Fish Health

Plastic pollution is a global concern, leading to the abundance of macro-and microplastics (MPs) in the marine environment and subsequent accumulation in many marine organisms, particularly small pelagic and oceanic fish species. These small fishes are usually considered as the non-target catch or by-products of marine capture fisheries. However, these by-catch fishes convert into fishmeal due to their excellent nutritional value, and thereby, it used as the primary ingredient of artificial feeds for aquaculture and livestock animal production. The fishmeal and fish feed facilitates MPs' entry into the aquaculture systems when the MPs− contaminated feeds are supplied to cultured fish for regular feeding. Thus, MPs get access to interact with the elements of the culture pond ecosystem and leading to subsequent alterations in the physiological and behavioral attributes of cultured fishes. Consequently, MPs may accumulate in the edible portions of cultured fishes, which may cause severe physiological disorders in fish consumers. Thus, human exposure to MPs becomes a significant threat to global public health. Therefore, this review discussed the factors associated with MPs' introduction to the aquaculture systems via fishmeal. In addition, this article enlightened the possible consequences of MPs on the pond ecosystem, cultured fish physiology, and consumer health. We hypothesized that the growing concern among people about MPs might be impacted the demand for aquaculture goods. This study recommended taking necessary steps towards improving the MPs' screening process during fish feed production and focusing on more exclusive studies to elucidate the impacts of MPs on sustainable aquaculture production.

Penyakit ikan adalah masalah yang sering membelenggu industri akuakultur. Gangguan penyakit ikan ini mungkin menyebabkan ikan merasa tidak selesa, selera makan menurun, daya tahan ikan menjadi lemah, hilang keseimbangan tubuh serta boleh menyebabkan kematian ikan. Penyakit ikan adalah sesuatu yang boleh menyebabkan gangguan terhadap ikan secara langsung dan tidak langsung. Penyakit yang menyerang ikan peliharaan atau ikan ternakan boleh berpunca daripada penyakit yang disebabkan oleh organisma patogen dan bukan patogen, makanan, atau keadaan alam sekitar lain yang tidak menyokong kehidupan ikan. Bahagian Biosekuriti Perikanan, Jabatan Perikanan Malaysia bertanggungjawab dalam menyelaras semua aktiviti kawalan rasmi, analisis rasmi dan jaminan rasmi terhadap ikan hidup dan hasilan ikan daripada sektor perikanan tangkapan dan akuakultur. Program pemantauan biosekuriti kesihatan ikan atau lebih dikenali sebagai program survelan penyakit ikan dilaksanakan bagi tujuan memantau status kesihatan ikan di peringkat ladang dan premis pengeksport berdasarkan kepada risiko penyakit. Survelan penyakit ikan ini dilaksanakan dua kali setahun bagi setiap ladang serta premis pengeksport. Objektifnya adalah untuk mengesan penyakit baharu dan penyakit sedia ada. Survelan ini juga menjadi bukti sekiranya negara/ zon/ kompartmen dilanda wabak penyakit dan status bebas penyakit tertentu, sebagai kawalan penyakit bagi tujuan perdagangan, mengetahui pelaksanaan kawalan dan pelupusan bagi ikan yang dijangkiti penyakit berdasarkan langkah biosekuriti yang tepat dan berjaya. Sampel ikan yang diambil daripada program survelan akan dibawa ke makmal biosekuriti perikanan bagi tujuan analisis penyakit berdasarkan program yang telah dirancang setiap awal tahun. Senarai penyakit di bawah Program Survelan Kesihatan Ikan bagi ikan hiasan, udang, ikan termasuklah White Spot Syndrome Disease (WSSD), Koi Herpes Virus (KHV), Spring Viraemia Virus (SVC), Epizootic Ulcerative Syndrome (EUS), Irido dan Megalocityvirus. Dengan membaca buku ini, pembaca mendapat gambaran ringkas tentang penyakit ikan secara khusus dan mengetahui secara ringkas mengenai program survelan penyakit ikan yang dijalankan dan dilaksanakan oleh Bahagian Biosekuriti Perikanan, Jabatan Perikanan Malaysia selaras dengan keperluan World Organisation for Animal Health (OIE). Di samping itu, salah satu keistimewaan buku ini adalah berkenaan topik Geographic Information System (GIS) yang merupakan satu eleman yang digunakan dalam pemetaan lokasi pensampelan ikan yang dijalankan oleh Bahagian Biosekuriti Perikanan. GIS diperlukan untuk mendapatkan data spatial dan realiti dunia sebenar, sebagai penyelesaian masalah ruang (spatial) dalam urusan pentadbiran dan pengurusan selain daripada keperluan teknologi terkini. Buku ini digarap dengan isi dan gaya bahasa khas yang mudah difahami. Semoga buku ini dapat memberikan manfaat kepada pembacanya.

Abstract

Thirty snakehead fish, Channa micropeltes (Cuvier, 1831) were collected at Lake Kenyir, Malaysia. Muscle, liver, intestine and kidney tissues were removed from each fish and the intestine was opened to reveal cestodes. In order to assess the concentration of heavy metal in the environment, samples of water in the surface layer and sediment were also collected. Tissues were digested and the concentrations of manganese (Mn), zinc (Zn), copper (Cu), cadmium (Cd) and lead (Pb) were analysed by using inductively-coupled plasma mass-spectrometry (ICP-MS) equipment. The results demonstrated that the cestode Senga parva ( Fernando and Furtado, 1964) from fish hosts accumulated some heavy metals to a greater extent than the water and some fish tissues, but less than the sediment. In three (Pb, Zn and Mn) of the five elements measured, cestodes accumulated the highest metal concentrations, and in remaining two (Cu and Cd), the second highest metal accumulation was recorded in the cestodes when compared to host tissues. Therefore, the present study indicated that Senga parva accumulated metals and might have potential as a bioindicator of heavy-metal pollution.

The present study was conducted to know the fish health management practices and adaptations prevailing in the dominant fish producing state of India. Primary data was collected from the small and marginal fish farmers of West Bengal by personal interview. Literature review was also done to collect secondary information. The study reveals that though West Bengal is a dominant fish producing state of India, yet the farmers are lacking scientific knowledge on fish health management and overall aquaculture practices. Scientific intervention is a felt need to enhance their knowledge and to formulate effective management strategies for aquaculture. 1. Introduction Aquaculture is the fastest-growing food production sector. India is the second largest inland fish producer in the world. West Bengal is one of the leading producers of freshwater fish and the largest producer of fish seeds in the country, contributing 30% of the total fish production and 62% of the total fish seed production in the country. Total fish production in the state has increased from 14.72 lakh tonnes in 2011-2012 to 16.17 lakh tonnes in the year 2014-2015 and fish seed production has increased from 13,846 million in 2011-2012 to 17,521 million in 2015-2016 (Handbook of fisheries statistics, 2016) [1]. In spite of the tremendous potential production, fishery sector has been suffering from outbreak of several diseases. Fish farmers of West Bengal have been experiencing about 26% production loss due to diseases and poor management in freshwater aquaculture sector. The aquaculture sector in India in general and West Bengal in particular is still deprived of the developments in fish health and disease management practices. The traditional practices by the fish farmers in effective health management is quite appreciating. The aim of the present review study is to highlight the age old practices and adaptations by the fish farmers of West Bengal to maintain fish health and maximise the production. The information will not only provide an account of the present scenario of fish health management by Bengal fish farmers but also give an account about the same in India. The present study is based on literature searches and analysis of secondary and primary data gathered through personal contacts with experts and the experiences gained by the authors during interaction with aquaculturists as a part of extension service.

This study evaluates the hematological response of rainbow trout fingerlings to crowding stress induced by high
stocking densities, during a 33 days period. A number of 254 rainbow trout, with an average weight of 29.51 ± 1.32
g, were divided into four rearing units in order to create different stocking densities: in DS1-2.64 kg/m3, DS2-5.16
kg/m3, DS3-7.12 kg/m3 and in DS4-9.42 kg/m3. To determine the leukograma and also the absolute number of
leukocytes, blood samples were collected after the experimental trial and used immediately to make smears.
Physiological stress induced by maintenance under different stocking densities is reflected by rainbow trout
leukograma. We can notice a decrease of absolute number of leukocytes, with direct implication of stocking density
level, from 69.79±10.22 (x103cel./mm3) in DS1 to 46.34±9.83(x103cel./mm3) in DS4. In this experiment, the immune (defense) system has been influenced by stocking density, the general reduction of leukocytes number being a
characteristic response to stressful conditions.

Abstract. Hematological indices are important parameters for the evaluation of fish physiological status.  The purpose of this experiment was to evaluate how level of the stocking density influence the blood physiology of of juvenile rainbow trout  Oncorhynchus mykiss) reared in a recirculating system. The experiment was conducted over a period of 33 days. A number of 254 rainbow trout with an average weight of 29.51 ± 1.32 g were divided into four rearing units in order to create different stocking densities: in B1-2.64 kg/m3, with an average weight of 31.68 g/ex, B2 – 5.16 kg/m3 with an average weight of 30.39 g/ex, B3 – 7.12 kg/m3 with an average weight of 28.52 g/ex and B4- 9.42 kg/m3 with an average weight of 27.46 g. The sampling of O. mykiss blood from the four variants before and after the
experimental trial allowed determination of hematological indices. Red blood cell counts (RBCc), haematocrit values (Ht), haemoglobin concentration (Hb), mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH) and mean corpuscular haemoglobin concentration (MCHC) were
measured and analyzed, with routine methods used in fish hematology (Blaxhall & Daisley 1973; Svobodova 2001). Some hematological indicators (Hb, MCV, MCH) had been influenced by the stocking density. The results of our research provide a contribution to the knowledge of the hematological parameters of the rainbow trout reared in different level of stocking densities, under the recirculating systems condition.

Vibrio vulnificus, a zoonotic bacterial pathogen was isolated for the first time from kidneys of black scorpionfish Scorpaena porcus collected from the south Mediterranean basin (western coast of Tripoli, Libya) during the early summer of 2013. Fish exhibited typical signs of Vibriosis with furuncle like lesions, skin hemorrhages, fin rot and congested spleen. The abdominal cavity, liver, intestinal wall, and gonads were suffering from mild larval nematode infection. Interestingly, a huge portion of the kidney tissue was replaced with the anisakids nematode Anisakis pegreffi. This is considered the first report ofV. vulnificus / A. pegreffi in the Mediterranean black scorpionfish. The identities of the retrieved V. vulnificus isolates were confirmed using morpho-chemical and molecular tools. The research lead us to conclude that the deteriorated nature of the sewage polluted seawater at the western coast of Tripoli could have played a detrimental role in facilitating the invasion wi...

Background: Persistent mortalities were observed in rainbow trout (Oncorhynchus mykiss) propagation farms around of Hamedan Province in western of Iran in September 2009. Affected fish, with size of 100-150 g., showed lethargy, spiral swimming and had dark color, hemorrhages at base fins and vent, anal prolapse, reddening of maxilla and mandibular areas, palate, gill operculum and eyes. Objective: The aim of this study was to control and prevent for eliminating the adverse environmental factors and excessive stresses to reduce the ERMD occurrence. Methods: Environmental parameters measuring revealed low water quality i.e.; pH = 5, high temperature (18-20 o28 C), excess ammonia (NH3 = 0.05 mg/L), dissolved oxygen (O2 = 4-5 mg/L), marginal carbon dioxide (CO2 = 8 mg/L) and H2S gas bubbling. The fish were also subjected to low quality feed, overcrowding, handling stress, and high aquatic plant growth. Twenty five bacteriological samples were collected from the lower intestine, posterior kidney of moribund fish. Samples were cultured on TSB media and Yersinia selective agar. Results: Results revealed the presence of Gram-negative and motile rods which had the expected biochemical characteristics. So the isolated bacterium was confirmed to be Yersinia ruckeri which had a positive agglutination with rabbit anti-K ruckeri serum. Conclusion: For the antibiotic sensitivity test, combination of Sulfamerazine and Oxytetracycline was recommended. Recommendation protocol was issued as control and prevention measures to eliminate the adverse environmental factors and excessive stresses to reduce the disease occurrence.

Vibrio vulnificus, a zoonotic bacterial pathogen was isolated for the first time from kidneys of black scorpionfish Scorpaena porcus collected from the south Mediterranean basin (western coast of Tripoli, Libya) during the early summer of 2013. Fish exhibited typical signs of Vibriosis with furuncle like lesions, skin hemorrhages, fin rot and congested spleen. The abdominal cavity, liver, intestinal wall, and gonads were suffering from mild larval nematode infection. Interestingly, a huge portion of the kidney tissue was replaced with the anisakids nematode Anisakis pegreffi. This is considered the first report ofV. vulnificus / A. pegreffi in the Mediterranean black scorpionfish. The identities of the retrieved V. vulnificus isolates were confirmed using morpho-chemical and molecular tools. The research lead us to conclude that the deteriorated nature of the sewage polluted seawater at the western coast of Tripoli could have played a detrimental role in facilitating the invasion wi...

The study assessed the level of awareness of farmers on the dangers associated with the use of antimicrobial agents in fish hatcheries. Thirty-six fish hatcheries farmers were randomly selected for the survey using structured questionnaire. The questionnaire was used to gather information on the socio-demographic characteristics of farmers, pattern of application of antimicrobial agents and the level of awareness of farmers on dangers of use of antimicrobial agents. Descriptive statistics was used to analyze the results. The result showed that both males and females were involved in fish hatchery practices and all the farmers had one form of education or the other. Antimicrobial agents were administered by 85.71% of the farmers themselves without the supervision of an authorized personnel with 64% applying them prophylactically. The mode of application of antimicrobial agents is through water, in-feed application, and injection. About 42% gave no response on whether they think indiscriminate use of antimicrobials in fish hatcheries is dangerous while 38.71% believe it is dangerous. This indicates that the awareness level of most of the farmers is low. Hence, there is need for adequate sensitization of farmers on the dangers associated with the use of antimicrobial agents in fish health management.

The aim of this study was to test the effectiveness of a probiotic Bacillus for the prevention of motile aeromonad septicemia (MAS) disease caused by Aeromonas hydrophila in African catfish (Clarias gariepinus). The study consisted of the inhibition testing of A. hydrophila by Bacillus (in vitro) and the application of probiotic in African catfish (in vivo). The in vivo test, consisted of five treatments such as the addition of probiotic Bacillus P4I1 Rif R , Bacillus P4I2 Rif R , Bacillus P4I1 Rif R + Bacillus P4I2 Rif R (Kom), positive control (K+; only added with A. hydrophila) and negative control (K-; without probiotic nor A. hydrophila addition). African catfish (13.35±2.80 g) was maintained in 15 aquariums (40 L in volume) with 30 fishes each for 30 days. Probiotic bacteria was applied in water once a day, whereas pathogenic bacteria A. hydrophila Rif R (10 3 cfu/mL) were added once in earlier treatment (except for the negative control). The result showed that the optimal concentration of Bacillus to inhibit A. hydrophila on in vitro test was 10 4 cfu/mL. In vivo test showed that the addition of probiotic in media of cultivation could reduce the number of A. hydrophila, improve immune response, and also increase the survival of African catfish compared to positive control. Application of probiotic P4I1 Rif R showed the highest survival (92.23%) of all treatments. ABSTRAK Penelitian ini bertujuan untuk menguji efektivitas probiotik Bacillus dalam pencegahan penyakit motile aeromonad septicaemia (MAS) yang disebabkan oleh Aeromonas hydrophila pada ikan lele dumbo (Clarias gariepinus). Penelitian terdiri atas pengujian penghambatan bakteri probiotik Bacillus terhadap A. hydrophila secara in vitro, dilanjutkan dengan aplikasi pada budidaya ikan lele dumbo (in vivo). Pada uji in vivo, penelitian terdiri atas lima perlakuan yaitu budidaya ikan lele dumbo dengan penambahan probiotik Bacillus P4I1 Rif R , Bacillus P4I2 Rif R , kombinasi probiotik Bacillus P4I1 Rif R + Bacillus P4I2 Rif R (Kom), kontrol positif (K+; hanya ditambahkan A. hydrophila) dan kontrol negatif (K-; tanpa pemberian probiotik dan A. hydrophila). Ikan lele dumbo (13,35±2,80 g) dipelihara pada akuarium volume 40 L dengan kepadatan 30 ekor/akuarium selama 30 hari. Bakteri probiotik ditambahkan pada media pemeliharaan ikan setiap hari, sedangkan bakteri patogen A. hydrophila Rif R (10 3 cfu/ mL) diberikan sekali pada awal pemeliharaan (kecuali pada kontrol negatif). Hasil penelitian menunjukkan bahwa konsentrasi terbaik pada penghambatan in vitro adalah dengan penambahan Bacillus 10 4 cfu/mL. Hasil uji in vivo menunjukkan perlakuan penambahan probiotik pada media budidaya efektif dapat menekan jumlah bakteri A. hydrophila, memperbaiki respons imun, dan meningkatkan kelangsungan hidup ikan lele dumbo dibanding kontrol positif. Perlakuan probiotik P4I1 Rif R memberikan hasil terbaik dengan tingkat kelangsungan hidup tertinggi yaitu 92,23%.

Vibrio vulnificus, a zoonotic bacterial pathogen was isolated for the first time from kidneys of black scorpionfish Scorpaena porcus collected from the south Mediterranean basin (western coast of Tripoli, Libya) during the early summer of 2013. Fish exhibited typical signs of Vibriosis with furuncle like lesions, skin hemorrhages, fin rot and congested spleen. The abdominal cavity, liver, intestinal wall, and gonads were suffering from mild larval nematode infection. Interestingly, a huge portion of the kidney tissue was replaced with the anisakids nematode Anisakis pegreffi. This is considered the first report of V. vulnificus / A. pegreffi in the Mediterranean black scorpionfish. The identities of the retrieved V. vulnificus isolates were confirmed using morpho-chemical and molecular tools. The research lead us to conclude that the deteriorated nature of the sewage polluted seawater at the western coast of Tripoli could have played a detrimental role in facilitating the invasion w...

A study to compare the intensity and prevalence of parasites in the organs of pond cultured fish was carried out at the African Regional Aquaculture Centre, Aluu, Rivers State. A total of 85 Clarias gariepinus samples were examined from 3 earthen ponds. All Ponds had same water sources and were limed and screened. Fish were fed with processed feed at five percent biomass. For parasitological analysis, skin and gill scrapes were made and viewed while stomach and intestine from dissected fish samples were slit open and rinsed in search of helminthic worms. Fifty-one fish were infected giving a prevalence of 60% but only the external organs; gills and skin were parasitized. Gill infection had organ prevalence of 51% while skin yielded 80.4% prevalence. Mean intensity was higher in the gills (153), than in skin (29.1). The following parasites were identified; Chilodonella sp. (0.3%), Ichthyophthirius sp. (41.1%), and Trichodina sp. (55%), Icthyobodo sp., (1.0%) and Gyrodactylus sp. (2.4%). ANCOVA and Chi square analysis, nonetheless, showed no significant relationship between gill and skin infection. Skin infection is predicated upon the wider surface area available to fish parasites while they get attached to the gills as water flows through the operculum. The absence of internal parasites maybe due to pond preparation processes carried out before stocking, and the restriction of feeding to processed feeds. It is therefore recommended that fish farmers take into consideration adequate pond cultural activities and feed administration, with an aim to curtail the zoonotic threats posed by fish infections.

Twelve biochemical parameters were measured in serum blood samples from rainbow trout (Oncorhynchus mykiss) maintained under controlled conditions. Forty-five samples were taken every 3 months (T1–T4) over the course of one year to define baseline values. The effect of fish total weight (TW) was also evaluated. Principal component analysis showed a clear separation between T4 and T1, and T2 and T3, indicating an increase in certain biochemical parameters with weight. Linear regression analysis showed how TW significantly explained 11–67% of the variability observed for nine parameters out of 12. Pearson’s correlation matrix showed a significant positive correlation (p < 0.05) between TW and albumin, alkaline phosphatase, alanine-aminotransferase, creatinine, gamma-glutamyl transferase, magnesium, phosphorus and total protein. Furthermore, significant correlations (p < 0.05) between the majority of the biochemical parameters were found, indicating that growth can influence seve...

Vibrio vulnificus, a zoonotic bacterial pathogen was isolated for the first time from kidneys of black scorpionfish Scorpaena porcus collected from the south Mediterranean basin (western coast of Tripoli, Libya) during the early summer of 2013. Fish exhibited typical signs of Vibriosis with furuncle like lesions, skin hemorrhages, fin rot and congested spleen. The abdominal cavity, liver, intestinal wall, and gonads were suffering from mild larval nematode infection. Interestingly, a huge portion of the kidney tissue was replaced with the anisakids nematode Anisakis pegreffi. This is considered the first report of V. vulnificus / A. pegreffi in the Mediterranean black scorpionfish. The identities of the retrieved V. vulnificus isolates were confirmed using morpho-chemical and molecular tools. The research lead us to conclude that the deteriorated nature of the sewage polluted seawater at the western coast of Tripoli could have played a detrimental role in facilitating the invasion w...

Vibrio vulnificus, a zoonotic bacterial pathogen was isolated for the first time from kidneys of black scorpionfish Scorpaena porcus collected from the south Mediterranean basin (western coast of Tripoli, Libya) during the early summer of 2013. Fish exhibited typical signs of Vibriosis with furuncle like lesions, skin hemorrhages, fin rot and congested spleen. The abdominal cavity, liver, intestinal wall, and gonads were suffering from mild larval nematode infection. Interestingly, a huge portion of the kidney tissue was replaced with the anisakids nematode Anisakis pegreffi. This is considered the first report of V. vulnificus / A. pegreffi in the Mediterranean black scorpionfish. The identities of the retrieved V. vulnificus isolates were confirmed using morpho-chemical and molecular tools. The research lead us to conclude that the deteriorated nature of the sewage polluted seawater at the western coast of Tripoli could have played a detrimental role in facilitating the invasion w...