Showing papers on "Fishing published in 1973"

Hydromechanics of Fish Schooling

Abstract: VARIOUS explanations for fish schooling have been put forward1, including the rate of predation2,3, social4 and genetic1 factors. Hydrodynamical effects appear to be important to obligate schooling species. They commonly show migratory movements4, and the schools usually consist of individuals of the same size range6,7 (with similar cruising speeds, as these depend on body-length) swimming in synchronization and in regular arrays8. The endurance of the fish is found to be increased twice to six times when in schools16. These factors may have practical significance, as many commercially important species are found in schools and knowledge of their possible speed and stamina can help design efficient fishing gear.

Distribution pattern of the major exploitedmarine fishery resources of India

Abstract: The annual estimated total marine fish catch in India for the period 1951-65 is 0 • 68786 million metric tons The marine fish production of the countries bordering the Indian Ocean in 1966 was 2-2 million metric tons, of which 40-5% was from India In the annual average catches for 15-year period in the states, Kerala has ranked first (31 -47%), followed by Maharashtra (22-4%), Madras (14-91%), Gujarat (16-9%), Mysore (8-3%) and Andhra (7 • 57%) The contribution to marine fisheries from West Bengal, Orissa, Goa, South Andamans and Laccadive Islands is about 1% from each or even less Statewise distribution pattern of the major fish groups, the component species, their life habits in relation to seasonal fluctuations in the fisheries have been discussed A series of illustrations has been made to show the fishing craft and gear commonly used in different States, the fish species obtained and their fluctuations in the landings from quarter to quarter The landings by the exploratory and commercial fishing trawlers form about 1% of the total marine fish landings The vessels operating from different bases, the common types of gear used and the catch per hour returns obtained in respect of different categories of vessels are discussed Productive areas have been charted in the regions covered by vessels operating from Bombay, Karwar, Mangalore, Cannanore, Cochin, Tuticorin, Mandapam and Visakhapatnam The species abundance in each region and depthwise distribution as revealed by trawler landings have been recorded Indian Ocean contours, currents, regional upwelling, hydrology and plankton intensities have been shown in charts from the available information, to enable understanding their relation to fluctuation in the fisheries

Effects of fishing on the Tilapia nilotica (Linne‘ 1757) population in Lake George, Uganda over the past 20 years

Abstract: Summary The size of the Tilapia nilotica population in Lake George was determined using purse seines. Production, mortality rate, size at maturity, and other parameters of the population were also determined. In Lake George, the factors that regulate the population of T. nilotica are both natural and artificial. The restricted size of nursery zones, strong fish-killing storms, predation and old age are some of the natural regulators. For the adult population, mortality due to these factors is low (natural mortality coefficient, M=0.1). However, commercial fishing appears to have a stronger controlling force. Since the intensification of commercial fishing in 1950, the size of the fish caught has been decreasing, whereas the number of fish caught has been increasing yearly, probably as a result of increasing effort and the use of small mesh nets. These two trends may be the cause for T. nilotica to mature at a smaller size than they did 15 years ago.

Man-made changes in the eastern Mediterranean Sea and their effect on the fishery resources

Abstract: The construction of the Suez Canal caused extensive faunistic changes in the eastern Mediterranean Sea. Thirty species of Red Sea fishes are known to occur along the Mediterranean coast of Israel and Lebanon; 21 of them are common, and among them 16 appear regularly in the commercial catches. It is estimated that they constitute 21% of the Israeli trawl fishing and 8% of the inshore fishery. The construction of the Aswan High Dam in 1964 stopped the seasonal Nile floods of August–December. It was reported that, simultaneously, the Egyptian sardinella fishery collapsed. However, the Israeli sardinella fishery in post-Aswan years does not show any decrease in catches as compared with the period before 1964.

The Efficacy of Midwater Artificial Structures for Attracting Pelagic Sport Fish

Abstract: Field experiments were conducted in the northeastern Gulf of Mexico off Panama City, Florida to evaluate the feasibility of using man-made midwater structures for attracting pelagic game fish to improve sportfishing catch rates. Significantly greater catches of little tunny (Euthynnus alletteratus), king mackerel (Scomberomorus cavalla), and dolphin (Coryphaena hippurus) were made around experimental structure sites than in adjacent control areas when equal experimental fishing effort was used. Multiple structures attracted larger numbers of coastal pelagic bait fish and produced larger catches of pelagic game fish than single-structure units. The distance offshore or water depth of structure locations affected both the species of fish attracted and the number of fish caught. Charter fleet vessels fished around one of the experimental structures for several hours and reported total numbers of pelagic game fish caught and catch rates at least double those in “other areas” for that day.

The calanoid copepod family Pontellidae from the Indian Ocean

Abstract: The problems of immediate concern regarding the fishery of Indian oil-sardine, Sardinella longiceps, areas follows: Researches should be keyed up on three main lines, namely, behaviour studies through analysis of the distribution patterns of the fish in relation to the environment, population studies to know the homogeneity of the exploited population as well as its strength and parameters and spawning studies for detection, delimitation and evaluation of the spawning areas Development should include redeployment of eff'ort beyond the present fishing zone, introduction of purse seining on a large scale and the socio-economic problems of the fishing community The fluctuations so characteristic of the oil-sardine catches are most probably because of oscillations in the annual recruitment of the juvenile broods which, in turn, appear to be linked up with variations in the intensity of the south-west monsoon A weak or erratic monsoon is suspected to bring about conditions which are not conducive to successful reproduction and survival of the young fish A hypothesis is proposed that while a certain minimum amount of rainfall during the spawning period appears a necessary condition, it certainly is not the only responsible factor for production of a good year class A symposium on both the oil-sardine and the Indian mackerel is suggested to inincrease the effectiveness of future attempts of more penetrative studies, since many of the problems are common for both the fisheries which constitute the 'dual-species neritic pelagic fisheries system' of south-west coast of India

Economics of Fishery Management

Abstract: In an unmanaged fishery the costs of catching a unit weight of fish will tend to rise until they are equal to the value of the catch. There is likely to be an excessive amount of fishing which adds to the costs, but adds little or nothing to the total catch, and may even decrease it. In practice the amount of fishing will often exceed the equilibrium, due to delays in reacting to falling catch rates, year-to-year fluctuation in the fishery, etc. The labor and capital engaged in fishing is often relatively immobile, and once excess capacity has developed it is not easily reduced without special measures.A number of different measures are available to control both the amount of fishing and the sizes of the fish caught. These are outlined, and the advantages and disadvantages briefly discussed. Several of the methods of controlling the amount of fishing tend to add to unit costs, and therefore offer little long-term benefits. These benefits can only be assured by control of the total capacity engaged in a fi...

The fish resources of the ocean. Fishing News (Books) Ltd., Surrey, England, xi+special map section+255 pp. Price £ 10.50.

Abstract: Gulland, J. A. [Compiler and Editor] 1971. The fish resources of the ocean. Fishing News (Books) Ltd., Surrey, England, xi+special map section+255 pp. Price £ 10.50.

Sequence of Exploitation of Stocks in Multispecies Fisheries in the Laurentian Great Lakes

Abstract: The Laurentian Great Lakes have been fished with gradually increasing intensity for about 150 years. Their fish communities have been stressed by a broadening variety of other cultural influences besides fishing. A series of recent analyses have identified and distinguished effects due to fishing from those due to other cultural stresses. These analyses are here carried a step further, showing the fishing-up and overfishing sequence, through time, of various species as a function of their economic value to the fishermen. Some elements of a theory are proposed that interrelate a number of whole-system variables; if elaborated further such a theory should be useful in modelling and managing competing fisheries that harvest a number of ecologically interrelated species, perhaps more or less indiscriminately. Further, the theory should permit modelling and managing of other cultural stresses on the fish community, such as nutrient loading and toxic pollution that may act contemporaneously with fishing.

Fishing rod holder

Abstract: A fishing rod holder constructed primarily of weather resistant material, said material being flexible in either hot or cold weather, and particularly designed and constructed for the storage and protection of fishing equipment such as fishing rods and the like, in boats, campers, trailers, automobiles, and the like.

Big game fishing chair

Abstract: The invention provides a fishing chair, especially for large game fish, in which the heavy leg muscles of the fisherman, such as the thigh muscles, can be used to play and tire the fish rather than using the arm muscles.

Attracting and Controlling Coastal Pelagic Fish with Nightlights

Abstract: Field experiments were conducted in the northeastern Gulf of Mexico to evaluate techniques for using sequentially-operated lamp strings and moving lamps to lead and concentrate light-attracted coastal pelagic fishes. Fish were successfully led between sequentially-operated under-water lamps separated by distances up to 20 meters. Mobile lamps were used to lead fish distances up to approximately 1 kilometer. Fish aggregations which form daily around man-made structures were held after dark and led clear with moving lamps for capture by purse seine. A combination of nightlighting and man-made structure fish attraction techniques are proposed for harvesting coastal pelagic fish aggregations which occur around existing petroleton drilling platforms, well heads, and other areas presently inaccessible to conventional fishing gear.

India and the indian ocean fisheries

Abstract: This account deals with the present yield and its composition, potential resources- both qualitative and quimtitative from the inshore and offshore grounds as well as oceanic areas, in relation to the productivity of the Indian Ocean as evidenced by organic production, planlcton biomass and chlorophyll distribution. The paper also includes notes on the different aspects of problem-oriented research and stresses the need for extending our fishing horizon in order to place the Indian fisheries on a firm footing vis-a-vis that of countries exploiting the Indian Ocean resources. INDIA contributes about 40 % of the fish landings of the Indian Ocean and ranks seventh among the major fish producing countries of the world. But when viewed against the world production of 61 million tonnes of marine fish in 1970, India's share was only just over a million tonne representing about 2%. At present a quarter of a million persons are actively engaged in actual fishing producing annual landings valued at Rs. 1,200 million. The industry also provides employment to 1.4 million persons. There are about 10,000 mechanized crafts which land 15% of the total production. Over 600 million rupees worth of sea food is exported to different countries, With a coast line of 5,600 km and an operational advantage over wide sectors of the Indian Ocean, India should have a pre-eminent position in marine fish production and this vital sector should play a greater role in the country's economy. Reccsnt studies made during the International Indian Ocean Expedition reveal that there are several areas in the Indian Ocean which are exceptionally rich in nutrients, chlorophyll, organic production and zooplankton biomass. Consequently these areas could sustain large stocks of fish. This paper deals with the present yield and its composition and the potential resources as estimated from exploratory surveys as well as other biological factors. It also emphasises the possible contribution by India towards a full and rational exploitation of the resources of the Indian Ocean.

The rainbow trout Salmo gairdneri (Rich.) fishery of Lake Titicaca

Abstract: Rainbow trout were introduced to Lake Titicaca in 1942. A commercial trout canning operation started in 1961 but terminated in 1970. Data for this study were collected in 1966 and 1967, with the object of examining the life history, biology, and commercial fishery of Titicaca rainbow trout. Trout were caught commercially and experimentally by gillnets in different parts of the lake. Lake Titicaca lies across the border of Peru and Bolivia at 3212 m above sea level. The physico-chemical characteristics of the lake appear ideal for self-sustaining populations of rainbow trout. Growth was constant throughout the year, and was good in relation to growth rates of rainbow trout in other parts of the world. Spawning took place in the tributaries in the winter. Recruitment to the fishery occurs in 7.62 cm stretch mesh gillnets at about 27 cm fork length. The total annual commercial catch increased to 500 metric tons in 1965 before subsequently decreasing. The simplest explanation for the decline in total catch would be the increase in fishing mortality due to increased fishing effort, although it is possible that the decline in water level has had some effect. It appeared possible that the lake could sustain an annual catch of about 350 tons.

Hunters, Trappers, and Gatherers of the Sea: a Comparative Study of Fishing Strategies

Abstract: This study is a comparison of fishing strategies in three areas: the Newfoundland offshore fishery, the inshore salmon fishery of British Columbia, and an oyster fishery of Cornwall, England. From ...

The crab fishery resources of India

Abstract: Crabs support a sustenance fishery of appreciable importance, although, its present status is not comparable with that of those major crustacean fisheries such as prawns and lobsters. In addition to the marine fishery, large number of crabs are landed from the estuaries and brackish water lakes adjoining the coastal areas. To meet the increasing demand for frozen crab meat and to develop an organised crab fishing industry, an evaluation of the existing resources is quite essential. The fishery at present is supported mostly by the edible crabs belonging to the family Portunidae and available information on the various aspects of the fishery show that the fishing is restricted to the inshore areas mostly by operations of small indigenous crafts and gears. In most of the places crabs form an ancillary catch along with other crustaceans and fishes, intensive fishing for crabs alone existing only in selected areas. The annual catch which is less than 4,000 tonnes is subject to marked fluctuations. However, the distribution of the species and the trend in production indicate scope for further expansion. An attempt is made here to study the abundance and production of crabs from three general areas, viz., west coast of India, Gulf of Mannar and Palk Bay and the northern part of the east coast from Point Calimere to Sunderbans with a view to understand the crab resources of the country. The estimation of the potential resources of the offshore waters as indicated by the trawler catches is also mide. The need for biological investigattions on factors governing yield and crab population is stressed.

Assessment of Fish Flesh Tainting Substances

Abstract: Increased use of lakes and rivers for sport and commercial fishing in the vicinity of large municipal and industrial discharges has led to the realization that fish in many bodies of water are not palatable The dischargeof organic compounds has led to the contamination of fish flesh to such an extent that fishing is curtailed more because of poor eating quality rather than the lack of fish To evaluate the magnitude of the tainting of fish flesh in a large river, studies were conducted on the flavor of channel catfish (Ictalurus punctatus Rafinesque) flesh from the Ohio River from Pittsburgh, Pa, to Cairo, Ill Tasting of fish flesh determined that a panel could differentiate between fish held upstream and downstream from a wastewater discharge Caged test fish exposed for three days acquired a minimum of 70 percent of the off-flavor of native fish

Acceleration of assessment of fish populations and comparativestudies of similar taxonomic groups

Abstract: Proper assessment of the impact of fishing on the various fish populations is essential for the efficient management of the fishery resources of the country. Three types of assessment have been distinguished. A preliminary assessment just indicates if fishing is affecting the stock. The second type of assessment predicts long-term effect of fishing on a stock without taking into consideration the effect of fluctuating environmental factors. The final type, which is obviously the ultimate objective of all assessments, takes into account changing environment in forecasting the effect of fishing on a stock. Various diagnostic characters and parameters needed to be estimated for each type of assessment are indicated. Quicker methods of estimating some of the parameters are indicated. The role of comparative study of similar taxonomic group for such estimation of some of the parameters has been mentioned.

Economic Evaluation of Sport Fisheries—What Do They Mean?

Abstract: During 1968 we surveyed anglers in Idaho to assess: (1) gross annual expenditures by sport fishermen, (2) net value and consumer surplus of various high quality sport fishery resources in the state, and (3) distribution of fishing effort within Idaho by resident and nonresident anglers. Our objective in this paper is to: use the 1968 survey to review and evaluate techniques for assigning values to sport fisheries; compare our data with other surveys and plead for consistency in deriving economic values; and, lastly, to ask “what should these values mean to resource decision makers?” Using transfer costs assessed by mail questionnaires, we simulated demand functions for eight fisheries in Idaho. These fisheries accounted for 45% of the days fished by anglers in 1968. The estimated net value was %4,700,000, consumer surplus was %9,435,000, and capitalized net worth (at 4 3/4% interest) was %100 million. Anglers spent about %21 million on all fishing in Idaho in 1968. We found considerable variance ...

Research on the luring of fish schools by utilizing underwater acoustical equipment

Abstract: The device for gathering fish schools by using underwater acoustical equipment was conceived on the idea that if fish schools could be lured to a location and driven into a fish net by emitting the effective sound, fishing efficiency could be increased. The underwater sound projector of a flat frequency response from 150Hz up to 4,500Hz was produced, corresponding to acoustic features of fish. Yellowtail responded to their swimming and bait eating sound of 5-17dB re 1 ubar. The catch of squid was definitely more for the periods of emitting effective sound than for the periods of not emitting sound. Mackerel and jack mackerel responded to its swimming and bait eating sound of higher than 22dB and ascended. In the stationary net fishing, fish was lured by sound into the net and the big catch never got before was obtained.

Sharks, rays and skates as a potential fishery resource offthe east coast of India

Abstract: The sharks, rays and skates form one of the important commercial fisheries of India, the average annual landings for 10 years (1958-67) being 33,442 m. tons. Of this, 15,537 m. tons are landed along the east coast and 17,605 m.tons along the west coast and the rest at Andaman and Nicobar and Laccadive groups of islands. Reports indicate that the Indian Ocean offers valuable fishing grounds for these fishes, especially for the larger varieties which can substantially augment the supplies of food, liver-oils, fins and shagreen. Along the east coast, good fishery for elasmobranchs exists along the coasts of Orissa, Andhra Pradesh, Madras State and in Andaman Islands. These fishes are caught almost round the year, the sharks on hook and line and in drift gill nets at depths varying from 16 to 100 metres and majority of rays and skates in trawl nets, drift and bottom set gill nets and shore seines at depths ranging from 4 to 100 metres. The common species of sharks include the blacktip-finned sharks of the genus Carcharhinus, species of Scoliodon, the hammer-head sharks, Sphyrna spp., the tiger-shark, Galeocerdo cuvieri and the zebra shark, Stegostoma fasciatum. The whale shark, Rhincodon typus, is occasionally landed. Rays of commercial importance are the cownose ray, Rhinoptera javanica shoals of which make frequent incursions into coastal waters of Gulf of Mannar, the butterfly ray, Gymmura poecilura, Himantura spp., Amphotistius zugei, Pastinachus sephen and the devil ray, Mobula diabolus. The common skates include Rhynchobatus djiddensis and Rhinobatus granulatiis and the saw-fishes of the genus Pristis. From the present trend, it would appear that the catches of elasmobranchs off the east coast could be substantially increased by extending fishing operations to deeper waters especially in the Gulf of Mannar and by the use of stronger nets from mechanised vessels. Fruitful results may also be expected along the east coast, including Andaman Islands by exploratory surveys to chart potentially rich grounds for these fishes.

Albacore oceanography off Oregon : 1970

Abstract: During July 1970, albacore boats trolling surface jigs (jig boats) had record catches in an area off the mouth of the Columbia River. The jig fishery declined suddenly in late July and was poor throughout the remainder of the summer. No obvious oceanographic changes were correlated with these drastic changes in fishing success. Favorable water temperatures extended through August, traditionally the month of highest albacore landings in Oregon. Bait boats, which chum with live bait, had good fishing off Oregon from mid-August to October, indicating that the poor success of jig boats during this time was caused by the behavior of albacore relative to surface-trolled fishing gear. It is postulated that albacore descended into subsurface water in response to a change in availability of their preferred prey, the saury; here they were less accessible to jig boats than bait boats. Saury were common in the stomachs of albacore during periods of good jig fishing and were usually the dominant food where high albacore catches were made by our research vessel. The first albacore catches of the season were probably from an area of warm temperature and low salinity representing Columbia River plume water. The subsequent migration to the north appeared to be along the oceanic edge of the plume. In general, high catches by boats were not within the core of the plume but in 15.5°C water, especially in areas where a horizontal thermal gradient was apparent. 800-1,300 fish per boat day were reported on 30 July, averaged only 50 fish on 31 July.2 Although jig fishing continued to be poor during the rest of the summer off Oregon, bait boats enjoyed good fishing into October. The purpose of this paper is to describe ocean conditions and albacore catches in Oregon waters during the summer of 1970 in hopes of better understanding the small-scale spatial distribution of albacore tuna and the dramatic changes in their availability that occurred in 1970. SOURCES AND TREATMENT OF DATA Catch data for the 1970 albacore season off Oregon were derived from fish boat logs sent directly to us from fishermen or obtained through other agencies from fishermen. Thirtythree jig boats and two bait boats submitted usable records to us from our original dis2 Laurs, R.M. 1970. U.S. Bur. Commer. Fish., Albacore Bull. No. 70-3 and 70-4, La Jolla, Calif. Manuscript accepted October 1972. FISHERY BULLETIN: VOL. 71, NO.2, 1973. 489 tribution of 421 special logs to fishermen in Oregon, Washington, and California prior to the 1969 albacore season. These logs were unique in that they were designed to obtain several entries per day from fishermen so that variations of catch rate over small spatial areas could be examined. In addition, the Fish Commission of Oregon obtained 116 jig boat and 8 bait boat logs, California Department of Fish and Game made available 45 jig boat and 8 bait boat logs, and the InterAmerican Tropical Tuna Commission provided 2 jig boat and 11 bait boat logs. The catches of each type of boat were averaged for each day regardless of fishing location off Oregon. Catches of jig boats were also assigned to 10' latitude X 10' longitude blocks based on their reported loran positions. Generally catches could be assigned to a specific block. If a boat cruised over a large area and catches could not be assigned to specific blocks, the data were not plotted. No adjustment was made for the effect of boat size or number of lines on catches. It should be pointed out that our catch data do not necessarily represent average catches made by the fleet in an area because they are from only part of the fleet. Sea-surface temperature was measured on remote sensing overflights using a Barnes PRT-5 infrared radiometers at an altitude of 150 m or 500 ft (Pearcy and Mueller, 1970). A total of 15 flights were made from 22 July to 15 September on HU-16 aircraft either from the U.S. Air Force 304th Aerospace Rescue and Recovery Squadron, Portland, Oreg., or from the U.S. Coast Guard Station, Port Angeles, Wash. On two RV Cayuse cruises, temperature was measured with bathythermographs, and temperature and salinity with a SalinityTemperature-Depth system. Stations were usually 10 miles apart. On the 27 July2 August cruise, water transparency was determined with a submarine photometer, and 6-ft Isaacs-Kidd midwater trawl collections were taken at 5 knots to a depth of about 100 m Reference to trade names does not imply endorsement by the National Marine Fisheries Service, NOAA. 490 FISHERY BULLETIN: VOL. 71, NO.2 along the cruise track at night. Volume of water filtered was estimated from flowmeters mounted in the mouth of the trawl. Albacore were caught from the Cayuse by fishing between hydro stations using standard trolling methods with a maximum of eight lines. Time and location of catches during daylight hours were recorded. All fish collected were measured in fork length; stomachs removed and preserved immediately with Formalin for subsequent examination of their contents.

The lobster fishery resources of India

Abstract: The increasing demand for frozen lobster tails from world markets has brought the Indian spiny lobster to the lime light. An assessment of the total lobster resources of the country is made. Among half a dozen species of spiny lobsters reported from the different coastal areas and which are enumerated, Panulirus homarus is the most important from the commercial point of view. Details of the distribution of the different species along the coastline are given. Kanyakumari District on the south-west coast is the area with the maximum production. An estimate of the population of this and nearby areas is made both by the fishing success method as well as the Petersen method of tag recovery. The two population estimates are quite in agreement. Based on the population estimates the present rate of exploitation is also calculated. Species of potential commercial importance obtained in recent exploratory cruises in deeper waters off Kerala are mentioned.

Floatable fishing device

Abstract: A floatable fishing device comprising a float and fishing lamps to indicate catches of fish on hooks associated with the device. A pair of pendulum operated switches actuate two lamps, of different colors, depending on the direction of the swinging of the pendulum when the float is inclined by the pull of caught fish. The float is provided with a guide rod. A ring secured to the free end of a fishing line is slidable on the guide rod. A plurality of hooks are attached to the fishing line in spaced relationship. The device permits the fisherman to fish at a remote distance.

Age and Growth of Horse Mackerel Trachurus murphyi off Chile

Abstract: Horse mackerel, Trachurus murphyi, were collected during the fishing seasons of 1962–1963 and 1963–1964 from three different fishing areas off the coast of Chile. Age and growth were studied through the otoliths and length frequency distribution of the fish. More than 90% of the captures consisted of 4- to 6-year-old fish. The oldest specimen, measuring 63.5 cm and weighing 2,400 grams, was 10 years old. The major growth occurred during the first year of life.