the least widely distributed and least abundant of the billfishes in 

 the eastern Pacific. Swordfish are abundant in waters around Baja 

 California. Mexico, and near northern Peru and southern Ecuador. 

 They are also frequently encountered in or near the cool upwelled 

 water along the equator. 



Trends in abundance, as reflected by catch/1.000 hooks and total 

 catch, are discussed. On the southern grounds of the striped marlin 

 fishery, apparent abundance of this species has dropped to about a 

 third of its highe.st level, but fishing success has remained constant 

 on the northern grounds. Catches of striped marlin reached their 

 peak in 1968 (337.000 fish); by 1970 the catch had dropped to 180.000 

 fish. Apparent abundance and catches of blue marlin also decreased 

 from levels in the early 1960's. In 1963. 75.000 blue marlin were 

 taken but the catch decreased to about 22.000 fish by 1966 and has 

 fluctuated about that level since. Because so few black marlin are 

 taken in the eastern Pacific, trends in the abundance of this species 

 are not discussed. The longline fishery for sailfish in the eastern 

 Pacific began in a substantial way in 1965 with a catch rate of about 

 80 fish/1.000 hooks on the major sailfish grounds but by 1970 this 

 had dropped to about 11 fish/1.000 hooks. Also catches on these 

 grounds dropped from a peak of about 370.000 fish in 1965 to about 

 210.000 fish in 1970. Catches of swordfish continued to increase from 

 the beginning of the fishery in the 1950's until 1969. the peak year. 

 when about 112.000 fish were landed. Catches decreased in 1970. 

 although effort decreased also. The apparent abundance of 

 swordfish has shown no general decreasing trends. 



A general discussion of the needs of scientific research on 

 billfishes is given in the final section of the report. 



(675.) Proceedings of the International Billfish Symposium, 

 Kailua Kona, Hawaii, 9-12 August 1972. Part 2. Review 

 and Contributed Papers— Billfish Fishery of Taiwan. By 

 H. C. Huang. July 1974, p. 332-335. 



ABSTRACT 



Billfish landings made by Taiwan fishing vessels from 1962 to 

 1971 were analyzed and described briefly. Billfishes are commercial 

 ly harvested in Taiwan by deep-sea and inshore longline fisheries 

 and the harpoon fishery. The important species caught include 

 swordfish. striped marlin. blue marlin. black marlin. and sailfish. 

 The deep sea longline fishery has developed rapidly since 1954 and 

 the lanaings of billfishes have increased accordingly. Fishing 

 operations nave covered the major fishing grounds of the Pacific. 

 Indian, and Atlantic Oceans. The inshore longline fishery still 

 confines its activities to waters around Taiwan; billfish landings 

 made by this fishery fluctuate annually. 



676. Price Spreads and Cost Analyses for Finl'ish and Shell- 

 fish Products at Different Marketing Levels. By Erwin S. 

 Penn. March 1974, vi + 74 p., 15 figs., 12 tables, 12 app. 

 figs., 41 app. tables. 



ABSTRACT 



The rapid increase of fi.sh prices has recently caused public 

 concern. To find the cause of the difference between the price the 

 fisherman receives for his product and the ultimate price paid by the 

 consumer, the report analyzes the distribution of the consumer's 

 dollar paid to the retailer as well as to the wholesaler, processor, 

 and fi.snerman. 



Selected for this study are seven finfish. two canned fish, and 

 four shellfish products. The difference or margin between selling 

 and purchasing prices of each level and the share of the consumer's 

 dollar by each level and each cost component are calculated for each 

 fish product. The report also analyzes the costs and profits incurred 

 by each marketing function and describes the major influence on 

 margin differences. 



"The objective of the study is to give individual firms in the 

 fishery a systematic guide to examine their margins, costs, and 

 profits for each fish product; compare them with the data presented 

 m this study, as national averages for the same product; and 

 determine whether there is room for improvement for their 

 performance and services. 



677. Abundance of Benthic Macroinvertebrates in Natural 

 and Altered Estuarine Areas. By Gil Gilmore and Lee 

 Trent. April 1974, iii + 13 p., 11 figs., 3 tables, 2 app. 

 tables. 



ABSTRACT 



The abundance of benthic macroinvertebrates during March- 

 October 1969 in West Bay. Texas, was compared between 1) a 

 natural marsh area. 2) an adjacent marsh area altered by channel- 

 ization, bulkheading. and filling, and 3) an open bay area. Animals 

 representing four phyla were caught. Abundance indices (areas 

 combined) of the four groups in terms of numbers were 66.4% 

 polychaetes, 29.6% crustaceans, 2.5% pelecypods. and 1.5% 

 nemerteans; volumes were 44.0% polychaetes, 40.8% pelecypods, 

 10.7% nemerteans, and 4.4% crustaceans. 



When all organisms were combined, they were slightly more 

 abundant numerically and over twice as abundant volumetrically in 

 the marsh than in the canals and were least abundant in the bay. 

 Polychaetes were most abundant in the canals and least abundant in 

 the bay; abundance was highest at stations with low to intermediate 

 amounts of silt and clay or where vegetative matter was composed 

 mostly of live sea grasses or detritus. Crustaceans were more 

 abundant in the natural marsh than in the other two areas and 

 showed a definite preference for sandy substrate in marsh areas. 

 Pelecypods were numerically most abundant in the bay but 

 volumetrically the marsh had the highest standing crop. 

 Nemerteans were most abundant in the marsh and least abundant m 

 the bay. 



In general, the seasonal abundance of polychaetes and 

 nemerteans varied little during the study, whereas crustaceans and 

 pelecypods were abundant only during the spring and early 

 summer. An exception to this seasonal abundance pattern was the 

 reduction in numbers of polychaetes at the uppermost canal station 

 where the habitat was apparently unsuitable due to low oxygen 

 levels during the summer and early fall. 



678. Distribution, Abundance, and Growth of Juvenile 

 Sockeye Salmon, Oncorhynchus nerka, and Associated 

 Species in the Naknek River System, 1961-64. By Robert 

 J. Ellis. September 1974, v -i- 53 p., 27 figs., 26 tables. 



ABSTRACT 



The Naknek River system contains eight interconnected and 

 generally biologically discrete basins, each with a different ratio of 

 spawning grounds to rearing area for sockeye salmon. Oncorhyn- 

 chus nerka, and different densities of juvenile sockeye salmon and 

 associated species of fish. Juvenile sockeye salmon and other pelagic 

 species were sampled with tow nets at night. Sockeye salmon were 

 the most common and abundant species in all basins, followed by 

 threespine sticklebacks, ninespine sticklebacks, and pond smelt. 

 Eighteen other species of potential competitor or predator fish were 

 present. 



In the summers of 1961 to 1963. juvenile sockeye salmon in the 

 pelagic areas had a characteristic pattern of abundance for the 

 entire system: abundance (catch per tow)of age increased from 

 early summer to midsummer and then declined to late August. The 

 abundance in late August varied about threefold and, in general, 

 was independent of variations in the number of parents from 1960 to 

 1963. 



In July the abundance of age fish in each basin was 

 proportional to the amount of known contiguous spawning ground, 

 but by late August this relation no longer existed. This change was 

 at least partly due to migration of the age fish— generally from 

 basins of greater abundance of fish to those of lesser abundance. 

 The larger and faster growing fish were the first to migrate. Not all 

 basins were involved in these migrations. 



The production of sockeye salmon smolts in the Naknek system 

 is relatively stable. At least three major factors probably contribute 

 to this stability: ( 1 ) the presence of several major .spawning units or 

 race.s in widely separated spawning grounds of different types, (2) 

 the presence of several connected lakes, and (3) the migratory 

 behavior of juvenile sockeye salmon during their first summer. 



A mechanism which prevents the population of juvenile sockeye 

 salmon from exceeding some upper limit is not apparent in the 

 N.iknek system. A reduction in growth in areas of high density was 

 not apparent in the Naknek system in 1961 64 and apparently did 

 not occur in 1957 65. Many kinds of predators on juvenile .salmon are 

 present but probably are not limiting production of smolts. 



The data on abundance and growth of juvenile sockeye salmon 

 and the distribution of the escapement and spawning grounds 

 indicate that it should be possible to increase the production of 

 .sockeye salmon in the Naknek system. Two of the major basins. 

 North Arm and Brooks Lake, which constitute about 35% of the 

 system, are now producing juveniles at very low levels. North Arm 

 appears to suffer from too little spawning area, whereas Brooks 

 Lake appears to have adequate spawning area but too few 

 spawners. 



12 



