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At least 271 records · Page 15Linked to original sources
USGS2018

Evaluating spatial and temporal variability in growth and mortality for recreational fisheries with limited catch data

Understanding the spatial and temporal variability in life-history traits among populations is essential for the management of recreational fisheries. However, valuable freshwater recreational fish species often suffer from a lack of catch information. In this study, we demonstrated the use of an approach to estimate the spatial and temporal variability in growth and mortality in the absence of catch data and apply the method to riverine smallmouth bass ( Micropterus dolomieu ) populations in Pennsylvania, USA. Our approach included a growth analysis and a length-based analysis that estimates mortality. Using a hierarchical Bayesian approach, we examined spatial variability in growth and mortality by assuming parameters vary spatially but remain constant over time and temporal variability by assuming parameters vary spatially and temporally. The estimated growth and mortality of smallmouth bass showed substantial variability over time and across rivers. We explored the relationships of the estimated growth and mortality with spring water temperature and spring flow. Growth rate was likely to be positively correlated with these two factors, while young mortality was likely to be positively correlated with spring flow. The spatially and temporally varying growth and mortality suggest that smallmouth bass populations across rivers may respond differently to management plans and disturbance such as environmental contamination and land-use change. The analytical approach can be extended to other freshwater recreational species that also lack of catch data. The approach could also be useful in developing population assessments with erroneous catch data or be used as a model sensitivity scenario to verify traditional models even when catch data are available.

Pennsylvania↗
USGS2006

Forecasting effects of climate change on Great Lakes fisheries: models that link habitat supply to population dynamics can help

Future changes to climate in the Great Lakes may have important consequences for fisheries. Evidence suggests that Great Lakes air and water temperatures have risen and the duration of ice cover has lessened during the past century. Global circulation models (GCMs) suggest future warming and increases in precipitation in the region. We present new evidence that water temperatures have risen in Lake Erie, particularly during summer and winter in the period 1965–2000. GCM forecasts coupled with physical models suggest lower annual runoff, less ice cover, and lower lake levels in the future, but the certainty of these forecasts is low. Assessment of the likely effects of climate change on fish stocks will require an integrative approach that considers several components of habitat rather than water temperature alone. We recommend using mechanistic models that couple habitat conditions to population demographics to explore integrated effects of climate-caused habitat change and illustrate this approach with a model for Lake Erie walleye ( Sander vitreum ). We show that the combined effect on walleye populations of plausible changes in temperature, river hydrology, lake levels, and light penetration can be quite different from that which would be expected based on consideration of only a single factor.

Canadian Journal of Fisheries and Aquatic Sciences↗
USGS1970

Walleye fishery of Lake Erie in 1943-62 with emphasis on contributions of the 1942-61 year-classes

The commercial fishery for walleyes ( Stizostedion vitreum vitreum ) in Lake Erie virtually collapsed in the late 1950's. The extreme decline in production was attributed primarily to a succession of weak year-classes, caused by habitat deterioration (increased water temperatures, enrichment, and pollution) in western Lake Erie. Unusually high fishing intensity and high yields of walleyes in the mid-1950's contributed to the collapse.Annual lakewide production of walleyes dropped from a record high of 15 million lb in 1956 to a record low of 717,000 lb in 1962. Canadian catches exceeded those of the United States only during the high production years of 1956–58; U.S. fishermen took 71% of the total catch in 1915–62.On the basis of the numbers of fish of the various year-classes in the fall trapnet samples at Sandusky, Ohio, in 1943–62, all but one of the 1942–52 year-classes were above average strength, and all but one of the 1953–61 year-classes were below average. Fish of the 1953–61 year-classes grew much faster than those of the 1942–52 year-classes. The strong 1948 year-class was followed by a series of progressively weaker year-classes until 1958; year-class strengths remained low through 1962.

Journal of the Fisheries Research Board of Canada↗
USGS1972

Lake Erie: Effects of exploitation, environmental changes and new species on the fishery resources

In no other lake as large as Lake Erie (surface area, 25,690 km 2 ) have such extensive changes taken place in the drainage basin, the lake environment, and the fish populations over the last 100 years. Deforestation and prairie burning led to erosion and siltation of valuable spawning grounds. Marsh spawning areas were drained. Lake-to-river spawning migrations were blocked by mill dams. Accelerated cultural nutrient loading increased total dissolved solids by nearly 50% (1920-70). Average summer water temperatures increased 1.1 C. Phytoplankton and zooplankton abundance increased severalfold. Severe oxygen depletion developed in the bottom waters of all three basins of the lake. Lake sturgeon were fished out as nuisance fish in the late 1800s. The commercial fisheries for lake trout, lake whitefish, and lake herring collapsed by 1940 and those for blue pike and walleye by 1960. Yellow perch production became unstable in the 1960s. The effects of exploitation, environmental changes, and new species on these fish populations are discussed.

Lake Erie↗
USGS1982

Decline of lake herring ( Coregonus artedii ) in Lake Superior: an analysis of the Wisconsin herring fishery, 1936-78

Annual harvests of lake herring ( Coregonus artedii ) in American waters of Lake Superior declined from an average of 2 million kg in 1936–62 to less than 25 000 kg in 1978. Analysis of commercial fishing records revealed that the sequential overexploitation of discrete unit stocks caused the collapse of the herring population in Wisconsin waters. In each of six major spawning areas, catch exceeded the productive capacity of the stock and the stock failed. Because stocks in the six areas were exploited sequentially, mostly in groups of two or three simultaneously, the demise of the stocks was not readily apparent until the last two failed in the early 1960s. After the collapse of the last major spawning stock, the fishery dwindled but may have continued to overexploit the remaining small stocks. The residual populations were apparently able only to replace themselves. Some form of density-independent mortality was apparently operating to prevent their recovery during the 1960s and 1970s. Key words : lake herring, overfishing, Lake Superior

Canadian Journal of Fisheries and Aquatic Sciences↗
USGS1994

Problems of stock definition in estimating relative contributions of Atlantic striped bass to the coastal fishery

Stock contribution studies of mixed‐stock fisheries rely on the application of classification algorithms to samples of unknown origin. Although the performance of these algorithms can be assessed, there are no guidelines regarding decisions about including minor stocks, pooling stocks into regional groups, or sampling discrete substocks to adequately characterize a stock. We examined these questions for striped bass Morone saxatilis of the U.S. Atlantic coast by applying linear discriminant functions to meristic and morphometric data from fish collected from spawning areas. Some of our samples were from the Hudson and Roanoke rivers and four tributaries of the Chesapeake Bay. We also collected fish of mixed‐stock origin from the Atlantic Ocean near Montauk, New York. Inclusion of the minor stock from the Roanoke River in the classification algorithm decreased the correct‐classification rate, whereas grouping of the Roanoke River and Chesapeake Bay stock into a regional (“southern”) group increased the overall resolution. The increased resolution was offset by our inability to obtain separate contribution estimates of the groups that were pooled. Although multivariate analysis of variance indicated significant differences among Chesapeake Bay substocks, increasing the number of substocks in the discriminant analysis decreased the overall correct‐classification rate, Although the inclusion of one, two, three, or four substocks in the classification algorithm did not greatly affect the overall correct‐classification rates, the specific combination of substocks significantly affected the relative contribution estimates derived from the mixed‐stock sample, Future studies of this kind must balance the costs and benefits of including minor stocks and would profit from examination of the variation in discriminant characters among all Chesapeake Bay substocks.

Maryland↗
USGS1953

Fluctuations in the fisheries of State of Michigan waters of Green Bay

Green Bay, traditionally a major center of production, has assumed in recent years a position of overwhelming dominance in the commercial fisheries of the State of Michigan waters of Lake Michigan. Within the 4-year period 1945-1948 the commercial take in State of Michigan waters of Green Bay increased from 3,317,000 pounds in 1945 to 7,909,000 pounds in 1948, and it was 7,782,000 poinds in 1949. At the same time the percentage contribution of Green Bay to the State total for Lake Michigan rose each year, increasing from 36.5 in 1945 to 65.4 in 1949. The tremendous upswing in commercial production in Green Bay can be attributed to the abnormally high abundance of three important species--the lake whitefish (Coregonus clupeaformis), the lake herring or shallowwater cisco (Coregonus [=Leucichthys] artedii), and the walleye or yellow pikeperch (Stizostedion v. vitreum)--and to a marked rise in fishing intensity.

Fishery Bulletin of the U.S. Fish and Wildlife Ser↗
USGS1994

The strategic plan of the American Fisheries Society

In August 1994, at its annual meeting in Halifax, Nova Scotia, the Executive Committee of the American Fisheries Society (AFS) approved a new Strategic Plan. The plan sets out eight goals that define a vision of AFS in the year 2001, and provides strategies to achieve each goal. Accomplishing the plan should position AFS to be more responsive to member needs and more effective at meeting the challenges facing the resource and profession under future expected conditions. The plan provides opportunities for every member to help shape AFS for the 21st century. In this paper, we describe the process of strategic planning, the goals and strategies of the AFS Strategic Plan, and how the plan is implemented through AFS annual work plans.

Fisheries↗
USGS1990

Use of fish corrals in the seine fishery of the Virgin Islands

Although selected aspects of the commercial fishery in the Virgin Islands have been documented since the early 1930's, fish corrals and their use have not been described. This account, based on personal observations made during 1985-86, summarizes commercial fishing methods in the Virgin Islands (U.S. and British), documents the use of fish corrals, and serves as an introduction to the methodologies of this harvesting technique. Interviews of commercial fishermen about how and when fish corrals are used provided information not available from direct observation.

Marine Fisheries Review↗
USGS1959

The electrical resistivity meter in fishery investigations

A portable resistivity (or conductivity) meter is easily used in fishery investigations to obtain rapid and precise measurements of the electrical resistance (or conductance) of waters. These measurements can be used to estimate the total dissolved solids content of waters, to facilitate the selection of appropriate gear for efficient electrofishing, and to determine the velocity, stretch-out, dilution, and effective range of a solute over miles of a stream in conjunction with chemical reclamation operations. Applications of resistivity measurements on Appalachian streams are discussed.

Special Scientific Report - Fisheries↗
USGS1994

Reproductive and trophic ecology of the soldierfish Myripristis amaena in tropical fisheries

Squirrelfish of the genus Myripristis are valued in small-scale fisheries throughout much of the tropics. The life history and species biology of most of these soldierfishes is poorly known. For the brick soldierfish, M. amaena, in Hawaii and Johnston Atoll, we found that sexual maturity for both sexes was reached between 145 and 160 mm standard length at about six years of age - a large fraction of the apparent maximum size and lifespan. Fecundity was relatively low and increased as the fifth power of body weight. Spawning peaked from about early April to early May, and a secondary peak occurred in September. Myripristis amaena is a nocturnal predator, feeding mostly on meroplankton, especially brachyuran crab megalops, hermit crab larvae, and shrimps, but also taking a variety of benthic prey. In pristine fish communities, holocentrids were abundant, quantitatively important (often dominant) reef predators and prey. Myripristis amaena (and probably other common and important soldierfish) seems to be relatively long lived (at least 14 years), slow growing, and late maturing. The populations suffer considerable natural predation and depend mainly on the largest and oldest fish for reproduction. Heavy, unregulated fishing of these soldierfish, especially at prereproductive size, may severely reduce populations.

Fishery Bulletin↗
USGS2024

Assessing habitat use and population dynamics of fisheries resources at Kaloko Fishpond

Throughout Hawai'i, fishponds are considered by their local communities as important cultural touchstones, a source of local, sustainably produced food, and an important component to the development of community-based management for nearshore fisheries. Within Kaloko-Honokōhau National Historical Park, the restoration of Kaloko Fishpond for traditional aquaculture management is a goal of both the National Park Service (NPS) and Hui Kaloko-Honokōhau, a community-based group of kia'i, i.e., caretakers and native Hawaiian cultural practitioners. However, existing data on the demographics and condition of the fish populations within the pond, and the fish-habitat quality are poor to non-existent. Therefore, the objectives of this study were to: catalog fish species composition and distribution in the pond; estimate the abundance of focal species/taxonomic groups; and evaluate the occupancy patterns of the invasive algae Acanthophora spicifera and Upside-down Jellyfish Cassiopea andromeda. As part of these objectives, a survey protocol and analysis framework were designed and evaluated to ensure that the NPS and community group would be able to refine and implement them to continue their monitoring efforts. We conducted dual-observer shore-based visual surveys multiple times per week during September-October 2020 and April-September 2022. A total of 41 species/taxonomic groups were recorded over the course of the surveys. The largest number of species/taxonomic groups were observed at survey stations located on or near the kuapā, or wall separating the fishpond from the ocean. N-mixture models fitted to the data estimated a total population of 353 – 392 mullets, 134 – 192 flagtails (āholehole), and 189 – 277 Milkfish (Awa) Chanos chanos occurring within the 1.2-ha portion of Kaloko Fishpond that could be surveyed visually from the shoreline. Multi-season occupancy models fitted to the surveyed presence of A. spicifera and Upside-down Jellyfish indicted sites throughout most of the pond exhibited moderate and consistent occupancy (ψ = 0.30 – 0.40) throughout much of the pond, except for the northeast corner of the pond (Kaloko Iki) where colonization rates were lower and extinction rates higher than other areas within Kaloko. The visual survey method developed for this study provides a low-cost and effective starting point for the development of methodology that can be used both by NPS personnel and volunteers from the community group. However, we were only able to estimate fish populations for approximately 24% of the area of Kaloko Fishpond with this method. Given that the deeper areas of Kaloko Fishpond are completely inaccessible to the visual survey method used, generating population estimates for the entire pond based on the parameters estimated in the current study is not recommended without further investigation into fish movement and habitat use. Various means to refine this protocol to better meet the needs and abilities of the NPS and community group are proposed.

Hawaii↗
USGS1957

History of Red Lakes fishery, 1917-38, with observations on population status

A historical account traces the development of the commercial fisheries of the Red Lakes, Minnesota, from its inception in 1917 as a war measure through 1938. The trends of production and catch per unit of effort were followed for the principal species with notes on statistics of the minor fishes. Life history data were recorded for the walleye and yellow perch. A historical account was presented of the artificial propagation of the walleye and whitefish from 1918 through 1938.

Special Scientific Report - Fisheries↗
USGS2018

Species‐ and habitat‐specific otolith chemistry patterns inform riverine fisheries management

Geology and hydrology are drivers of water chemistry and thus important considerations for fish otolith chemistry research. However, other factors such as species and habitat identity may have predictive ability, enabling selection of appropriate elemental signatures prior to costly, perhaps unnecessary water/age‐0 fish sampling. The goal of this study was to develop a predictive methodology for using species and habitat identity to design efficient otolith chemistry studies. Duplicate water samples and age‐0 fish were collected from 61 sites in 4 Missouri River reservoirs for walleye Sander vitreus and one impoundment (Lake Sharpe, South Dakota) for other fishes (bluegill Lepomis macrochirus , black crappie Pomoxis nigromaculatus , gizzard shad Dorosoma cepedianum , largemouth bass Micropterus salmoides , smallmouth bass M. dolomieu , white bass Morone chrysops , white crappie P. annularis , and yellow perch Perca flavescens ). Water chemistry (barium:calcium [Ba:Ca], strontium:calcium [Sr:Ca]) was temporally stable, spatially variable, and highly correlated with otolith chemistry for all species except yellow perch. Classification accuracies based on bivariate Ba:Ca and Sr:Ca signatures were high (84% across species) yet varied between floodplain and main‐channel habitats in a species‐specific manner. Thus, to maximize the reliability of otolith chemistry, researchers can use species classifications presented herein to inform habitat selection (e.g., study reservoir‐oriented species such as white bass in main‐channel environments) and habitat‐based classifications to inform species selection (e.g., focus floodplain studies on littoral species such as largemouth bass). Overall, species and habitat identity are important considerations for efficient, effective otolith chemistry studies that inform and advance fisheries and aquatic resource management.

North Dakota, South Dakota↗
USGS2024

Importance of a lake-wetland complex for a resilient Walleye fishery

Wetlands serve as unique habitats that can support high biodiversity. Large-scale loss of wetland habitats can threaten important linkages between lake and wetland habitats that could affect diversity and growth of aquatic organisms. In this study, we compare prey diversity and abundance as well as Walleye ( Sander vitreus ) diets and condition in a large glacial lake (Lake Kampeska, South Dakota) with a connected wetland to better understand seasonal changes in the benefits provided by each habitat. We examined seasonal differences (spring, summer, and fall) through two years (summer 2021 through fall 2022) between the habitats using prey fish catch per unit effort, richness, Shannon diversity, and Bray–Curtis dissimilarity as well as Walleye relative weight, percent of empty stomachs, diet weight, stomach fullness, diet energy, and diet taxa importance. The prey fish community was more diverse and abundant in the wetland, and Walleye consumed more prey (by weight) in the wetland during all seasons except spring. Wetland reconnection can be a tool for managers to improve water quality while providing seasonal habitat needs for fish. Additionally, the diversity of prey resources provided by wetlands, many of which are unique, support resilience in the face of ecological change. Protection of wetlands may be critical for maintaining healthy and resilient fisheries into the future.

South Dakota↗
USGS1990

Benefit-cost analysis of fishery rehabilitation projects: A Great Lakes case study

Tools of benefit-cost analysis are used to evaluate a project to rehabilitate the yellow perch fishery of Green Bay, Wisconsin. Both sport and commercial fishers harvest from this stock, which has been suffering from much reduced productivity since the early 1960s. The project is composed of commercial quotas and other regulations. Measures of benefits and costs were used that explicitly incorporate uncertainty about the potential level of success of the project. The analysis shows that commercial fish producers will more or less break even compared to where they would have been without the project, but that substantial recreational benefits can be expected. This case study illustrates how benefit-cost analysis can provide useful insights into the potential economic returns from rehabilitation projects. It also dramatizes unresolved research issues, particularly in the area of sport fishing valuation.

Wisconsin↗
USGS2017

Performance and application of a fluidized bed limestone reactor designed for control of alkalinity, hardness and pH at the Warm Springs Regional Fisheries Center

Springs serving the Warm Springs Regional Fisheries Center, Warm Springs, Georgia, have pH, alkalinity, and hardness levels thatlie under the range required for successful fish propagation while free CO 2 is well above allowable targets. We evaluate a pretreatment process that exploits limestone’s (CaCO 3 ) ability to react away hydrogen ions (H + ) and carbon dioxide (CO 2 ) while increasing alkalinity (HCO 3 − ) and calcium (Ca2+) concentrations, i.e. CaCO 3 + H + ↔ HCO 3 − + Ca 2+ CaCO 3 + CO 2 + H 2 O ↔ Ca 2+ + 2HCO 3 − Limestone sand was tested in both pilot and full scale fluidized bed reactors (CycloBio®). We first established the bed expansion characteristics of three commercial limestone products then evaluated the effect of hydraulic flux and bed height on dissolution rate of a single selected product (Type A16 × 120). Pilot scale testing at 18C showed limestone dissolution rates were relatively insensitive to flux over the range 1.51–3.03 m 3 /min/m 2 but were sensitive (P < 0.001; R 2 = 0.881) to changes in bed height (BH, cm) over the range 83–165 cm following the relation: (Alkalinity, mg/L) = 123.51 − (3788.76 (BH)). Differences between filtered and non-filtered alkalinity were small(P > 0.05) demonstrating that limestone was present in the reactor effluent primarily in the form of dissolved Ca(HCO 3 ) 2 . Effluent alkalinity exceeded our target level of 50 mg/L under most operating conditions evaluated with typical pilot scale values falling within the range of 90–100 mg/L despite influent concentrations of about 4 mg/L. Concurrently, CO 2 fell from an average of 50.6 mg/L to 8.3 mg/L (90%), providing for an increase in pH from 5.27 to a mean of 7.71. The ability of the test reactor to provide changes in water chemistry variables that exceeded required changes allowed for a dilution ratio of 0.6. Here, alkalinity still exceeded 50 mg/L, the CO 2 concentration remained well below our limit of 20 mg/L (15.4 mg/L) and the pH was near neutral (7.17). Applying the dilution ratio of 0.6 in a full scale treatment plant at the site reduced by 40% the volume of spring water that is directed through each of three parallel reactors that combined react away 49,000 kg of limestone/yr.

Aquacultural Engineering↗
USGS2021

Marine ecotourism for small pelagics as a source of alternative income generating activities to fisheries in a tropical community

Overharvest has led to marine ecosystem degradation and declining fishery catches in many tropical communities. To allow stocks to recover and provide increased flows of food and income, reductions in fishing effort are necessary. The development of Alternative Income Generating Activities can help to reduce the economic reliance of coastal communities on fishing, potentially reducing pressure on fish stocks. Here we assess the local conditions which have enabled the creation of Alternative Income Generating Activities to fishing based on marine ecotourism in Moalboal, Philippines. Importantly, while marine ecotourism typically centers around charismatic megafauna, a combination of nearshore fringing reefs, the establishment of nearshore marine protected areas and the occurrence of a massive herring aggregation provide a large tourism draw to this community. Using a combination of regional and local economic statistics and stakeholder surveys, we implement an economic valuation of the Moalboal marine ecotourism for 2018 and compare this valuation to an independent estimate of the extractive value of the herring aggregation. The Moalboal case indicates that a combination of strong community engagement in the governance of the ecotourism resource, a network of locally managed marine protected areas and the retention and distribution of economic benefits within the local community have led to a significant marine ecotourism sector. We contextualize these conditions into a set of potential enabling conditions for marine ecotourism as an Alternative Income Generating Activity to fishing to contribute insights to diversifying livelihood opportunities beyond extractive fishing for coastal communities in the tropics.

Moalboal, Cebu Island↗