LENGTH-WEIGHT RELATIONSHIPS FOR THREE ELASMOBRANCH SPECIES FROM THE SEA OF MARMARA  

Length-weight relationships for three elasmobranch species from the Sea of Marmara

Ali İşmen, Cahide Çiğdem Yığın, Mukadder Arslan İhsanoğlu, Burak Daban

Çanakkale Onsekiz Mart University, Marine Science and Technology Faculty, 17100, Çanakkale, TURKEY

Abstract

Length-weight relationships were estimated for three elasmobranch species from the Sea of Marmara. Specimens were collected by beam trawl between September 2011 and July 2014. A total of 192 individuals (130 Raja clavata, 45 Scyliorhinus canicula, 17 Torpedo marmorata) were examined. Results indicated that R. clavata and S. canicula have positive allometric growth and T. marmorata has negative allometric growth. Due to the lack of data on length-weight relationships of elasmobranch species in the Sea of Marmara, these results contribute to our knowledge of this species.

Keywords: Marmara Sea, length-weight relationship, Raja clavata, Scyliorhinus canicula, Torpedo marmorata

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NATIONAL ACTION PLAN FOR THE CONSERVATION OF CARTILAGINOUS FISHES IN THE TURKISH WATER OF THE EASTERN MEDITERRANEAN SEA

National action plan for the conservation of cartilaginous fishes in the Turkish water of the eastern Mediterranean Sea

Bayram Öztürk

Department of Marine Biology, Faculty of Aquatic Sciences, Istanbul University, TURKEY
Turkish Marine Research Foundation, P.O. Box 10, Beykoz, Istanbul, TURKEY

Abstract

National action plan for the conservation of cartilaginous fishes in the Turkish water of the eastern Mediterranean Sea is discussed. Four main threats for the cartilaginous species are listed, as bycatch in trawl, trammel nets and purse seines, unreported and unregulated fishing, marine pollution and habitat loss. Some action plans are proposed for the conservation of the cartilaginous species in the area.

Keywords: Turkey, National Action Plan, cartilaginous fishes, eastern Mediterranean Sea, threats, conservation

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SEASONAL ARRIVAL AND FEEDING OF INJURED COASTAL SHARKS AT FISH FARMS IN THE EASTERN MEDITERRANEAN   

Seasonal arrival and feeding of injured coastal sharks at fish farms in the eastern Mediterranean   

Adi Barash, Renanel Pickholtz, Hagai Nativ, Shahar Malamud, Aviad Scheinin, Dan Tchernov

Leon Charney School of Marine Sciences, University of Haifa, Haifa, ISRAEL
School of Zoology, Tel Aviv University, Tel Aviv, ISRAEL
Morris Kahn Marine Research Station, Sdot-Yam, ISRAEL

Abstract

Every summer coastal sharks (mostly sandbar sharks, Carcharhinus plumbeus) come to feed at open-sea fish farms near the Israeli coast, ever since their opening. Three of these sharks appear to suffer injuries of various degrees. At least one of the injured individuals, which suffers from a broken lower jaw, has been sighted at the fish farms every year since 2011. Providing a constant source of food to supplement feeding of wildlife has been shown to have both negative and positive impacts on wild populations and individuals. It may be possible that injured sharks, who have reduced abilities to find food in the wild, rely on such human related food sources to survive. Implications on the long-term effect of provisional feeding on sharks are discussed.

Keywords: Carcharhinus plumbeus, provisional feeding, elasmobranch, aquaculture, Eastern Mediterranean

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THE FIRST RECORD OF BIGEYED SIXGILL SHARK, HEXANCHUS NAKAMURAI TENG, 1962 IN ALBANIAN WATERS    

The first record of bigeyed sixgill shark, Hexanchus nakamurai Teng, 1962 in Albanian waters    

Rigers Bakiu, Marko Cakalli, Ioannis Giovos

Department of Aquaculture and Fisheries, Faculty of Agriculture and Environment, Agricultural University of Tirana, Koder-Kamez, ALBANIA
iSea, Environmental Organisation for the Preservation of the Aquatic Ecosystems, Ochi Av. 11, 55438, Agios Paulos, Thessaloniki, GREECE

Abstract

Bigeyed sixgill shark (Hexanchus nakamurai) is a deepwater cow shark species, native but rare in the Mediterranean Sea. The species commonly is misidentified as its congeneric Hexanchus griseus, a much more abundant species in the basin, creating confusion on the actual distribution and abundance of H. nakamurai in the Mediterranean Sea. In this work, we present the first confirmed record of the bigeyed sixgill shark in the Albanian Sea. The individual was captured off the coast of Himara by a professional fisherman and identified in situ by two researchers.

Keywords: Bigeyed sixgill shark, Albanian coast, Ionian Sea, Mediterranean Sea

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LENGTH-WEIGHT RELATIONSHIPS FOR THREE ELASMOBRANCH SPECIES FROM THE SEA OF MARMARA  

Length-weight relationships for three elasmobranch species from the Sea of Marmara   

Ali İşmen, Cahide Çiğdem Yığın, Mukadder Arslan İhsanoğlu, Burak Daban

Çanakkale Onsekiz Mart University, Marine Science and Technology Faculty, 17100, Çanakkale, TURKEY

Abstract

Length-weight relationships were estimated for three elasmobranch species from the Sea of Marmara. Specimens were collected by beam trawl between September 2011 and July 2014. A total of 192 individuals (130 Raja clavata, 45 Scyliorhinus canicula, 17 Torpedo marmorata) were examined. Results indicated that R. clavata and S. canicula have positive allometric growth and T. marmorata has negative allometric growth. Due to the lack of data on length-weight relationships of elasmobranch species in the Sea of Marmara, these results contribute to our knowledge of this species.

Keywords: Marmara Sea, length-weight relationship, Raja clavata, Scyliorhinus canicula, Torpedo marmorata

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SOME POPULATION PARAMETERS OF SCYLIORHINUS CANICULA(LINNAEUS, 1758) FROM THE NORTHEASTERN MEDITERRANEAN SEA  

Some population parameters of Scyliorhinus canicula(Linnaeus, 1758) from the northeastern Mediterranean Sea  

Ebru Ifakat Ozcan, Nuri Başusta

Fisheries Faculty, Munzur University, Tunceli, TURKEY
Fisheries Faculty, Firat University, 23119, Elazig, TURKEY

Abstract

A total of 1150 lesser spotted dogfish (Scyliorhinus canicula L., 1758), (562 female, 588 male) were collected by commercial trawlings in depths of 155-400 m in the Northeastern Mediterranean Sea between March 2012 and May 2014. Total length and weight of the fish were ranged from 12.0 to 51.0 cm and 4.13 to 396.0 g, respectively. It was determined that female/male ratio was 1:1.2. Monthly length frequency data of S. canicula were analyzed using FISAT II for estimating population parameters, including asymptotic length (L), growth coefficient (k) and recruitment pattern to assess the status of the stock. The parameters of von Bertalanffy growth equations were estimated as L=56.70 cm, K=0.20 year-1 and t0= -1.60 year and W= 622.01 g. The growth performance index (Ф’) value was calculated as 2.808. Length-weight relationships was found to be W=0.0013*L3.239 (R2=0.97), SE of b=0.016 and 95 % confidence intervals of b = 3.209-3.271. The type of growth shows positive allometric growth (b>3). Catch rates were calculated as 34.94 cm for females and 35.04 cm for males. Instantaneous mortality coefficient, natural mortality (M), fishing mortality coefficient (F) and total mortalities (Z) exploitation rate were estimated of S. canicula as Z = 1.06 year-1, M = 0.47 year-1, F = 0.59 year-1. The exploitation rates (E) was determined as 0.56 year-1. Therefore on the S. canicula distributed in Iskenderun Bay were under fishing pressure.

Keywords: Scyliorhinus canicula, growth, length-weight relationships, mortality, catch rate

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USING UNCONVENTIONAL SOURCES OF INFORMATION FOR IDENTIFYING CRITICAL AREAS FOR THE ENDANGERED GUITARFISH IN GREECE

Using unconventional sources of information for identifying critical areas for the endangered guitarfish in Greece 

Ioannis Giovos, Archontia Chatzispyrou, Nickos Doumpas, Vasilis-Orestis Stoilas, Dimitrios K. Moutopoulos

iSea, Environmental Organisation for the Preservation of the Aquatic Ecosystems, Thessaloniki, GREECE
Hellenic Centre for Marine Research, Institute of Marine Biological Resources and Inland Waters, Anavyssos, 19013, Attica, GREECE
Technological Educational Institute of Western Greece, Department of Fisheries and Aquaculture Technology, Mesolonghi, GREECE

Abstract

Guitarfishes characterized by special life history traits and comprised a very fragile resource, whereas the insufficient scientific information makes them a group for major conservation concern of the world oceans. The present study aims to present new records on guitarfishes based on unconventional data collection comprised by citizen scientists’ reports, social and mass media search, in-depth targeted interviews with expert fishermen and on official reconstructed fisheries statistics. This multiple-folds analysis represents a valuable case study for determining potentially important areas for these endangered species with scarcity of records in Greece. Results exhibited a high concertation of guitarfish sightings in two areas of the Greek Aegean part, both very close to published sightings from the Aegean coast of Turkey. We found that the axis of North to South, from Lesvos Island down to Rhodes Island is a critical area for guitarfish in the Eastern Mediterranean Sea. Additional information on guitarfish sightings will confirm our findings, enrich our knowledge on guitarfish occurrence in the Greek Seas and contribute in future recommendations on their protection, to avoid extinction of these rare batoids in the area.

Keywords: Rhinobatidae, eastern Mediterranean, hot spots, citizen science, Local Ecological Knowledge, Rhinobatos rhinobatos, Glaucostegus cemiculus

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Length-weight relationships of Glaucostegus cemiculus (Geoffroy Saint-Hilaire, 1817) from the Aegean Sea and northeastern Mediterranean coasts of Turkey

Length-weight relationships of Glaucostegus cemiculus(Geoffroy Saint-Hilaire, 1817) from the Aegean Sea and northeastern Mediterranean coasts of Turkey

Elizabeth Grace Tunka Bengil, Asiye Başusta, Nuri Başusta

Akdeniz Koruma Derneği, Doga Kent Villaları, 3360 sokak, No.7/16, Urla, Izmir, TURKEY
Faculty of Fisheries, Ege University, Bornova, Izmir, TURKEY
Fisheries Faculty, Firat University, 23119, Elazig, TURKEY

Abstract

Glaucostegus cemiculus individuals were collected from two different areas, the estuary of the Gediz River, Izmir Bay (Aegean Sea) on the west and Karataş, Iskenderun Bay on the northeastern coasts of the eastern Mediterranean. Total of 383 individuals (190 male, 193 female) were examined. Individuals ranged between 30-148 cm TL and 81-12010 g. The length-weight relationships were estimated for each area, each sex and combined data, and for Izmir Bay, Iskenderun Bay and combine data were all positive allometry and was as W=0.0021L3.13, W=0.0015L3.15, and W=0.0018L3.12, respectively.

Keywords: Glaucostegus cemiculus, length-weight relationships, eastern Mediterranean, Izmir Bay, Iskenderun Bay

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Vol.24 – 2018 – No.1

Introductory pages

Length-weight relationships of Glaucostegus cemiculus (Geoffroy Saint-Hilaire, 1817) from the Aegean Sea and northeastern Mediterranean coasts of Turkey
Elizabeth Grace Tunka Bengil, Asiye Başusta, Nuri Başusta

Morphometric relationships and growth of common stingray, Dasyatis pastinaca (Linnaeus, 1758) and marbled stingray, Dasyatis marmorata (Steindachner, 1892) in the northeastern Levantine Basin
Hacer Yeldan, Sedat Gündogdu

Chondrichthyan fishes in catch composition of the bottom trawl fishery on the coast of Didim, Turkey
Halit Filiz, Sercan Yapıcı, Gökçen Bilge 

Using unconventional sources of information for identifying critical areas for the endangered guitarfish in Greece
Ioannis Giovos, Archontia Chatzispyrou, Nickos Doumpas, Vasilis-Orestis Stoilas, Dimitrios K. Moutopoulos

Some population parameters of Scyliorhinus canicula (Linnaeus, 1758) from the northeastern Mediterranean Sea
Ebru Ifakat Özcan, Nuri Başusta

Length-weight relationships for three elasmobranch species from the Sea of Marmara
Ali İşmen, Cahide Çiğdem Yığın, Mukadder Arslan İhsanoğlu, Burak Daban

The first record of bigeyed sixgill shark, Hexanchus nakamurai Teng, 1962 in Albanian waters
Rigers Bakiu, Marko Cakalli, Ioannis Giovos

Occurrence of trypanorhynch cestod in blackmouth catshark, Galeus melastomus Rafinesque, 1810 (Scyliorhinidae) from the Gulf of Antalya, Turkey
Ercüment Genç, Emre Keskin, M. Cengiz Deval, M. Tunca Olguner, Doğukan Kaya, Nuri Başusta

Seasonal arrival and feeding of injured coastal sharks at fish farms in the eastern Mediterranean
Adi Barash, Renanel Pickholtz, Hagai Nativ, Shahar Malamud, Aviad Scheinin, Dan Tchernov

National action plan for the conservation of cartilaginous fishes in the Turkish water of the eastern Mediterranean Sea
Bayram Öztürk