As Israelis consume more seafood, Mediterranean and Kinneret produce less
Can overfishing here and abroad be stopped in time to save the last undomesticated food?
While humans cultivate the other components of their diet, whether plants or animals, most fish and other edible maritime creatures are hunted in their natural environment. That’s why seafood is usually called “the last undomesticated food.” But probably not for long. According to a report published in 2011 by the International Program on the State of the Ocean, in the past 20 years the worldwide demand for fish has doubled, while their supply in nature has been cut in half.
To understand where this trend is leading, we must begin at the first stop: the wholesale market for sea fish in Israel, known as Delal (an Arabic word meaning public auction). There are two such markets in Israel − in Jaffa and at the Kishon Port in Haifa. The merchandise there is unloaded from trucks that have just arrived, full of fish that were loaded onto them from boats returning from a night of fishing.
Every morning at 5:30 the two markets fill up. Several dozen wholesale merchants gather around three stalls at each market and purchase fish at a public auction. The sales manager at each stall proudly presents the crates, announces the type of fish they contain and their weight, and collects a large number of bids. The highest is written on a piece of paper and set aside until the auction is over, when the winning bidder will purchase the crate’s contents.
While the fish merchants seem energetic and full of vitality, the fish are somewhat less so. The quantity, variety and size of Israeli salt water fish have been shrinking by the year. According to figures collected by the fisheries department of the Agriculture Ministry, in the past decade there has been a 40 percent decline in the local quantity of fish. Other figures, published in 2010 by the state comptroller in a comprehensive report on the fishing industry in Israel, indicate a decline of 80 percent. The two fish in the worst situation are grouper (lokus) and cod, with a decline of 75 percent since the early 1990s.
Uri Sharon, a veteran fishermen at Jaffa Port, does not need numerical data to realize that the situation is grave. For five years he hasn’t caught a cod or a yellowmouth barracuda. He confirms that the fish are also becoming smaller, a diagnosis that accords with the findings of a study by professors Ehud Spanier and Dor Edelist from the Institute for Maritime Studies at the University of Haifa. They discovered that 10 types of fish, of the 20 most common species on the Mediterranean coasts, have seen a significant reduction in size in the past two decades.
While there are fewer and fewer fish, there is an increasing demand for them. This is due not only to growing taste for Asian cuisine, or even the Peruvian ceviche that can be found today in every self-respecting restaurant in Israel. Due to the worldwide increase of the middle class, more people can afford to buy fish. In addition, of course, is a growing health consciousness that includes an awareness of the nutritional advantages of fish and preference for them over land animals.
“I see today how children eat fish in a restaurant, and don’t believe how far we have come,” says one fish merchant.
While in the past, in the diaspora, most Jews lived in cities far from the sea, many Israelis grew up near the coasts of the Mediterranean Sea, Lake Kinneret and the Gulf of Eilat, and it’s only natural that over the years they became accustomed to the culinary culture of coastal dwellers. The average Israeli consumes about 2,000 fish in his lifetime; in one year he eats about eight kilograms of fish, which add up to 75,000 tons of fish consumed annually in Israel.
The sushi bubble expanding before our eyes is not a phenomenon unique to Israel. Worldwide, 32 percent of fish species are suffering from overfishing. They are unable to produce enough offspring, which means that they are liable to become extinct within a decade. A similar danger threatens 60 percent of the remaining species. Ninety percent of large fish species, such as the blue-finned tuna or the cod, have disappeared almost entirely due to overfishing in the second half of the 20th century.
“If this trend continues to the middle of the present century, all of commercial fishing will collapse,” declared the United Nations in a special report published last year about the worldwide fishing industry.
The fishing industry has a tendency to describe a glorious past. Legend has it that 30 years ago, people would enter the waters of the Nahariya coast up to their waists, and catch lokus, mullet and other fish with their hands. Today you hardly see any fish there. Eilat fishermen like to tell about happy nights of fishing for tuna, which would arrive en masse at the Eilat coast in the 1980s. Until they stopped coming. In the past decade there has been no commercial fishing whatsoever in Eilat.
There is a fish problem in the Kinneret too. In 2006 there was a total catch of 150 tons of tilapia, while a year later the amount declined to 51 tons. That is the smallest catch on record in the past 40 years. The fish situation in the Kinneret is so bad that every year the Agriculture Ministry populates the lake with about 2.5 million tilapia, 190,000 silver carp and 850,000 mullets. The comptroller’s report mentions, among other things, the following sad and strange story: In 2008, 100,000 mullets were brought to the Kinneret. The fish arrived shortly before the start of Shabbat, the workers didn’t have time to put them into the lake and they were forgotten in the closed containers. They all died of suffocation.
In 2009 a joint team of the environment and agriculture ministries recommended a two-year hiatus in fishing in the Kinneret and in the rivers that feed it, to enable the fish population to recover. Over 11 million shekels were budgeted for the purpose, but the plan that was supposed to get underway in March 2010 was repeatedly postponed for various reasons. Meanwhile fishing in the Kinneret continues, in spite of the pathetic catch.
In the Mediterranean the situation is somewhat better, but there too the fish are swimming to extinction at a distressing rate. Zeno Meyer, a fish merchant from Ashdod who also owns a fishing boat, says that in the past decade he has noticed a significant decline in the fish supply. “My seven workers go out to fish every day only so I’ll have a way to employ them. I don’t profit from most of the trips out to sea.”
Meyer blames the absence of a properly administered fishing economy, and notes that in a well-run country “all the Israeli fishermen would go to prison. We’re catching finger-sized fish, fish that nobody would dream of catching anywhere else in the world.”
Meyer is referring to the reduction of the size of the holes in the nets. In the past, he says, the fisherman used to cast nets with holes 25 millimeters in diameter, so that the small fish wouldn’t be caught in the net and would be able to grow and spawn a new generation of offspring. But as the fish supply dwindled, the diameter of the holes was reduced. Today the holes are only 18 mm. in diameter. They catch almost anything they encounter and are quickly leading to the exacerbation of the situation.
When asked why he doesn’t start using a net with wider holes, Meyer explains: “In order for me to use a different net, all the fishermen have to use a different net. If I do it alone, I’ll catch a tenth of what the others catch. I can’t afford to do that.”
Not everyone agrees about the reasons for the declining fish supply. The Agriculture Ministry attributes it to the serious competition from imported fish and the inability to monitor crime that is related to fishing. The state comptroller, the fishermen and the merchants blame the decline on defective management of the fishing industry within the Agriculture Ministry. The state comptroller’s report noted that the fisheries department doesn’t limit fishing, doesn’t regulate the diameter of the holes in the nets and doesn’t enforce the restrictions that do exist.
The fishing regulations determine the minimum diameter permitted in the Mediterranean: For trawlers, 24 mm. between knots; for standing nets that are used for most coastal fishing, 14 mm. between knots; and for traps, 30 mm. According to the fisheries department, the Kinneret fishermen seem to be more law-abiding than their colleagues in the Mediterranean: “Legal fishing nets have a 80-mm. holes. For years the Kinneret fishermen used 62-mm. nets for mullets. The director of the fisheries department decided to implement a gradual transition to nets with regulation-size holes. Starting in 2009, under the instructions of the legal adviser of the Ministry of Agriculture and Rural Development, the fisheries department enforces the regulation based on measurement of the size of the fish that are caught, and the enforcement data indicate that most of the fishermen refrain from fishing with illegal nets.”
Letting the sea recover
“If we fish less, we’ll catch more,” they all say, but they don’t behave accordingly. The restriction on fishing can be enforced in two ways: either within a specific area, or over a specific time period. Or both. Surprisingly, it was actually President George W. Bush, not known as a committed environmentalist, who in January 2009, just before leaving the White House, declared the largest maritime nature reserve in the world: 505,757 square kilometers in the Pacific Ocean where fishing is prohibited. A year later, Britain established a maritime nature reserve surrounding the Chagos archipelago in the Indian Ocean, with an area of 554,000 square kilometers.
Israel has six maritime nature reserves, all of them near the coast, in the shallow area called the “continental shelf.” Environmental organizations and the Israel Nature and Parks Authority are trying to promote the declaration of additional maritime nature reserves, mainly in deep-sea areas. They claim that only declaring 20 percent of Israel’s sovereign maritime territory as a nature reserve would rescue the sea and the fish.
Prof. Ariel Diamant, director of the National Center for Mariculture of the Oceanographic and Limnological Research Institute, says: “Maritime nature reserves are a positive thing and we’ll be very happy if they’re declared, but we shouldn’t have the illusion that they represent a comprehensive solution to the problem.”
He is joined by Dr. Eli Galanti of the department of geophysics and planetary sciences at Tel Aviv University, who transfers the discussion to the issue of time: “These are a few isolated areas, which won’t help to rehabilitate the sea. The real preservation has to be done by means of a cessation of fishing for periods of time that will enable to sea to recover.” In Italy, for example, fishing is prohibited for 45 days during the fishes’ spawning season; in Cyprus for 150 days; in Senegal, Egypt and Turkey, for 60 days. In Israel fishing is permitted all year round. Why? Because of a perpetual argument between the fishermen and the Agriculture Ministry. The former agree in theory to stop the fishing for three months, but on condition that their salaries are paid by the ministry during this period, “as it common in other places in the world,” they note. The Agriculture Ministry has expressed a willingness in principle for such an arrangement, but on condition that the account books of the entire industry be put in order; at present the situation is quite chaotic.
One winter day, while the sun was slowly climbing above the houses leading to the Jaffa port, a lively conversation began among several fishermen who had just returned from the sea and loaded their merchandise onto the trucks that would transport it to the Delal. All the fisherman were unanimous in their opinion that fishing must be stopped during the three months when the fish are spawning (one female fish can lay about 200,000 eggs. Catching a few pregnant females causes a significant reduction in the number of fish).
The argument was about the size of the payment they expect to receive for that purpose from the Agriculture Ministry. One of the fishermen, a very tough character, suddenly scolded his friends: “What are you all chattering about? The way the fish situation looks at the moment, we’ll all agree to stop fishing even if they don’t pay us a shekel.” Silence reigned. It was interrupted only by the sound of a crate of pandora fish falling to the ground.
The study by Spanier and Edelist concludes with a list of recommendations for the fishing industry and with the following statement: “Today there is significant estrangement and lack of trust between the fishermen on the one hand and the Agriculture Ministry’s fisheries department and its employees on the other, which undermines the chances of the two sides of conducting a dialogue or a proper fishing economy.” One of their recommendations to the Agriculture Ministry is “listening attentively to the fishermen’s complaints and practical handling of them ... Creating trust in the system may sound like a distant dream at the moment, but the present study has taught us about the possibility of creating such trust with relative ease.”
Tsafrir Gidron, the maritime coordinator of Zalul Environmental Association of Israel, insists that trust in the system is still a distant dream. “It doesn’t look as though the fisheries department is planning any initiative or regulation to save the sea,” he says. Even if there is such regulation, he adds, its chances of success are not certain.
“The fisheries department deals only with commercial fishing, without any environmental orientation; that’s why it’s not certain that stepping on the brakes and stopping the unrestrained fishing will bring about rehabilitation of the sea.”
Zalul, which has to its credit one of the greatest environmental successes in Israel’s history, the removal of the fish cages from the Gulf of Eilat, has been trying in the past year to promote a single Mediterranean authority that would combine all aspects of the maritime system, including the environmental issue.
The tragedy of trawling
There are many fishing methods, but there is no question that trawling is the most roundly criticized. Here, a boat or boats drag a net through the water for three or four hours, sweeping up everything caught in it. “On the surface you see a fishing boat with seagulls above it, everything looks serene and pastoral, but on the sea bottom tremendous damage is being done − a massive ‘shaving’ of the sea floor,” says Galanti.
The section of sea floor that has been shaven by a trawler requires a year to recover and restore life to itself. Trawling could be compared to several bulldozers simultaneously attacking one dunam of forest. United Nations data indicate that in 2010 trawling led to the destruction of 8 percent of the world’s fishing areas.
Uri Sharon operates a trawler. For years he fished with a net cast from a small boat not far from the beach, but as the decades passed the number of fish declined, as did his livelihood. Sharon has six children and a great love for the sea, which is why he decided to switch to trawling. In 1997 he purchased a trawler together with a partner, and since then he has been using this method.
Sharon’s boat is one of 22 active trawlers in Israel. It is surprising to discover that the Agriculture Ministry permits the operation of 30 boats, and that the eight taken out of service ceased to operate only because of the small number of fish. But even in their absence, trawling supplies 55 percent of the maritime catch in Israel and is carried out in an area of over 3,000 square kilometers. In contrast, in other countries along the Mediterranean coast, trawling supplies only 15 percent of the fish.
Another tragic element of trawling is the custom of tossing back an average of about half the fish caught in the nets. These fish are dead. They are thrown back for two reasons: either because they are too small or because they are not commercial species. A study by Prof. Bella Galil of the Oceanographic and Limnological Research Institute and Prof. Menachem Goren of Tel Aviv University shed light on the first reason. The two found that the average size of a fish caught in Israel is one-fifth the size of the same fish caught in Turkey. Clearly the main reason for that is the supervised fishing economy in Turkey, which enables the fish there to grow and multiply.
Jonathan Borowitz, chef and owner of the Cafe 48 restaurant, discusses the second reason: “The commercial value of a fish is a relative matter and depends on time periods and trends. Once they used to throw shrimps, calamari and sardines back into the sea, because they weren’t commercially valuable. Today they’re considered the catch of the day. At the beginning of the month, for example, the price of shrimps soared to NIS 200 per kilo in the Israeli markets.”
Down on the farm
At this point it is already clear that our seacoasts are unable to meet the demand for fish in Israel. So where do all the fish come from? Two thirds are imported, and of the local third, only 14 percent come from maritime fishing, while the other 86 percent originate in local aquaculture. Like many other culinary innovations, aquaculture also began in Japan. But Israel is considered one of the pioneers in the field.
There have been fish ponds here since 1938. In the 1970s there was a small revolution in the field, when Israeli growers succeeded in raising their first non-local wild fish − the sea bream, or denis. The researchers of the Oceanographic and Limnological Research Institute are responsible for domesticating it. After 20 years of research on its biology, fertilization methods and feeding patterns, it was transferred for commercial production to fish cages in the Gulf of Eilat. At the height of production, Ardag Red Sea Mariculture, which operated the cages owned by five kibbutzim in the Arava, succeeded in producing 3,000 tons of denis annually. Everyone knows how this success ended. But not many people know that Ardag didn’t stop producing denis, it simply transferred to the Mediterranean.
In 2008, with its new name Dag Hayam, it joined the Israeli company Subflex, which invents and develops equipment for aquaculture, and Tzemah, which manufactures fish food, to operate the largest fish farm in the world for growing fish in the open sea. About 1,000 tons of denis are raised in 16 cages attached to one another, opposite the Ashdod coast.
On one of the rare sunny days this winter, Dag Hayam and Subflex hosted a delegation of several leaders from the Caribbean islands, who were on a tour of the Mediterranean to check out the possibility of purchasing the equipment and learning the technique. On a cruise ship leased for the purpose, representatives of the Israeli companies sailed with their guests from Ashdod Port to the site of the cages out at sea, a trip of about 40 minutes. The timing was perfect: Several men were just then pouring Tzemah food pellets into the cages. From above the surface of the water the cages look like a line of huge round containers. A video clip screened afterward on the ship shows what happens inside them: Tens of thousands of fish swim in circles.
Dudi Gada, the fish farm manager, and Josef Melchner, the marine products director of Subflex, explain happily that “this time, as opposed to the Gulf of Eilat, the green organizations are supporting us. We developed the system together with the Industry, Trade and Labor Ministry and the chief scientist, and we even brought in the green organizations. The strong currents in the area scatter the waste over a large area and the sea absorbs them efficiently.”
The strong currents contribute to scattering the waste, but they also make it very difficult to raise the fish. When the sea is stormy there’s a danger that the system will be destroyed. The Subflex patent provides a solution − a mechanism that immerses the cages during a storm. For 60 days a year the cages sit on the sea floor until things calm down. This activity is another source of pride for the operators of the farm: During those days it’s impossible to feed the fish, which saves 60 days of feeding and tons of expensive food pellets. Most of the fish survive this starvation regimen, and when they mature they are removed from the cages, subjected to an attack of cold in order to maintain freshness and are sold all over the country.
Industrialization at the expense of taste
In addition to denis, other types of fish are bred commercially in Israel. Two years is the average time it takes to raise a fish, from the day it hatches until it is removed from the water. Aquaculture in Israel yields a total of slightly less than 20,000 tons annually. The turnover of the industry is estimated at NIS 540 million, and it employs 500 people directly and about another 1,500 indirectly (in logistics, packing houses, merchants, and so on). There are 38 pond farms in Israel (the cages of denis in the Mediterranean are not included in this figure). An average fish farm operates about 20 adjoining ponds.
Yossi Yaish, secretary general of the Israel Fish Breeders Association, says growers’ profits total only 8 percent, because of the high accompanying costs. In addition to the local production, there are imports from all over the world − for example the 11,000 domesticated tilapia (about 4,000 tons) imported to Israel annually.
Aquaculture has several drawbacks. One of them is mentioned by restaurateur Borowitz: “I’ll never prepare ceviche from farm fish. It’s true that some of them grow in the sea and are considered salt-water fish, but in terms of taste it’s definitely not the genuine article. During one of my visits to the Sinai coast I ate wild denis, which the owner of the shack had caught with his fishing rod that day. One can immediately see that it has teeth and solid white meat, it has experienced something during its life − it pursued other fish, was pursued by them. It was a rich and tasty fish.
“The denis raised in cages, on the other hand, are fish that are fed with extraterritorial food and live in such crowded conditions that they can’t move. They are the product of an industrial system whose final objective is to create protein. This industrialization comes at the expense of taste, and often at the expense of the environment as well.”
Borowitz, who received his culinary training in New York and is familiar with the international food scene, says that the last word in fish restaurants worldwide is menus that spell out the fish’s country of origin and the way it was raised and caught; this is done to develop consumer awareness.
“On the one hand, aquaculture enables greater control of the resource, but on the other hand it creates very great pressures on the environment,” says Gidron of Zalul, describing the environmental drawback. Most of the rivers in Israel are polluted, and one cause is the sewage from fish ponds. That problem is supposed to be solved by the reform in the fish pond industry, which is to be implemented in the coming months. Sewage water will not be allowed to flow for nine months a year, but only for three months, and only after the water undergoes purification. Recycling ponds will be built for the sewage water, and settling ponds for the organic material that emerges from the water.
The Agriculture Ministry will invest in equipment to increase the yield of fish per area unit. The fish will be marketed in the framework of a joint council. Decisions on industry planning will be made in that same council.
The cost of the reform is NIS 115 million, and its purpose is to solve two problems: drawing water from the rivers to fill the ponds, and letting the polluted waste from the ponds flow back into the rivers. This reform, and to a great extent the entire industry, lack concern for the welfare of the fish.
Industrially raised fish live in conditions 17,000 times more crowded than those of fish in nature. In order to produce small fish to populate the ponds, the females undergo various treatments, including a cruel “squeezing” of the eggs from their bodies. When the people from Dag Hayam are asked about the welfare of the fish, they give the interviewer a strange look. For them it’s a bizarre question, and the answer is also bizarre: “They get fat, which means that things are good for them.”
Yaish, who to a great extent reflects the spirit of the Fish Breeders Association, has a similar answer: “The fish receive good conditions: water, oxygen and food.”
Among the many people interviewed for this article, Galanti is the only one who took the question seriously. “Fish in fish cages don’t fulfill their fish potential in any way,” he said. “They aren’t supposed to swim in circles, to live alongside so many other fish and to be fed such quantities of food. As in any commercial raising of animals, the motivating criteria in raising fish is minimum investment and maximum production, which always comes at the expense of the animals’ welfare.
“There’s a tendency to differentiate fish from other animals,” notes Galanti, enumerating several reasons: “First of all, because they live in the sea, a mysterious medium that we don’t know well. They also lack vocal cords, feathers or fur − characteristics that make us feel a certain emotional closeness to other animals. Despite that, many studies have shown that these are highly developed creatures, that live within sophisticated social systems and have a proven ability to feel emotions such as fear and pain.”
Fish have another trait that is fascinating in human terms. They eat meat. This is the only carnivore, with very rare exceptions, that human beings eat. Cows, pigs, sheep, goats, poultry and even somewhat more exotic animals in the meat industry, such as horses, are vegetarians. Fish are not. This fact has several far-reaching implications. First of all, it means that in order to raise fish for food you have to feed them with fish or other sea creatures, among other things. That leads to the equation familiar to any beginning fish breeder: Two kilograms of other fish are needed in order to produce one kilogram of the desired fish.
These other fish, which become the food pellets of the commercially bred fish, are usually caught in the sea.
That means that the existence of aquaculture does not necessarily reduce the fishing pressure at sea. From an environmental-global perspective it’s a disturbing dilemma. From a human-commercial perspective it raises the production cost and creates a serious financial problem. The primary means of reducing this financial burden is to create food pellets composed mainly of vegetable protein, usually soya or corn. As a result, the meat of the fish that consume the pellets is less tasty, as Borowitz described, and less nourishing. The most familiar example of food supplements for fish is beta-carotene, which is produced from carrots and is given to salmon raised in captivity, in order to give them the salmon’s natural pink color.
The fishes’ source of food also has halakhic implications (relating to Jewish law). It’s possible that denis or tilapia, or any other kosher fish that is pulled out of the water, dined on shrimps, octopus or some other non-kosher invertebrate. That does not violate the kashrut situation of these fish, but in order to receive a kashrut certificate there is still a need for a kashrut supervisor in every fish warehouse. That’s why next month, Israel’s largest importer of fish, Tiv Taam, will open a subsidiary to be called Snapir Hayam, which will import kosher fish.
Tiv Taam opened its non-kosher importing business six years ago, with great success. While the Delal supplies about 200 kg. of fish daily, the vehicles exiting the Tiv Taam warehouses distribute about 800 kg. of fish per day all over the country. The sources are varied: Holland, Egypt, Norway, Senegal, Sri Lanka, France, Turkey and others − as is the variety of fish, which all come chilled (as opposed to frozen, which is considered inferior). In addition to the chilled fish, there are mussels, lobsters, crabs, clams and oysters, which arrive alive. All the merchandise is sold from four to seven days after it has been removed from the sea, which requires a swift and complex logistical system. Another financial challenge facing fish importers is an import levy ranging from NIS 8.5 to NIS 11 per kg., depending on the type of fish.
“Fish is a cruel product,” says Moshe Fenster, whom everyone calls “Musi,” from the fish store at the Carmel Market in Tel Aviv.” If you haven’t sold it on the first day, it will sell you on the fourth day.” Regulations in Israel give the fish only a five-day shelf life. An extended visit to Musi’s store demonstrates that fish buyers represent a wide array of social classes and culinary knowledge, from private consumers without the faintest understanding of fish, through foreign workers from the Philippines and Thailand, to young chefs who leading the trend of fish and seafood that is common in restaurants today.
Musi began running the store 26 years ago, when his father, Yehoshua, retired. A large black-and-white picture hangs on the wall of the store, in which Yehoshua Fenster is seen with crates bursting with carp at his feet. Although the quantity of fish has declined today, the variety of fish and the types of dishes prepared from them is steadily increasing. All that leads Musi to express a profound concern for the fish situation. “Our greed is killing the sea,” he says, predicting that in the end the soaring costs of fuel “will rescue our sea from ourselves.”
Fish in numbers
• Annual fish consumption per person worldwide is 17.2 kg.; in Israel it is 7.7 kg.
• The UN report on food production for 2011 said fish production should be increased by 100 percent by 2050 to meet demand
• The worldwide catch is three times what the sea is capable of reproducing
• About 20 million fishing boats are operating worldwide
• The fishing industry receives annual subsidies totaling $27 billion
• 64 percent of the total area of seas and oceans are not under the sovereignty of any country
• The products of the illegal fishing industry (no permits or tax payments) are estimated at 11 million to 16 million tons of fish annually, about one-fifth of legally reported fish production
• In 1990 the aquaculture industry produced 1 million tons of fish; in 2008 it produced 52.5 million tons
• Since 1975 aquaculture has grown faster than any other food-production industry, at a rate of 9 percent annually
• Industry turnover is $78 billion annually
• About 45 percent of the production of fish and fish oil is used as feed for pigs, poultry and fish
• In 1948 the consumption of fish produced by aquaculture was 7.7 percent of all fish consumption; today it is 40 percent
• China exports 61 percent of international aquaculture products
• Demand for fish in Israel: 75,000 tons annually
• Imports of fish to Israel: 60-65 percent of consumption
• Salt-water fish (catch of the Israeli fishing industry): 2,447 tons (14 percent of local production)
• Aquaculture in Israel: 19,186 tons (86 percent)
• Area of fish ponds in Israel: 25,000 dunams
• The leading fish in Israeli aquaculture: denis, followed by tilapia