians whereas in reefs there is a huge which may influence size. For the main primary trophic diversity: green, brown, red fleshy Nematods and plathyhelminths level and equivalently and crustose algae, angiosperm too, but the annelids (“true morphological shaping groups sea-grasses, Tridacna molluscs worms”, rough 15 000 species) of the ecosystem, in reefs, with zooxanthellae, seven order appeared to me, aside the there are about 108 genera of sponges associated with evolved deuterostomiana, as and 800 species of hermatypic zooxanthellae or cyanobacteria, a third superphyllum, with corals. Hubbell et al. (2008) large foraminifers symbiotic mouth and anus derived from estimate the number of Amazon with zooxanthellae, diatoms, blastopore (“schizostomian”). tree species to be 12 500, and chlorophytes, rhodophytes or Hamilton et al. (2010), for free undigested chloroplasts, And for micro-organisms, whole tropics, to be 50 000. and the chordate ascidians with most remains to be known. But introgression by common the particular pro-eu-karyotic Reefs have the “help” of been pollinisators, the presence of Prochloron sp. (synthesis in bathed by the whole planktonic interspecific hybrids allowing Pecheux, 1998). Rare species ecosystem, of course, important a flux of genetic pools between contribute surely over all equally in their economy. related species, might be more to complex ecosystem stability important than currently (cf. Isbell et al., 2011), the best Regionalism is similar, with evaluated (Danthu, 2011). Such measure of fit biodiversity. two main provinces in reefs, phenomenon is also current in Caribbean and Indo-Pacific, corals (Vollmer and Palumbi, Main groups of the upper trophic and three in tropical forests, 2002), where the morphological level seem roughly at equality, Amazon, Congo basin and definition of species is not echinoderms, crustaceans, big South-East Asia, and many

DIODON 16 ACTUALITES

Dive with the best Mauritian Scuba Diving Association Tel./Fax: (230) 454 0011 Email: [email protected] www.msda.mu

50 centres de plongées à Maurice

Affiliated to CMAS

DIODON 17 DIODON 17 environnement minor ones. There is a great Acknowledgments I am Jetz W, Thomas GH, Joy JB, difference between coral grateful to Charles Birkeland, Hartmann K, Mooers O (2012) The global diversity of birds in space and reefs and tropical forests: who helped me with data and time. Nature 491:444-448 Tropical forests occupied in correction of the English. This May RM (2010) Tropical Arthropod the past about 10%-15%, work was supported by French Species, More or Less? Science 329: and now 5%-7% of Earth AAH n°2504010. 41-42. surface (convergent sources), Paulay G (1997) Diversity and distribution of reef organisms. In whereas reefs, with 284 803 References Birkeland C (ed) Life and Death km2 (Spalding et al., 2001, but Allwood AC, Walter MR, Burch IW, of Coral Reefs. Chapman & Hall, deeper water not evaluated) on London, pp 298-353 Kamber BS (2007) 3.43 billions- Pecheux M (1998) Review on coral Earth (mean radius 6 371 km), year-old stromatolite reef from the reef bleaching. Atoll Res Bull, occupy only 0.558%. How Pilbara Craton of Western Australia: Edilivre, Paris, France, printed in can an ecosystem with twenty Ecosystem scale insights to early life on 2013, 255 pp. Available at www. times less spatial distribution Earth. Precambrian Res 158:198-227. reefbase.org or martin-pecheux.fr have more variability? It is Note: that calcification is evaporitic, Reaka-Kudla ML (1997) The quite amazing. Moreover, who will believe them? global biodiversity of coral reefs: Barnosky AD (2001) Distinguishing a comparison with rain forests. many reefs like those scattered the effects of the Red Queen and Court In: Reaka-Kudla ML, Wilson PE, across the Pacific Ocean are Jester on Miocene mammals evolution Wilson EO (eds) Biodiversity II: isolated (Volkov et al., 2007). in the Northern Rocky Mountains. understanding and protecting our Why are tropics more diverse? J Vertebr Paleontol 21:172-185 biological ressources. Joseph Henry Press, Washington DC, pp 83-108 An old question. Because they Danthu P (2011) Pour une gestion Saltzman M (2011) Plankton key durable des baobabs et des écosytèmes are old stable ecosystems (Jetz to origin of Earth’s first breathable à baobabs des Îles de l’Océan Indien: et al. 2012)? But there are atmosphere. Proc Nat Acad Sciences approche de la diversité biologique, migrations. Perhaps because US, 140:8456-8460. Note: I am not des usages et des représentations with temperature, energy sure of that. And there was nobody des espèces du genre Adansonia to breath. activation of enzymes is lower, à Madagascar, aux Comores et à Spalding M, Ravilious C, Green allowing a greater facility to Mayotte. In: FRB (ed). La biodiversité E (2001) World Atlas of Coral create new pathways. Why are des îles de l’océan Indien, Colloque Reefs. UNEP World Conservation tropical animals so coloured? 14-15 December, Paris. pp 39-41 Monitoring Center, University of California Press, 424 pp. Available That, I really don’t know. Hamilton AJ (2010) Quantifying uncertainity in estimation of tropical from.http://www.reefbase.org Arthropod Species richness. Am Nat Strain D (2011) 8.7 million: a new So, to conclude, it appears to 176:90-95 estimate for all the complex species on Earth. Science 333:1083 me clearly that reefs are the Hubbell SP, He F, Condit R, Borda- Volkov I, Banavar JR, Hubell SP, most diverse Earth ecosystem. de-Agua R, Kellner J, ter Steege H Maritan A (2007) Pattern of relative (2008) How many species are there in This is a supplementary reason species abundance in rain forests and to worry of strong reef decay Amazon and how many of them will coral reefs. Nature 450:45-49 for a global cause, CO2, go extinct ? Proc Nat Acad Sciences Vollmer SV, Palumbi SR (2002) US, 105:11498-11504 whereas we “know” how to Hybridization and the evolution Isbell F and 14 authors (2011) High of coral reef diversity. Science stop rapidly deforestation. plant diversity is needed to maintain 296:2023-2025 ecosystem services. Nature 477:199- 202

DIODON 18 biologie

MOLLUSQUES ENDÉMIQUES DE L’OCÉAN INDIEN 1 4. Le cône textile vaulbert, Conus (Cylinder) textile vaulberti Lorenz 2012

Le célèbre cône textile, aucune ombre bleutée, jaune Conus textile Linnaeus 1758, orangée ou rouge orangée, connu pour sa beauté et sa ni condensé en taches plus dangerosité, se rencontre sombres. L’apex est aussi dans tout l’ouest de l’Océan blanc au lieu d’être rose pâle Indien et la Mer Rouge dont à rouge orangé. L’ouverture l’Ile Maurice. Lors d’une est plus large, en particulier récente visite dans la région dans sa partie antérieure, la en 2012, dont à St Brandon partie postérieure étant plus (Cargados Carajos), le Dr. F. resserrée. Lorenz a isolé la population L’habitat du Conus textile de cônes textiles de St. vaulberti est représenté par Brandon en une sous-espèce des zones peu profondes : le cône textile vaulbert, du lagon de St Brandon, Conus textile vaulberti sous des rochers et à moitié Lorenz 2012. Certains autres enterré dans un sable fin Figure 1 : Le célèbre cône malacologistes en feraient et propre. On ne le trouve textile même une espèce à part : aucune part ailleurs. Conus vaulberti. D’autres tentatives en ce sens avaient déjà étaient faites dans le Dans la communauté Figure 3 : Conus textile passé. En effet un spécimen hypothétiquement originaire des malacologistes, on a vaulberti de St Brandon avait été nommée Conus textile f. scriptus l’habitude d’utiliser le nom par Sowerby en 1858. Cependant le nom scriptus ayant scriptus pour les spécimens déjà été utilisé par Deshayes par deux fois pour nommer de cônes textiles qui présentent une variante plus pâle des cônes (en 1823 et en 1831), et Sowerby n’ayant décris de leurs motifs, et que l’on peut trouver dans le sud de scriptus que brièvement sans citer la localité d’origine, Madagascar ou ailleurs dans l’Océan Indien, mais en le Dr. Lorenz décida de décrire à nouveau l’espèce sur aucun cas ces cônes n’ont la forme plus étroite et plus de nouvelles bases et avec une origine certaine. cylindrique du cône textile vaulbert, ni leur coquille plus légère et moins épaisse, ni l’apex blanc, ce qui fait Ce cône textile vaulbert bien de cette sous-espèce, une sous-espèce endémique diffère des autres cônes de St Brandon. textiles par plusieurs caractères : sa coquille est Nathalie von Arnim plutôt petite, ne dépassant pas 50 mm, alors que celle du cône textile peut aller Références : jusqu’à plus de 100 mm. Elle est par ailleurs plus ƒƒ Lorenz F. (2012) A new subspecies of Conidae légère, moins épaisse, from Mauritius (Gastropoda). Schriften zur avec une forme plus Malakozoologie 27: 21-24. [30 December 2012] cylindrique. De plus le ƒƒ WoRMS taxon details (http://www.marinespecies. graphisme, plus finement org/); Conus (Cylinder) textile vaulberti Lorenz, dessiné, ne présente que 2012 deux couleurs : un fond ƒ blanc avec un motif tireté ƒ Eric Le Court de Billot & David Touitou, Conidae en forme de tente, mais from Mauritius. Seashell collector.com [november plus triangulaire, de 2013 Last Update : January 2014] couleur marron foncé sans Figure 2 : Conus textile vaulberti

DIODON 19 biologie

Figure 4 : Conus textile

Figure 5 : Conus textile vaulberti

DIODON 20 ACTUALITES Expedition to Agalega

observations from shore, of cetaceans inhabiting the surrounding waters was recorded.

The goal of this expedition was to obtain baseline information on marine mega-fauna to be used as a reference for future expeditions and to enable long- term monitoring. These data will also be useful when making decisions regarding the future of the island and its management in terms of marine resources. In addition, it is hoped that data will be used to develop a more sustainable balance between fishing activities, development, economic growth and the conservation of the marine environment and resources. 10°25’S, 56’40’E and about 560 km south of Mahe (Seychelles). The trip north was rough with constant wind and While some basic rapid assessments of birds, turtles occasional showers. We arrived at the islands mid- and other marine resources have been conducted, morning on June 26th. Our stay was scheduled to be 3 or they are limited in number, and no previous cetacean 4 days however, due to rough sea conditions which made surveys have been conducted. The Mauritius Marine unloading the cargo difficult, we did not depart the island Conservation Society (MMCS) is currently running a until the afternoon of the 2nd July. The return trip was a project concerning the diversity of marine mega-fauna lot smoother and we were able to record more sightings. around Mauritius – this trip was an opportunity to include a larger area in this study. Overall 10 observations of cetaceans were recorded along with 232 bird and 12 marine debris sightings Data collection began the day of departure, June 24th during 35h35 and 988.5km of observation effort. 2013. The research focused primarily on occurrence and No turtles were observed while at sea. Eleven distribution of cetaceans (whales and dolphins), marine species of bird and five species of cetacean were turtles and seabirds during the voyage. On the island, recorded in addition to some unidentified (Table 1). any evidence, such as bones, accounts from locals or

Table 1: List of seabird and cetacean species encountered during the voyage. Bird Species Sightings Cetacean Species Sightings

Common Noddy, Anous stolidus 16 Spinner dolphin, Stenella longirostris 1 Lesser Noddy, Anous tenuirostris 1 Humpback Whale, Megaptera novaeangliae 1 Sooty tern, Sterna fuscata 132 Unidentified whale 1 Tropicbird, Phaethon sp. 7 Unidentified dolphin 2 Red-tailed Tropicbird, Phaethon rubricauda 14 Unidentified Beaked whale 1 White-tailed Tropicbird, Phaethon lepturus 2 Pilot whale, Globicephala macrorhynchus 3 Fairy tern, Gygis alba 39 Sperm Whale, Physeter macrocephalus 1 Masked Booby, Sula dactylatra 6 Sub-antarctic Skua, Catharacta Antarctica 1 Frigate, Fregata sp 1 Petrel/Shearwater Pterodroma spp. / Puffinus spp. 4 Unidentified 8

DIODON 21 ACTUALITES Locals informed us that whales would occasionally strand on the south west of both the north and south islands. One local was wearing a necklace made with the tooth of a whale, likely a beaked whale, and also showed us a skull.

Turtles were seen in the lagoon on both sides of North Island and an adult green turtle (Chelonia mydas) was observed surfacing to breath in the vicinity of the anchored ship (outside the lagoon) as loading was occurring for departure. Unfortunately, we also found the remains of nine adult individuals while we walked around the islands including some egg shells.

Seabirds were observed nesting on both islands but seemed to be concentrated on South Island. The most common species included Fairy terns, and common and lesser Noddys. Sooty terns and Frigate birds were only seen in flight and in very small numbers.

While we focused on the cetaceans, turtles and seabirds, with the additional time we also took the opportunity to collect information on invasive species, conducted marine debris transects, and also distribution data on the Agalegan Day Gecko. We were lucky to observe the Sacred Ibis (there are only about 20-25 individuals on the islands) but did not manage to find the coconut crabs.

The information collected during this Only larger cetacean species were encountered on the return trip including expedition will be included in the humpback whales (Megaptera novaeangliae), pilot whales (Globicephala final report for the Diversity Project macrorhynchus), beaked whales and sperm whales (Physeter macrocephalus). due to be completed in October this There was an additional sighting of an unidentified whale. year. The additional data will be shared and hopefully published to On the island, we found evidence that cetaceans certainly inhabit the increase awareness of environmental surrounding waters. The head of a dolphin was found on the beach on the issues such as marine debris and turtle north east coast, North Island. Head shape, colouration and teeth count indicate poaching. a spinner dolphin (Stenella longirostris). This one appeared to have been partially eaten by a shark. Imogen Webster Scientific Coordinator

DIODON 22 monde Culler whales keep a balance Victoriaictoria LaurieLaurie

MIRG researchers watch killer whales off Ningaloo Reef.

THE triumphant return of humpback whales along “It’s probably just a matter of time before we see a the West Australian coast is a rare recovery story in decrease to a more sustainable level,” he said. conservation that lifts the spirits. The WA researchers, working with scientists from the US Nat­ional Oceanic and Atmospheric Administration, have After several decades of commercial slaughter, humpback been tracking the seasonal appearance of killer whales sightings are now commonplace as they migrate along in the region since 2008, using satellite tagging and the the coast. collection of tissue samples.

Pods of a few hundred remaining animals in the 1960s They have observed the killer whales targeting newborn have grown by about 10 per cent each year; an estimated humpback calves off the Cape Range Peninsula and 30,000 now move between their feeding grounds in Ningaloo coast. “A huge food source of 3000 vulnerable Antarctica and calving grounds as far north as Camden calves per year simply can’t be ignored for too long,” Sound in the Kimberley. says Mr Totterdell.

Yet there is another recovery story that may ensure “From only very sporadic reports in previous decades, that humpbacks are kept in healthy but not excessive killer whales are now seen consistently throughout numbers. winter.”

A team of Australian and US researchers has observed The joint team has submitted its first scientific paper on a small increase in killer whales, or orcas. The result is Ningaloo’s killer whales for publication. But the real more predators hunting down and killing the humpbacks’ thrill lies in witnessing survival behaviour at play in the calves. natural world, says Mr Totterdell.

The cycle of survival and sacrifice in the wild constitutes “Being there to document the return of the apex predator a natural check on exploding species numbers, says in this ecosystem is pretty special.” researcher John Totterdell, from the WA-based Marine Information & Research­ Group. Reprint from : « The Australian » September 3rd 2014

The estimated stable population before commercial whaling was about 18,000 so the population of 30,000 is unlikely to last, Mr ­Totterdell said.

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Bulletin de l’Association pour la Protection et la Sauvegarde de la Mer. Le MMCS est également la commission scientifique de la Mauritian Scuba Diving Association.

The Mauritius Marine Conservation Society c/o The Mauritius Underwater Group Railway road Phoenix REPUBLIQUE DE MAURICE Tel : (230) 696.53.68 E-mail : [email protected] Site web : www.mmcs-ngo.org

Rédacteur en chef Nathalie von Arnim

Equipe de rédaction Nathalie von Arnim, Sophie Laran, Ghislain Dorémus, Laura Mannocci, Olivier van Canneyt, Pierre Watremez, Adèle Cadinouche, Violaine Dulau-Drouot, François-Xavier Mayer, Devis Monthy, Norbert Andrianarivelo, Yvette Razafindrakoto, Anli Toilibou, Vincent Ridoux, Alec Reade, Imogen Webster, Martin Pecheux, Yann von Arnim.

Photo : Kelsey Roberts Blanchiment du corail de feu en plaque (Blade Fire Coral) Millepora Complanata, en Floride (juillet 2014)