An in-depth study of the biology, trophic ecology and catchability of the invasive pufferfish Lagocephalus sceleratus from southern Turkey, eastern Mediterranean Sea

The silver-cheeked toadfish (Lagocephalus sceleratus) is an invasive species of highest concern. Its population must be controlled to mitigate its negative impacts on marine ecosystems, fishers, fisheries and human health. This study thoroughly investigates the biology, diet and catchability of the L. sceleratus stock from Finike, Turkey from March 2017 to February 2018 in order to better manage its invasion. A total of 751 specimens were sampled for this study with a M/F ratio of 1.25/1. The species becomes sexually mature at three and a half years of age, and Lm50 was 41.39 cm for males and 42.08 cm for females. Its spawning season in this region was from June to August, peaking in July. Its diet was mostly crustaceans in spring, fish in summer and both fish and crustaceans in winter. This species consumed a large amount of other pufferfish species, resulting in over a quarter of its fish diet. The trophic level of L. sceleratus was 4.41, demonstrating that it is indeed a top predator carnivore in the eastern Mediterranean Sea. Ingested fishing gear parts such as net pieces and hooks were found in about 10% of the fish. A slight modification of longlines using steel branch lines and a swivel hook resulted in double the catch per unit effort than standard longlines, so this technique can be used to target and control more of this invasive species, which is a national priority.El pez globo (Lagocephalus sceleratus) es una especie invasora de gran preocupación. Es necesario controlar su población para mitigar sus impactos nocivos en los ecosistemas marinos, los pescadores, la pesca y la salud humana. Este estudio investiga minuciosamente la biología, la dieta y la capturabilidad del stock de L. sceleratus en Finike, Turquía, desde marzo de 2017 hasta febrero de 2018, con el fin de mejorar la gestión de la invasión. Se muestreó un total de 751 ejemplares para este estudio, con una proporción de machos/hembras de 1,25/1. L. sceleratus alcanza la madurez sexual a los tres años y medio de edad, y la Lm50 fue de 41,39 cm para los machos y 42,08 cm para las hembras. Su temporada de desove en esta región fue de junio a agosto, alcanzando su punto máximo en julio. Su dieta consistía principalmente en crustáceos en primavera, peces en verano y tanto peces como crustáceos en invierno. Esta especie consumía una gran cantidad de otras especies de peces globo, lo que representaba más de una cuarta parte de su dieta de peces. El nivel trófico de L. sceleratus fue de 4,41, lo que demuestra que L. sceleratus es en efecto un carnívoro depredador de alto nivel en el Mar Mediterráneo Oriental. Se encontró ingestión de partes de artes de pesca en aproximadamente el 10% de los peces, como trozos de redes y anzuelos. Una ligera modificación del palangre utilizando líneas de acero y un anzuelo giratorio resultó en valores duplicados de CPUE en comparación con palangres estándar, lo que se puede utilizar para enfocar y controlar más de esta especie invasora, lo cual es una prioridad nacional

Population parameters and feeding properties of some puffer fish in Finike bay (Antalya).

TEZ11760Tez (Doktora) -- Çukurova Üniversitesi, Adana, 2019.Kaynakça (s. 115-134) var.xiv, 135 s. : res. (bzs. rnk.), tablo ; 29 cm.Balon Balıkları Akdeniz’e yayılımcı tür olarak yerleşen, artan oranda popülasyonlar oluşturan indopasifik kökenli türlerdir. Özellikle Lagocephalus sceleratus barındırdığı toksinden dolayı insan sağlığına tehdit oluşturmaktadır. Bu nedenle akademik çevreler diğer istilacı türlere oranla bu türe daha fazla ilgi göstermektedir. Bu çalışmada Finike Körfezi’nde dağılım gösteren balon balıklarının bazı popülasyon parametreleri ve beslenme özellikleri araştIRIlmıştır. Çalışma kapsamında Finike Körfezi’nde Tetraodontidae familyasına ait dört balon balığı türüne (Lagocephalus sceleratus, Lagocephalus suezensis, Torquigener flavimaculosus ve Lagocephalus spadiceus) ait 1310 adet birey 2017 yılı Mart ile 2018 Mart ayları arasında aylık olarak 12-165m arası derinliklerden elde edilmiştir. Örnekler genel olarak paraketa ve uzatma ağlarından elde edilmiştir. Çalışmada boy-ağırlık dağılımları, boy-ağırlık ilişkisi, büyüme parametreleri (L?, W?, K, t0), eşey dağılımı, ilk eşeysel olgunluk boyu ile Gonadosomatik Indeks (GSI), Kondisyon faktörü ve Hepatosomatik indeks değerlerinin aylık değişimi ve beslenme özellikleri belirlenmiştir.Puffer fish are invasive species of Indo-Pacific origin that has rapidly invaded the eastern basin of the Mediterranean and have established increasing populations. Especially Silver-cheeked toadfish L. sceleratus is a threat to human life by the fact that it is toxic. For this reason, the academic and administrative interest in this species is much higher than the other invasive species. In this study, some population parameters of the pufferfish were studied in the Finike Bay, Eastern Mediterranean Sea. A total of four fish species from tetradontidae family (L. sceleratus, L. spadiceus, L. suezensis and T. flavimaculosus) in the Finike Bay were determined and 1310 individuals were collected by monthly sampling interval from Finike Bay between March 2017 and March 2018 by using different types of nets and long lines, at depths ranging from 12m to 165m. Length and weight distributions, length weight relationship, growth parameters (L?, W?, K, t0), sex ratio, maturity stages, length at first maturity, Gonadosomatic Index (GSI), condition factor, Hepatosomatic index and feeding of pufferfish were determined.Bu çalışma Ç.Ü. Bilimsel Araştırma Projeleri Birimi tarafından desteklenmiştir. Proje No: SÜF 2010 D2

Determination of the reproductie period of S. solea and S. lasscaris which distributed in the Gulf of İskenderun.

TEZ10395Tez (Yüksek Lisans) -- Çukurova Üniversitesi, Adana, 2015.Kaynakça (s. 45-48) var.ix, 49 s. : res. (bzs. rnk.), tablo ; 29 cm.Bu çalışmada, İskenderun körfezinde dağılım gösteren Solea solea ve Solea lascaris’in üreme döneminin belirlenmesine amaçlanmıştır. Örneklerin temin edilebilmesi için aylık olarak yapılan saha çalışmalarında trol ve uzatma ağı operasyonları gerçekleştirilmiştir. Örnek temin edilme durumuna göre her ay birer saatlik 3 ile 5 arasında trol operasyonu yapılmıştır. Trol örneklemelerinde “Geleneksel Akdeniz Tipi Trol Ağı” kullanılmıştır. Bazı aylarda trol örneklemelerinden yeterli miktarda Solea solea bireyi elde edilememiştir. Bu aylarda gerekli Solea solea bireyleri fanyalı dil uzatma ağları ile yapılan operasyonlarla temin edilmiştir. Örneklerin değerlendirilmesinde trol ve uzatma ağlarından elde edilen tüm bireyler birlikte kullanılmıştır. Elde edilen sonuçlar; Solea solea’nın su sıcaklığının en düşük olduğu Ocak-Mart ayları arasında, Solae lascaris’in ise Mart-Nisan aylarında ürediğini göstermiştir. Solea solea ve Solea lascaris’in dişi bireylerinin ilk eşeysel olgunluk boyları ise sırasıyla 26.37cm ve 13.23cm olarak belirlenmiştir.In this study, determination of the spawning period of Solea solea and Solea lascaris which distributed in the Gulf of İskenderun, was aimed. During field work, trawl and gillnet operations were carried out monthly to obtain individuals of Solea olea and Solea lasscaris as target species. From 3 to 5 trawl operations were made each month according to providing of samples. Each trawl operations were conducted for one hour. For trawl samplings, “Traditional Mediterranean Type Trawl Net” was used. Enough amount for individually Solea solea were not obtained in some trawl sampling. Individuals of Solea solea for this months were provided by gillnet. All individuals obtained from trawl and gillnet were used for assessment of samplings. The obtained data showed that Solea solea spawn from January to March which water temperature was lowest, Solea lascaris spawn from March to April. First sexual maturity length of female Solea solea and Solea lasscaris 26.37cm and 13.23cm were determined respectively.Bu çalışma Ç.Ü. Bilimsel Araştırma Projeleri Birimi tarafından desteklenmiştir. Proje No: SÜ2012YL5

A biological and ecological study of the invasive pufferfish Torquigener hypselogeneion (Bleeker 1852) [conspecific Torquigener flavimaculosus Hardy & Randall, 1983] in the Eastern Mediterranean

The highly toxic orange-spotted toadfish Torquigener hypselogeneion (Bleeker 1852) [conspecific Torquigener flavimaculosus Hardy & Randall, 1983] is now a very common invasive fish in the Eastern Mediterranean. Its small size, well under 20 cm, may have concealed the danger it represents, and little is known about its biology or ecology. Here, the spawning seasons, gonado- and hepato-somatic index and condition factors of T. hypselogeneion from 3 locations of the Eastern Mediterranean are presented, based on a total of 1360 individuals sampled, i.e., 216 from Finike, 817 from Fethiye (both Turkey), and 327 from Cyprus. Our results show that T. hypselogeneion is a carnivorous species that forages on sandy bottoms, with a preference for small invertebrates, especially the small invasive gastropod Cerithium scabridum, crustaceans (hermit crabs, other crabs and barnacles), and sea urchins; however, at least in some localities, they appear to forgo eating during their peak reproductive period. The parameters of the von Bertalanffy Growth Function for T. hypselogeneion in the Eastern Mediterranean were: asymptotic length = 17.4 cm (total length; TL) and K = 0.96 year-1, implying a longevity of about 4 years, while the mean length at first maturity was about 10 cm (TL) for both sexes. An average-sized adult female (13 cm TL, 45.7 g live weight) was found to contain 1,250 eggs per gram body weight. Based on its high invasiveness and negative impacts to ecology of the Eastern Mediterranean and the human health, we suggest that T. hypselogeneion should be listed as a priority invasive species and that its population closely monitored within the Mediterranean Sea