Lobster fishing in Ceylon Item Type article Authors De Bruin, G.H.P. Download date 26/09/2021 18:03:04 Link to Item http://hdl.handle.net/1834/32108 1 PUBLISHED BY THE FISHERIES RESEARCH STATION, CEYLON PRINTED AT THE GOVERNMENT PRESS, CEYLON FISHERIES RESEARCH STATION DEPARTlVIENT OF FISHERIES, CEYLON Bulletin No. 9 LOBSTER FISI-IING IN CEYLON by G. H. P. DE BRUIN, (Research Officer, Department of Fjsherjes) 1960 CONTENTS PAGE INTRODUCTION 5 LOBSTER TRAPS USED IN EXPERIMENTS 7 EXPERIMENTAL OPERATIONS ON THE EAST COAST 9 EXPERIMENTAL OPERATIONS ON THE WEST COAST 10 LOBSTER GROUNDS 13 CATCH PER UNIT TRAP 16 DEVELOPMENT OF A COLLAPSIBLE LOBSTER TRAP 17 SUMMARY 18 LIST OF TABLES I. NUMBER OF LOBSTERS CAUGHT BY 10 SETS OF EACH DESIGN OF TRAP 10 II. NUMBER OF LOBSTERS CAUGHT BY 10 SETS OF TRAPS OF 4 DIFFERENT TYPES (AFTER MODI· FICATIONS TO CREEL AND TRAP OF NEW DESIGN) 11 III. CATCH PER UNIT TRAP IN GENERAL • • 16 IV. CATCH PER UNIT TRAP ROUND LIHINI GALA 16 LIST OF FIGURES 1. CANADIAN "PARLOUR AND BED-ROOM" 7 2, SCOTTISH CREEL 7 3. CORNISH "INK-WELL" 8 4. CANE-TRAP (NEW DESIGN) 8 5. CREEL AFTER MODIFICATION 10 6. TRAP OF NEW DESIGN AFTER MODIFICATION 10 1. (a) DISTRIBUTION OF LOBSTERS ON EAST COAST BETWEEN TRINCOMALEE HARBOUR AND BOULDER POINT 12 (b) DISTRIBUTION OF LOBSTERS ON EAST COAST BETWEEN PASSIKUDAH AND KALKUDAH 12 8. DISTRIBUTION OF LOBSTERS OFF COLOMBO 14 9. DISTRIBUTION OF LOBSTERS IN GALLE HARBOUR 15 10. COLLAPSIBLE TYPE OF TRAP 17 J. N. R 9154-758 (4/60) INTRODUCTION THE presence of spiny lobsters in the reefs The above methods suffer from several lying off the coasts of Ceylon is known to disadvantages. First and foremost, the fisher­ local fishermen and skin divers. However, man has to remain idle out at sea watching a well established fishery for these lobsters his gear. Secondly, the chances of his losing does not exist as fishermen engaged occasionally his gear, if he were operating with nets, are in this activity catch only a few lobsters during great. Finally, the returns are very poor the course of a day's fishing. due perhaps to the inefficiency of his gear. The gear that is used in some parts of the In contrast to this, the methods employed Island, such as in the Galle harbour, is very in western countries to capture the lobster similar to the device employed by crab fishermen Homarus vulgaris Edw. possess several to capture the crab Scylla serrata (Forsk.). advantages over the methods used in Ceylon. This device consists of a heavy iron ring about Fishermen set their traps at the beginning of 2-! ft. in diameter carrying a conical shaped the season and thereafter go out each day to net. A rope is stretched across the diameter collect the lobsters, rebait the traps or to of this ring and the bait is fixed at the middle of the rope. The bait generally used is animal shift the traps to different ground. No time entrails. Three strands of rope are attached is wasted in watching the traps. The gear is to the ring at three points on its circumference. very sturdy and seldom damaged. It is lost The free ends of these strands are joined to a only in very rough weather. Moreover, the single rope which is used to haul the gear out designs that are used have been exhaustively of the water. About four or five of these tested as lobsters which enter the traps seldom structures are carried on an outrigger canoe escape. to the grounds where lobsters are known to Considering the present state of development exist. The fisherman sets his gear about 10 to of lobster fishing in Ceylon, it is not possible 15 yards apart and hauls them for inspection to state whether lobsters are found in sufficient after about 15. minutes. Hauling has to be numbers in the seas off Ceylon. This know­ quick and continuous since experience has ledge is very important before the introduction taught the fisherman that any sudden jerk of new methods of fishing can be made. during the process of hauling would result in Experiments were therefore conducted to the escape of the lobsters. determine the most efficient type of trap that Another device used by local fishermen is could be used to appraise the resources present " bottom set nets ". These nets are those in the coral reefs and other rocky areas. discarded by commercial drift net fishermen Designs of traps, similar to those used in and are very old. The nets are set before Scotland, England, Wales and Canada, were sunset and hauled in the early hours of the made locally. These were tested for efficiency morning. Very often the nets get caught to in areas known to be inhabited by spiny coral· and rock and seldom is it possible to lobsters. recover them intact. The space on the outrigger canoe, which is Apart from these two methods fishermen the craft commonly used by local fishermen also catch spiny lobsters with a baited is restricted. Attention was therefore directed hook and line. Of the three methods in use, to convert the most effective trap into a this is the most unsatisfactory as it gives the collapsible form so as to be able to carry smallest catch. economically sufficient numbers of traps. LOBSTER TRAPS USED IN EXPERIMENTS Some of the popular traps employed to capture iron of ! inch in diameter. Quarter inch lobsters in western countries are the Canadian round iron bars were welded to the base "parlour and bed-room", the Scottish creel 1! inches apart and similar bars were used and the Cornish "ink-well ". These three for the top and the doors. Cotton types as well as another of a new design were netting was employed to make the funnel used in the tests to capture the spiny lobster shaped entrances and to cover the sides in Ceylon. These traps are described below : of the trap. The dimensions of the trap were 32 inches long, 20 inches broad (a) Canadian "parlour and bed-room ". The and 12 inches in height. Each trap "parlour and bed-room" type which is weighed 40 lbs. when complete. used on the east coast of Canada is divided into two compartments. Two (b) Scottish Creel. Typically, the Scottish funnel shaped entrances situated creel has two funnel shaped entrances immediately opposite each other lead situated diagonally opposite each other into one compartment-" the parlour". leading into a single chamber as seen in Each of these funnels has a brass ring fig. 2. The funnel shaped entrances, six inches in diameter at the inner end. in the traps used in the experiments A third funnel shaped entrance but were provided with brass rings 6 inches in without an inner ring leads from the diameter at their inner ends. " parlour " into the second compartment The creels were similar in dimensions of the trap-the " bed-room ". This to the Canadian type and were constructed entrance into the bed-room is situated out of the same material. Each weighed at right angles to the two entrances 40 lbs. when complete. leading into the " parlour " as seen in fig. 1. Canadian lobster fishermen use Fig. 1. Canadian "parlour and bed-room". Fi),;. 2. Scottish Creel. wood to construct the frames of their (c) Cornish " ink-well". The traditional lobster pots and cover the frames with large Cornish pots are made of willow. netting. In place of wood, which needs The "ink-wells" used in Ceylon were heavy ballast to sink, the frames of the however made of cane. As the name traps used in the experiments were made of implies, the base of the ink-well type of 1 trap is circular and was 3 ft. in diameter weighing 50 lbs. was therefore firmly in those used in the experiments. The secured to the base of the trap. This rim of the ink-well was 1 ft. in diameter proved sufficient to sink the trap and while the inner end of the funnel leading anchor it in calm weather. from the rim into the trap was 5 inches (d) Cane-Trap (new design). This trap was in diameter. Arches of stout cane i inch constructed for the purpose of comparison in thickness were fixed 2 inches apart with the " ink-well " type of trap and from each other to the base of the trap was made of cane. Unlike the" ink-well" and the rim. These arches were joined type, the entrances are situated at the to each other by circles of cane i inch sides as seen in fig. 4. The base of the in thickness. Cane rods i inch in thick­ ness were fixed 2 inches apart across the base of the trap and were secured by i inch cane rods 2 inches apart. As can be seen in fig. 3 the entrance into the trap is at the top. A lobster can gain access to the bait within the trap only after climbing to the rim of the trap and then crawling down into its recesses. Fig. 4. Cane-Trap (new design). trap and the cone shaped entrance are of the same dimensions as in the " ink-well " type. In place of arches, semi-circular hoops of cane i inch in thickness were fixed to the base of the trap and were secured one to another by circles of cane i inch in thickness situated 2 inches apart. Fig. 3. Cornish "ink-well", As in the "ink-well" type, a heavy The cane "ink-wells" needed ballast iron ring 50 lbs.