Showing papers on "Fishing published in 1981"

Disappearance of common skate Raia batis from Irish Sea

Abstract: Records show that the common skate, Raia batis, has declined in abundance in the Irish Sea since the early years of the twentieth century, and is now very rare. As I report here, it is possible to calculate the highest mortality which the species will withstand without collapsing. It is likely that the mortality due to fishing has exceeded this level for some time and that the species will not recover while fishing continues. This represents the first clear case of a fish brought to the brink of extinction by commercial fishing.

A guide to the common sea fishes of southern Africa

Abstract: This reprint features the latest regulations regarding catch restrictions and current angling and spearfishing records The guide includes some 324 of the fishes most likely to be seen or caught in Southern Africa waters, from the little coral fish that inhabit the Northern Natal reefs and estuaries to the might of the black marlin and the great white sharks Each species is photographed in full colour to show the characteristic shapes and identifying colours and markings to best advantage A full page is devoted to each species description, elements of which include notes on natural history, local and world-wide distribution maps, and angling and spearfishing records as well as catch restrictions

International Commission for the Conservation of Atlantic Tunas (ICCAT)

Abstract: The fishing of tunas in the Atlantic began in the mid-fifties. At the present time about 20 states are fishing this species, having a total catch of 4.5 million tons in 1975. The main portion of catch is of Spain and Japan (in 1973 68.5 and 48.0 thousand tons respectively).

Relation Between Sport-Fishing Catchability Coefficients and Salmon Abundance

Abstract: Pacific salmon sport-fishing data without time trends in the catchability coefficient q or in fish abundance N show that q is larger at lower N. This phenomenon causes serious management problems because it creates critical thresholds in population size and fishing effort that can lead to stock extinction. The inverse relation between q and N directly parallels the analogous relation shown by some predators in natural ecosystems.

Man and Fisheries on an Amazon Frontier

Abstract: 1. Physical and biological portrait of the Rio Madeira basin.- 2. Cultural backdrop of the Rio Madeira basin.- 3. The fisheries.- 4. Fishing area, effort, and yield.- 5. Natural history of the food fishes.- 6. Problems and prospects.- Author index.- Index to scientific names.

Effects of Angling on a Previously Fished and an Unfished Warmwater Fish Community in Two Wisconsin Lakes

Abstract: Population structure and other vital statistics were determined for warmwater fish populations in two adjacent lakes for two successive 3-year periods. Allen Lake (7.8 hectares), containing bluegills Lepomis macrochirus, pumpkinseeds Lepomis gibbosus, yellow perch Perca flavescens, largemouth bass Micropterus salmoides, and northern pike Esox lucius, was open to angling during, and for about 10 years before this investigation. Mid Lake (4.7 hectares), with the same species, was closed to angling until fishing was permitted throughout the second 3-year period. Before angling began in Mid Lake, large proporations of the populations were of large, old fish, and total annual mortality rates (which were natural mortality rates) were low. The fished populations in Allen Lake comprised mainly small or intermediate size fish throughout the study. After angling in Mid Lake the fish populations and their vital statistics became like those in Allen Lake: Length- and age-frequency distributions shifted towar...

Satisfaction bonus from salmon fishing: implications for economic evaluation.

Abstract: The salmon seine fishery of Southeast Alaska is a tightly regulated and very competitive commercial enterprise. Despite relations marked by competition, small groups of skippers cooperate with one another to the extent of sharing information as they ...

Hobikiami Sail Trawling in Japan

Abstract: Sail trawling of Hobikiami fishing consists of a boat drifting sideways downwind while towing a net. This picturesque fishing method was invented about 100 years ago as a means to reduce the then labor-intensive methods. Hobikiami trawling is analogous to flying a kite wherein kite, tail of kite, and man correspond to sail, boat, and net respectively. This technique while undergoing many modifications has remained endemic to its area of origin, Lake Kasumigaura and nearby Lake Kitaura, central Japan, because of particular requirements of the wind. The wind must be approximately parallel to the long axis of the lake, and of moderate strength and frequency during the fishing season from July through December. Diesel trawlers, which are largely independent of the weather, have replaced Hobikiami fishing on Lake Kasumigaura. Today, Hobikiami fishing is maintained on a small scale on Lake Kitaura. It is carried out by parttime fishermen-farmers who live beside the lake. Unless Hobikiami fishing can be...

Relative Harvestability by Angling of Blue Catfish, Channel Catfish, and Their Reciprocal Hybrids

Abstract: One hundred and eighty-seven each of channel catfish, Ictalurus punctatus, blue catfish, Ictalurus furcatus, and their reciprocal hybrid crosses were stocked communally in a 0.1-hectare pond (7,480 fish/hectare) in April 1977. Each group was heat-branded prior to stocking for subsequent identification. The fish were grown for 181 days, after which the pond was fished for 35 man-hours (350 man-hours/hectare) on October 16 and 17. The pond was drained on October 19 and the remaining fish were harvested. A total of 290 kg (518 fish) was harvested by fishing and draining. Seventy-five (14.5%) of the fish were caught by the anglers in the two days. The hybrids were more susceptible to angling than the parent species. Heterosis for catchability was 158.6% by number and 203.6% by weight of fish caught. Channel catfish ♀ x blue catfish ♂ hybrids were more catchable than the reciprocal hybrids. Average length of all fish that were caught was greater than for those that were not caught. Fishing success in ...

Atlantic Skipjack Tuna: Influences of Mean Environmental Conditions on Their Vulnerability to Surface Fishing Gear

Abstract: Pertinent data and literature are examined to determine the effects of the environment on the spatial distribution of skipjack tuna, Katsuwonus pelamis, in both the Atlantic and Pacific Oceans. Environment/skipjack distribution relationships derived from this information are applied to longterm annual mean distributions of dissolved oxygen and thermal structure for the Atlantic Ocean between lot. 40"N and 40% The depth of skipjack habitat is mapped. Within the defined habitat areas, high vulnerability of skipjack tuna to surface gear is inferred and areally compared with the long-term catch of the FIS (French, Ivory Coast, and Senegalese) fleet to confirm the validity of this approach. This technique is then used to hypothesize areas of vulnerability of skipjack to surface gear outside the range of the FIS fleet effort in the western Atlantic. Finally, the effects of surface winds on fishing operations are discussed and those areas where wind speed may hamper operations are outlined for the Atlantic Ocean between lot. 30"N and 30"s. environmental indicators to infer habitat limits of skipjack tuna appears preferable to habitat forecasts based on skipjack tuna forage or migration patterns because of the limited data available to assess these factors. In contrast, a comparatively large amount of physical oceanographic data is available for comparison with catch statistics since oceanographic observations are routinely made for other purposes. Physiological experiments on captive skipjack tuna from the Pacific have been carried out to ascertain habitat preference as functions of several environmental indicators (Dizon, 1977; Dizon et al., 1977, 1978). No attempt has been made to integrate existing environment/ habitat relationships and data .with Atlantic catch data to define those areas where skipjack tuna should be available to surface gear. This paper attempts to do this and, in doing so, to develop working hypotheses for identifying areas of potential skipjack tuna concentration as an aid to exploiting and managing the resource. R . H . Evans is with the Southwest Fisheries Center, National Marine Fisheries Service, NOAA. La Jolla. C A 92038; D. R . McLain is with the Pacific Environmental Group, National Marine Fisheries Service, N O M , Monterey, C A 93940; and R. A. Bauer is with Compass Systems, Inc., San Diego, CA 92109.

Efficiency of Electric Fishing for Salmonids in Relation to River Width

Abstract: The efficiency of electric fishing for salmonids was found to decrease with increasing river width. The results demonstrated that mean efficiencies in excess of 50% could be obtained using two anodes up to a river width of about 6.5 m and using three anodes up to a river width of about 11 m. Yearling and older fish were captured more efficiently than fry at equivalent river widths and this was discussed in relation to differences in their behaviour.

Bioeconomics of the Ocean

Abstract: Since early times man has utilized the biological resources of the ocean for food and other needs. Today marine fisheries contribute approximately 14% of human global consumption of animal protein; in many countries the proportion is much higher-about 60% in Japan, for example. Other commercial products obtained from biological marine resources include oils (edible and industrial), glues, drugs, insulin, agar and other products of marine algae, fertilizers, furs, shark leather, poultry and animal feeds, and pearls and other jewelry items. Many native coastal populations have traditionally depended almost exclusively on marine resources such as fish, shellfish, mollusks, whales, seals, and sea turtles. The biological resources of the ocean are thus clearly of major economic importance. Unfortunately they have also often been subject to serious overexploitation. Several major fish stocks have collapsed following extensive exploitation; examples include baleen whales' (blue, fin, humpback, right, and bowhead whales), Atlantic and Pacific herring, Peruvian anchoveta, and California sardine. Increases in demand, combined with more efficient technology for harvesting, processing, and preserving fish, have led to increased fishing intensity on many stocks. Nevertheless, as noted elsewhere in this issue, total world catches have in recent years increased at a rate of less than 1% per year. Catches of "traditional" species

Motivations of New York and Virginia Marine Boat Anglers and Their Preferences for Potential Fishing Constraints

Abstract: Four potential marine recreational angling constraints were identified as appropriate for use where needed in the Mid-Atlantic region: (1) limit the catch kept per angler per day, (2) set minimum size limits on catch kept, (3) limit an angler to two fishing rods and lines, and (4) prohibit the sale of fish caught by anglers. More than one-half of the New York and Virginia marine anglers who fish from boats in the Mid-Atlantic region and who were interviewed reported they either favored or were neutral to the four constraints considered, assuming some constraint was needed. A minimum size limit was most acceptable; more than 80% of the anglers either favored this constraint or were neutral. Eighty-three percent of the anglers reported that their rate of participation in fishing would not be affected, regardless of which constraint might be imposed. Anglers were motivated to take their marine fishing trips for a variety of reasons—having fun, change from daily routines, social interaction, enjoying...

Long distance fishing system

Abstract: An improved apparatus and method for fishing at a location in water relatively remote from where the fisherman is positioned on land, under conditions where there is a wind blowing in a direction from the fisherman toward the location where he wants the hook and bait to be located in the water, the improved apparatus and method to be used with a conventional fishing rod, reel, fishing line, fishing jig, hook and bait.

An analysis of catch and effort data from the u. s. recreationalfishery for billfishes (istiophoridae) in the western north atlantic ocean and gulf of 'mexico, 1971-78 1

Abstract: Catch and effort data from the United States recreational fishery for billfishes in the Atlantic Ocean and GulfofMexico were examinedto evaluate their usefulness in determining trends in abundance. In the Gulf of Mexico, data were recorded from both organized fishing tournaments and from non­ competitive fishing. A fishing power model was developed and comparisons made between catch per unit effort from tournament data, nontournament data, and Japanese longline data. The results indicate that catch and effort statistics for white marlin, Tetrapturusalbidus, and sailfish, Istiophorus platypterus, in the Gulf of Mexico appear to be reliable and can be aggregated to provide a means of indexing relative abundance of these species. The model did not appear to be appropriate for blue marlin, Makaira nigricans, however. The general trend in catch per unit effort from 1972 to 1978 for sailfish and white marlin in the Gulfof Mexico appears to be downward. Based on catch per unit effort from all fishing areas, there appears to be a single stock ofwhite marlin in the western North Atlantic and Gulf of Mexico. In 1971, the National Marine Fisheries Service's Southeast Fisheries Center initiated research on the billfish stocks of the western North Atlantic Ocean and Gulf of Mexico. The purpose of this research was to develop and evaluate a method of detennining changes in relative abundance ofbiIl­ fish stocks using catch and effort data from the recreational fishery. This report has beenprepared to present a description of this research, evaluate the reliability of the sampling techniques, and rnake a preliminary determination ofthe validity of catch and effort data from the recreational fiShery as an indicator of changes in relative abundance ofbillfish populations. THE RECREATIONAL FISHERY

Easter Island Fishing

Abstract: T HE STUDY OF fishing gear, fishhooks in particular, has proven fruitful in investigating technological change and past cultural relations in Polynesia. Previous examinations of Easter Island fishhooks established their basic Polynesian affinities (Metraux 1940; Golson 1965; Emory 1972; but see Heyerdahl 1961, 1968), emphasized similarities with those from the Marquesas and Mangareva (Sinoto 1967, 1970), and identified the Easter Island two-piece fishhook as a local development comparable to innovations in Hawaii and in New Zealand (Emory, Bonk, and Sinoto 1968). In contrast to many other Polynesian islands, Easter Island offers little historic and ethnographic information about local marine subsistence (Ayres n.d.a); the little that is known suggests technological and methodological elaboration consistent with the locally limited material resources and the impoverished marine biota. The shortage ofcanoe timber was noted even in the earliest historic times, suggesting that deep water angling for large fish was quite restricted, particularly during the last three to four hundred years. Evidence for an emphasis on netting techniques is offset by the rocky coastline, which lacks productive shallow coral reef flats. Weirs or traps were never elaborated; preEuropean spear fishing is not well documented. Despite Metraux's assertion (1940: 172) that the nature of the earlier Easter Island marine subsistence is virtually unknowable, examination of comparative data on fishing methods and technology, of ecological factors, and of archaeological remains provides a base for formulating testable hypotheses characterizing the nature and development of the island's marine subsistence economy. Morphological variation in Easter Island fishing gear must be considered from three

By-catch of the shrimp fishery in India

Abstract: Every year as much as 21 million tonnes of edible marine fish are thrown away at sea by shrimp trawlers, which amounts to roughly the same quantity of fish eaten annually by the people of the developing countries in a world of increasing hunger we cannot afford to indulge in the luxury of this practice of dumping the trash fish over-board the fishing vessel in this connection a study was made to understand the shrimping by-catch and its utilisation in this country and the results are reported here. The present study makes it clear that nothing much from the shrimp trawler catches is wasted in india and almost all the fishes, which are termed trash fish and discarded over board the vessel in some of the developed countries, are utilised either for human consumption or as fish meal and fish manure. However it is to be pointed out that the handling, processing and utilization of the fish catches, need further improvement.

Factors affecting fish production and fishing quality in new reservoirs, with guidance on timber clearing, basin preparation, and filling

Abstract: : Fishing pressure on U.S. reservoirs is increasing rapidly and may double in the next 20 years. To meet increasing fishing demands, effective practical plans must be implemented to maximize and prolong the high spot-fish production that characterizes new impoundments. This report reviews literature on fishery resource development and fish production in new reservoirs and provides guidance on filling and site preparation techniques that should enhance fish production and angling quality. During filling, reservoirs are extremely productive because virtually all allochthonous nutrients, detritus, and drowned terrestrial animals, as well as autochthonous production (primary and secondary), are retained in the basin. After a new impoundment is filled, fish production and harvest are high for the first 5 to 10 years but progressively decline as the reservoir ages. Strong year classes of fish may be produced in years of increased precipitation which increases inflow of nutrients and detritus from the drainage basin and raises the lake level to inundate woody vegetation, forest litter, and/or herbaceous plants. Declines in reservoir fisheries primarily result from the losses of nutrients and detritus to outflow and sediments and from the use of detritus by invertebrates and fish. Concerns during filling include timing of inundation and control of water levels. Concerns for reservoir clearing depend on trade-offs among factors such as mosquito control, water quality, recreation, and fish production. On the basis of biological observations, practical methods of clearing reservoirs are presented, but the effectiveness of various methods has not been evaluated, because of insufficient quantitative data.

Northwest Atlantic Fisheries Organization (NAFO)

Abstract: The Northwest Atlantic is the most important fishery region of the World Ocean, where until recently about 20 countries have been engaged in fishing operations, having a total catch of 2.5 million tons.