Contents lists available at ScienceDirect Marine Pollution Bulletin journal homepage: www.elsevier.com/locate/marpolbul Determination of the healthiness of aquaculture fsh by enzymes and histopathological methods Fatma Telli-Karakoç a,b, ⁎ , Nurhayat Barlas c a KTU-SMSF, Department of Marine Sciences and Technology Engineering, Çamburnu, 61530 Sürmene, Trabzon, Turkey b TUBITAK-MRC, Environment Institute, 41470 Gebze, Kocaeli, Turkey c HU, Science Faculty, Biology Department, Beytepe, 06800 Ankara, Turkey ARTICLEINFO Keywords: Endocrine disrupters Enzymes (EROD, CAT, SOD) Fishes Metals (i.e. Ni, Cu, Zn, As, Cd, Pb and Hg) Aquaculture ABSTRACT The health of fshes from select aquacultures was investigated by conducting histopathologic and enzymatic analyses, as well as by examining pollutant accumulation rates in fsh tissues ranging in age from juvenile to two years old. Histopathologic examinations demonstrated that the fshes had some abnormalities in their livers, spleens, intestines and reproduction systems, such as lipidation, ovotestis formation, lysis and enlargements of the tissues. The occurrence rate of these abnormalities was not very frequent but also not negligible. Statistical analysis demonstrated that enzyme activity (i.e. CAT, EROD, SOD) and protein concentration fuctuated pre- dominantly by age and season. These parameters were not found to be related to the fsh farm or other spatial changes, when their existing environmental conditions were not extreme (i.e. polluted or otherwise unsuitable). Metal concentrations (i.e. Ni, Cu, Zn, As, Cd, Pb and Hg) were never found to be higher than national or in- ternational regulatory limits. The quality of the fshes caught from optimal farm conditions may be evaluated as good quality for human consumption. 1. Introduction Human beings have evolved from a lifestyle of migration to a more stable residential lifestyle, and consequently, they have learned to produce a continuous food supply via land-based agricultural activities. Water-based aquacultural activities were also developed. The frst re- cord of aquacultural activities began in China in 3500 BCE, which in- volved the cultivation of carp in freshwater ponds and rice paddies (http://www.aces.edu, 2018). In many developing countries, an es- sential source of protein is fsh. The latest estimate by FAO suggests that, as of 2010, fsh accounted for 17% of the global population's in- take of animal protein and 6.5% of all protein consumed. Fish is also a major source of livelihoods and income, particularly in developing countries. It is estimated that > 158 million people in the world depend directly on fsh-related activities such as fshing, fsh farming, proces- sing and trading. Fish is a particularly nutritious food, rich in numerous micronutrients that are often missing in human diets, especially those of the poor. Specifcally, fsh contains essential nutrients (e.g., vitamins B12, A, D, etc.), long-chain fatty acids, omega-3 fatty acids, protein, calcium, iron and zinc (FAO, 2018; HLPE, 2014). The relationship between pollution and aquaculture is complex. Sources of pollutants may come from land-based sources, industrial and shipping activities, fsh feed, localized high concentrations of fsh feces in a constrained area and boats used in aquacultural facilities. Animals are very sensitive to physical and chemical changes. The efects on fshes may vary from interference with their body functions to cell damage. The tolerance of animals varies with their stage of develop- ment. Thus, a very young animal may be more sensitive to pollutants than an adult. Aquaculture fsh cannot select their living environment even if the quality of the water worsens. From the beginning of the settlement of cages and during on-going operations, the environment of an aquaculture and the condition of the fsh farms must be controlled properly (i.e., selection of the aquaculture area (depth, distance from land, distance from discharges and industrial areas, etc.), food type, current system and physical-chemical properties of the water). If these are not adequately controlled, the environmental impacts or otherwise poor conditions may negatively afect fsh health. For example, if there are many chemical pollutants, they may afect the normal functions of the endocrine systems of living organisms. These chemical compounds are not only artifcially produced compounds, such as organochlorine pesticides, polyaromatic hydrocarbons, trace metals, polychlorinated biphenyls (PCBs), bisphenol A, alkyl phenols, and phthalates; naturally occurring endocrine disrupting compounds (EDCs) can also profoundly alter reproductive physiology and ultimately impact entire populations https://doi.org/10.1016/j.marpolbul.2019.110535 Received 9 April 2019; Received in revised form 5 August 2019; Accepted 20 August 2019 ⁎ Corresponding author at: KTU-SMSF, Department of Marine Sciences and Technology Engineering, Çamburnu, 61530 Sürmene, Trabzon, Turkey. E-mail address: fatma.tellikarakoc@ktu.edu.tr (F. Telli-Karakoç). Marine Pollution Bulletin 149 (2019) 110535 0025-326X/ © 2019 Published by Elsevier Ltd. T