The effects of biofloc technology (BFT) were tested on growth performance, water quality, haemolymph parameters and hepatopancreas histology with and without BFT for the speckled shrimp. In this study, eight different experimental groups were formed (four BFT and four control groups) to measure the effects of different feeding rates on compensatory growth of speckled shrimp. BFT treatments were performed with zero water exchange and planned as BFT1: gradually feed decreasing group 4, 2 and 1% bw, BFT2: 4% bw, BFT3: 2‐days feed with 4% bw, 1‐day fasted, and BFT4: 1‐day feed with 4% bw, 1‐day fasted. In control treatment, the same trial groups were constituted for comparing with BFT at a 50% daily water exchange: C1 (gradually feed decreasing group: 4%, 2% and 1% bw), C2 (4% bw), C3 (2‐days feed with 4% bw, 1‐day fasted), C4 (1‐day feed with 4% bw, 1‐day fasted). There were significant differences between BFT and C groups in terms of some water quality (p < 0.05). In general, BFT had an effect on haemocyte profile. At the histological examination, there were no pathological findings in both BFT and control groups. The growth parameters of speckled shrimps in BFT groups, as well as the whole body crude protein ratios and crude ash contents, were higher than the control group (p < 0.05). The results confirmed that biofloc utilization increased with decreasing feeding.

Fish parasites act as a vector of other pathogenic diseases such as bacteria and virus in fish. Although it has been long known that fish parasites can act as a vector for bacterial pathogens, their role in the transmission of specific bacterial pathogens via particular parasites in the off-host stage has been neglected. The aim of the present study was to disclose that if the copepod parasite, Lernanthropus kroyeri in the off-host stage, can store up the aquatic bacterial pathogens: Aeromonas hydrophila, Photobacterium damsela subsp. piscicida, Vibrio (Listonella) anguillarum, V. harveyi, V. vulnificus, and V. alginolyticus. Our results using the Loop-mediated Isothermal Amplification (LAMP) method demonstrates that the bacteria, V. anguillarum is internally present in the off-host copepod parasites, L. kroyeri. It was also found that the parasite, L. kroyeri could survive in the off-host stage for a given time with its potential of vectoring ability in terms of transmission of the bacterium to the fish. This study demonstrates evidence that the copepod parasite in the off-host stage on the gills of sea bass is a reservoir of pathogen bacteria, Vibrio anguillarum.

The use of biofloc technology (BFT) in narrow-clawed crayfish (Astacus leptodactylus) culture for 45 days was evaluated by production performance and physiological status of crayfish. Four different stocking densities of crayfish were tested in BFT (20, 41.66, 62.5, ). Water quality parameters were monitored to sustain desired levels for crayfish and biofloc management. The growth performance of narrow-clawed crayfish did not show any significant differences among the groups. However, the survival rate changed by the stocking density. Hemolymph indices represented by total hemocyte counts and relative abundance of hyalinocyte, semi-granulocyte, and granulocyte were not affected by different stocking densities. Overall hemolymph glucose and lactate levels of narrow-clawed crayfish reflected mild stress in response to BFT conditions. Hemolymph protein concentrations did not change by the stocking ratio in BFT. Hemolymph protein levels were in the normal range, indicating the healthy status of the individuals. The hepatopancreas histology was observed as a typical morphology for healthy crayfish in all stocking densities in BFT. Notwithstanding the relatively lower survival rate in higher stocking density of narrow-clawed crayfish, the results of the present research revealed that the adaptation of narrow-clawed crayfish to BFT conditions is promising for the crayfish culture.

One of the constraints in fish disease management in aquaponic systems is related to undesired effects of chemicals on fish, plants and beneficial bacteria. Plant-derived compounds with nontoxic features to fish, plants, and microflora provide an alternative treatment strategy against the harmful pathogens in the aquaponic system. The present study assessed the antiparasitic activity of garlic (Allium sativum) and onion (A. cepa) extracts against Gyrodactylus elegans (Monogenea) in vivo and in vitro, and physiological stress responses in carp, Cyprinus carpio, treated with these extracts in an aquaponics system. Garlic and onion extracts exhibited in vitro antiparasitic activity against G. elegans. The mean survival time of G. elegans in vitro ranged from 30 sec to 6 min depending on the concentration and exposure time both for garlic and onion extracts. For garlic extract EC50 (median effective concentration) was 8.37±4.75 mg/mL in 3 min exposure and for onion extract 4.72±7.10 mg/mL. These concentrations were in vivo tested in carp heavily infected with G. elegans as a single application for 3 min. In vivo treatment of carp with garlic and onion extracts reduced G. elegans found on the skin by 14.4% and 19.8%, respectively. In both treatment groups, the physiological stress response of carp was mild based on the alterations in the secondary stress indicators (hematocrit, plasma glucose, and lactate). The stress indicators of carp returned to normal levels after an hour recovery in freshwater. The antiparasitic potential of onion and garlic extracts may be considered as an alternative treatment to reduce Monogenean infections in aquaponic systems.

Bu çalışmada, ekonomik tarak türleri arasında yer alan Akdeniz deniz tarağı (Pecten jacobaeus)’nın mevsimsel besin içeriği ve iz metal içerikleri değerlendirilmiştir. Örnekler Antalya Körfezi'nde faaliyet gösteren ticari balıkçı teknelerinin trol ağlarından hedef dışı av olarak 2017-2018 yılları arasında alınmıştır. Deniz taraklarının bazı büyüme indeksleri belirlendikten sonra, ham besin bileşimi, amino asit ve element analizleri gerçekleştirilmiştir. Sonuçlara göre; kondisyon indeksi ve gonadosomatik indeks en yüksek yaz mevsiminde, et verimi ise en yüksek sonbaharda tespit edilmiştir (P