212 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 

 ARTIFICIAL PROPAGATION. 



The artificial propagation of mackerel was more extensively prose- 

 cuted in 189G than in any previous year. The long-contiuued scarcity 

 of mackerel on the Atlantic coast of the United States seemed to 

 warrant some eflbrts on the part of the Government to increase the 

 supply by artificial means. The limitations of mackerel culture dei)end 

 on the erratic movements of the fish in a given season or on a given 

 part of the coast and the difiiculty of securing healthy eggs in large 

 quantities from fish taken by the commercial fishermen. During the 

 summer of 189G, 24,000,000 mackerel eggs were collected. The work 

 was largely experimental and only a small percentage of fry was hatched, 

 but the outlook is good for a great expansion of mackerel propagation. 



The egg of the mackerel is one of the smallest dealt with by the fish- 

 culturist, being only -.^^ inch in diameter. Being provided with a large 

 oil-globule, it floats at the surface, like the eggs of many other marine 

 fishes. Within 48 hours after fertilization it generally begins to sink, 

 remains iu suspension a short while, and then falls to the bottom, 

 where it remains until hatching ensues. 



Owing to the inability to retain mackerel in ponds or live-cars pend- 

 ing the ripening of the eggs, as is done with the cod, it is necessary to 

 depend for the egg supply on the nets of the fishermen. The eggs 

 collected at Woods Hole are secured from fish captured in pound nets 

 near Chatham and at other points on the southern Massachusetts coast; 

 at Gloucester traps in the vicinity furnish the eggs. As the nets are 

 usually hauled only once or twice a day, the fisli have often been caught 

 for many hours, and the tender eggs have undergone considerable loss 

 of vitality; the quality of the eggs seems to have a direct relation to 

 the length of time the fish have been in the nets. 



One of the most favorable grounds for collecting mackerel spawn is 

 Casco Bay, on the coast of Maine. Mackerel are taken chiefly in drag 

 nets set about 4 o'clock p. m., and hauled from 9 o'clock p m. to day- 

 light. Eggs from fish caught iu the first hauls of the nets are of much 

 better quality than those taken in the last lifts. 



In collecting eggs from pound nets the spawn-takers accompany the 

 fishermen when they visit their nets and overhaul the mackerel as they 

 are taken into the boats. The collection of eggs from the drag-net 

 fishermen requires the si^awn-takers to remain on the fishing-grounds 

 from early in the afternoon until the next morning. 



There is nothing peculiar in the methods of stripping the fish, mixing 

 the eggs and milt, and transferring the eggs from the field to the hatch- 

 ery. Although both the wet and the dry methods of fertilization have 

 been practiced, the latter apparently gives better results. The average 

 number of eggs taken from a fish is probably about 40,000. Three 

 mackerel, stripped at Woods Hole in 1893, yielded 434,500 ripe eggs, an 

 average of 144,833 eggs. As many as 546,000 eggs have been taken 

 from a 1^-pound fish, aud the largest fish probably yield fully 1,000,000 



