Written by: Noor Fatima B.S student, Faculty of Agriculture Sciences and Technology, Bahauddin Zakariya University, Multan, Pakistan. Pakistan is blessed with many agriculture resources and Livestock is one of them. In Pakistan, the most important component of agriculture is livestock and constitutes 56.3 per ce...
Dr. Madiha Rehman
DVM, M.Phil (Veterinary Parasitology), Bahauddin Zakariya University, Multan, Pakistan
Pakistan’s Seafood Industry
Pakistan is enriched with agricultural land and a vast area covered with waters providing a diverse flora and fauna to harbour a large variety of land and marine beings. Fisheries is a sub-sector of agriculture and yet a major contributor to seafood fulfilling all the nutritional requirements of human beings and also of marine and land animals. This sector plays an important role in strengthening Nation’s economy and it also reduces the pressure exerted by high prices of mutton, beef and poultry. The fisheries sector is a source of livelihood for those living in coastal areas. Inland fisheries along with the marine system is a famous activity in the form of business enterprise. Seafood is the most widely consumed eating entity in the world. Among seafood, fish is the most nutritious commodity available for human consumption. Fish is consumed as a healthy food source and is an important food resource all over the world. It is an important source of protein and vitamin-D and many essential nutrients for human beings. Fish also plays a vital role in producing high-quality animal protein. Pakistan is well endowed with water resources, sharing three of the largest Sea Ports including Karachi port, Muhammad Bin Qasim port and Gwadar port, a diverse Marine and freshwater system and ocean coastline spread in Sindh and Balochistan provinces. The country is reasonably rich in marine and inland fishery resources and therefore significantly contributes to the fisheries sector. This sector has a lot of economic and social significance in the country. According to the Economic Survey of Pakistan 2018-2019, the share of the fisheries sector in agriculture value is 2.10% and National GDP accounts to 0.4%, producing 575 thousand metric tonnes of marine and inland fisheries (out of which 390000 metric tons from marine). A total of 130830 metric tons of fish and fish products was exported with export earnings of about 39246 million rupees. Overall fisheries sector grew by 0.79%.
Impact on Human health
Fish meat is low in fat percentage and contains 14-16% protein. An estimated one billion people rely on fish as their primary food source. It also contains a large quantity of long-chain omega-3 polyunsaturated fatty acids, selenium (Se) and mercury (Hg). Fish consumption has a beneficial effect on cardiovascular disease (CVD) risk, particularly, fatal coronary heart disease (CHD). Omega 3 fatty acids reduce the cancer risk by almost 30% especially cancer associated with colon, oesophagus, breast, ovary, and prostate. The metabolic product of protein from fish is Taurine which is important for the development of the brain and retinal tissue. It plays a vital role in the reproductive system and body functioning. Female that eat fish during pregnancy have reduced risk of delivering a premature baby. Fish oil reduces the risk of cardiovascular disease and improves blood vessel elasticity. Elderly people who consume fish once a week may have a low risk of developing dementia including Alzheimer’s disease. It is helpful for diabetes patients to manage their sugar levels. Fish-eating reduces the risk of Asthma, especially in children. Products produced by processed fish are fish glue, fish oil, fish emulsion, fish hydrolysate (groundfish), fish meal and fish sauces.
According to an estimate in 2015-2016, per-capita fish consumption in Pakistan is 2 kg, while in Sri Lanka it is 15.3 kg. On per capita terms, fish and fish-based food consumption grew from 9 kg in 1961 to 20.3 kg in 2016 in developed countries, with an average rate of about 1.5% increase per year. Fish consumption varies from country to country. The major reason for the low consumption in Pakistan is related to the fact that most of the produce is exported. Pakistan’s seafood exports have increased by 27.94% to 198420 tons fetching 451 million dollars during the fiscal year 2017-2018. Pakistan exports fish mainly to Hong Kong, Indonesia, Egypt, Middle East, UK, Thailand, South Korea, Bangladesh etc. China is the largest buyer of Pakistan’s fish and fish preparations. Pakistans’s fish and fish products exports capture 2.2 to 2.5 dollars per kilogram which are found to be lower in Pakistan’s average price of around 7 dollars per kg. Fish can be preserved by different methods like marinating, pickling and smoking and cooked by baking, frying, grilling, poaching and steaming.
Fish borne parasites
Parasitism in fishes is economically significant, hence their study and understanding are of prime importance. Decreased productivity, increased mortalities, reduction in growth rates, poor quality meat and immunosuppression in hosts are some of the widely studied parameters to be checked in the farming of fishes either for family consumption or to be sold as a business enterprise. From one aspect the parasites dwelling in fishes are related to health risks but from another view, this risk is far less important than the risk from hidden bacterial illness, which is present in almost all foods. Roundworms (nematodes) are the most prevailing parasites present in marine fishes. These nematodes are usually called herring worms or cod worms by local people. The presence of parasites in fishes is important from a zoonotic point of view because humans can acquire these parasites from these infected fishes. A variety of parasites naturally live inside or on the fishes. Their occurrence in fishes provides information about the population and ecological biodiversity. Both endoparasite as well as ectoparasite harbour these fishes. These parasites are present in large numbers either on the surface of the fish, within the gills, or both. When attached to gills, preferably living outside, cause respiratory problems and death will occasionally occur when additional environmental stresses are present in the aquatic system. Protozoal parasites are present only on the skin, fins and scales but not gills and these ectoparasites usually do not cause death, unless they are accompanied by a secondary bacterial infection. The external parasites include monogeneans, parasitic copepods, seawater leeches and larvae of gnathiid isopods. Fish are the intermediate hosts to four trematodes (including Clonorchis, Opisthorcis, Heterophis and Metagonimus species) and two nematodes (including Gnathosoma specie and Capillaria phillipinensis). Humans acquire these parasites by eating infected, raw or insufficiently cooked or poorly preserved fish meat.
Properly cooked fish has no concern about human health but eating raw fish or lightly preserved fish like sashimi and sushi can be sometimes fatal. An internal temperature of -20°C (-4°F) for 7 days is enough to kill the parasites. The home freezer doesn’t produce enough cold to kill parasites. In the traditional method of fish farming, the fishes live all or part of their lives in freshwater which is considered unsuitable probably due to the presence of parasites. Fishes can be categorized into either freshwater or saltwater fishes. Salmon and trout are anadromous, means they hatch in freshwater then head out to sea (salt water) and then return to freshwater again to reproduce.
In developed countries like the USA, the chances of parasitism by raw fish is rare. About 40 cases per year are recorded by fish borne parasites. These parasites are of three types; Anisakis (roundworm/nematode), Clonorchis Sinensis (trematode/fluke) and Diphylobothrium (cestode). Out of these nematodes and trematodes are most common while cestodes have been rarely reported in humans.
Anisakis is a zoonotic parasite having highest medical importance because of several allergic reactions and gastrointestinal symptoms. Allergic Reaction is caused by ingestion of seafood or breathing of vapours while preparing or cooking seafood. Another mode of transmission of the disease includes handling and eating of raw fish. These symptoms are prevalent in countries where it is common to eat raw or undercooked fish such as in countries in Asia, Eastern Europe, Africa and North and South America. In the last two decades, Anisakiasis has become a serious zoonotic disease with a dramatic increase in prevalence throughout the world. The highest prevalence of anisakiasis is found in North Asia and Western Europe. Parasitic infections can be simply avoided by boiling, burning and preserving fish in salt/vinegar and freezing overnight.
Diphylobothrium causes central irritability, skin numbness, tingling, increased heart rate, muscle weakness, gastrointestinal illness, anaemia, and vague abdominal discomfort.
Clonorchiosis causes skin and eye infection along with enlarged liver, jaundice, ulceration, cholangiocarcinoma, and gastrointestinal issues. According to an estimate 18 billion people worldwide are infected by Clonorchiosis. In heavy infections, chronic cholangitis may progress leading to atrophy of liver parenchyma and portal fibrosis. If the mass of flukes obstructs in the biliary tree then it causes Jaundice and cancer in Gall-bladder.
Measures to be taken:
- Proper cooking of fishes plays a vital role in controlling the disease.
- If cooking is scheduled, freeze the fish at -20 ℃. for a minimum of 7 days.
- Awareness among society can be created by conducting seminars and training programs.
- Provision of laboratory facilities for the identification of the causative agents (parasites).
- By educating the general public and societies about parasitic diseases.