brought together scientists actually involved with polar bears in their respective countries and resulted in the formation of an active international polar bear specialists group. The 1968 meetings and subsequent meetings in 1970 and 1972 provided for exchange of information, joint analysis of research needs and priorities, the coordination of several phases of research, and consideration of an international treaty for polar bear research and management.

During its 1972 meeting, the polar bear specialist group was asked by the IUCN to consider the need for an international treaty. After the group learned that proposals had been made, or would soon become effective, that would stop hunting on the high seas, it suggested there was no immediate need for a treaty, a protocol was suggested whereby each country would sign a statement agreeing not to harvest bears on the high seas. The IUCN will circulate such a protocol.

The IUCN, realizing that a treaty will probably come up for consideration in the future, is revising the draft treaty considered at the February 1972 meeting, based on discussions at this meeting.

Pending legislation

The State of Alaska's position on pending ocean mammal protection legislationu was stated in House subcommittee hearings on such legislation in September 1971. Briefly stated, Alaska's position is that the State should retain exclusive management jurisdiction of those marine mammals and other resident species which occur on its land areas and in territorial waters when such species are not endangered and the State has a sound and effective research, management, and enforcement program for them. Past and present activities and plans for the future demonstrate that Alaska's program for polar bears meets these criteria. Alaska therefore believes that management jurisdiction on polar bears, and especially of those animals occurring within its territorial bounds, should remain with the State.

REFERENCES CITED

Lentfer, J. W. 1972. Polar bear sea ice relationships in Bears-Their Biology and Management, I.U.C.N. Publ. New Series No. 23.

Lentfer, J. W. 1972. Alaska polar bear research and management, 1970-1971. Proceedings of the Third Working Meeting of Polar Bear Specialists, I.U.C.N. Morges, Switzerland.

Manning, T. H. 1971. Geographical variation in the polar bear (Ursus maritimus Phipps). Canad. Wildl. Serv. Rpt. Series No. 13.

Senator HOLLINGS. We are going to hear this afternoon Dr. Perrin and Dr. Small. The other witnesses will be offered an extensive opportunity to testify the week after next when we convene again for another 2 days. We will only be able to have Dr. Perrin and Dr. Small this afternoon.

The committee will reconvene at 2 o'clock. Thank you for coming, gentlemen.

We will stand in recess.

(Whereupon, the committee recessed at 1:10 p.m., to reconvene at 2 p.m., the same day.)

AFTERNOON SESSION

Senator HOLLINGS. The committee will please come to order. We will start this afternoon with Mr. William Perrin.

STATEMENT OF WILLIAM F. PERRIN, FISHERY BIOLOGIST, NATIONAL MARINE FISHERIES SERVICES, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE

Mr. PERRIN. My name is William Perrin, fishery biologist, a member of the Population Dynamics Group at the Southwest Fisheries

Center of the National Marine Fisheries Service located in La Jolla, Calif. I have organized my statement around three major topics.

First, I will briefly summarize the history of the problem. Next, I discuss the species of porpoise involved, their distribution and life history. Lastly, I will review our research effort.

American fishermen have been fishing for tuna off Mexico and Central America since the early 1930's. As early as 1932 an American tunaboat fished as far south as the Galapagos Islands. In the 1930's, 1940's, and early 1950's, however, almost all tunafishing in tropical waters was done not by purse seiners, but by "baitboats," boats using live bait and hook and line. This was because the cotton nets then in use would not stand up to the warm water; they rotted so fast that it was not economically feasible to use them. Purse seining was for the most part restricted to the cold water tuna fisheries.

In the 1950's, the American fishermen were caught in an economic squeeze by low priced imports of Japanese-caught tuna. They had to become more efficient. This coincided with the availability for the first time of nets made of synthetic fibers that would not rot in warm water. The first nylon tuna net was fished by a Peruvian boat in 1954.

In 1957, the first American baitboat was converted to purse seining. A chain reaction followed, and by 1961, 75 U.S. distant water vessels were converting or undergoing conversion. The direct involvement of porpoise in the tropical fishery dates from this period. The fishermen had known for a long time that tuna and porpoise run together. In the baitboat days, they often found fish by spotting the splashes of the porpoise above them. They did not have much luck, however, in catching these fish.

When they stopped the boat in the middle of a porpoise school to catch the fish with it, the porpoise usually moved away in a very short time, taking the fish along.

When these same boats became equipped with purse seines in the early 1960's, the art of catching tuna traveling with porpoise developed very rapidly. The fishermen found that if they can set the net around the porpoise school, they usually get the associated fish. They began to put aboard high-powered speedboats.

When a porpoise school senses the approach of a tunaboat, it begins to run. The job of the speedboats is to consolidate the porpoise and slow them down so the net can be gotten around them. This corralling procedure, which may take only a few minutes or as long as a half-hour, is controlled and coordinated by radio from the crow's nest of the tunaboat. Most of the larger seiners now launch four chaser speedboats for each set.

We do not know why the porpoise and tuna school together, but the association is very tight. Often, a piece of the porpoise school evades capture, and that piece may take all the fish with it.

Therefore, fishing success depends to a great degree on the captain's ability to encircle with the net the entire porpoise school. A school may consist of anywhere from a few dozen porpoises to several thousand.

The yellowfin tuna fishery associated with porpoise has become a major part of the overall yellowfin tuna fishery in the eastern tropical Pacific. This is evident from the records of the Inter-American

Tropical Tuna Commission, and is shown in the table which is included.

I won't read the table but I request it be made part of the record. Senator HOLLINGS. It will be included.

(The table follows:)

YELLOWFIN TUNA CATCH FROM PORPOISE SCHOOLS IN IATTC YELLOWFIN REGULATORY AREA (YRA) OF THE EASTERN TROPICAL PACIFIC, 1966-70

[Unpublished data from IATTC; all landings rounded off to nearest 1,000 short tons]

The table shows that on the average, about one-half of the yellowfin tuna taken in the area regulated by the Commission are taken from porpoise schools. We do not have data for the area of the eastern Pacific tuna fishery that lies outside the regulatory area. Once the net has been set around the whole school complex, and the bottom of the net has been "pursed," or closed off to prevent escape of the fish straight down, the problem arises of releasing all of the porpoises alive, without losing the fish.

Considerable effort is given to getting the porpoise out alive, for two very practical reasons: (1) The porpoise obviously will not be of much use as future indicators and aggregators of tuna if they are dead, and (2) if they die in the net, then they must be hauled aboard and laboriously separated from the fish, wasting many hours of valuable fishing time and causing extra wear and tear on the net and handling equipment.

A net ripped because of too much weight can take days to mend. The point is that the fishermen try very hard to get the porpoise out alive, because it is to their immediate and long range benefit to do so.

To do this, soon after they started fishing on porpoise in the early 1960's, they developed a procedure they call "backing down." They first haul in about three-quarters of the net with no fish. aboard yet they are still in the net. Then they wait until the porpoise are at the surface near the far side of the net circle and the fish are close to the boat, whereupon they run the engines full reverse, sinking the corkline a few feet under at the far end of the net and moving the whole net through the water. The effect is to pull the net out from under the rafting porpoise. This is a very delicate operation, because if the fish find the opening, they too will escape. The man in the crow's nest watches the fish closely, and if they head toward the porpoise, he immediately runs the engines forward, causing the sunken corkline to bob to the surface.

The majority of the porpoise in the net are gotten out with the backing-down operation. Sometimes it works extremely well, and every last animal escapes. Other times it is less successful because the currents, winds, or gear malfunction cause the net to collapse, leaving very little water surface area inside the net.

Backing down is also less efficient when there is a very large catch, either of fish or porpoise, large being over 100 tons of fish and/or 1,000 porpoise.

During the backing down, men in skiffs at the corkline help get the porpoise started over the corks. They also disentangle animals caught in the webbing near the surface.

After backing down, when the net has been hauled almost all the way in and is being brailed, or emptied of the fish catch, crewmen jump into the "sack" and lift remaining live porpoise over the corkline. This is very dangerous because often there are large sharks in the net.

The porpoise that die in the net apparently suffocate after becoming entangled in the webbing underwater. Underwater movies show that they often swim headlong into the webbing and twist up in it even when there is an escape opening nearby. We don't know why they do this.

In the last year, there has been a major technological development that bears on the problem. Last spring, a captain named Harold Medina developed a net modification. He replaced a large section of the net in the backing down area with smaller-than-usual mesh webbing-2-inch mesh instead of 414-inch mesh. The idea is that the porpoise are less likely to become entangled when they hit the net if the mesh openings are smaller.

This modification is rapidly being adopted by the entire fleet and is a definite improvement. From the data available to us now from four cruises with the new net, we estimate that it has cut porpoise. mortality by as much as 75 percent. On the average, about 90 percent of the encircled porpoise are saved by using the modified

net.

That is the history of the problem to date. Now I will turn to the animals.

I have to emphasize at the outset that our knowledge of these animals is fragmentary. They are very difficult to study because they are large, elusive, and occur in areas distant from research centers. The study of small cetaceans is decades behind the study of terrestrial mammals, and the situation is especially bad for the tropical forms.

First, I'll run down a list of the species. As far as we can determine at present, there are eight species of porpoise involved in the fishery; three in a major way, and five in a very minor way.

The most important is the spotted porpoise. Spotted porpoise from the tuna fishery have been referred to the species Stenella graffmani, but the relationship between these animals and a similar spotted porpoise in Hawaiian waters and the western Pacific, referred to as S. attenuata, is not clear.

They may belong to a distinct species or may be only geographical races of the same species. There are two forms of spotted porpoise in the eastern Pacific. One, which is larger, up to 250 pounds, occurs

very near the coast and around islands from the Gulf of California in the north to Colombia in the south in small schools, and apparently is not involved in the fishery.

The fishermen do not set their nets on these animals because they do not congregate with tuna. The other form is smaller, up to about 180 pounds, and occurs farther offshore in large schools that wander over areas hundreds of miles square. This is the porpoise most sought by the fishermen. They call it "spotter." It occurs at least as far west as 145° west longitude, about two-thirds of the way to Hawaii.

We suspect that there is a gap in the distribution between these animals and the Hawaiian spotted porpoise, but we need more data before we can be certain. We do not know what the population size is and there are no good estimates.

The second kind of porpoise involved to a major extent in the fishery is the spinner porpoise. Again the relationships between this animal and the spinner porpoises in other parts of the world are not clear, but we are provisionally calling it Stenella longirostris.

As with the spotters, there are two sorts of spinner porpoise in the eastern Pacific, but both are involved in the fishery. One occurs from Baja, Calif., to Colombia and seaward about 500 miles and is called "spinner" by the fishermen.

The other, different in coloration and in form of the appendages, occurs farther offshore and is called "whitebelly spinner." For the time being, we are assuming that these are geographical variants of the same species, but they may be distinct. They are both small animals; adult females may weight as little as 85 pounds.

Again there is an apparent break in the distribution of spinner porpoises between 145° west longitude and Hawaii.

Spotted porpoise and spinner porpoise occur together in large school complexes with single-species subunits. The makeup of the mixed school ranges from all spotters to all spinners.

The fishermen usually do not deliberately set their nets on allspinner schools, such schools seldom carry large amounts of fish. Most of the capture of spinners is incidental to the capture of spotters in mixed schools. We do not yet have enough data to make an accurate estimate of the relative aboundance of the two species in the eastern Pacific or in the fishery.

The third major species is the "whitebelly porpoise," also known as the common dolphin and the saddleback dolphin, a species of Delphinus.

I am referring to all these animals as porpoises. This is the fisherman's term. In other areas of the United States and in scientific circles, these animals are called dolphins but to the fishermen, a dolphin is a fish. So I am using the term porpoise to avoid confusion with the other animals that the fishermen know.

So, when you say dolphins and porpoises in the tuna fishery, you are referring to a number of species of either dolphins or porpoises, depending on who you are talking to.

We have very little information on this animal in the tropics. Tuna boat records indicate that sets on "whitebelly" schools account for at least 5 percent of the sets on porpoise in certain areas off