Page images
PDF
EPUB

Appendix D.

NATURAL ENEMIES.

whale.

The only important enemy of the fur-seal The killerknown to man is the killer-whale (Orca gladia

tor). These killers visit the islands on their way north about the end of April, and return in September. In the fall they hug the shore, keeping in the kelp or moving about the rocks as near inshore as they find sufficient water to float in. They are sometimes seen in squads circling round and round the islands, catching young pups by dozens. At first the pups are said to pay no attention to the enemy, sometimes swimming right into the killer's mouth, but before the end of the season they learn what the presence of the killer means, and rush out of the water and up on the rocks whenever one comes near shore. The killers generally arrive early in September, and remain as long as the pups stay, which is usually until the latter part of November.

391

Appendix E.

FOOD OF THE FUR-SEAL.

CONTENTS OF STOMACHS OF FUR-SEALS KILLED AT

THE PRIBILOF ISLANDS.

August 1-3, 1891.

Examination

Islands.

One hundred and eighteen stomachs of fur-made on Pribilof seals were examined jointly by the United States and British Bering Sea Commissioners at St. Paul and St. George Islands, August 1 and August 3, 1891, with the following results:

stomachs.

All the stomachs were opened immediately Contents of after the seals were killed. Ninety-three out of

the one hundred and eighteen were empty, except for the presence of a little mucus, bile, frothy slime, dark brownish blood, and parasitic worms. Blood in some form was present in five stomachs, and nematode worms about three inches in length were found in most of the stomachs opened.

Twenty contained pebbles, or pebbles and beach-worn shells, either alone or in connection with other contents, the quantity varying from from a single small pebble to a handful.

2716-50

393

Contents of

stomachs.

Examination

made at Wash

ington, D. C.

Four contained beaks of squid or cuttlefish (identified by Dr. William H. Dall as probably Gonatus fabricii), of which three sets were in one stomach, two sets in another, and one each in the remaining two.

Two contained fish bones, of which one consisted of the vertebræ and a few other bones of a cod (Gaddus morrhua); the other the ear bones of a similar fish.

One contained a large Isopod crustacean (identified by Prof. Sidney I. Smith as "apparently a species of Rocinela, a genus very close to Æga").

One contained a small bit of kelp.

CONTENTS

OF STOMACHS OF FUR-SEALS KILLED

IN THE NORTH PACIFIC OCEAN.

April 22-May 1, 1892.

The stomachs of 104 fur-seals killed by pelagic sealers in the North Pacific off southeastern Alaska, April 22-May 1, 1892, between latitude 56° 45' and 58° 58', and mostly sixty to eighty miles from shore, were examined by the naturalist of the United States Fish Commission steamer Albatross. Of the 104 stomachs, 67, or 64.4 per cent. were empty. Of the remaining 37, 30 contained 37 fishes and 18 contained 728 squids or cuttlefish.

stomachs.

Most of the stomachs containing food have Contents of been submitted to us for examination, and the fishes have been identified by Dr. Tarleton H. Bean, Ichthyologist of the United States Fish Commission.

Of the 30 containing fishes, 15 contained red rock fish or rock cod (Sebastichthys, 5 of which were found in 1 stomach, making 19 in all), 2 contained salmon, 2 pollock (Pollachius chalcogrammus), 2 ling, 1 stickleback (Gasterosteus cataphractus), and 9 small fishes too much digested to admit of ready identification. Two contained pebbles, and several intestinal worms.

Although squids were found in only 18 of the 37 stomachs containing food, a large number were generally found in each stomach—as many as 419 beaks in one instance, and 319 in another. In all, 1,456 beaks, representing 728 squids, were found in the 18 stomachs, an average of 40 to each seal. Owing to the small size of the individual beaks, particularly those of the younger squids, many were probably lost in emptying and transferring the stomach contents, so that the number here given is certainly below the number originally contained.

« PreviousContinue »