Halil Şen

Ege University · Department of Aquaculture

Sea-cage fish farms cause wild fish to aggregate nearby. Nevertheless, it is still not clear to what extent the attraction effect around sea-cage fish farms varies according to the type and size of the reared species. We examined this attraction effect in six sea-cage fish farms across the Aegean Sea using an integrated approach combining these var...

About ten specimens of the sandbar shark, Carcharhinus plumbeus, were observed beneath a fish farm sea-cage off the Arsuz coast in Iskenderun Bay, northeastern Mediterranean Sea, on 15 October 2021. Sandbar sharks have been reported to aggregate around fish farms when the seawater temperature reaches >24°C swimming around cages in groups of 10-20 i...

In this study, a shoal of bull rays, Aetomylaeus bovinus (E. Geoffroy Saint-Hilaire, 1817), around a sea-cage fish farm in Iskenderun Bay, Turkey is reported. Such an aggregation is probably due to ontogenetic shift but may also be a factor of reproductive process as some pregnant females were observed. The number of individuals recorded, in all mo...

This study aims to determine the relationship between physico-chemical variables on a seasonal basis and wild fish assemblages beneath sea cage fish farms. Assemblages of wild fish were counted monthly on two separate days at each of six fish farms between August 2015 and July 2017, by six rapid visual counts (RVC) in 5 minutes with scuba by two di...

This study sought to determine seasonal variations in wild fish assemblage events associated with fish farms with respect to fish biodiversity, abundance and biomass along the Turkish Aegean Sea. Assemblages of wild fish were determined bimonthly with six rapid visual counts (RVCs) at six fish farms in both the Izmir (Northern Aegean Sea, NAS) and...

A total of 48 randomly selected fish farms from the coasts of Izmir and Muğla, Aegean Sea, were visited to face-to-face interviewing with fish farmers in the sea-cage fish farms between July 2015 and July 2017. Data were collected concerned mainly the following two aspects in the area: (i) actual problems on the sea-birds and other predators such a...

Akyol O., Özgül A., Şen H., Düzbastılar F.O., Ceyhan T. 2019. Determining potential conflicts between small-scale fisheries and sea-cage fish farms in the Aegean Sea. Acta Ichthyol. Piscat. 49 (4): 365-372. Background. Fish farms attract both juvenile and adult wild fishes in great numbers and diversity. These wild fishes also become an easy target...

The effects of individual rearing technique on the growth and survival of Octopus vulgaris (Cuvier, 1797) were investigated. Therefore, wild octopuses were reared in the transparent, perforated and caped polyethylene terephthalate (PET) pots (10 l). The assay was established as one free group rearing as a control (12.7 kg/m3 of stoking density) and...

Temmuz 2015 ve Temmuz 2017 arasında, Ege Denizi’nde İzmir ve Muğla kıyılarından rastgele seçilmiş 48 balık çiftliği ziyaret edilmiş, ayrıca balık çiftlikleri etrafında av yapan toplam 329 kıyı balıkçısıyla yüz yüze anketler yapılmıştır. Anketlerde balık çiftliklerinden balık kaçış nedenleri sorulmuştur. Verilen yanıtlar predatör saldırıları, fırtın...

Structures, floating on the surface of the ocean attract both juvenile and adult fishes in great numbers and diversity. Natural and artificial Fish Aggregation Devices (FADs) in open seas are widely recognised for their capacity to attract pelagic fishes. It can be assumed that floating sea-cages act as a kind of FAD. Even, fish aggregations beneat...

Pelagic fish are known to be strongly attracted to floating structures, including coastal cage farms, sometimes in dense aggregations. Distinctly, floating fish cages, adopted as a sort of fish aggregating devices (FADs) attract fish. Although, occurring of wild fish communities around the sea-cage farms are well-known, this phenomenon is not docum...

This Collective Article presents information on 37 taxa belonging to 6 Phyla and extending from the western Mediterranean to the Levantine Sea. The new records were found in 10 countries as follows: Algeria: first reports on the presence of the fish species Lesueurigobius sanzi, L. friesii, L. suerii and Luvarus imperiali; France: first record of t...

Sepia officinalis üzerine 2-fenoksietanolün (2-PhOH) etkisi incelenmiştir. 2-PhOH’ün farklı dozları (0,10; 0,15; 0,20; 0,25 ve 0,30 ml/L) 15 litrelik şeffaf cam akvaryumun içinde bulunan ve sürekli havalandırılan 10 litre deniz suyunda (pH 7,68; O2 6,8 mg/L; sıcaklık 19,7°C ve tuzluluk ‰37) çözündürülmüştür. 2-PhOH uygulamalarından sonra sübyeler h...

Maja crispata (Risso 1827)’nın larval gelişimi ve yaşama oranı üzerine yem:larva oranının etkileri incelenmiştir. Denemeler 21,6 ± 0,5°C su sıcaklığında yapılmıştır ve larvalar beş yem:larva oranı [5 Artemia/larva (A1), 10 Artemia/larva (A2), 15 Artemia/larva (A3), 20 Artemia/larva (A4) ve 25 Artemia/larva (A5)] ile beslenmişlerdir. Tüm gruplarda,...

In this preliminary study, it was aimed adaptation of common octopus (Octopus vulgaris) by individually stocking technique. Therefore, totally 10 individuals captured from the sea, were placed in a 10 L of plastic transparent perforated bowls by individually. Adaptation periods of the species lasted 5 days with 80% of the survival rate.

ARAŞTIRMA MAKALESİ RESEARCH ARTICLE Sübye [Sepia officinalis (Linneaus, 1758)]'nin iç kabuk gelişimi The cuttlebone development of common cuttlefish [Sepia officinalis (Linneaus, 1758)] Abstract:The cuttlebone development of Sepia officinalis, which is an important criterion for its embryonic development, was redefined as detail during the 30 stage...

Effects of potassium dichromate (K2Cr2O7) on skin ulcers upon the mantle tip of musky octopus (Eledone moschata) in controlled conditions were investigated. Therefore, the trials on five octopuses were performed at 0.1, 0.15 and 0.2 gL-1 concentrations of potassium dichromate by bath method. The bath applications were carried out at 20.3 ± 0.1 °C f...

On 2 June 2010, an abnormally pigmented specimen of Solea solea L. with a total length of 222 mm was obtained near Tuzla, from the Izmir Bay of the Aegean Sea. This is the first record of abnormal pigmentation in the wild common sole from the Aegean Sea. The specimen fish is patterned with both hypermelanosis on the blind side and hypomelanosis on...

The aim of the preliminary study was to determine the feeding preference of the musky octo-pus (Eledone moschata) from its natural habitats. A total of 471 specimens were measured and their fully or partially full stomachs were fixed in 6% formaldehyde, and then analyzed in the laboratory. The degree of stomach fullness was estimated from 471 indiv...

The efficacy of 2-phenoxyethanol (2-PhOH) as an anaesthetic for the musky octopus, Eledone moschata (Lamarck, 1799), was examined. Different doses (1.0, 1.2, 1.4, 1.6, and 1.8 mL L(-1)) of 2-PhOH were prepared in 20 L transparent plastic containers containing 10 L of continually aerated seawater (pH 8.2, O(2) 8 mg L(-1), salinity 37.2% at 15.3 degr...

zet: Bu çalışmada doğadan olta ile avlanan ergin sübyelerin kontrollü koşullarda yumurtlaması, yumurtalarının gelişimi ve açılım oranları incelenmiştir. Yumurtlama, 17.4±1.1°C su sıcaklı-ğında, 46 günlük bir dönemde aralıklı olarak 32 kez gerçekleşmiştir. Embriyonik gelişim serisi içinde ilk kez dorsal mantoda kromatofor oluşumu safha 23 (Lemaire,...

A specimen of the musky octopus, Eledone moschata, of 188 mm mantle length and 1414 g total body weight, was caught on 12 February 2007 by trammel net in İzmir Bay. The given sizes are the maximal for this species at the present time.

This is the first study related to the effects of cadmium (Cd) on the development and hatching of eggs of Loligo vulgaris. The eggs were exposed to concentrations varying from 10 to 100,000 microg Cd/l for up to 1 month. During the study period natural sea water salinity (37 PSU), ambient temperature (ranging 16.5-21.5 degrees C) and light conditio...

Reproductive properties of Eledone moschata from the north-eastern Aegean Sea are reported for the first time. A total of 471 specimens was collected during monthly samplings from December 2004 to November 2005. The mantle lengths of the species were between 4.5 and 15.0 cm with an average of 8.1 cm ±0.15 for 204 males, and between 2.7 and 14.0 cm...

The objectives of this study were to evaluate the effects of 2-phenoxyethanol (2-PE), which is an anaesthetic, on survival rates of normal juveniles and malformed juveniles having lordosis or nonfunctional swim bladders of European sea bass (Dicentrarchus labrax L., 1758) and to establish the LC50 (the concentration lethal to 50% of test animals at...

The ink-sac development of european squid's (Loligo vulgaris Lamarck, 1798) eggs during the embryogenesis. In this study, the ink-sac development, which is critical feature for embryogenesis of cephalopods and it wasn't seeking in previous studies, of European squid (Loligo vulgaris Lam., 1798), which is very important and highly economical species...

Arnold (1965)’un gelişim şemasına göre, kafadanbacaklıların embriyonik gelişiminde belirleyici bir kriter olan huni (sifon) tüpü gelişimi, ticari değeri oldukça yüksek olan kalamar (Loligo vulgaris) için incelenmiştir. Denemede uzatma ağlarından toplanan 12 adet morula safhasındaki L. vulgaris yumurtası kapsülü kullanılmıştır. Yumurta kapsülleri, i...

Loligo vulgaris is a commercially important squid throughout the Mediterranean region and is a candidate species in biomedical and aquaculture research. Some loligo species (L. opalescens, L. forbesi, Sepiteuthis lessoniana) have now been cultured through some successive generations in closed, recirculating seawater systems. The effects of salinity...

Temperature tolerance of common squid (Loligo vulgaris Lamarck, 1798) eggs in controlled conditions was investigated between May 21, 2002 and March 04, 2003. The treatments were performed as 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, and 28°C at 37 ppt. Illumination was kept at dim light for 13-49 days before hatching. A mean dorsal mantle length of...

The effects of salinity on the development and incubation of European squid (Loligo vulgaris, Lamarck, 1798) eggs were investigated from December 2001 to March 2002. The egg capsules were incubated in 37‰, 34‰, 31‰, 28‰, and 0‰ salinity without any acclimation process. Mean temperature was 12±2.O°C. Illumination was maintained at 1.5 lux at the wat...

Effects of temperature on development and incubation of squid (Loligo vulgaris Lamarck, 1798) eggs. In this study, embryonic development time and hatching success of squid (Loligo vulgaris Lamarck, 1798) eggs, which were incubated at different temperatures, was investigated. In this purpose, total 8 experimental groups were performed at each 4 degr...

Effects of photoperiodicity on development and incubation of squid (Loligo vulgaris Lamarck, 1798) eggs. In this study, effects of photoperiod on development and incubation of European squid (Loligo vulgaris Lamarck, 1798) eggs were investigated. The egg capsules were incubated at 14 h light/10 h dark (P1; daily light period), 10 h light/14 h dark...

A female individual of Ommastrephes bartrami, which belongs to the Ommastrephidae family, was caught from the shallow waters ofzmir Bay (Aegean Sea). It set a new record for bothzmir Bay and northern Aegean Sea of Turkey. Its morphological features were re-examined and its photograph was taken.