Age, growth and mortality rates of discard species (Uranoscopus scaber, Neogobius melanostomus and Gobius niger) in the Black Sea

Abstract

Uranoscopus scaber, Neogobius melanostomus and Gobius niger are called non-commercial fish species and also caught as discarded in Turkish fisheries. Samplings were carried out by bottom trawl, gillnet, purse seine net operations in the Turkish Black Sea coasts. The results of the study showed that age of these species were 0-V ages for Uranoscopus scaber and Gobius niger, and 0-VII ages for Neogobius melanostomus for both sexes. The von Bertalanffy growth parameters, total mortality rate (Z), natural mortality rate (M) and fishing mortality rate (F) were calculated for each species separately. Keywords: Age, growth, mortality rates, Uranoscopus scaber Neogobius melanostomus, Gobius nigerÖz: Uranoscopus scaber, Neogobius melanostomus ve Gobius niger Türkiye balıkçılığında ekonomik olmayan balıklar olarak adlandırılmakta ve ıskarta edilmektedirler. Bu çalışmanın örnekleri Karadeniz kıyısında kullanılan dip trolü, uzatma ağı ve gırgır ağları ile avlanmıştır. Bu çalışmadan elde edilen sonuçlar, Uranoscopus scaber ve Gobius niger türünün yaşlarının 0-V arasında, Neogobius melanostomus türünün ise 0-VII yaş arasında değiştiğini göstermiştir. Von Bertalanffy büyüme parametreleri, toplam ölüm oranları, doğal ölüm oranları ve balıkçılık ölüm oranları ise her tür için ayrı ayrı hesaplanmıştır.

Age, Growth and Reproduction of Neogobius melanostomus (Pallas 1814) (Perciformes: Gobiidae) in the Southern Black Sea

“…The instantaneous total mortality rate (Z), natural mortality (M) and fishing mortality (F) were estimated as 0.625, 0.479 and 0.145, respectively. Similarly, Kasapoğlu (2016) found Z=0.54, M=0.29 and F=0.145 in similar study region. Nikolskii (1954) reported that the species reaches sexual maturity at two years old in females and three years old in males.…”

“…There are various studies in the regions for this species Abdoli et al, 2009;Yankova et al, 2011, Hôrková andKováč, 2014;Macun, 2017) however studies from the Black Sea, especially the southern part are scarce (Engin, 2008;Gözler et al, 2003;Kurt, 2005;Kasapoğlu, 2016).…”

Life history of the river goby Glossogobius callidus (Teleostei: Gobiidae)

“…Overall, G. callidus had higher mortality rates compared with G. niger from Turkey (Filiz & Toğulga, 2009), and female Neogobius caspius (Eichwald 1831), however, had low mortality rates than male N. caspius (Aghajanpour et al ., 2016) from the Caspian Sea and Aphia minuta (Risso 1810) from Italy (La Mesa, 1999). Furthermore, N. melanostomus had higher mortality rates than G. callidus (Kasapoğlu, 2016).…”

Growth characteristics ofUranoscopus scaberLinnaeus 1758, inhabiting the Iskenderun Bay (Northeastern Mediterranean)

“…(Golani et al., 2006). It is caught by bottom trawl and it has limited commercial value in Turkish seas fishery (Demirhan et al., 2007; Erdoğan Sağlam & Sağlam, 2013; Golani et al., 2006; Kasapoglu, 2016). The maximum total length published for U. scaber is 40.0 cm (Roux, 1990).…”

“…Although a few studies have been carried out on age and growth of Atlantic stargazer in the Black Sea (Demirhan et al., 2007; Erdoğan Sağlam & Sağlam, 2013; Kasapoglu, 2016), there is no information on the performance of this species along the Mediterranean coasts of Turkey. Rizkalla and Bakhoum (2009) reported some biological aspects from Egyptian waters (Eastern Mediterranean) and only one study exists on the growth of Atlantic stargazer from Tunisian waters in the western Mediterranean (Bondka & Kartas, 1986).…”