The fish stocks in the Moray Firth are an important food source for the sea birds and marine mammals of the firth. They are also the natural resource which has allowed fishing to play its vital role in the economic and social development of the area.
The knowledge of fish distribution and abundance in the Moray Firth is restricted to catch data of commercially fished species (catch includes both landings and discards) and occasional SERAD trawl surveys. For those species that are not commercially important, distribution and abundance are poorly understood.
Herring (Clupea harengus)
Information suggests that some young herring in the Moray Firth originate from, and recruit to, the stocks off the west of Scotland, in addition to the North Sea stocks. After spawning, juvenile herring stay in the Firth before returning to the west coast in their third year.
The inner Moray Firth is an important nursery area for herring. These one-two year old herring were exploited for many years in the Beauly, Inverness and Cromarty Firths by a winter drift net fishery. These fish move out to the open Firths in the spring.
Herring were the mainstay of the Scottish fishing industry from the 1900's to the 1960's and were of major economic importance in post war years. Herring declined drastically in the North Sea from the 1950's, leading to the closure of the fishery in 1977 as a result of overfishing of adults and immature fish on nursery grounds and the poor survival of young herring. From 1977 until 1983 all directed catches of North Sea herring, including those of the Moray Firth were banned in order that stocks could recover.
Sprat (Sprattus sprattus)
Sprat spawn in the deep water in the approaches to the Moray Firth from March to August and larvae disperse in a southerly direction. Large numbers of fish then move inshore to overwinter from late September/October to February/March. The Moray Firth is one of the main overwintering areas for sprat on the east coast of Scotland. There are no clearly defined nursery areas for sprat and little is known about relations between separate sprat populations.
In recent years, North Sea sprat spawning stocks have declined, possibly due to a series of poor year classes accompanied by an increase in fishing. An additional management problem arises because sprat are present in the same areas as juvenile herring and the latter therefore form a large proportion of the catch. In order to protect the herring in the inner Firths, the area is now closed to sprat fishing from October 1 to March 31.
The demersal fish of the Moray Firth belong to coastal stocks and there is little migration from the Firth to other coastal areas. Fishing mortality is high and the demersal fish population appears to be supplemented by those from other coastal areas. Historically there was a large demersal fishery in the Moray Firth. Between World War 1 and the start of World War 2, 75% of Scottish demersal catches were taken from the Moray Firth. Prosperity continued until after World War 2 but the fishery has since declined due to the over-exploitation of the stock.
Plaice (Pleuronectes platessa)
Like all flat fish, the plaice starts out life looking like other fish. As larval fish develops, one eye migrates to the top of the head and the body flattens out. A plaice's eyes are on the right side of the head and its body is covered in bright orange spots.
The Moray Firth is the most important spawning ground for plaice in the North Sea. Spawning takes place in January or early February, off the south and north-west coasts. Residual currents probably retain larvae, although some may move south if they should enter the east flowing current on the outer southern coast of the Firth. Young plaice stay in the Firth and are found along the sandy bays of the south coast which provide good nursery areas. One and two year old fish are distributed throughout the area and three year old fish aggregate in the southern part of the Firth in August and September. The commercial catch is correspondingly high here in these months.
Lemon Sole (Microstomus kitt)
Evidence suggests that movements of lemon sole occur parallel to the coast rather than inshore to offshore. The outer Moray Firth is one of the main spawning areas for lemon sole in the northern North Sea. Spawning is widespread wherever there are adults and takes place in deeper waters from May to September. It is believed that the planktonic larvae are likely to be retained within the Moray Firth. Larvae become bottom-living on grounds inhabited by adolescent and adult stocks, preferring hard and rocky sediments with gravel.
Cod (Gadus morhua)
Cod enter the inner Moray Firth for spawning. Juvenile Cod remain inshore throughout the year but, after spawning, adults move to deeper water to feed during the summer. Immature cod leave the Firth as 2 year old fish. Fishing mortality is high and it is possible that fish from other coastal areas supplement stocks. There is a high catch of cod in March which is likely to be associated with spawning migration into the shallow waters and many fish of more than 3 years old are caught in this period.
Haddock (Melanogrammus aeglefinus)
Haddock are present in the Moray Firth in large numbers in summer and autumn. Adults migrate into deeper waters in January and February, spawning there in March and April. Juvenile haddock move into the shallow waters of the Firth and remain there throughout the year. The patterns in fish movements are reflected in the catch with peak numbers landed in summer when adults
Whiting (Merlangius merlangus)
The dispersal of whiting is complicated and from parasitological studies there is evidence of some mixing between the Moray Firth and Shetland stocks. Information on spawning is sparse although it is known that the main North Sea whiting ground extends into the Moray Firth. Whiting move to waters less than 100m deep to spawn and the spawning season reaches a peak in April.
OTHER NON-COMMERCIAL SPECIES
Thornback ray (Raja clavata)
The thornback ray is well camouflaged against the sea bed, enabling it to pounce on bottom living crabs and small fish. It gets its name for the sharp spines which cover its back and tail.
Lumpsucker (Cyclopterus lumpus)
This slow moving fish clings to the rocks in shallow water using a well developed sucker. Lumpsucker eggs are often sold as caviar.
Wolf fish (Anarichus lupus)
The wolf fish's big teeth allow it to crush crabs, sea urchins and other shellfish. The wolf fish's diet wears down its teeth but they grow back. It can go through several sets of teeth in its lifetime.
Two spotted goby (Gobiusculus flavescens)
Commonly found under seaweeds, the goby is able to use its pelvic fins to attach to rocks and avoid being swept away by surging waves. It is a short lived fish with a life span of up to two years.
Ballan wrasse (Labrus bergylta)
Variable in colour from dark green to bright orange, this fish swims around the kelp fronds using its pectoral, or side, fins. It feeds on mussels and other molluscs which it bites and sucks from the rocks
Long spined sea-scorpion (Taurulus bubalis)
Well camouflaged against the rocks, the sea-scorpion is easily recognised by its large, flattened head bordered by spines. It hunts by stealth, pouncing on unsuspecting crabs or shrimps and engulfing them in its jaws.
Lesser spotted dogfish (Scyliorhinus canicula)
Like all sharks, the dogfish's skeleton is made of lightweight cartilage rather than bone. Its skin is covered in 'denticles', which make it very rough if stroked the wrong way. The dogfish hunts at night for molluscs and crustaceans.