Fresh herrings1,464,296cwts.worth£1,212,493Cured herrings8,797,106„„5,333,113Total10,261,402„„£6,545,606
The quantity of herrings caught by other European countries is as follows—
cwts.£France (1911)7,846,503529,739Germany (1913)Fresh148,35475,738„ „Salted1,030,039563,033Holland (1911)1,685,751919,973Norway (1912)4,404,400580,570Denmark (1912)845,295140,051Sweden (1912)861,420205,555Belgium (1911)13,0005,00016,834,7623,019,659
Thecod is widely distributed in the northern and temperate seas of Europe and America. It lives close to the bottom, in from 25 to 50 fathoms of water, and feeds upon fish, small crustacea, worms and mollusca. The cod spawns in the Spring. Of the 4,000,000 or so eggs that are spawned by a single female cod, comparatively few are hatched, and fewer still reach maturity. The young are about 1 in. long by the beginning of the summer, and become fit for the market at the end of the second year. Usually, the fish are mature at the end of the third year, and then measure about 3 ft. in length, and weigh from 12 to 20 lbs. They are in the finest condition in October, November and December.
In addition to its great value as a food fish, the cod, like the sturgeon, yields isinglass (a pure fish gelatine) from its swimming bladder, and oil from its liver. Cod-liver oil is largely used as a remedy for scrofulous complaints—probably owing to its content of vitamins. It is also used effectively in cases of pulmonary consumption.
Cod is fished along the coasts of Newfoundland and Labrador, and on the Banks. The Banks stretch for about 300 miles in a south-east direction from the coast of Newfoundland towards the middle of the North Atlantic. They are swept by the cold Labrador current. A branch of the Gulf Stream passes over the southern portion of the Banks. These currents bring enormous quantities of plankton and small fish, which provide excellent food for the many varieties of fish and small,invertebrate, marine animals that inhabit the Banks. These, in their turn, provide abundant food for the cod.
The cod, together with other demersal fish, including haddock, hake and pollack, is caught with baited hooks and lines. This fishery has continued with unbroken prosperity for nearly four centuries. In addition to the Newfoundland boats, a large number of American boats set out for the Banks from Gloucester (Mass.). Most of the boats are sailing boats of about 35 tons capacity, and of sturdy construction. Each boat carries eight dories—small row-boats about 15 ft. long—amidships. The crew consists of a captain and cook, and sixteen men—two for each dory.
The “Banks” stretch for about 300 miles, by 200 miles wide, in a south-easterly direction, towards the centre of the North Atlantic. The depths in which the fishing is carried on range from 20 to 120 fathoms off the coast of Newfoundland, from 15 to 90 fathoms on the Banks, and from 100 to 135 fathoms at the edge of the Banks. The vessel starts out for the fishing grounds with about 400 hogsheads of salt, and from 15,000 to 25,000 lbs. of bait. The bait is generally frozen squid and herring. Capelan is also used as bait, but has to be obtained at Miquelon, the last port of call before putting out to the Banks. The bait must be well iced, as the cod will not bite well if the bait be tainted.
During the second trip, squid is used as bait and is caught on the fishing grounds.
As the boat approaches the fishing grounds, the dories are made ready. Each dory carries four tubs of baited lines. A tub contains nine lines, each 50 fathoms long. When fishing, these lines are all strung together, so that each dory will run a string 1,800 fathoms long—about two miles. Each line carries about 90 hooks—thatis, 3,200 hooks to each dory. A vessel with eight dories will thus set about 16 miles of line, carrying about 25,000 hooks. The hooks are attached to the lines by means of shorter lines called “gangings”—in Scotland they are known as “snoods”—about 2 ft. long. The complete line, as set by a dory, is called a “trawl.”
On arriving at the fishing grounds, soundings are made to determine the depth and character of the bottom. The best fishing is obtained over a gravel bottom. The trawls are then set while the vessel is in motion (a flying set), and if the fish are found to be abundant the vessel drops anchor.
The flying set is carried out as follows: The dories are towed astern and, when the right spot has been selected, are dropped at regular intervals until all are away. Each dory as it is dropped rows off at right angles to the course of the vessel, and in the same general direction, throwing out its trawl as it proceeds until it is all set. The vessel then returns diagonally across the fishing grounds to the starting point, picking up the dories as their trawls are set. After a time, the dories are dropped again in the same order as before, and the men haul up the trawls and take the fish off. Each dory is then picked up in succession together with her catch. If this flying set is successful, and other conditions are favourable, the vessel drops her anchor and fishing proceeds.
The manner in which the trawls are set depends upon the tide. They are always set as far as possible with the tide. Thus, the dories on the side of the vessel against which the tide is flowing row out against the tide, until they are about a trawl-length from the ship. They then set the end of the trawl at the point, and work towards the vessel. On the other side of the vessel the trawl is set from the vessel with the tidetowards the dory. Each end of the trawl is attached to an anchor by a line 1 fathom in length, and to a buoy by a line 25 fathoms longer than the depth of the water at that point. Thus, the trawl is situated just above the ground. The trawls are set once a day and drawn three hours afterwards, or set in the afternoon and drawn the following morning. The shorter the time between setting and drawing, the better the condition of the fish. In hauling the trawl, one man stands in the bow of the boat and hauls in the trawl, detaching the fish, the other man receiving the trawl and coiling it. A dory carries on an average 1,000 lbs. of fish, and may sometimes make two or three trips before the line is cleared.
The fish are “gaffed” from the dories to the fishing vessel and are kept on deck, packed between division boards to prevent sliding or turning of the fish by the movements of the vessel.
When the fish are all aboard, they are split and cleaned and salted down. The crew is divided into splitting gangs, each consisting of three men—the throater, the gutter, and the splitter. The throater grasps the fish by the head with the left hand, and, holding it with its back on the edge of a tub, cuts its throat just behind the gills, and makes a slit down the belly. The head is then broken off by downward pressure against the edge of the tub, and the fish is passed on to the gutter. He opens the belly with his left hand, removes the liver for oil, and tears out the viscera. The fish then goes to the splitter, who completes the ventral splitting of the fish and removes the backbone.
After being well washed, care being taken to remove all blood, the fish are passed down a canvas chute into the hold, where they are carefully salted and piled in “kenches.” The fish are laid on their backs alternatelynape and tail, salt being liberally sprinkled between the adjacent layers. Nearly 11⁄2bushels of salt are used per 100 lbs. of fish. The pickle formed by the salt and the juices of the fish drains away to the bottom of the hold, from which it is pumped overboard. As the kench or pile settles, more fish are added, so as to keep the compartment full. Kenching begins in the forward compartment of the hold, and is carried on from side to side of the vessel. Each kench is about 4 ft. by 7 ft., and the full height of the hold. The refuse is thrown overboard.
In addition to the “trawl” fishing, many boats use hand-lines. For this purpose, the lines are somewhat smaller, and only 13 ft. long. About 100 barrels of bait are taken (slack-salted clams obtained on the coast of Maine), any additional bait that may be required being caught on the fishing grounds—squids, hagdens, and clams taken from the stomachs of fish.
When the vessel reaches the fishing grounds, the dories row away in all directions, each man for himself. The dory is anchored in water from 18 to 40 fathoms deep. Each fisherman uses two lines carrying two hooks a piece. The boats generally go out at sunrise and return to the fishing boat about six hours later. Two boatloads—that is, 2,000 lbs. of fish—make a good day’s work.
On returning to the vessel the fish are pitched on deck and counted, only cod of over 22 ins. length being considered. Smaller fish, and the “shack”—pollack, haddock, cusk and hake—being counted separately. The fish are then dressed and salted, as already described.
In some cases, hand-line fishing is carried on from the deck of the fishing boat itself, while the boat drifts. Each man uses one line carrying two hooks. The baitconsists of iced cockles, broken with a hammer. The positions on the deck are followed by the crew in rotation, to give all an equal chance. As the fish are “landed” they are thrown on to the deck, each man keeping his count by cutting out the tongues and keeping them in a separate bucket.
On the Georges Bank, south-east of Gloucester, which is one of the favourite fishing grounds, the fish are caught by hand-line from the deck of the ship while at anchor. Frozen herring are used as bait, when possible. All the fish caught on the Georges Bank are salted, except the halibut, which is iced. Some idea of the value of these grounds is gained from the fact that a single fisherman may take 500 fish in a day. The Georges Bank area yields about 70 per cent of the total catch, the Grand and Western Banks accounting for the remaining 30 per cent. Approximately 60 per cent of the fish are brought in iced, and 40 per cent salted.
On returning to port the fish are pitchforked on to the wharf, and sorted into snappers (less than 16 ins. from nape to tail), medium, and large (over 22 ins.) Generally, they are divided as follows: 4 per cent snappers, 41 per cent medium, and 55 per cent large. Each class is weighed separately and carefully examined for any indication of spoilage. Any suspected fish are thrown out. The fish are then washed and put with salt into butts in the store. Fish that are brought in iced whole are sorted and weighed, and then beheaded, gutted, and split and salted. About eight bushels of salt are used to each hogshead of fish. The fish are kept, salted down in hogsheads until required, care being taken that the fish are kept covered with strong brine.
After salting, the fish are dried. The salting processeffects partial drying by extracting a large proportion of the flesh fluids of the fish. The extraction of water by the salt is assisted by kenching, the fish at the bottom of the kench being pressed down by the weight of those above.
The fish are taken from the butts as required, and are piled in a kench about 4 ft. high, to express and drain off the pickle. At the end of two days the fish are re-piled, the top fish becoming the bottom, and so subjected to full pressure. If the weather is unfavourable for drying, they are re-kenched every two or three days.
The fish are then dried by exposing them to wind and sun on a bed of latticework about 8 ft. wide and 30 ins. above the ground, and as long as necessary, called a “flake.” The drying yard is known as the flake yard. The latticework is constructed of triangular-section, wooden laths, placed about 3 ins. apart, the fish resting on the upper edges of the laths.
In the hot weather, the fish are protected from sunburn by canvas awnings, and from rain at night by coops.
With a warm sun and a good breeze, drying will be complete in about 10 hours. Thorough drying throughout the body of the fish is accomplished by drying on the flakes until the surface is dry and crystallized. The fish is then kenched, and the dry surface salt extracts more moisture from the interior. The fish is then dried again, thus ensuring a much more complete result.
Fish are also dried in some factories in large, steam-heated shelf driers. This method is inclined to be too rapid, with the result that the fish are only surface dried instead of being uniformly dried right through.
After drying, the fish are kenched in the store until required. They are then skinned, the bones are removed, and they are moulded into blocks which are cut up into cakes for packing and export.
It is estimated that the loss in weight during the different operations is as follows—
Dressing40per centSalting (full pickle)17„Drying4„Skinning and boning13„Total loss74„
The fresh waste, skins, bones, etc., of the fish are worked up for glue, the residue being manufactured into fertilizer. The best glue is obtained from the skins. The cod and cusk skins are superior in this to the skins of hake and haddock.
The oil is extracted from the livers. That from fresh livers is refined and used for medicinal purposes, while that from old livers is used for tanning chamois leather. The value of this oil is considerable, as much as £150 being received by a boat in one trip for the oil alone.
In 1914, Newfoundland exported 60,000 tons of cod meat, worth £1,600,000. The chief market is the Mediterranean.
Unlikethe drift net, which only catches fish of one species and of fairly uniform size when they are swimming near the surface, the trawl net scoops up practically all the inhabitants of the sea bottom, including round fish, e.g. cod and haddock; flat fish, e.g. sole and plaice, as well as various invertebrates (jelly fish), and marine plants and stones. The trawl is essentially a flattened, conical net that is dragged open-mouthed along the sea bottom. The two kinds of trawl in common use—the beam trawl and the otter trawl—differ in the method that is adopted for keeping open the mouth of the net. The beam trawl is used by sailing vessels, the otter trawl by steamers.
Sailing trawlers are divided into two classes: first class smacks and second class cutters. The smack is a two masted vessel with fore and aft rig, generally making a five or six day voyage, and trawling in depths of up to 40 fathoms. The cutter makes shorter voyages—20 hours—and generally keeps within territorial waters.
To work a beam trawl successfully, it is necessary to know the character of the sea bottom, whether rough or smooth, and also the time and direction of the tide. The net is trawled with the tide a little faster than it is running, so that sufficient resistance is encountered to keep the net extended. In shooting the trawl, great care must be taken to make it alight on its runners in the correct position for trawling. If the net be twisted, or if it alight upside down, it has been shot “foul,” and has to be hauled up and shot again. In preparing for a shot the net is lowered over the side by adjusting the bridle ropes, and the beam is coaxed into its proper position while the net is still near the surface. The net is then gradually lowered, the boat moving slowly forward. The trawl is generally hauled for the duration of a tide—that is, six hours—during which time it will travel about 15 miles. The net is generally hauled in by a steam capstan, driven by a small donkey engine. When the trawl comes alongside, the beam is secured and the net is gradually hauled over the side by hand until the cod end appears; this is then made fast to a rope and tackle, and hauled above the deck. The cod line is untied and the fish are discharged upon the deck.
Since trawling is generally carried out on smooth ground, the greater proportion of the catch consists of certain kinds of demersal fishes that frequent sand and gravel. Of these, the most important are cod, haddock, whiting, ling, hake, catfish, sole, plaice, turbot, and brill. Certain of these species also frequent rocky ground, and are taken in such areas by the line fishermen.
Generally speaking, line fishermen work in deeper water than trawlers and capture larger fish, though of fewer species, e.g. cod, halibut, ling, skates and rays.
The original sailing trawlers are rapidly being superseded by steam trawlers. The first steam trawling company was formed in 1882. It had a capital of £20,000 and a fleet of four vessels. It trawled on the Dogger Bank for three years with marked success. After this the future of steam trawling was assured. The steam trawler is many times more efficient than a smack, for it can fish in nearly all weathers, including calm, and it can trawl over rough bottoms, owing to its greater power, and can go much further afield.
Fig. 15MODERN STEAM TRAWLER (SECTION)Total length, 160 ft.Length between perpendiculars, 148·5 ft.Greatest breadth (frame), 23 ft.Draught, 133⁄4ft.Explanation of Section.—1. Wheelhouse. 2. Captain’s cabin. 3. Collision bulkhead. 4. Crew’s quarters. 5. Store for gear, nets, etc. 6. Chain locker. 7. Fish-pounds (on deck). 8. Fish-hold. 9. Cross bunker (for coal). 10. Main bunker. 11. Passage to bunker. 12. Steam-winch. 13. Stokehold. 14. Lifeboat. 15. Triple expansion engines (650 indicated h.p.). 16. Bathroom. 17. Mate’s quarters. 18. Dining-room and berths for engineers. 19. Storeroom.Larger image(124 kB)
Fig. 15MODERN STEAM TRAWLER (SECTION)
Total length, 160 ft.Length between perpendiculars, 148·5 ft.Greatest breadth (frame), 23 ft.Draught, 133⁄4ft.
Explanation of Section.—1. Wheelhouse. 2. Captain’s cabin. 3. Collision bulkhead. 4. Crew’s quarters. 5. Store for gear, nets, etc. 6. Chain locker. 7. Fish-pounds (on deck). 8. Fish-hold. 9. Cross bunker (for coal). 10. Main bunker. 11. Passage to bunker. 12. Steam-winch. 13. Stokehold. 14. Lifeboat. 15. Triple expansion engines (650 indicated h.p.). 16. Bathroom. 17. Mate’s quarters. 18. Dining-room and berths for engineers. 19. Storeroom.
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Modern British steam trawlers travel as far afield as Iceland, Newfoundland and Morocco.
Steam trawling developed rapidly, and resulted in a correspondingly rapid decrease in the number of sailing trawlers. Between 1893 and 1903, the number of first class smacks in Great Britain decreased from over 2,000 with an average tonnage (net) of 57·4 to less than 900 with an average tonnage (net) of 40. From 1903 until the present day, the number had remained between 900 and 800; it would seem, therefore, that the relative numbers and importance of smacks and steam trawlers gradually attained to a condition of equilibrium. Between 1900 and 1906 the increasing importance of steam trawling received a temporary check. A steam trawler in those days would cost about £10,000 to construct and about £5,000 a year to operate; their commercial success, therefore, depended upon correspondingly large and valuable catches of fish being obtained. When first introduced on the fishing grounds round the coast their superior efficiency and speed amply compensated for their high cost. About 1900, however, the catch obtained by these vessels on the home fishing grounds began to diminish, and the fishermen became alarmed lest the greatly increased efficiency of steam trawling should prove to be its own undoing, and result in the depopulation of the fishing grounds by over-fishing. Between 1900 and 1906, the number of steam trawlers fishing from British ports only increased by 200, whereas, during the preceding 10 years, the numbers had increased from a few hundred to over 2,000.
The anticipated exhaustion of the home grounds led to the steam trawler prospecting further afield. These longer voyages, as far as Iceland and the White Sea and Morocco, were very successful. The result of this was that larger steam trawlers were built, capable of undertakinglong voyages of many weeks’ duration. Between 1900 and 1906 the average net tonnage of the steam trawlers increased from 54 to 62. The steam trawlers, in opening up new and more distant fishing grounds, left the home grounds to the smacks. Consequently we find that the smacks confined their operation to the smooth ground in home waters, leaving the rough and more distant grounds to the steam trawlers. A direct result of this gradual redistribution of the fisheries between sailing smacks and steamers was the development of specialized fishing ports. Such ports as Lowestoft, Brixham and Ramsgate, off which good fish are obtainable and which are within easy access of good markets, have retained their importance as smack ports; on the other hand, the development of steam trawling has led to the rapid growth of deep water ports, such as Fleetwood, Grimsby, Hull, Aberdeen, and Milford Haven. In Grimsby, originally one of the greatest strongholds of smack fishing, smacks have been entirely displaced by steam trawlers, owing to the special facilities which the port offers in being near cheap coal, in possessing deep water, and in being in direct rail communication with large markets for trawl fish.
There is no doubt that the rapid development of steam trawling was accelerated by the invention of the otter trawl. This is not only a larger net than the beam trawl, but is for all but small, flat fish, a much more efficient instrument. From the study of market statistics between the years 1889 and 1898 Garstang has calculated that a steamer caught on the average between four and seven times as much fish in the year as a sailing smack.
Fig. 16I.—PLAN ON DECK.II.—PLAN BELOW DECK.Plan of Arrangements on and below Deck.—(I) On deck: 1. Winch. 2. Hatches. 3. Gallows. 4. Bollards. 5. Fish-pounds. 6. Steam-winch (for trawl). 7. Blocks. 8. Officers’ messroom. 9. Galley. 10. Ventilators. 11. Funnel. 12. Bunker-hatches. 13. Engine-room skylight. 14. Bathroom. 15. Mate’s cabin. 16. Lifeboat.(II) Below deck: 1. Collision bulkhead. 2. Crew’s quarters. 3. Storeroom. 4. Iceroom. 5. Fish-hold. 6. Reserve coal bunker. 7. Main bunker. 8. Side bunkers. 9. Stokehold. 10. Main pump. 11. Auxiliary pump. 12. Engines. 13. Dynamo. 14. Cabin. 15 and 16. Chief and second engineers’ quarters.Larger image(124 kB)
Fig. 16I.—PLAN ON DECK.II.—PLAN BELOW DECK.
Plan of Arrangements on and below Deck.—(I) On deck: 1. Winch. 2. Hatches. 3. Gallows. 4. Bollards. 5. Fish-pounds. 6. Steam-winch (for trawl). 7. Blocks. 8. Officers’ messroom. 9. Galley. 10. Ventilators. 11. Funnel. 12. Bunker-hatches. 13. Engine-room skylight. 14. Bathroom. 15. Mate’s cabin. 16. Lifeboat.(II) Below deck: 1. Collision bulkhead. 2. Crew’s quarters. 3. Storeroom. 4. Iceroom. 5. Fish-hold. 6. Reserve coal bunker. 7. Main bunker. 8. Side bunkers. 9. Stokehold. 10. Main pump. 11. Auxiliary pump. 12. Engines. 13. Dynamo. 14. Cabin. 15 and 16. Chief and second engineers’ quarters.
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A modern steam trawler is from 150 to 160 ft. long by 25 ft. beam and 12 ft. depth, constructed with a high bow and a low, flat stern. Her net tonnage isfrom 60 to 200, her bunker capacity 250 tons, with storage room for up to 120 tons of fish. She is fitted with triple expansion engines of from 40 to 85 horse power. The forward part of the ship is occupied by the living quarters of the crew, rope and net store, iceroom, and fish-hold. Larger vessels, making trips to distant grounds, will take as much as 30 tons of broken ice; this ice is distributed over the fish in layers, after they have been cleaned and gutted. In practically all modern fishing ports there is a special ice factory situated near the quay, and ice is manufactured by the ammonia process, crushed, and delivered to the ships through zinc-lined chutes. The fish-hold in the forward part of the ship extends right across the ship and is from 9 to 10 ft. high, divided by a partition into two compartments, each compartment fitted with two shelves 5 ft. long, on which the fish are piled. These shelves reduce compression and facilitate the storage of the fish, the front of each compartment being closed with boards as it becomes full. She generally carries three or four trawl nets, one on her starboard and the other on her port, one or two being down below in reserve. The boat is fitted with four gallows, two forward and two aft, one on each side of the boat. These gallows are used for lifting the otter boards out of the water when the trawl is hauled in.
The ship carries nine hands, consisting of skipper, mate, boatswain, two deck hands, cook, two engineers and a fireman.
On the fishing grounds, fishing is continuous. The net is trawled for from two to four hours, although on grounds where fish is plentiful (e.g. Iceland) the trawl is frequently hauled every half-hour. It is then hauled aboard, and the cod end containing the fish is swung over the deck. The cod line is unfastened so that thecod end of the net opens, and the fish are discharged into a pound formed on the deck by horizontal 9″ × 3″ deal boards. The net is cleaned and shot again.
On smooth ground trawling is commercially possible at all depths down to 300 fathoms. In few cases, however, is trawling carried on at greater depths than 200 fathoms.
Owing to the large amount of stores and repairs, etc., connected with the maintenance of a fleet of steam trawlers, most large owners maintain fairly elaborate premises in the neighbourhood of the fish dock. These premises generally consist of a net-making hall in which nets are made by women working with shuttles, a large bath of tar or tanning material below in which the net is soaked, also a wood yard and blacksmith’s shop, containing a steam hammer, a plumber’s shop, a boat-builder’s shop, a large store-room fitted with the necessary stores and spares.
During the war the steam trawlers were commandeered by the Government for use as patrol boats and mine sweepers. It is estimated that 10 per cent of our steam trawlers and drifters and their crews were lost during the war.
Fig. 17A.—The otter trawl.B.—Attachment of board to net. OB. Otter board. B. Iron brackets. C. Chain to connect with warps. M. Metal strengthening pieces. M′. Iron shoe. HL. Head line. UW. Upper wing. LW. Lower wing. LL. Lacing connecting wings. GR. Ground rope. D. Balch of lower wing. SSS. Twine settings connecting balch to ground rope. A. Headline and lacing connected to board by shackle. B. Toe of ground rope connected to board by shackle.C.—Bosom of a bobbin foot-rope for use on rough ground. AB. Balch line on head of belly and connecting with bosom of wings. SS. Wire seizings connecting balch to small intermediate bobbins, 6″ diameter (EE). Large bobbins up to 24″ diameter (FF).Larger image(187 kB)
Fig. 17
A.—The otter trawl.B.—Attachment of board to net. OB. Otter board. B. Iron brackets. C. Chain to connect with warps. M. Metal strengthening pieces. M′. Iron shoe. HL. Head line. UW. Upper wing. LW. Lower wing. LL. Lacing connecting wings. GR. Ground rope. D. Balch of lower wing. SSS. Twine settings connecting balch to ground rope. A. Headline and lacing connected to board by shackle. B. Toe of ground rope connected to board by shackle.C.—Bosom of a bobbin foot-rope for use on rough ground. AB. Balch line on head of belly and connecting with bosom of wings. SS. Wire seizings connecting balch to small intermediate bobbins, 6″ diameter (EE). Large bobbins up to 24″ diameter (FF).
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When steam trawling was first introduced it aroused general opposition, for there was not only the fear that their efficiency would lead to over-fishing in certain grounds, but it was said that the trawl, when dragged along the bottom, destroyed the eggs and killed the immature fish. The line fisherman found that steam trawling made it more difficult to catch demersal fish with baited hooks. He attributed this to the effect of over-fishing, but it is probable that contact with the otter trawls had made the fish rather more shy and, therefore, more difficult to catch by this method. It is unlikely that steam trawling will lead to serious over-fishing,except possibly amongst such sedentary fish as soles and plaice. It must be remembered that trawling is only commercially possible on comparatively smooth ground and down to depths of about 200 fathoms. Probably, therefore, the actual area trawled is only a small proportion of the total area that is inhabited by fish. It is possible, of course, that extensive and long continued trawling in a confined and relatively isolated area may scare the fish away; it is probable, however, that any area in which over-fishing appears to have produced temporary exhaustion will tend to recover automatically, since it would naturally be abandoned temporarily by the trawlers for more profitable fishing grounds. There is no doubt that trawling, unless the size of the mesh is carefully controlled, tends to remove large numbers of immature fish. Generally in ordinary beam trawling—cod, plaice, haddock, etc.—the mesh varies from 3 ins. diameter near the mouth of the net to about 11⁄4ins. diameter at the cod end. If a much smaller mesh were used the resistance encountered by a full-sized net would be so great that it would be almost impossible to draw the net through the water. Smaller trawls of1⁄2in. mesh are used in shallow coastal waters for catching shrimps, small plaice and whiting. The size of mesh largely determines the size of fish that will be retained by the net, since the smaller, immature fish readily escape through the meshes. Of recent years the various fishery boards, with a view to preventing the catching of such small, immature fish, have increased the size of mesh that is to be used—particularly when trawling within the three mile limit, where the greatest proportion of immature fish is generally encountered. For steam trawlers working in deep water a 21⁄2in. mesh is generally used, but within the three mile limit it is frequently increased from 3 to 31⁄2ins.
Fig. 18THE CATCH ABOARD
Fig. 18THE CATCH ABOARD
Herring are caught with drift nets at night near the surface. In the daytime they frequent the sea bottom and can then be caught with a trawl net. Trawling for herrings was first practised by the fishermen of Milford Haven and Fleetwood in 1901. They used an ordinary otter trawl lined with a piece of herring net. A specially constructed herring trawl is now used, of which the cod end is made of 21⁄2in. mesh instead of the usual 31⁄2in.
When trawling for herrings the steamer goes at full speed, generally for two to four hours, unless a shoal is encountered, when half-an-hour is frequently sufficient.
Herrings are trawled in from 70 to 100 fathoms of water over a soft bottom. The main centre for trawled herrings is North-West of Ireland, other fisheries being carried on off the South-West of Ireland, the West of Scotland, and in the North Sea. In 1913 over 500,000 cwts. of herrings were taken with trawl nets in these areas.
This method of catching herrings aroused serious opposition among the drift net fishermen. They asserted that the trawl catches and destroys a high proportion of immature fish, and also destroys the herring eggs as it passes along the sea bottom. In 1913 the matter was investigated by a Parliamentary Committee, but any Government action was checked by the outbreak of war.
Since 1905 the trawling grounds frequented by British steam trawlers have been divided for statistical purposes into eighteen fishing areas. The names and areas of these regions are shown in the chart of the trawling grounds (Fig. 19).
Table Ishows in hundredweights the average catch per day’s absence from port in different areas.
Fig. 19CHARTSHOWINGTRAWLING GROUNDSFrequented by British Trawlers, the “Regions” into which they are divided for statistical purposes, and the approximate area of each in square miles (Nautical) calculated from the 3 mile limit to the 200 metre line.No. of Region.Name.Approx. area insq. mls. nauticalI.White Sea128,917II.Coast of Norway29,648III.Baltic Sea134,891IV.North Sea129,804*V.North of Scotland (Orkney and Shetland)18,096VI.Westward of Scotland32,099VII.Iceland36,608VIII.Faröe4,949IX.Rockall3,430X.West of Ireland9,066XI.Irish Sea15,743XII.Southward of Ireland50,416XIII.Bristol Channel8,613XIV.English Channel25,238XV.West of France25,422XVI.North of Spain5,464XVII.Coast of Portugal9,997XVIII.Coast of Morocco10,499Total678,900*Excluding Area G, over 200 metres, and the Moray FirthLarger image(383 kB)
Fig. 19
CHARTSHOWINGTRAWLING GROUNDS
Frequented by British Trawlers, the “Regions” into which they are divided for statistical purposes, and the approximate area of each in square miles (Nautical) calculated from the 3 mile limit to the 200 metre line.
No. of Region.Name.Approx. area insq. mls. nauticalI.White Sea128,917II.Coast of Norway29,648III.Baltic Sea134,891IV.North Sea129,804*V.North of Scotland (Orkney and Shetland)18,096VI.Westward of Scotland32,099VII.Iceland36,608VIII.Faröe4,949IX.Rockall3,430X.West of Ireland9,066XI.Irish Sea15,743XII.Southward of Ireland50,416XIII.Bristol Channel8,613XIV.English Channel25,238XV.West of France25,422XVI.North of Spain5,464XVII.Coast of Portugal9,997XVIII.Coast of Morocco10,499Total678,900*Excluding Area G, over 200 metres, and the Moray Firth
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TABLE I190619131920White Sea40·1544·1225·45Iceland44·2246·1058·54Faröe31·1928·1927·03Rockall38·9839·2749·53North of Scotland25·0125·7627·31North Sea17·6014·0824·94English Channel11·368·9525·70Irish Sea15·6611·9418·79Bristol Channel13·1513·9826·38West of Scotland21·1828·1128·17West of Ireland21·4830·2225·87South of Ireland26·9723·7426·63Biscay15·9813·2218·73Portugal and Morocco6·5513·8119·29
In England and Wales more fish is landed by trawlers than by all other methods of fishing combined. Trawl-caught fish—soles, plaice, turbot, halibut, cod—are much more valuable than fish caught by drift nets, e.g. herring and mackerel. In England and Wales, in 1913, the weight of pelagic fish caught amounted to 389,262 tons, and of demersal fish 418,038 tons. Although the quantity of the demersal fish was, therefore, only little larger than of the pelagic fish, its value was £7,463,003, compared with £2,531,979, the value of the pelagic fish.
Shellfishare divided into two classes: Crustacea, including the lobster, crab, shrimp, prawn, and mollusca, including the oyster, mussel, cockle and periwinkle. Shellfish generally abound in comparatively shallow water near the shore.
Perhaps the most important members of the crustacea are the various minute, pelagic copepoda, of which incalculable myriads form an important constituent of the plankton in all seas. These copepoda live upon the diatoms and other microscopic, marine vegetable life floating at the surface of the sea. The most important edible members of the crustacea are the lobster and the shrimp.
The lobster is found along the coasts of the North Atlantic and Mediterranean, particularly along the European coasts from Norway to the Mediterranean, and off North America from Labrador to Cape Hatteras, The lobster lives in shallow water at about 12 fathoms depth, and frequents a rocky bottom. The lobster’s eggs remain attached to the female until the larvae hatch out. From 10,000 to 12,000 eggs are carried in this way by a female lobster. She protects them from the ravages of fish that will otherwise consume them as food, and by keeping them constantly irrigated with fresh sea-water she promotes their healthy life and development. The eggs may take as long as twelve months to hatch, and although “berried” lobsters are seen in greatest numbers in the spring they are also captured at all seasons of the year.
When hatched the young lobster larvae leave their mother and float up to the surface water, where they develop for a time among the plankton. During the larval period the lobster is a free and active swimmer.
The young larvae are consumed in large quantities by fish such as herring, mackerel and sprat, especially during the summer months when they are most abundant. While developing into a complete lobster it passes through at least three distinct changes of form. When the larva has attained the length of about 3/5 in. it already possesses many of the characteristic features of the adult. Soon afterwards, it sinks to the sea bottom and gradually grows into a complete adult. During the growth of the lobster it frequently casts its shell and grows a new one. Growth only takes place when the shell is cast and while the new shell is hardening. During the first few weeks of its life the lobster casts its shell about once a week, but this casting happens less and less frequently as the lobster grows older. The new shell is formed beneath the old one, and although at first quite soft rapidly hardens when the old one has been cast off. Most adult lobsters cast their shells in July, August and September.
A lobster grows slowly, and when from 9 to 10 ins. long is probably from four to five years old. It becomes mature when about 6 ins. long—that is when about three years old.
The lobster is usually caught in creels or “pots” baited with portions of stale fish—generally flounder, skate, eels, etc. Lobster fisheries tend to deteriorate in value very rapidly. Owing to the lobsters’ keen sense of smell, the method of capture by means of creels or pots is very efficient, so that the lobsters are caught in great numbers, with the result that the fishery soon shows signs of exhaustion, the average size of the lobstercaught becoming smaller. The lobster fishery is entirely confined to the shallow water near the shore, and can only be replenished and maintained by the young lobsters that hatch out in that neighbourhood. Large quantities of lobster spawn are destroyed every year when berried lobsters are caught. It is estimated that, on an average, 30 per cent of the lobsters caught are berried females. The fishermen either remove the spawn and throw it back into the sea—where, of course, it almost certainly becomes fish food—or sell it to be used in making certain special sauces.
Various attempts have been made by legislation in different countries to prevent the capture of berried females, and so protect the lobster spawn, but, since berried females are found all the year round and comprise about 30 per cent of all the lobsters captured, it is practically impossible to prohibit the capture of berried lobsters without seriously penalizing the fishermen.
A better policy would be to hatch lobster eggs in large numbers artificially, and when the young lobsters are well established add them to the natural stock. This is actually done on a large scale and with excellent results in America and Norway.
In Europe lobsters are generally sent to market in a fresh state, but in America they form the basis of an extensive canning industry. In 1913 over 2,500,000 lobsters were captured round the coasts of Great Britain and Ireland, the total value of the fish being more than £110,000.
Shrimping is one of the most important methods of inshore fishing, and gives employment to a large number of fishermen round our coasts. The shrimp is found on sandy or muddy ground in shallow water near the coast. A female shrimp, like the lobster and the crab, carries its eggs under its tail.
Shrimps are caught with a fine-meshed trawl net, drawn by a boat or by horse and cart, or with push nets or hose nets. One great objection to shrimping is that the shallow, sandy areas on which it takes place are much frequented by young fish—particularly dabs, plaice, soles, whiting and codling. Owing to the small mesh of the shrimp trawl, these small fish are captured in large numbers and are generally dead or dying when discharged from the net. Generally, the shrimps are separated from the small fish by riddling, and the smaller shrimps are then separated from the larger ones by a second riddling process, and are returned to the sea. The shrimps are thrown into boiling salt water, rapidly stirred for a few seconds, and spread out on the deck to cool. From three to four hauls are made per day, a good day’s fishing consisting of from 30 to 40 quarts of shrimps. Large numbers of shrimps are potted.
The other important group of shellfish is the mollusca. Molluscs, i.e. “soft creatures,” are essentially soft, mobile animals, protected by shells. They are classed as bi-valves, for example oyster and mussel, and uni-valves, for example limpet and whelk. There is no real difference between a bi-valve and a uni-valve, for what appear to be the two shells of the bi-valve are really one shell divided into two parts by a line of soft, uncalcified material which forms a hinge between the two halves of the shell; this hinge tends to keep the shell open, but the muscular action of the living animal inside keeps it closed when required.
With the exception of the mussel, very few shellfish actually live on the shore between the tide marks. Most of the seashore shells are brought by the sea from animals that lived in from 10 to 20 fathoms of water. The cockle lives buried in the sand, about an inch belowthe surface. The oyster lives on stones and shells below low-water mark.
All molluscs are attached tightly to the shell at one or two points, and cannot be removed from the shell alive. In the case of the bi-valves the animal is attached to the two shells by a muscle which draws the two valves of the bi-valve together. When this muscle is relaxed, for example in normal circumstances, when feeding at the bottom of the sea—the shell remains open. Some shellfish—notably the scallop—actually swim by opening and shutting the two valves of their shell.
The most important uni-valves are the periwinkle, the limpet and the whelk. Uni-valves possess a well-marked head and neck, a pair of eyes and a mouth. They are remarkable for the possession of a tongue, formed like a ribbon rasp, furnished on its upper surface with a large number of small teeth. The number and arrangement of these teeth differ in different species. With this ribbon rasp the uni-valve, for example a dog-whelk, can rasp a hole through the shell of an oyster and feed upon the contents.
Bi-valves do not possess a ribbon rasp, neither have they a projecting head, nor in most cases any eye. They possess a mouth, furnished with four flapper-like lips or gill plates. They feed on microscopic, floating plants that are drawn within their mouth by currents set up in the water by the rhythmic vibrations—from three to four hundred strokes per minute—of millions of hairs that hang down from soft plates supported under the protecting arch of the shell and called the “beard.” These currents of water not only bring food to the mouth of the bi-valve, but also irrigate the gill plates and so enable the animal to breathe. The oyster lies on the sea bottom with its muscle relaxed and its shell gaping.
A North European oyster acts alternately as female and male. It produces eggs—as many as a million in a season—and a fortnight after the eggs have been shed, the same oyster produces millions of spermatazoa, which form a cloud of fine dust in the water. These spermatazoa rapidly scatter in all directions, and, entering the tubular reproductive sacs of oysters that are producing eggs, fertilize them.
American and Portuguese oysters are definitely male and female, the eggs being discharged by the female and fertilized subsequently in the sea by the male.
The eggs remain attached to the parent’s gill plates, and in a day or so develop into minute, shell-less oysters. The parent oyster is then said to be “white-sick.” About two days later the young oysters have become dark-coloured and are found to have formed minute convex shells, rather like those of a cockle. The parent is then “black-sick.” A week later the young oysters escape and rise in thousands to the surface water, swimming by means of fine hairs or cilia that are attached to the upper edge of the shells. They are carried far and wide by tides and surface currents. Many are eaten by young fish and shrimps. As they grow the shells become heavier, and after a time they sink to the sea bottom. This is known as the “fall of spat.” If they fall on stony ground, where they will be well irrigated and nourished through the movement of the water, they will thrive. Many, however, fall on soft, unsuitable ground and perish.
The European oysters spawn in the summer (from May to September). They become mature in three years, are at their prime in from five to seven years, and rarely live longer than ten years.
Oysters are gathered from natural beds or from artificial grounds. The oyster breeders place movabletiles or frames for the spat to fall on. When the young have become affixed to these “stools” they are frequently carried away to develop in a different locality. The oysters are finally fattened in sea ponds or inlets that contain a large diatom population. At Marennes, on the west coast of France, the water in which the oysters are grown contains a particular blue diatom. After feeding upon these diatoms, the beard of the oyster becomes stained a bluish-green colour—the well-known “Marennes vertes” oysters.
A natural oyster bed is formed on stony ground free from mud and sand, so that the oyster, after becoming attached to a stone, is completely surrounded by clear sea-water. Oysters do not flourish in water containing less salt than ordinary sea-water. Thus, there are no oysters in the Baltic Sea.
The chief enemies of the oyster are the dog-whelk that bores through the shell, and the starfish that pulls the valves apart and attacks the oyster inside.
The oyster is widely distributed in tropical and temperate seas all over the world. The approximate value of the annual oyster crop of the world is £4,000,000, representing a crop of 10 billion oysters.
In Europe up to 75 per cent of the oysters are reared from spat in artificial beds—not more than 7 per cent being “native.” In the United States, however, over 40 per cent are still obtained from natural beds.
The simplest form of oyster culture is the preservation of the natural bed. These beds are easily destroyed or made unproductive by over-dredging. Colonies are broken up. Other animals are admitted. Breeding oysters are covered up by stones and shells, and suffocated. Ridges suitable for the development of the spat are broken down.
After the beds have been properly protected andpreserved the next stage is to extend the area of the natural beds. This involves a knowledge of the conditions of depth, temperature, salinity and character of bottom that are necessary to the successful growth of the oyster. Finally the productivity of an oyster “park” and the quality of its produce can be greatly improved by providing artificial “stools” for the reception and development of the spat. Many substances can be used for this purpose. The Romans used earthenware tiles, and similar tiles are used to this day in France. Brushwood, trees, stones and stakes, and old oyster shells (cultch) are also used.
The earthenware tiles used in France are hollowed on one side to receive the spat, and are coated with lime to facilitate the removal of the oysters when they are a year old. They are then from1⁄2to 1 inch in diameter, and are picked off the stools and placed on stands where they are thinned out from time to time as they grow.
The chief oyster fisheries in Britain are at Whitstable, Colchester and Brightlingsea. Nearly 40,000,000 oysters were gathered on the coasts of England and Wales in 1920, and were sold for about £250,000.
Perhaps the next most important edible bi-valve is the mussel. Frequently, mussel beds are situated near the mouth of rivers, and consequently tend to be contaminated by sewage. It has been established by various investigators—notably Dr. Klein and Professor James Johnstone—that mussels are able to cleanse themselves of sewage pollution in a comparatively short time if they are re-laid in sterilized water. Experiments on a large scale have been carried out with the mussel beds at the mouth of the Conway river since September, 1916. The mussels are gathered from the beds and placed about two deep on wooden grids in a largeconcrete cleansing tank of 40,000 gallons capacity. The mussels are first thoroughly hosed with water at high pressure to remove all adherent mud, etc. The tank is then filled with sterilized sea-water and the mussels are allowed to remain in it for 24 hours. During this period the mussels effectually free themselves from bacteria. The tank is then emptied, the mussels are hosed again, the tank is again filled with sterile water and after a further 24 hours is emptied. The mussels are once more flushed with the hose. After this treatment the mussels reach a high standard of purity. The scheme has proved to be a complete success, not only from a scientific point of view, but also as a commercial proposition. The sum of 1s. per bag of mussels (140 lbs.) is charged to the fishermen for this treatment.
Whalesare the most important members of a large family of land animals including also the seals, walrus, and porpoise, that have gradually become adapted to live in the sea. They have acquired an externally fish-like form, but in every other respect they retain the characteristic features of mammalian structure. They are warm-blooded, air-breathing quadrupeds, that suckle their young. In the whale, the fore-limbs have become simple five-fingered flippers, while only isolated, vestigial bones of the hind-limbs remain buried uselessly in the body. Unlike fishes, the tail is set horizontally, thus enabling the creature to rise easily to the surface to breathe. The warm-blooded body is kept warm by a layer of fat placed immediately beneath the skin, and varying in thickness from 8 to 20 ins., and known as the blubber. The nostrils, instead of being situated at the end of the snout, are placed far back at the apex of the head to form the blowhole.
Whales are divided into two well-marked groups, known as the whaleboned and the toothed whales respectively, according to the particular form of their dentition.
The most important of the whaleboned whales is the Greenland, or Arctic Right, whale. It attains a length of upwards of 45 to 50 ft., and is remarkable for the enormous extent of its head and mouth cavity. The head extends for a third of the length of the body, so that the mouth cavity may be as much as 18 ft. long, 12 ft. broad and 11 ft. in height, the dimensions of a small chapel! The upper jaw is narrower than the lower and arches backwards, thus increasing the actualheight of the mouth cavity and providing ample room for the blades of whalebone with which the jaws are furnished in place of teeth. These blades of whalebone number about 380, and range in length from 8 ft. to, in exceptional cases, 12 ft. They are suspended in the mouth of the whale like stalactites, set fairly close together, and, since the edges of each blade are fringed with fine whalebone, the whole arrangement forms a very efficient strainer. This enables the whale to feed upon the plankton—or “krill,” as it is called by the whalers—and small fish, e.g. herring and capelan. The whale fills his enormous cavern of a mouth with water containing the floating food particles, and then, by raising his tongue, slowly expels the water through the whalebone sieve. The food particles are retained by the whalebone, and are then licked off and swallowed.
The Greenland whale inhabits the Arctic seas north of latitude 54°N. A closely related variety, the Bowhead whale, forms the basis of a fishery in the Behring Sea.
The largest whales known are the so-called Rorqual whales. The name of these whales is derived from the large number of longitudinal folds or pleatings that form a characteristic feature of their throat. Rorqual whales attain a length of from 80 to 85 ft. The head is relatively small, and the long, slender body carries a distinct dorsal fin. The whalebone is coarse and short. The Rorqual whales are the most abundant and widely distributed of all whales. They are found in all open seas, with the exception of those in the extreme Arctic and Antarctic regions.
The Southern Right whale, or Black whale, is found in the temperate seas of both Northern and Southern hemispheres.