FIRST RECORD OF PACHYGRAPSUS MAURUS (LUCAS, 1846) IN THE NORTHERN TUNISIAN COAST

First record of Pachygrapsus maurus (Lucas, 1846) in the Northern Tunisian coast

Moez Shaiek, Sami Ben Haj, Mehdi Aissi, Ibrahem Ben Amer

Association Méditerranée Action-Nature (MAN, NGO), 01 rue d’Istanbul, 7000 Bizerte TUNISIA
Faculty of Natural Resources and Environmental Science, Omar Mukhtar University, El-Bayda, LIBYA

Abstract

The cryptogenic grapsid crab Pachygrapsus maurus (Lucas, 1846), is a native species in the Mediterranean Sea that has been reported since the 1990s in several parts of the central basin such as the Maltese islands and Italian coast. However, the species presence in the areas such as eastern Algeria, Tunisia and Libya has not been documented previously. In September 2016, a preliminary survey was carried out to investigate the marine biodiversity in the channel of Bizerte (Northern Tunisia), during which P. maurus was observed and documented. Individuals were captured, photographed and identified based on key morphological features. The number of individuals observed indicates the species is well-established within the specialized rock and boulder habitat with strong wave exposure preferred by this species.

Keywords: Pachygrapsus maurus, central Mediterranean, North Africa, Grapsidae

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Vol.23 – 2017 – No.2

Encounter rate and relative abundance of bottlenose dolphins and distribution modelling of main cetacean species in the north Aegean Sea (Greece)
Cristina B. Milani, Adriana Vella, Pavlos Vidoris, Aristidis Christidis, Emmanouil Koutrakis, Georgos Sylaios, Argyris Kallianiotis

Protists (Ciliophora, Gromiida, Foraminifera) in the Black Sea meiobenthic communities
Nelli G. Sergeeva, Derya Ürkmez, Igor V. Dovgal, Murat Sezgin

Occurrence of the alien marine red alga Galaxaura rugosa in Turkey
Ergün Taşkın, Murat Çakır, Barış Akçalı

New record of giant devil ray, Mobula mobular (Bonnaterre, 1788) from the Gulf of Antalya (Eastern Mediterranean Sea)
Nuri Başusta, Elif Özgür Özbek

First record of Pachygrapsus maurus (Lucas, 1846) in the northern Tunisian coast
Moez Shaiek, Sami Ben Haj, Mehdi Aissi, Ibrahem Ben Amer

On the capture of a pregnant bluntnose sixgill shark Hexanchus griseus (Chondrichthyes: Hexanchidae) from the Gulf of Tunis (Central Mediterranean Sea)
Khadija Ounifi-Ben Amor, Mohamed Mourad Ben Amor, Jeanne Zaouali, Christian Capapé

First record of Idotea ostroumovi Sowinsky,1895 (Isopoda) in the Black Sea coast of Turkey
Murat Sezgin, Murat Tepeyurt, Bülent Topaloğlu

Notes on the fisheries compensation for the Independenta/Evriali incident in the Istanbul Strait, Turkey
Bayram Öztürk, Esra Billur Balcıoğlu

A new locality for common box crab, Matuta victor (Fabricius, 1781), from the eastern Mediterranean Sea 
A. Suat Ateş, Tuncer Katağan, Mehmet Sert, Şükran Y. Özdilek

Encounter rate and relative abundance of bottlenose dolphins and distribution modelling of main cetacean species in the North Aegean Sea (Greece)

Cristina B. Milani, Adriana Vella, Pavlos Vidoris, Aristidis Christidis, Emmanouil Koutrakis, Georgos Sylaios, Argyris Kallianiotis

Conservation Biology Research Group, University of Malta, Msida MSD 2080 MALTA
Fisheries Research Institute of Kavala, 64007 Nea Peramos, Kavala, GREECE
Department of Environmental Engineering, Democritus University of Thrace, Xanthi, GREECE

Abstract

The encounter rate, relative abundance and distribution of bottlenose dolphins were investigated as part of a first detailed study on cetacean populations in the Greek North Aegean Sea. Sighting data were recorded between 2005 and 2013 through dedicated scientific marine surveys, covering 14,701 km. The line-transect sampling method was used to estimate relative abundance, using Distance software 6.0. Bottlenose dolphins presented an overall encounter rate of 0.46 groups/100km (2.5 dolphin/100km) and a mean group size of 3.45 (SE=0.38). The yearly relative abundance in the area was estimated after post-stratification at 377 individuals (95% C.I.=289–465; CV=18.37). Environmental modeling has been proposed for the main species of the study area using GAM and PCA; dolphin sightings were then correlated to eight environmental variables (distance from the coast, depth, slope, gradient of salinity, median salinity, gradient of temperature, median temperature and mean current). Bottlenose dolphin sightings were significantly correlated to depth and median temperature. This research presents the first data on encounter rate, relative abundance for the species and species distribution in relation to environmental variables in study area which are essential for effective conservation and management considerations.

Keywords: DISTANCE sampling analysis, Generalized Additive Modelling (GAM), Marine Protected Areas, North Aegean Sea, Principal Component Analysis (PCA), Tursiops truncatus