Showing papers on "Fishing published in 1972"

Fish catching methods of the world

Abstract: Chapter one. Catching methods in fisheries an introduction. Chapter two. Fishing by gathering. Chapter three. Male and female divers. Chapter four. Animals as a help in fisheries. Chapter five. Fish harvesting after stupefying. . Chapter six. Spearing, harpooning and shooting fish. Chapter seven. Fishing with clamps, tongs, rakes and wrenching gear. Chapter eight. Line fishing:basic implements. Chapter nine. Line fishing: gear and methods. Chapter ten. Fishing for sport and recreation. Chapter eleven. Attracting, concentrating and frightening fish. Chapter twelve. Pole-hooks and rippers. Chapter thirteen. Net material and the art of net-making. Chapter fourteen. Natural and artificial shelters. Chapter fifteen. Permanent and temporary barriers. Chapter sixteen. Trapping. . Chapter seventeen. Fishing in the air. Chapter eighteen. Mechanical fishing gear: traps, lines and snares. Chapter nineteen. Gillnetting. . Chapter twenty. Entangling nets. Chapter twenty one. The drive-in fishery. Chapter twenty two. Cover pots and cast nets. Chapter twenty three. Liftnets and fish wheels. Chapter twenty four. From the scoop basket to the stow net. Chapter twenty five. Dredges and beamtrawls. Chapter twenty six. Fishing with bottom trawls. Chapter twenty seven. Trawl fisheries in three dimensions. (Fishing with pelagic trawls). Chapter twenty eight. Seining in fresh and sea water. Chapter twenty nine. Fish shoals and surrounding nets. Chapter thirty. Fishing systems and harvesting machines. Chapter thirty one. Fishery and gear research. Chapter thirty two. Fishing effects on fish stocks and environment. Appendix . Classification of catching methods. A.1 Principles of classification. A.2 Main groups of catching methods. A.3 Revised classification. Bibliography. Subject index. Species and product index

An ecological study of georgia coastal fishes

Abstract: The distribution of fishes in relation to ecological factors was studied in a Georgia estuary and adjoining beach and coastal plain creek waters to establish fundamental base lines for the ecology of a relatively undisturbed section of the coast. The distributions of 168 fish species were related to nine recognizable habitats, temperature, and salinity. Length frequencies and spawning seasons were determined for most of the trawled species that contributed significantly to fish production in the estuary. Collecting by a variety of techniques permitted evaluations of types of life cycles, of diversity in the various aquatic habitats, and of distribution patterns within the estuarine complex and adjoining waters. Numbers of species collected in nine aquatic habitats were as follows: beach - 114, lower reach of the estuary - 100, high marsh - 56, upper and middle reaches - 61, oligohaline creek - 40, fresh water - 39, tidal canal - 22, low­ salinity tidal pool - 22, high-salinity tidal pool - 37. Estuaries are highly productive and support im­ Portant sport and commercial fisheries. A ma­ jority of the nation's commercial finfish and shellfish species and many coastal sport fishes utilize the estuarine environment during at least part of their life cycle. Estuaries are important recreational areas, especially for fishing, partly because of their proximity to civilization. Un­ fortunately, this proximity and lack of pollution controls have resulted in mass degradation of the nation's estuaries through pollution, filling, and dredging. Pre-pollution studies are essen­ tial for the precise evaluation of the ecological impact of stresses on estuaries. The normal functioning of estuaries must be understood be­ fore scientists can evaluate the effects of var­ ious stresses on estuaries. There is an urgent need to determine the significance of coastal ha­ bitats to the various life history stages of coastal fishes. The central Georgia coast presents an oPPortunity to study the ecology of fishes in a relatively undisturbed estuary and establish fundamental base lines for the detection and evaluation of pollution. Aspects of fish ecology that have been selected for examination include

An evaluation of the acadja method of fishing as practised in the coastal lagoons of Dahomey (West Africa)

Abstract: A method of fishing using installations of the fish-park type, known collectively as acadjas, is common in the coastal lagoons of Dahomey. Acadjas are installed in shallow sheltered waters and are constructed of dense masses of branches planted in the muddy bottom. Two main types exist, small circular acadjavis and large rectangular avas, but these may be combined to give a variety of other forms. After construction the acadjas are left for varying periods before being fished. Many species of fish are found in the installations, but the majority of these are only casual invaders and most of the catch consists of 3 species only. The fish population appears initially to be derived from immigration, but after c. 2 months of implantation, increases exponentially by growth and reproduction. Acadjas that are fished after short periods of installation are therefore regarded as refuge traps, drawing fish from the surrounding environment, where those that are left longer before being fished, develop their own populations. The yield of the acadjas also increases logarithmically with increasing densities of branches planted. Properly managed acadjas may be regarded as a method of fish culture, which, because of the exceptional yields that can be attained, are a potential means of development for shallow mud bottomed waters such as the West African coastal lagoons.

Native Use of Fish in Hawaii

Abstract: This book provides a lot of information on the importance of fishing in ancient Hawaiian society It includes drawings of fish with both Hawaiian and scientific names

Hunting and Fishing Focus Among the Miskito Indians, Eastern Nicaragua

Abstract: The amounts of native animals taken in hunting and fishing by Amerind peoples are almost unknown. The interrelationships of cultural and ecological systems determine to a large extent hunting and fishing returns, focus, and strategies. This study presents data obtained in a coastal Miskito Indian village in eastern Nicaragua. Measurements were made of meat yields by species and of the time and distance inputs involved in securing fish and game. Hunting and fishing focus and strategies are adaptive mechanisms enabling the Miskito to achieve high and dependable returns from a limited number of species. Several factors are examined which influence hunting and fishing focus: dietary preferences and prohibitions, costs involved, differential productivity and dependability of particular species, seasonality and scheduling, and the impact of cash market opportunities for faunal resources. Under the impetus of population growth and rising aspirations, the Miskito's efforts to secure increasing numbers of animals for both subsistence and market are leading to severe pressures on selected species and to cultural and ecological disruptions.

What Fishermen Look for in a Fishing Experience

Abstract: Personal interviews were conducted with 100 fishennen to determine the relative importance of eight selected factors that influence the success of a typical l-day fishing trip. Elements of the natural environment water quality, natural beauty, and privacy while fishing were consistently rated as the most important factors influencing fishing enjoyment. Size and number of fish caught, weather conditions, and ease of access to fishing waters were rated of moderate importance. Facilities available were rated as of low importance. Few differences were found between factor rankings for stream and for lake fishing experiences. Shifts in the importance of factors across different groups of fishermen were also investigated. Results of the study indicate that the concept of fishery management should be broadened to incorporate environmental management7 if quality fishing experiences are to be provided. FISHING EXPERIENCE * Moeller and Engelken 1253 hours per acre, along with an unknown but obviously balancing natural death rate and recruitment, iis combination will produce a fishable population of smallmouth bass for an indefinite period. The hybrid crappies now representing hybrids of F2 generations have added interest to the angling in East Pond, without contributing greatly to the yield. There is no evidence that the lake chubsuckers have become overly abundant, and no attempt has been made to make an estimate of this segment of the population. Fishing has been jokingly defined as a jerk at one end of the line waiting for a jerk at the other end. This may be an acceptable definition for the nonfisherman, but those of us who like to fish know that fishing involves much more the enjoyment of the outdoors, the companionship of friends, and, if we are lucky, a sizzling pan of freshly caught fish. Most anglers are quick to admit that their interest is not solely in the fish they catch but in fishing itself (Ley 1967). A survey of over 4,000 Ohio fishermen showed that more than half obtained as much enjoyment from a fishing trip if they caught no fish as they did if they caught fish (Addis and Erickson 1969). Other studies have shown that at least two-thirds of the nation's fishermen catch less than one-third of all the fish caught and that half of these fishermen catch no fish ( Sport Fishing Institute l964). LITERATURE CITED BENNETT, G. W. l9S4. Largemouth bass in Ridge Lake, Coles County, Illinois. Illinois Nat. Hist. Survey Bull. 26( art. 2 ) :217-276. , AND W. F. CHILDERS. 1957. The smallmouth bass, Micropterus dolomieui, in srannwater ponds. J. Wildl. Mgmt. 21 ( 4 ): 414X24. , AND . 1966. The lake chubsucker as a forage species. Progr. FishCulturist 28 ( 2 ): 89-92. BUCK, D. H., AND C. F. THOITS, III. 1970. DYnamics of one-species populations of fishes in ponds subjected to cropping and additional stocking. Illinois Nat. Hist. Survey Bull. 30(art. 2) :69-165. Received for publication March 13, 1972. This content downloaded from 207.46.13.103 on Thu, 20 Oct 2016 04:08:04 UTC All use subject to http://about.jstor.org/terms Table 1. Comporison of fishermen in the present study group with a random sample of licensed fishermen in six northeastern stotes. PRESENT IN SIX NE CHARACTERISTICS STUDY STATESa Average age (years) 40 40 Fishing experience (years) 26 24 Male ( percent ) 90 87 Married ( percent ) 79 87 Rural background (percent) 68 56 White collar job (percent) 46 45 a Data from Bevins et al. ( 1968 ). 1254 Journal of WilEUffe Management, Vol. 36, No. 4, October 1972 and are managed to provide maximum exposure to natural surroundings. Respondents were questioned about their past fishing experiences and socioeconomic backgrounds. Fishermen were also asked to evaluate, on the basis of their own past experiences, the relative influellce that eight selected factors had on their enjoyment of a typical 1-day fishing trip. The factors were selected to describe aspects of the fishing experience -most of which can be controlled or influenced by resource managers. These factors are ease of access to water, facilities available, natural beauty of the area, privacy while fishing, llumber of fish caught, size of fish caughtv water quality, and weather conditiorls. Fishermen were given two cards that randomly listed the eight environmental factors one card was for lake fishing, an(l one was for stream fishing. They were asked to indicate, by a check luark along a three-point scale, the relative irnportance of each factor influencing their enjoyment of a typical l-day fishing trip. Data were first analyzed by calculatirlg an average importance score for each of the eight environmental factors. Weighted factor scores were determined as follows: a factor was scored 3 if it was rated very important; 2, if important; and 1) if llot irnportant. Although this artificial systena does not provide a precise interval measurement, it is useful in describing the general overall ranking patterns among the factors. To determine how factor ratings shifted across different fisherman groups7 respondents were separated into categories based on s;s background characteristics: age, past fishing experience, willingness to pay to fish) leisure time available, educational level7 and background residerlce. Average factor ratings were calculated for each group of fishermen. The chi-square test was used to determine whether statistical It would be incorrect to the long run, the size and suggest that, in number of fish caught are not important to fishing enjoyment. In many instances, however, other factors significantly influence fishing enjoyment The purpose of this study was to provide some basic insights into the relative importance of factors that influence the overall enjoyment of a fishing trip. Shifts in the relative importance of various factors across different groups of fishermen were also investigated. The study was undertaken to provide fishery and resource managers with basic information about how the quality of a fishing experience may be improved. METHODS Personal interviews were conducted with 100 licensed fishermen during the summers of 1969 and 1970. Respondents were selected from among fishermen who took part in a limnological and fisheries research program conducted at the Heiberg Memorial Forest Fishing Ponds, managed by the State University College of Environmental Science and Forestry, Syracuse, New York. The objective of the Heiberg research project was to determine the effects of fishing pressure on growth, survival) and feeding habits of stocked fish in controlled access ponds. The ponds are in a wooded area This content downloaded from 207.46.13.103 on Thu, 20 Oct 2016 04:08:04 UTC All use subject to http://about.jstor.org/terms FISHING EXPERIENCE * Moeller and Engelken 12S5 differences existed between the distributions of scores given to a particular factor by the different groups. THE STUDY GROUP Fishermen interviewed in this study were not selected at random from a population of license holders. A comparison of characteristics of the study group with characteristics of fishermen in other studies will help to evaluate the representativeness of the study group. The characteristics of anglers in six northeastern states were described in a regional mail survey of 6,S89 randomly selected licensed fishermen (Bevins et al. 1968). Characteristics of fishermen interviewed in our study compare favorably with characteristics of fishermen in this large sample survey (Table 1). Seventy percent of those surveyed had never previously fished the Heiberg ponds, and 82 percent had fished for more than S years prior to this survey. Also, the fishermen included in our study did most of their fishing in places other than the Heiberg ponds. RESULTS Overall Factor Ratings To determine whether any differences in factor ratings occurred between lake fishing or stream fishing, fishermen who fished in both lakes and streams were asked to rank the eight factors separately for each kind of fishing experience. Although the absolute rank value assigned to the two kinds of fishing experiences varied, the relative overall ranking of the eight factors was essentially the same. Because no major differences were found in the relative ranking of environmental factors for lakes and streams, the weights were combined to form a mean ranking >

An Analysis of Temperature Effects on the Inshore Lobster Fishery

Abstract: In the past, water temperature has been utilized in combination with some measure of fishing effort in the development of economic estimator or predictor equations for the yield of the lobster Homarus americanus. The hypothesis that the inshore lobster fishery in the United States has been overfished since the end of World War II to the point where increases in fishing effort since that time have had only minor effects on the yields was examined. It was shown that suitable yield prediction equations could be developed using only lagged and present temperatures as the independent variables. Comparisons were made of equations developed for the Maine fishery and sections of the Canadian fishery. Further analyses were done comparing equations developed using winter vs. summer temperatures and surface vs. bottom temperatures.

Hunting and Fishing Focus Among the Miskito Indians, Eastern Nicaragua

Abstract: The amounts of native animals taken in hunting and fishing by Amerind peoples are almost unknown. The interrelationships of cultural and ecological systems determine to a large extent hunting and fishing returns, focus, and strategies. This study presents data obtained in a coastal Miskito lndian village in eastern Nicaragua. Measurements were made of meat yields by species and of the time and distance inputs involved in securing fish and game. Hunting and fishing focus and strategies are adaptive mechanisms enabling the Miskito to achieve high and dependable returns from a limited number of species~ Several factors are examined which influence hunting and fishing focus: dietary preferences and prohibitions, costs involved, differential productivity and dependability of particular species, seasonality and scheduling, and the impact of cash market opportunities for faunal resources. Under the impetus of population growth and rising aspirations, the Miskito's efforts to secure increasing numbers of animals for both subsistence and market are leading to severe pressures on selected species and to cultural and ecological disruptions.

Effects of Fishing on the Atlantic Menhaden Stock: 1955–1969

Abstract: To determine the effect of purse-seine fishing on the Atlantic menhaden (Brevoortia tyrannus) population, we analyzed data from 1955–69 on fishing activity and catches. Changes in fishing efficiency necessitated establishment of an abstract effort unit, the 1965 vessel-week. Catch per unit of effective effort in 1965 was one-fifth that of 1955. Our instantaneous natural mortality rate (M) estimate was 0.37. At the current recruitment age, 1.5 years, reducing F, instantaneous fishing mortality, to about 0.8 would slightly decrease the yield per recruit, but would increase the spawning stock and ultimately allow annual catches of 400,000–500,000 metric tons, the maximum sustained yield.

An exposition on the definition of fishing effort

Abstract: The term "fishing effort" is well defined in population dynamics litpraturp. The tprm as defined in the population dynamics literature is, however, difficult to reconcile with broader definitions of fishing effort, particularly those having pconomic implications. The present paper discusses the distinction between the definitions and gives some pxamples in the context of allocating inputs, the capacities of fishing hoats, and several stocks to the catch in a manner which maximizes profits. Managerial hehavior is also an important input to the fishing process; this is discussed in a dpcision theory format where decision quality can be measured relative to entropy in the decision environment affording a comparison among decision environments in terms of information and an imputed valuation of a bit of information under various circumstances. The convpntional measures of the quality of the decision environment are often based upon expected catch. Alternate measures are discussed which include the expected loss or the risk involved in the decision process. The deployment of fishing effort is one of the fundamental components of fishery management. While fishing effort has been rather precisely defined in the population dynamics literature, ef­ fort has not been well defined in its broadest con­ text. This paper considers the definition of fish­ ing effort with special reference to the develop­ ment of techniques which are useful not only for the definition of effort in the usual strategic sense, but for the definition of effort in the tact­ ical and operational sense as well. This defini­ tion is requisite for considering fishing as a total system (see Rothschild, 1971). The transformation of wild stocks of fish into the "catch" is generally considered to be medi­ ated by the quantity of fishing effort expended in the process of harvesting the catch. The measurement of the magnitude of fishing effort is of central importance to the theory of the dy­ namics of exploited fish populations because the various "optimal" catches which are developed in this theory must ultimately be related to op

Loch Lomond: Man's Effects on the Salmonid Community

Abstract: Loch Lomond, the largest area of fresh water in Great Britain, has been utilised by man for many hundreds of years. There are fifteen species offish at present in the loch: all of these are native. Several of them have formed the basis of commercial and sport fisheries in the past but the only two species of importance at present (as sport fish) are salmon (Salmo salar) and trout (Salmo trutta). Man has influenced the loch in ways other than fishing: several fish species have been introduced (none successfully); nutrient input is increasing; loch water is used for domestic and industrial supply; many forms of recreation take place on the loch; and it is of major importance as an amenity. In spite of these stresses there is no indication of any major change in the fish populations within recorded time; nor is there any evidence that they will alter in the foreseeable future, providing a rational conservation programme is developed for the area.

Biased Harvest Estimates from a Postal Survey of a Sport Fishery

Abstract: A partial creel census and a postal card survey were simultaneously employed to determine the harvest of wild brook trout (Salvelinus fontinalis) from several ponds. A comparison of the catch per effort ratios (c/e) from interviews and postcards revealed a positive bias in the estimates obained from returned postcards. The c/e ratios from postcards were double the c/e ratios from interviews. This discrepancy was partly due to the reluctance of unsuccessful anglers to return postcards. There was a significantly higher proportion of unsuccessful anglers from interviews than from postcard returns. Positive errors in the c/e ratios also resulted from a nonresponse of successful anglers and from more than one fisherman reporting on a single card. Estimates of fishing success from postcards seriously overestimated the season's harvest of trout and the exploitation rates.

A winter sport fishing survey in a warm water discharge of a steam electric station on the Patuxent River, Maryland

Abstract: An interview-count sport fishing survey was conducted from January through April, 1970, along a one-mile discharge canal of the Potomac Electric Power Company’s Steam Electric station located at Chalk Point, Maryland. An estimated 20,335 fishing trips, representing 77,943 hours of fishing, were made during the period sampled. On interview days, 8,758 fishermen were counted, and 4,716 were interviewed. An estimated 58,453 fish, representing 9 species, were taken, with an average of 0.71 fish caught per man-hour of effort. White perch,Morone americana, dominated the catch during all months sampled. No significant correlation could be made between water temperature of the canal and number of fish caught per man-hour of effort.

Results of the exploratory fishing operations of the Government of India vessels at Bombay base for the period 1961 - ' 67

Abstract: The fishing vessels of the Government of India, Deep Sea Fishing Station, Bombay, conducted exgloratory fishing operations in areas between latitudes lSoN to 23 10'N and longitudes 6So10'E t o 730 S0'E, cover ing 25,100 nautical square miles on the continental shelf during 1961-1967 . The paper presents the results of, operations giving details of regional, seasonal and depth distribution of fish categories.

Approaches to the evaluation and management of the fish stock in Kainji Lake, Nigeria

Abstract: Estimates of potential yield for Kainji Lake, and the methods of analysis by earlier workers are discussed. Also summarized is the state of the fishery after impoundment, between 1969 and 1971, based on experimental gillnet catches. Recent sampling of the young of the year along the littoral margin indicates that most of the commercially important species have spawned successful1y in the lake. An intense fishing mortality of juvenile fish, owing to the use of small mesh nets by local fishermen, presents a possible threat to the future establishment of the fish in the lake. The results of gill-net selection studies based on HOLT'S (1957) method are given. The data have been extracted from experimental gill-net catches with graded fleets of nets between 1969 and 1971. Recommendations based on the above studies have been made to ensure a successful establishment of the fish species in the lake and an increase in catch-per~unit effort in subsequent years.

Trout in Llyn Alaw, Anglesey, North Wales. II. Growth

Abstract: The annual and seasonal growth, length/weight relationship, changes in seasonal condition and specific growth rates of 17 types of trout in the newly flooded reservoir, Llyn Alaw, in Anglesey, North Wales, were investigated. Scales and length-weight data from 2076 trout caught by angling and netting during the first 4 years after impoundment were analysed to show the age, origins and growth of all fish both before and after flooding.

Japanese distant-water fisheries: a review'

Abstract: Most of the industrialized fisheries of Japan have developed under a licensing system controlled by the central government. Limitations on entry and the allocation of re­ sources based on a variety of social and economic considerations have resulted in the development of an extremely diversified industry. The postwar expansion of distant-water fisheries greatly accelerated the exploitation of resources in the North Pacific, as well as in many other areas of the world, and has caused numerous international conflicts. In addition to regional conventions for high seas fisheries, various bilateral agreements have been negotiated to cope with problems arising from jurisdictional claims by coastal states. While supporting narrow limits of national jurisdiction and the concept of free access to high seas fishing, Japan has accepted different forms of allocation as a means to accommodate the conflicting interests of the nations involved. Her domestic institutions and organization of the industry have helped the government make pragmatic arrangements with other nations. Whether or not a general agreement on fishery issues can be reached at the new Law of the Sea Conference, Japan will face more and harder international negotiations in view of the general trend of coastal states claiming broader zones of national jurisdiction. Each of the main sectors of the Japanese fishing industry, including inshore fisheries, offshore fisheries, distant-water fisheries, and aquaculture, now operates under severe constraints. Although the total catch of distant-water fisheries is still increasing due largely to intensified pollack fishing in the Pacific, long-term prospects for further ex­ pansion do not appear bright. Little progress has been made in the utilization of abundant resources of unconventional species. Thus, the rapid growth of domestic fish­ ery production is unlikely to continue. Increased joint ventures and other business ar­ rangements in foreign countries may provide a partial solution. Import decontrol for fishery products would contribute substantially to meeting immediate problems of supply shortage. This paper was originally drafted to provide, as part of the NORFISH study under the Wash­ ington Sea Grant Program which is supported by the National Oceanic and Atmospheric Ad­ ministration, some background information on the development and the present status of the Japanese high seas fisheries, particularly those which have bearing on various international arrangements in the North Pacific. Since, how­ ever, discussions on the future regimes of the sea have been carried out with increasing in­ tensity, the emphasis of the paper has shifted somewhat from descriptive information to a more analytical study of the international fishery

Fishing Industry in Ancient Egypt

Abstract: Prototypes of the more important contemporary fishing gear were in common use in Ancient Egypt. These included fish harpoons, hooks, hand and longlines, angling, trolling, cast nets, fish traps and baskets of various types, dip nets, weirs, seine nets (with and without pockets) and beam trawls. The seine and beam trawl appeared successively in the Old Kingdom (ca 2660–2180 B.C.) and Middle Empire (ca 2180–1640 B.C.), while the iron fish hook with barb, shank and eye or flange dates back to the New Empire (ca 1640–1075 B.C.). Archaeological material relevant to fishing consists of preserved samples, artifacts, models and papyrus scripts as well as relief illustrations in tombs and temple walls of scenes depicting fishing methods and crafts from various Dynasties. The importance of fisheries in the economy of Old Egypt is demonstrated by the exportation of fish commodities and the imposition of taxes on fishing rights and in the engagement of a large number of the population in fish industry. Fish processing included drying, salting, pickling, fish cake and fillet; various implements used were discovered. It is suggested that these basic fishing techniques (methods and gear) spread in time, along various routes, from Egypt to other parts of the world.

Past trends and recent research on the fisheries of Lake Victoria in relation to possible future developments

Abstract: EAFFRO and UNPP/LVFRP bottom trawl exploratory data have been used to describe the depth distributional pattern. relative abundance and magnitude of the demersai fishes in Lake Victoria. The results have been compared with the commercial catch estimates, and various interpretations of the trends in the annual catches and experimental biomass estimates in relation to possible future developments of the fishery have been suggested. Though it is highly desirable to develop the fishery such as by supplementary trawling, certain social and biological consequences and considerations needs to proceed in graded steps guided by several research disciplines. The past trends of the fisheries of Lake Victoria are briefly considered. Recent exploratory bottom trawl data, by EAFFRO and UNDP/LVFRP, have been used to define demersal fish stocks of Lake Victoria in terms of their magnitude, relative abundance and distribution pattern by depth. Enstence of disparity between the relative abundance of the various species in their commercial catches and in their present biomass estimates is pointed out and the various aspects associated with the necessary modification of the fishing practices are discussed. Further and continuing research of the bio-socio-economic vectors of the fishery will be necessary in order to generate the rationale of an efficient fishing regime for a rational management strategy and realistic utilization of the fishery resource.

The History of the International Council for the Exploration of the Sea

Abstract: In the middle of the last century many people believed that the living resources of the sea were inexhaustible and that Man by his puny efforts could not influence them to any material extent. At that time fishing was ill-developed. Trawling was limited to the use of the beam trawl, but with the introduction of steam for propulsion of fishing vessels and the hauling of nets, as well as the otter trawl, the intensity of fishing increased to such an extent that many scientists began seriously to doubt the idea of the inexhaustibility of the seas.

The Recent Trend in the Stock Size of the Pacific Population of the Common Mackerel off Honshu, Japan, as Viewed from Egg Abundance

Abstract: The spawning amounts of the Pacific Population of the common mackerel, Scomber japonicus HOUTTUYN, were surveyed for 1968, 1969 and 1970, as had been done for the earlier years in the previous report (WATANABE1)). Based on the information thus obtained, recent trends in the stock size and fluctuation of this population were clarified. The results are as summarized below: 1. Egg abundance was remarkably low for the years 1969 and 1970 as had previously been predicted. This was caused by the depletion of population of the III-age fish, year after year, since the 1965-year-class which had provoked a rapid decrease of the whole parent fish stock. 2. Possibly, the decrease of stock sizes of the 1965- to 1967-year-classes was attributable to high mortality in the very early stages of life, such as from egg to young. 3. Immature fish populations showed a slight increase since the 1966-year-class which was the minimum, but this was still lower than those of the 1964-year-class or older ones. For the years 1968-1970, immature fish suffered from stronger fishing intensity than before, intensified by not only a decrease of population but also an increase of the number of fish caught. 4. The egg abundance for both 1969 and 1970 were slightly less than 200×1012. This suggests that the reproductive strength could still be expected to continue to some extent. However, judging from the recent growth of fishing intensity upon immature fish, the increase of parent fish will not occur for long. 5. In order to increase the stock size of parent fish to produce the eggs at optimum levels, say 400×1012 or so, the fishing of immature mackerel should be controlled.

The biology of the agulhas sole, austroglossus pectoralis, part 1. environment and trawling grounds

Abstract: Summary The Agulhas sole is endemic to the south coast of South Africa. The physical, chemical and geological environment in which it lives is discussed. There is a strong correlation between the distribution of fine sediments and the Agulhas sole. The trawling grounds are named and described. A sustained yield is attributed to restocking from natural sanctuary areas, an increase in fishing effort together with better fishing techniques.

Variations in size and length composition of atlantic menhaden groupings

Abstract: This paper gives estimates of size (weight) and length composition of summer schools and fall school-aggregations of Atlantic menhaden based on single-set purse-seine catches and accompanying catch samples obtained in 1955-62. The data show that the fish school by length and the average size of summer schools decreases as the apparent abundance of fish in a given area of the coast decreases. The significance of the school concept in the study of the dynamics of the population and the effects of fishing upon it are discussed, and additional avenues of research are suggested. The Atlantic menhaden, Brevoortia tyrannus, is a schooling fish that occurs in the western At­ lantic Ocean from Nova Scotia to Florida and is the object of a purse-seine fishery over most of its range (Reintjes, 1969). The fishery is based on seasonal appearances of the fish schools in shallow waters overlying the inner half of the continental shelf (Roithmayr, 1963). Fisher­ men and aerial fish spotters, who locate and as­ sist in the capture of menhaden, have a working knowledge of school size, composition, and be­ havior, but there exists little quantitative infor­ mation on these and other aspects of the school­ ing phenomenon. Of primary interest to the fishery biologist are the degree to which the fish school by size, the relationship between size of schools and size of fish within schools, and the variation in size of schools in relation to changes in abundance of the fish and to fishing. These aspects of Atlantic menhaden schooling are the subject of this paper. The nature of density and fishery-related changes in the schooling of various pelagic ma­ rine fishes is not well understood, but sufficient evidence was put forward by different workers to indicate insight into the importance of this be­ havioral phenomenon. The significance of the

Trends in use and prospects for the future harvest of world fisheries resources

Abstract: Estimates of the potential yield from the marine environment have varied between 20–1000 million metric tons because they were based on poor and incomplete data and differing approaches to trophic level evaluation. The data is improving slightly and the estimates are beginning to agree within half an order of magnitude. We believe that the yield of marine fisheries could ultimately be expanded to ca. 400 million metric tons, by utilizing presently known but underutilized resources, by opening new fisheries in areas like the Indian Ocean and Antarctic and by improving systems of regulating the catch and fishing effort. In order to meet the maximum potential of the marine environment we will have to harvest at a lower trophic level in the food chain because most fish in higher trophic levels are being harvested at their maximum sustainable yield. This increasing harvest of smaller fish, plus the increasing demand for fishmeal for animal feed will cause an increasing proportion of the fish harvested to be used for reduction to fishmeal and oil.