Unusual catches and finds
In the southern North Sea, besides the resident species, there are many other species which are rarely caught or observed. These rarities can be roughly divided into five groups. The first group consists of species which belong in cold northern waters and are usually only found in the southern North Sea during the winter. The second group consists of warm-water species, which usually are observed in the summer . Lost ocean inhabitants form the third group and the fourth group consists of the presently rare group of species that live in sea, but migrate upriver to spawn. The fifth group is made up of species that arrive via ballast water.
Guests from colder regions
There is a group of fish living in deeper, colder waters in the extreme north parts of the North Sea, the northern Atlantic Ocean and/or the Arctic Sea. Every once in awhile, these species comes as 'guests' to the southern North Sea. It concerns the Greenland shark, the long-nosed skate, the sandy ray, the shagreen ray, the rabbit fish (a real deep-sea fish), the greater argentine, the skipper (an ocean fish), the roundnose grenadier (another deep-sea species), the hake, the silvery pout, the blue whiting, the wtich (Glyptocephalus cynoglossus), the pollack, the saithe, the tusk, the three-bearded rockling, the blue ling, the ling, the pearlfish, the megrim, the witch, the halibut and the thickback sole. Young specimen regularly enter the southern North Sea, particularyly in the winter. The hake and the three-bearded rockling enter the North Sea from the south as well as the north.
In 2006, the UK61 caught a northern species of ribbonfish (Trachipterus articus). This species is usually found at depths between 200 and 900 meters. It is regularly caught by stern trawlers in the northern North Sea. Before realizing what it was, the crew first called the 1.5 meter long fish a 'long -nout sea horse' due to its protruding mouth.
Again in 2006, a wreckfish (Polypirion americanus) was recognized at the fish market in Urk. This young specimen, around 50 centimeters long, was caught circa 50 kilometers off the coast of IJmuiden. In July 2007, the UK48 caught a 1-meter long wreckfish 7 miles west of Camperduin. Adult specimen can grow up to 3 meters and 100 kilograms. The species is related to the sea bass and lives as deep as 1000 meters. It is a tasty fish.
The TX10 caught a ling (Molva molva) in the Wadden Sea in 2005. Lings usually live along the coasts of the northern Atlantic Ocean. The specimen was a young fish twenty centimeters long. Adult specimen of this extended cod-like fish can grow to two meters.
Guest from warmer waters
Species from southern regions are regualrly found in the Wadden and North Seas. Some are only seen once in awhile when the temperature is favourable. Others stay on a regular basis in the southern section of the North Sea, while others float into the North Sea as eggs and larvae. This is true for the red mullet, which lays its eggs in the English Channel. Eggs, and adult fish as well, are not unusual to find along the Dutch, German and Danish coast.
In 2008, the sponge Suberites massa was suddenly reported in various areas in the delta waters. This sponge used to be found particularly in subtropical waters, the English Channel forming its most northerly habitat.
Reports of short-snouted seahorses in the Wadden Sea and delta waters continue to increase.
In 2002 in Vlissingen, the red bandfish (Cepola rubescens) was landed, a southern species found up to the English Channel.
Another southern species was caught in the same year, a bogue 35 centimeters long, also in Zeeuws waters.
There have only been a couple of reports of seahorses in the Wadden Sea. In August 2004, divers found at least a record number of ten seahorses in the Oosterscheld. It was the short-snouted seahorse. In 1998, a Texel fisherman caught a seahorse that was released again after a photo session.
In the winter, the opah comes to the North Sea during its migration journey for food, and even red sea-bream is occasionally seen in the North Sea, although their major distribution area lies further south. They do not have a regular area in the North Sea. The black sea bream also belongs to this category.
Five specimen of the trigger fish, a fish species that belongs along the coast of West Africa and the Caribbean area, were caught in the winter of 94-95, two in the vicinity of Texel and three in Zeeland.
Lost ocean inhabitants
Sometimes, fish that normally live in the Atlantic Ocean end up in the shallow North Sea, more or less by accident.
In the fall of 2004, a shade-fish (Argyrosomus regius) was brought to the fish auction in IJmuiden. This species is an extremely rare guest in the vicinity of the Netherlands, although its distribution area is from mid Norway to mid Africa, including the North Sea. Shade-fish are closely related to sea bass. Another species related to the sea bass is the striped bass. The last reports of this fish in Dutch waters was in 1998 and 2006.
In August 2004, the TX25 caught a trigger-fish in the Wadden Sea. Such catches of this unusual species, distantly related to the sunfish, are a rarity in the southern North Sea.
In September 2002, the TX43 caught a rudder fish, (Centrolophus niger). This ocean inhabitant lives at depths of around 200 meters and is rare in the North Sea. In February 2002, an intact rudder fish washed ashore on Terschelling.
In August 2002, an opah (Lampris guttatus) was trade in the auction at Urk, caught west of Denmark. Opahs usually only swim around in water between 100 and 400 meters deep. It does not belong in the North Sea but it is found in the Atlantic Ocean. It eats mainly cuttlefish. Opahs are regularly found along the Norwegian coast in the summer. This specimen weighed 64 kilograms. In August 1996, an opah was found on the beach of Terschelling and brought to the Nature Center and Sea Aquarium in West-Terschelling. The fish was almost one meter long.
On 3 November 1998, a live blue shark stranded close to the ferry boat dock on Ameland. Such a stranding along the North Sea coasts is extremely rare. The animal was 2.2 meters long. It was impossible to keep the animal alive. The Nature Center on Ameland had a model made of the animal.
Every once in awhile, tuna turn up in the southern North Sea. Large schools of tuna used to regularly swim in the early autumn up to the Doggersbank until the end of the 1960s. The population was hunted to a small scale by fishermen from Schleswig-Holstein, using lines and rifles. These animals probably belonged to the stock that spawned west of Gibraltar in June and were starved after long hunting journeys. It is now difficult to judge why the tuna disappeared from the southern North Sea.
The king gar (Scomberesox saurus) lives around Madeira in relatively warm water. In 1954, massive numbers of this species was chased onto the beach of Texel by bottlenose dolphins. Since then, king gars are only occasionally caught, as in 1982.
The UK 226 caught a fish unknown to the crew at the end of 2007. It turned out to be a black fish, or black ruff (Centrolophus niger), a deep-sea fish rarely found in the North Sea. Only five specimen were reported in the second half of the 20th century.
Electric rays are extremely rare in the North Sea. The SL 42 caught a marbled electric ray (Torpedo marmorata) in 1998. The KW 45 caught an electric ray (Torpedo nobiliana) in it net after a haul under the English coast by Flamborough. The name 'electric' comes from their capacity to release powerful electric shocks, which they do to stun their victims or protect themselves.
An enormous ray egg capsule
In May 2007, the TX 68 caught the egg case in its net, pictured left in the above photo. It is 29 by 12.5 centimeters; on the right is an egg case from a thornback ray, for comparison. The extremely large case is probably from a Norwegian skate, although it is even too large for that sort. The egg case was caught close to the Skagerak, the sea channel between Denmark and Norway, at a depth of 50 meters.
Living in the sea, spawning in freshwater
Anadromous fish live in the sea or in brackish water and migrate upriver to spawn. This migratory behaviour is becoming more difficult in the southern North Sea due to the closure of sea arms, the construction of locks and other large-scale water works. The pollution of the river water and the closure of spawning grounds have also become a large obstacle for many of these species.
Many anadromous species which used to be rather common have now become rare. It concerns, for example, the sea trout, twaite shad, allis shad and salmon and the salmon-related houting (Coregonus oxyrhynchus). Of this group, twaite shad is the most common species and is sometimes found in groups of one hundred speciemen.
Houting has not been seen in the Netherlands since 1940, but 1400 fish were caught in 2005, probably thanks to the re-introduction program in the German river the Lippe. In September 2002, houting was caught in the Wadden Sea near Den Oever. This fish is also more commonly seen in Schleswig-Holstein and Denmark waters of the Wadden Sea.
The opposite of anadromous fish species is the catadromous species, which live in fresh water but spawn in the sea, such as eel.
