ISSN:0002-8487    

DOI:10.1577/1548-8659(1985)114<1:SB>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Production indices for juvenile striped bass Morone saxatilis in the Chesapeake Bay and Roanoke River-Albemarle Sound regions have declined in recent years. A concurrent decline in harvest of striped bass along the Atlantic coast also has been observed. Lack of the occurrence of a dominant year class in the Chesapeake Bay since 1970 has affected the coastal harvest and the abundance of the spawning populations. Occurrence of another dominant year class will depend on two factors: Relatively good survival between the egg and juvenile life stages; and a sufficient amount of egg deposition to take advantage of the good survival conditions.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1985)114<3:PAHOAS>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The number of fisheries for striped bass Morone saxatilis in freshwater impoundments in the United States has increased dramatically over the last decade. A survey of fisheries agencies throughout the country was conducted to evaluate accomplishments and problems associated with management of striped bass and hybrid striped bass (male white bass Morone chrysops x female striped bass). Through 1981, fisheries for striped bass, hybrid striped bass, or both had been established in at least 279 lakes in 34 states. Mean annual harvest rates from striped bass, hybrid striped bass, and mixed (both fish in same lake) fisheries were 1.1, 0.7, and 3.0 kg/hectare, respectively. In reservoirs where they are established, these fisheries contribute an average of 13.6% to the total harvest by weight; their maximum contribution is 66.2%. Improvements in management have been limited by the lack of good objectives and of quantitative evaluations of stocking success. The most frequently cited management problem was mortality of adult striped bass due to thermal stress and to low dissolved oxygen concentrations. Other major problems included inadequate prey availability, emigration, predation on salmonids, and variable survival of introduced fish. Management potential can be greatly enhanced by additional information on the habitat requirements and predator-prey relations of these fish in impoundments.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1985)114<8:SBMILW>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The abundance of young striped bass Morone saxatilis in the Sacramento-San Joaquin Estuary has suffered an unsteady but persistent decline from population levels that were high in the middle 1960s. The decline was particularly severe in 1977 and abundance of young striped bass has been low every subsequent year. The adult striped bass population also has fallen during the past 20 years, but the exact period over which the decline occurred and the rate of decline are not clear. The adult population is now about one-quarter of its former size and there is little sign of recovery. We believe the Sacramento-San Joaquin striped bass population and the fishery that it supports are in serious danger. The cause is most likely one or more of four factors. (1) The adult population is now so low that egg production may be inadequate. (2) The plankton food supply of young striped bass in the western Sacramento-San Joaquin Delta and Suisun Bay has been greatly reduced each spring. Diversion of water from the delta for agricultural purposes is a prime suspect for the decrease in food production. (3) Large numbers of young fish are lost by entrainment in water diversions. (4) The population is stressed by toxic substances such as petrochemicals and pesticides. Additional studies are underway to help determine the principal cause(s) of the striped bass decline.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1985)114<12:TDOSBI>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Striped bass Morone saxatilis has a paradoxical record of distribution and abundance, including population declines in coastal waters and variable success of freshwater introductions. This record is analyzed for consistency with a hypothesis that striped bass are “squeezed” between their thermal and dissolved oxygen preferences or requirements. A commonality among diverse field and laboratory observations supports an inherent thermal niche for the species that changes to lower temperatures as fish age. This shift can cause local conditions, especially warm surface strata and deoxygenated deep water, to be incompatible with the success of large fish. Crowding due to temperature preferences alone or coupled with avoidance of low oxygen concentrations can lead to pathology and overfishing, which may contribute to population declines. Through a mixture of evidence and conjecture, the thermal niche-dissolved oxygen hypothesis is proposed as a unified perspective of the habitat requirements of the species that can aid in its study and management.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1985)114<31:SBTADO>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

A survey of 80 reservoirs in the United States with striped bass Morone saxatilis populations indicated some summer mortality of the species in 27 (34%) of the impoundments. Most of the reported mortality was of medium sized to large adults (> 5 kg). More mortality was reported in July-September than in other months. Reservoirs for which summer striped bass mortality was reported had significantly greater mean surface area, volume, maximum depth, and depth of water release than those without reports of striped bass mortality. However, the presence or absence of reported striped bass mortality bore no discernible relationship to reservoir morphometric or limnological features when 20 such characteristics were examined by multivariate analysis. The results suggest overall that summer mortality of striped bass is widespread geographically in reservoirs of the United States, but its occurrence is highly variable and by no means universal.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1985)114<62:SMOSBI>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Telemetry techniques were used to evaluate relationships between water quality and distribution of adult striped bass Morone saxatilis during an 18-month period in Watts Bar Reservoir, Tennessee. Distribution and movements of fish were influenced by water temperature and dissolved oxygen concentration. During winter and early spring, temperature was vertically and horizontally uniform, and striped bass were relatively mobile and occurred in both tributary arms as well as in the main body of the reservoir. As the reservoir warmed in summer, fish were less mobile and progressively limited to areas in the tributary arms where temperature was less than 24 C and dissolved oxygen exceeded 4 mg/liter. Parts of the tributary arms of Watts Bar Reservoir provided such areas due to hypolimnetic discharges from upstream impoundments and groundwater inflows. Striped bass were restricted to these areas until late fall, when the entire reservoir cooled and again was nearly isothermal. Knowledge of relationships between striped bass habitat use and water quality is useful for fishery management and resource protection for reservoirs; an example is provided for Watts Bar Reservoir.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1985)114<67:IOWQOD>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Adult and subadult striped bass Morone saxatilis began concentrating in two small spring-fed tributaries of the Alabama River in early June as ambient river temperatures approached 27 C. Fish collected from summer refuges had lower condition factors than those collected during April through May. Six swiped bass (2.7–5.9 kg) equipped with ultrasonic and radiotelemetry transmitters tended to seek cool-water refuges (22–26 C) in reservoirs during summer, but they tolerated temperatures 5–6 C higher during excursions of several hours from or between refuges.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1985)114<77:SSOTRB>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

In May and June 1982, before stratification, echolocator charts indicated that fish in the main basin of Lake Texoma (Oklahoma-Texas) were distributed from the surface to the bottom. With the onset of stratification and oxygen depletion in the hypolimnion in July, fish moved upward in the water column, avoiding anoxic conditions near the bottom. Stratification (defined more conspicuously by dissolved oxygen and conductivity than by temperature) became progressively more distinct in late summer, and by August temperatures in the epilimnion were greater than 28 C and dissolved oxygen in the hypolimnion was less than 2 mg/liter. Echolocator charts indicated that fish were concentrated immediately above the chemocline (8–12 m deep) where water temperature was 28.5 C and dissolved oxygen was 7.2 mg/liter. This concentration of fish included subadult and adult striped bass Morone saxatilis, which are known to congregate in the main basin of Lake Texoma during the summer. Despite the high temperatures in the epilimnion, and low oxygen conditions in the hypolimnion, no mortality of adult striped bass was observed. Although the available data indicate that a temperature-oxygen “squeeze” is typical in Lake Texoma in numerous summers, the reservoir has a large population of striped bass with many individuals larger than 5 kg.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1985)114<84:DDOSBA>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The ability to predict subsequent landings of striped bass Morone saxatilis from the indices of abundance of juveniles (young of the year) determined annually by the Maryland Department of Natural Resources was evaluated by multiple-regression techniques. About 57% of the variation in reported landings could be accounted for by the juvenile indices 2, 3, 4, and 5 years prior to the year of the landings for the period 1959–1983. Elimination of the first 4 years of record (1959–1962) increased the R2to 0.83. The regressions of reported landings on the indices of ages 2–5 striped bass for the periods 1964–1973 and 1974–1983 indicated that mortality in the fishable stock increased between the two periods. These results support the use of the juvenile indices for monitoring recruitment into the population and as a basis for management decisions.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1985)114<92:RBRCLA>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor