The possibilities for processing the various food fish are just as varied as the characteristics, such as flavour, origin, and behaviour of these fish.
Here we offer information on our most important types of fish and seafood:
Mackerel are among the tuna-like species. A biological particularity of mackerel: They do not have a swim bladder. This makes them very mobile and helps them protect themselves. Thus they can evade their enemies, e.g. spiny dogfish, porbeagle, tuna or dolphins, at lightning speed, swim to greater depths or rapidly get to the surface from the deep sea.
Mackerel are schooling fish and mostly stay close to the surface.
During the winter idle period they do not feed. With the advent of spring they feed on plankton (laciniate conches, micro-crustaceans). After the spawning season in late spring and summer the nutritional requirements increase abruptly. Then in groups they go hunting for spawn of herring, sprat, cod, whiting, and rockfish. In this process they move with the schools of herring over great distances. Mackerel can grow to as long as 50 centimetres and can live for as long as 11 years.
Due to their torpedo-shaped body shape, mackerel are often referred to as the most elegant food fish. Mackerel are elongated and streamlined. Other identifying characteristics are the strongly forked tail fin, the brilliant blue-green colour and the transverse stripes on the back. After the mackerel dies the blue-green colour changes quickly to a pure blue to blue-black. The flanks shimmer with colours of mother of pearl, the belly side is white. The entire body is covered with firm, small scales. As with all related types of this species, there are 5 individual small fins behind the second dorsal fin and behind the first dorsal fin.
The deep sea edge of the North Sea is the boundary of the mackerel habitat, which is an Atlantic fish although it prefers warm waters. From the North Cape along the European Atlantic coast, including the North Sea and West Baltic to the Mediterranean, it is present in various subspecies. It is found in American waters, and in the subtropics it is joined by the related type – the somewhat smaller – Spanish mackerel.
The main catch device used in the mackerel fishery is the trawl, which in recent decades has also been further developed for use at greater depths. To protect juveniles, which are particularly important for the long-term stock conservation, scientists recommend larger mesh widths that the juveniles can slip through. At the end of October 1997 EU ministers responsible for the fishery agreed an on amended version of the ordinance concerning technical measures for the protection of the stocks. In addition to the trawl, purse seines are also significant in the mackerel fishery. Because full-grown mackerel snap at everything that shines, mackerel has also become a popular deep-sea game fish, this however has more significance for sport than it does for the economic aspects.
As in the past, mackerel is economically significant for the fishing industry, due to its popularity with consumers. Mackerel is among the top ten on the scale of most popular food fish.
CHARACTER OF MACKEREL FLESH
The flesh of the mackerel has strong blood circulation and has a reddish colour in freshly caught fish. Mackerel can be prepared in many different ways. Whether grilled, boiled, poached, or fried, whether smoked or pickled, the fish is appealing due to its tender, juicy flesh and its excellent flavour.
In the time of the Romans, the viscera of the mackerel was air dried and added to food as a seasoning. In the third century A.D. this so-called “garum” was praised in the cookbook of Apicius as being particularly good for potency
© Fisch-Innovationszentrum e.V. (FIZ)
OCCURRENCE AND BEHAVIOUR
The herring is a schooling fish and lives in the transition area between northern, moderate and polar zones. It is found not only in the Baltic Sea and North Sea, but rather in the entire North Atlantic, from Norway around the Faeroe Islands and Northern Iceland, and from Greenland to North Carolina. Herring feed on animal plankton and themselves are the prey of many ocean marine animals, thus they are very highly significant for the marine ecosystem. They can grow to over 40 cm in length and live for more than 20 years.
Underwater the play of colours of the herring is fascinating: The back is luminous in all colours from yellow-green to blue-black to blue-green, with a discrete purple shimmer. The belly is white, the flanks, entirely silver – schools of herring swarms are also referred to as the “silver of the sea”. However when caught it looks somewhat nondescript with a blue-green colour. It has smooth gill covers, scales without thorns, the lower jaw is longer than the upper jaw. The ventral fin of the herring is behind the front end of the dorsal fin.
YEARLY PHASES OF THE HERRING
The different herring stocks also have different spawning seasons. For example, the cycle of the so-called autumn spawners starts with the warming of the ocean in spring. This is when plankton multiplies so that the emaciated winter herring finds a virtually inexhaustible feeding reservoir. By the beginning of summer the herring is full of with growth nutrients and building nutrients and that it needs in order to later form “milt” (sperm) or roe (eggs). Starting around August, sperm or eggs make up as much as a fifth of a herring’s weight. After spawning in the fall the herring starts again with new cycle and stores fat.
There are several ways to catch herring: On the high seas with trawls. With the aid of echo-sounders fishermen can locate schools of fish and precisely calculate the direction of the catch. In coastal waters herring are caught with gillnets, and directly on the coast they are caught with “Uferwaden” (pulled nets) and jigging reels.
Approximately 20% of the fish offered in the Federal Republic of Germany are herring and herring products. From time immemorial, herring has been one of the most popular food fish in Germany. In recent years its market share has been between 17% and 20%. This is due, not least to the variety of products that can be prepared from herring.
No other fish in history has had such economic and political significance, as herring. In the middle ages herring often saved people from famine.
The Danes were the first to catch herring in large quantities, and through the herring they became rich. Herring caused wars between England and Holland.
The rise of the Hanseatic League was also closely linked with herring. Around the year 1000 Bishop Otto von Bamberg is said to have “discovered” technique of salting of herring to preserve it. Thus a new phase was initiated in the fishing industry and seafaring. The preservability of salted fish enabled longer and farther ocean voyages than were previously possible.
Thus salted herring played a role in the discovery of new continents and the opening new trading routes. Through salting, herring, hitherto easily spoiled, became an important “export article”, and was delivered deep into Russia the Alps and the Balkans.
© Fisch-Innovationszentrum e.V. (FIZ)
The Atlantic salmon (Salmo salar), as well as its five “cousins” of the pacific salmon, which in quality are completely different and which belong to the genus, Oncorhynchus, spawn exclusively in fresh water and also spend their experience their juvenile phase in fresh water. Consequently they are considered freshwater fish. Depending on the type and climatic conditions, the small salmon in free nature remain in the headwaters of the rivers for up to four or five years, until they are ready to migrate into the sea
Then they migrate to the ocean. After a brief adaptation period in the estuaries the fish quickly gain weight through the feeding possibilities offered in the ocean. As predatory fish, they roam near the surface of the ocean as and feed on small fish (such as herring and sprat) and crustaceans. After 1 to 4 years in the ocean salmon migrate back to their home waters to spawn, to precisely the location where they were spawned. Observations have shown that distances of thousands of kilometres are travelled at average speeds of 50 to 60 kilometres a day.
On their journey to the spawning grounds the fish often must overcome major obstacles, such as waterfalls, that they overcome through powerful tail strokes and jumps. To facilitate the climb, in many areas artificial salmon leaps or salmon ladders are built. The powerful animals equipped with enormous fat reserves lose as much as 40% of their weight during the homeward migration and spawning. As opposed to the Atlantic salmon (Salmo salar), that can spawn as many as four or five times, all pacific salmon (Oncorhynchus sp.) die after the first spawning process.
The distinguishing characteristic for all salmon-like fish is the so-called adipose fin, a thick rayless fold of skin on the caudal peduncle (between dorsal fin and tail fin). The small salmon migrating into the ocean go through a physiological change that enables them to live in sea water with a salt content between 28 – 32‰. This process of smoltification also changes the appearance of the small salmon, now referred to as “smolt”. The small salmon lose their dark coloured stripes and get a silvery appearance with a dark back.
When approaching sexual maturity and the subsequent spawning migration from the ocean, and the climb to the “natal rivers”, the salmon, which were formerly silver with a dark blue back, at this point in time depending on type are arrayed in spawning colouration with olive to brown backs and yellow/reddish sides. The average age of a salmon until sexual maturity is 2 – 4 years depending on type.
The habitat of the Atlantic Salmon (Salmo salar), with a global catch of only 5,000 tons per year, is limited to the North Atlantic and the rivers that flow into it. The five Pacific salmon species exclusively inhabit the North Pacific and the rivers that flow into it. The catch is approx. 800,000 tons a year. Relative to the natural occurrence of Atlantic salmon – which even a hundred years ago were also found Central European rivers, – a dramatic decline in the catches has been observed. This resulted in the fact that even off the American and Canadian east coast, and even along the Norwegian coast a temporarily limited, total closure of fisheries was issued. Consequently, only rarely is genuine Atlantic wild salmon offered on the market.
On the other hand, in worldwide aquaculture, production of Atlantic salmon shows incredible growth rates. The salmon grow in net enclosures, anchored in the ocean, which reach a production volume of up to 10,000 m3, until they are ready for the market. This is the only form of production that ensures a year-round supply of high-quality Atlantic salmon for the worldwide market in the size desired by the respective customer.
The fish eggs are incubated in clear fresh water. After one year, the juveniles 12 to 16 cm in size, can tolerate salt-water and are confined in the net enclosure. In the net enclosure the salmon goes through a two to three-year growth phase in the ocean under natural conditions in ebb and flow. Through a balanced feed, enhanced with vitamins and minerals the salmon grow in a controlled manner. The feed is produced from fish species that are not suitable for the human diet. The addition of prawns or specific feed components ensures the pink salmon colour. The countries with the most significant salmon farming industries are Norway, Chile, Scotland and Ireland.
Popularity with the consumer and thus the economic significance of salmon have increased significantly in recent years. This has become possible through the expansion of aquacultures for salmon. Salmon is in the front rank of the most popular food fish in the Federal Republic of Germany.
© Fisch-Innovationszentrum e.V. (FIZ)
Mussels are invertebrates that are surrounded by a “lock” of interconnected shells. The mussel can open and close the shells through a close mussel. This muscle is so strong that the soft body is completely protected in closed status. Mussel meat is a high-quality food and is considered a delicacy.
Common mussels are dioecious. A female produces 5 to 12 million eggs. After one to two weeks the larvae hatch and swim freely for approximately 3 weeks and fasten themselves on stakes, rocks, mats and ropes. After four years, at the latest, the mussels reach their market size (5 to 8 cm). All mussels feed on fine plankton.
Mussels are becoming increasingly significant in the retail food industry. Consumer demand for mussels is continuously growing. Thanks to mussel farming the supply has become stable.
© Fisch-Innovationszentrum e.V. (FIZ)