Meagre (Argyrosomus regius), also called croaker, has been highly valued as a consumption fish since ancient times. The catch volume from the fishery cannot satisfy demand. Production of the species in aquaculture began in France and Italy at the end of the 1990s and in the meantime nearly 20,000 tonnes are supplied annually. Meagre is still considered a niche product but its potential is by no means exhausted yet.
It would be lying to describe meagre as a particularly striking or attractive fish. Its body shape with its two dorsal fins is perch-like, its sides and belly are pale to silvery white, its back and fins brownish or grey-black. The only spot of colour is to be found on the inside of its mouth cavity which in live fishes has a yellow or orange shimmer. What makes this fish so popular is its firm meat that renders it suitable for frying, baking or grilling but also for steaming, smoking or even marinating raw. It has a strong aroma and does not spoil easily because due to its moderate fat content it is less susceptible to oxidation.
The meagre is often seen as a typical Mediterranean fish species. With the exception of the south eastern region, where it is relatively rare, it can be found almost all along the Mediterranean coast, but its geographic range is much greater. In the north it extends as far as the south coast of Ireland and the North Sea (individual fishes sometimes even get into the Norwegian fjords), and the southern boundary is said to be at about 6° latitude in the Gulf of Guinea. It has even been known to have swum into the Red Sea through the Suez Canal. Although meagre can occasionally be found at depths of 200 or 300 metres they usually prefer shallower regions with depths of about 15 to 20 metres directly off the coast. There they like to be close to the bottom between stones and other structures that offer a hiding place and thus protection. Although the meagre is an oceanic marine species the fishes sometimes swim into brackish water, too, for example into tributaries of the Nile delta.
Outside of spawning time the fishes mostly live in smaller groups that can unite to form larger swarms near rocky cliffs or shipwrecks on the sea bottom. Other species are also attracted as if by magic to these habitats so that the meagre can find plenty of food there. In addition to the structure of their habitat and the availability of food, temperature is a particularly decisive factor for determining the location and behaviour of the fishes. Temperatures and their course trigger maturing processes and spawning times as well as influencing migration routes when the fishes are looking for feed. Meagre prefer temperatures of between 17 and 21°C, and tolerance limits are reached at 14 and 23°C. If temperatures are above or below these levels the fishes almost stop eating and become increasingly lethargic. Meagre are predatory fish and eat just about everything that they can overpower, but preferably smaller fishes such as sardines, silversides or young mullets (whose swarms they will often follow) but also shrimps that are swimming freely in the water. At the time of catching the fishes are mostly about 50 cm long but they have been caught at lengths of one and a half metres. The record for this species is said to be 2.3 metres and over 100 kg in weight. Males live to a maximum age of 15, females up to 20 years. Particularly large examples are mainly found off the coasts of West Africa.
Robust, undemanding and fast-growing
Every year in spring the mature fishes gather off certain coasts to swim together into shallow marine bays and estuaries to spawn. In the southern Mediterranean they spawn from April to July, further north usually somewhat later. Meagre use special muscles that are attached to their swim bladder to produce characteristic sounds ranging from a low-frequency hum to a muffled drumming that are even perceivable outside the water. These sounds are rather like that created when a person strokes their fingers over a tightly filled balloon. In the opinion of a lot of behaviour scientists the sounds are used for acoustic communication. The fact that the sounds are uttered more frequently and more intensely during spawning time is in line with this assumption.
In the Mediterranean meagre do not become mature until they are two or three years old. Their fertility is relatively high. First spawners produce nearly 200,000 eggs that measure about one millimetre in size. Females measuring just over one metre in length can even produce nearly one million eggs. Under normal temperature conditions that are equal to around 20°C during spawning time the larvae have eaten up all of the yolk sac four days after hatching and then begin active feeding. They initially remain close to the coasts and feed on the rich supply of plankton there but in autumn they swim into areas with water depths of 40 m for the winter where more consistent conditions prevail than in shallower waters. At this time, i.e. just a few months after hatching, the young fishes are often more than 3 cm in length and change from a pelagic to a bottom-dwelling existence which is characteristic of this fish species.
The fast growth of the fishes during the first months of their lives – something which is not unusual for nearly all the larger fish species – naturally constitutes a favourable precondition for aquaculture. Additional positive aspects include the facts that meagre is not very demanding, and even grows well at moderate temperatures of around 20°C, as well as that the fishes have a high market value, particularly larger ones weighing more than 2 kg. There is a disadvantage, however: the meagre is a predatory fish and as such requires protein-rich feed. Meagre farming is still a young branch of aquaculture: the fishes have been produced as a target species in aquaculture for only a few years. Up to 2007 annual production volume remained in the range of just a few hundred tonnes. Then it rose by 4,000 t per year in the years 2008 and 2009, reaching 15,000 t in 2010. Egypt, which has long been the biggest aquaculture nation in Africa, is the country that is behind this three-fold production increase. The FAO statistics name Egypt’s meagre production in 2010 at slightly more than 12,000 t.
Optimistic forecasts for aquaculture production
This is all the more surprising given the fact that very little information on the technology of hatching and farming meagre as developed in the south of France during the 1990s actually became public. At that time the French built up a stock of spawners and were the first to raise fry in a specialised hatchery. That was in 1996. Production was low at fi
rst but already in 1997 commercial aquaculture production started. What seemed very promising at first did not develop as hoped for, however, and the production level has even stagnated during recent years. Spain alone had a respectable production figure to report in the year 2012: 1,640 t, though even this was 43% lower than in 2011. Following the early successes, production in France dropped again to 400 t (2010) and production in Italy, where there is a good market for this fish, does not even reach 100 t (according to FAO statistics). In theory, meagre offers consumers and producers almost everything they could wish for. It tastes good, and slaughter yields are high, it is healthy, it has a high nutritional value with a low fat content, and its firm white meat can be prepared in almost any way. In practice, however, this branch of farming has not really got underway and remains rather sluggish, despite an observation made recently by M.C. Monfort in an FAO study (Studies and Reviews. General Fisheries Commission for the Mediterranean. No. 89. Rome, FAO. 2010. 28p.) that meagre was ”one of the best potential candidates for large scale farming in Europe”. So what is the reason for the fact that production has not really got off the ground?
Meagre are produced both in tanks on land and in floating net cages in the sea. The number of facilities in which this fish species is farmed is relatively low. It is often even only produced as a side-line of the regular programme in which mostly dorade and bass are farmed. Because demand for fry is still relatively low there are not many hatcheries that have specialised in meagre. There was allegedly only one company in the south of France in 2004 that offered meagre fry on a regular basis. In her FAO study Monfort named the number of young meagre that were sold from the hatcheries to European fish farms in 2008 at 8 to 10 million. According to her calculations that is sufficient to produce 14,000 to 18,000 fishes weighing 2 kg (under the assumption that overall mortality is equal to 10%). Although this result is not poor it is nevertheless too few to call mass production.
Farming meagre takes the same course as for other fishes in aquaculture. The fry are generally supplied at sizes of between 3 and 10 grams and are first put into small tanks or net cages for three months until they have reached a size of about 100 g. It is only after that that the actual grow-out phase begins, and the technology for this is very similar to that used when farming dorade and bass. In land-based facilities the meagre are mostly put into round and elongated concrete tanks whose walls are lined with plastic to prevent skin injuries. With stock densities of about 50 fishes per cubic metre the fishes reach weights of 1 to 1.2 kg within about two years. The target weight, however, is two to three kilograms since these fishes sell better. With volumes of 1,000 to 2,000 cubic metres the net cages for farming meagre in the sea are relatively small compared to salmon cages that offer 15,000 cubic metres capacity and more. Recently farmers have even begun keeping meagre in completely submerged cages that are 10 or 20 metres below the water surface. The living conditions in these cages are particularly good for meagre but they cost more and produce less fish because they are only stocked with 10 to 20 fishes per cubic metre.
Urgent need to expand sales markets
The feed required for producing meagre is typical of a large number of marine fish species. It contains 45 to 48% protein and 20 to 25% fat. The daily feed quantity (at water temperatures of over 18°C about 1-2% of fish biomass) is distributed in two or three portions spread over the day. In intensive farms the FCR is 1.6 to 1.7. Because meagre grow badly during the winter and the feed they consume is mainly stored as abdominal fat younger fishes are often taken out of the sea cages in late autumn when the water there becomes cooler and transferred to tanks on land until spring. Meagre are comparatively robust and not particularly susceptible to disease. In spite of this, care must be taken when handling the fishes for they soon lose scales through mechanical stress and are quite susceptible to eye injuries that can lead to blindness.
Apart from the necessary investment in farm installations and equipment it is feed and fry that constitute the biggest cost factor when farming meagre. The species is today still often produced as a side-line in dorade and bass farms to extend the product range. Market prices fluctuate with the seasons, supply volume and the size of the fishes between 5 to 7 EUR/kg for smaller fishes and 8 to 14 EUR/kg for fishes weighing over 2 kg. If the fishery lands large quantities of meagre the price can be even lower. Meagre is thus to be found in the medium price segment and so has to compete with other marine fishes such as haddock, hake or cod. If production volume rises the price for meagre would tend to fall further in the future.
This is certainly not likely to motivate commitment among potential investors, particularly since the market for meagre is still relatively small. The majority of fishes, both from the fishery and from aquaculture, are sold in Italy and southern France. Spain is also becoming more important. It would seem to be necessary to expand the markets if more meagre are to be produced in aquaculture. Interest in this fish is growing: at least it is now offered occasionally in a lot of European countries, mainly in superior restaurants and sushi bars. This is admittedly only one segment of the important sales channels for fish, but it is a start. After all, consumers have to get to know new fish species first, before they can like them.
Manfred Klinkhardt