pounds each, but one large fish was taken estimated at 195 pounds. Eighteen broadbill swordfish, Xiphias gladius, were captured, but two were lost in attempting to board them. An estimated ton was placed in the hold. Sharks varied in catch as much as albacore, but not necessarily within sets. A total of 2,026 shark, mostly great blue shark, Prionace glauca, was taken in the 30 sets. This represented an average of 1.7 per shackle with extremes of 0.3-5.4 per shackle.

Temperature, Secchi Disc Measurements: The average temperature fished for albacore was 60.1° F. with extremes of 57.4° F.-64.0° F. Greatest success was had generally in the upper and the poorest in the lower portion of this range. The surface temperature front shown in figure 1 was located 2° to 3° south of its normal position durJuly and August. Thirty bathythermograph lowerings to 180 feet were made. All but one were at gill-net stations; the lowering at station 2 was

omitted. Each was accompanied by Secchi disc readings. The average depth of the readings was 9 fathoms with extremes of 6 to 11 fathoms.

Night Light and Daylight Surface Observations: A 100-watt bulb extending about 1 foot from the ship and 10 feet above the water was turned on for a period of 30 minutes to one hour during darkness following the setting of the nets. The general absence of organisms under the light was striking. A close watch was kept during daylight hours to record the presence of life in the surface water. Although whales, seals, birds, and scattered sunfish were not uncommon, smaller organisms such as saury, vellela, and pelagic barnacles were rarely

seen.

Weather: Conditions were generally good for setting the nets and only three days were lost because of bad weather.

CENTRAL NORTH PACIFIC ALBACORE TUNA OCEANOGRAPHIC, AND PLANKTON SURVEYS (M/V Hugh M. Smith Cruise 46): An oceanographic and plankton survey and albacore fishing with troll ing, gill-net, and long-line gear in the central nort! Pacific area were conducted by the U. S. Bureau of Commercial Fisheries Pacific Oceanic Fishery In vestigations research vessel Hugh M. Smith from July 21-September 9, 1958.

The observation at the International Geophysical Year station at 21°11' N., 158° 19' W. consisted of two oceanographic casts; a 15-bottle cast to 1,400 meters was made at the time of high water at Honolulu Harbor and a 10-bottle cast to 500 meters was made at low water. Two oblique 0-60 meter plankton tows with a 1-meter net were made at 2300 and 2330 local zone time and bathythermograph casts were made at 1-hour intervals between the oceanographic casts.

The program for the remainder of the cruise was divided into two phases. Outside the primary albacore area which was defined roughly by the 66-55 F. surface temperatures, the program was limited to data which would be sufficient to permit the comparison of oceanographic and plankton conditions with those of previous years. Oceanographic observations consisted primarily of 13-bottle casts to 1,200 meters at approximately 90-mile intervals on the N.-S. transect and bathythermograph casts at 30-mile intervals. Samples from each bottle were analyzed on board for dissolved oxygen and inorganic phosphate and salinity samples were preserved for laboratory analysis. The biological program consisted of a 30-minute 0-140 meter oblique tow and a 30-minute surface tow and incidental trolling.

er than 60 miles on the N.-S. transects and bathythermograph casts were made at approximately 15-mile intervals and before and after gill-net and long-line sets. Oceanographic casts were

made on either side and bathythermograph casts were made at 1-mile intervals across a tempera

ture front centered at 41°30' N., 175°07' W. The temperature change in the front was from 61.5° F. to 63.5 F. in 4 miles.

Nineteen gill-net sets consisting of 10 shackles of 42" to 7" mesh net each were made at surface temperatures between 53.0° F. and 65.7° F. Albacore were taken in only 7 of the sets and the total catch was only 97 fish. The best catches were 49 at the station at 42 47' N., 175°08' W. and 26 at 43 29' N., 174 48' W. Repeat sets at these stations yielded only 7 and 3, respectively. The catches at the other three stations were 3, 4, and 5. Twenty skipjack (13 at one and 7 at the other) were taken in the two southernmost sets along 170 W. Other catches were 194 sharks, mostly great blue, a few bramids, boarfish, squid, and two fur seals in the set at 46° 34' N., 164 44' W.

Seven sets of the surface long-line gear were made. All sets either preceded or followed a gillnet set. Each set consisted of 20 baskets of 12hook gear having a buoy on each dropper so that the depth at which each hook fished depended solely on the dropper length. Each basket had 3-12 ft., 3-24 ft., 3-48 ft., and 3-96 ft. droppers. Only two albacore were taken, one on a 24-ft. and one on a 48-ft. dropper at the station at 42 48' N., 175 08' W. A total of 226 sharks (221 great blue, 4 mackerel, and 1 mako) were taken; the largest single station shark catch was 66 great blues at 42 13' N., 170° 11' W. Two alepisaurus were the only other fish taken.

Trolling was also very unproductive. Except for the run back to Honolulu five lines were trolled at approximately 6.5 knots during all daylight runs in waters having surface temperatures between 52° F. and 72 F. but only 13 albacore were taken. Although the vessel circled after each strike, they were taken individually except for two catches of 2 fish each. Only three of the albacore were tagged and released. Only one albacore school was sighted during the cruise--at 45 08' N., 174 47' W. while patrolling a long-line set. Although three albacore had been taken the night before in a gillnet set in the area, none was taken on the long-line set or the trolling lines.

Twenty-nine 0-140 meter oblique and 25 surface plankton hauls were made with the 1-meter net, and seven surface hauls were made with the 45cm. net. Five of the latter were made across the front centered at 41°30' N., 175°07' W.

Settled volume estimates of the 1-meter net nauls made in the field revealed a marked eastwest change in both the content and volume of the samples from the eastern and western limits of the albacore survey areas. For example along 160 W. longitude the 140-meter hauls averaged 280 cc. (range 135-360 cc.) and were composed of a mixture of euphausids, chaetognaths, and coelenterates and had no concentration of crustacea. Along 170 W. longitude the 0-140 m. hauls averaged 600 cc. (range 300-1200 cc.) and were mostly euphausids and calanus.

MARQUESAN SARDINE REPRODUCES IN HAWAIIAN WATERS: In 1955 the Pacific Oceanic Fishery Investigations (POFI) began introducing a sardine from oceanic waters near the Marquesas Islands into those near the Hawaiian Island of Oahu. Plants were made at the end of seven research cruises, with numbers ranging from 3,000 to 53,000. The most recent release was on June 23, 1958.

The scientists and fishermen found that these small fish of the herring family are abundant in the Marquesas and are very good bait for tunas. The releases into waters around Oahu were made in the hope that these sardines would spawn and thus augment the presently insufficient supply of bait for the local skipjack fishery.

Through the cooperation of commercial fishermen, there have been several recoveries of these introduced fish. Until the fall of 1958, these recoveries were all from waters near Oahu, the general area of the plantings. Recently, fishermen seining for bait near the islands of Kauai and Maui caught numbers of the Marquesan sardines. Although some of these recoveries could have been from recent releases, the small size of most of them is definite evidence that these Marquesan sardines have found Hawaiian waters to their liking and have successfully spawned.

Whether the sardine will become abundant enough to be economically significant should be answered in the next two or three years. If it does become abundant, the tuna bait supply in the islands might

be doubled or tripled, for the sardine seems to prefer sandy, rocky beaches rather than the slightly brackish bays generally utilized by the local nehu.

Even more significant is the hardiness of the sardine as contrasted with the delicate nehu. Properly handled, the sardine can withstand long ocean voyages and would permit Hawaiian fishermen to venture farther afield.

Additional benefits might accrue to reef fishermen for the sardine will augment the food supply of such fish as "ulua," opening the way to larger populations. In effect the sardine will convert zooplankton drifting by the islands into usable form for game fishes.

Aside from the commercial implications, the introduction represents an interesting zoogeographical experiment. The fish fauna of the Hawaiian [slands is poor in species compared to island groups to the southwest. Some authorities argue that the great distance to Hawaii is the controlling element. Others argue that suitable habitats for many species are absent here. Introduction circumvents the distance factor, and the early success of the transplanted sardine indicates that distance was the reason for its absence here.

Of additional interest is the fact that the introduction of the sardine to Hawaii is the first known instance of successful transplanting of a purely marine species of fish.

SECOND TILAPIA BAIT-REARING PROJECT INITIATED: As a result of the success obtained by U. S. Bureau of Commercial Fisheries biologists with the commercial pilot-plant tilapia tunabait rearing project at Paia on the Island of Maui, an experimental tilapia rearing plant was established at POFI's Kewalo docksite headquarters in August 1958 to investigate the effects of various diets on the rate of production of young and the effects of various sex ratios also on the rate of production of young. This plant produced about 54,000 young fish in September, and the results already obtained relate in an interesting way to the various factors being tested. Sex ratios of 1:2 and 1:3 (males to females) have been highly productive, whereas ratios of 1:4 and 1:6 were not. In addition, concentrations of 30 and 50 adult fish per tank of about 50 square feet bottom area produced many more young than 70 or 90 fish per tank. Of the three feeds being tested, one appeared much better in terms of young fish being produced than the other two.

While conclusions based only on a single month's operation can hardly be considered final, nevertheless these results indicate that the experimental design is sound and that the variables being inves

SKIPJACK TUNA BEHAVIOR STUDIES PROVIDE A POSSIBLE KEY TO NEW FISHING METHODS (M/V Charles H. Gilbert Cruise 41): The U. S. Bureau of Commercial Fisheries' research vessel Charles H. Gilbert returned to Honolulu on September 27 after completing a 52-day cruise in Hawaiian waters, according to the Director of the Pacific Oceanic Fishery Investigations. The cruise

The Service's research vessel Charles H. Gilbert. was designed to study the behavior of skipjack, also known as aku in Hawaii, in their natural environment, and measure certain variables in the environment itself. The cruise was part of a continuing program to determine the relationship between changes in the environment and changes in the abundance of skipjack in Hawaiian waters. As on earlier cruises, part of the observations were con

centrated in a small area off leeward Lanai, where at certain times the tuna tend to congregate. Skipjack were very scarce in this area during the cruise as compared to earlier cruises, and this provided contrasting conditions of fish abundance useful in comparing changes which may be noted in the sea itself.

A portion of the cruise dealt with a study of the reaction of skipjack to different conditions and substances. The biologists were making these observations from a caisson suspended from the side of the vessel. This caisson, a metal cylinder fitted near the lower end with glass ports, permits an observer to record the activities of the skipjack and bait on film, and to do so while remaining relatively comfortable and dry. During these behavior studies, the reaction of skipjack to blood, red dye, and certain skipjack skin extracts was recorded. In addition, the response of skipjack to a promising new bait fish, the threadfin shad, was tested. It appeared that the shad are indeed acceptable to the skipjack, as they were eaten up almost as soon as they hit the water. The importance of developing a reliable auxiliary bait supply is well known to all segments of the fishing industry and the threadfin shad is one of two fish being tested at present, the other being the tilapia.

Once during August and once during September the Charles H. Gilbert participated in the International Geophysical Year program by conducting hydrographic stations off Barbers Point, Oahu.