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At least 685 records · Page 38Linked to original sources

Water-balance modeling of selected lakes for evaluating viability as long-term fisheries in Kidder, Logan, and Stutsman Counties, North Dakota

Water levels in lakes and wetlands in the central North Dakota Missouri Coteau region that were either dry or only sporadically held water since before the 1930s have been rising since the early 1990s in response to an extended wet period. The lakes have remained full since the mid-1990s, which has provided benefits to migratory waterfowl, fisheries, and wildlife. A small shift in climate conditions, either to drier or wetter conditions, can have a large effect on the lake levels of these water bodies. The North Dakota Game and Fish Department identified five lakes as candidates for sustaining long-term fisheries. The lakes are in Kidder, Stutsman, and Logan Counties, and some lakes might receive inflow from mostly freshwater aquifers, such as the Central Dakota and Streeter aquifers, and were mostly dry during the early 1990s. After about 1995, the lakes had filled up and were deep enough to sustain populations of game fish such as walleye, perch, and northern pike. Before investing in development of permanent fisheries and associated infrastructure, such as campgrounds and boat ramps, fisheries biologists needed to know if the lake levels are likely to remain high in coming decades. The U.S. Geological Survey, in cooperation with the North Dakota Game and Fish Department, developed a water-balance model to determine the effects of precipitation, evapotranspiration, and groundwater interaction on lake volumes. The model was developed using climate input data and lake volumes for the calibration period 1992 through 2016, during which historical lake volumes could be estimated using land surface elevation data and Landsat images. Long-term (1940–2018) climate input data were used with the water-balance model to reconstruct historical lake volumes prior to the calibration period, and block-bootstrapping was used to simulate potential future climate input data and lake volumes for 2017 through 2067. The simulated future lake volumes were used to estimate the likelihood of annual lake volumes remaining consistent, increasing, or decreasing through the year 2067. Of the five lakes, Sibley Lake was the most likely to sustain a long-term fishery for a period longer than 50 years. The simulated lake volumes for Alkaline Lake, Big Mallard Marsh, and Remmick Lake indicated the lakes have a 50-percent chance to fall below 75 percent of their 2016 volume by about 2030, 2067, and 2025, respectively. Simulation results for Marvin Miller Lake were substantially different compared to the other four lakes and indicated the lake has a 50-percent chance to fall below 75 percent of its 2016 volume prior to 2025.

North Dakota↗

Invertibility aware integration of static and time-series data: An application to lake temperature modeling

Accurate predictions of water temperature are the foundation for many decisions and regulations, with direct impacts on water quality, fishery yields, and power production. Building accurate broad-scale models for lake temperature prediction remains challenging in practice due to the variability in the data distribution across different lake systems monitored by static and time-series data. In this paper, to tackle the above challenges, we propose a novel machine learning based approach for integrating static and time-series data in deep recurrent models, which we call Invertibility-Aware-Long Short-Term Memory(IA-LSTM), and demonstrate its effectiveness in predicting lake temperature. Our proposed method integrates components of the Invertible Network and LSTM to better predict temperature profiles (forward modeling) and infer the static features (i.e., inverse modeling) that can eventually enhance the prediction when static variables are missing. We evaluate our method on predicting the temperature profile of 450 lakes in the Midwestern U.S. and report relative improvement of 4% to capture data heterogeneity and simultaneously outperform baseline predictions by 12% when static features are unavailable.

Conference Paper↗

Piscicides and invertebrates: after 70 years, does anyone really know?

The piscicides rotenone and antimycin have been used for more than 70 years to manage fish populations by eliminating undesirable fish species. The effects of piscicides on aquatic invertebrate assemblages are considered negligible by some and significant by others. This difference of opinion has created contentious situations and delayed native fish restoration projects. We review the scientific evidence and report that short-term (< 3 months) impacts of piscicides to invertebrate assemblages varied from minor to substantial and long-term (> 1 year) impacts are largely unknown. Recovery of invertebrate assemblages following treatments ranged from a few months for abundances of common taxa to several years for rarer taxa. Variation in reported effects was primarily due to natural variation among species and habitats and a lack of adequate pre- and post-treatment sampling which prevents determining the true impacts to invertebrate assemblages. The factors most likely to influence impacts and recovery of aquatic invertebrate assemblages following piscicide treatments are: (1) concentration, duration, and breadth of the piscicide treatment; (2) invertebrate morphology and life history characteristics, including surface area to volume ratios, type of respiration organs, generation time, and propensity to disperse; (3) refugia presence; and (4) distance from colonization sources.

Fisheries↗

Agency approach to allocation of human capital and program composition for human-marine mammal interaction management in the United States

Introduction: Marine mammals have served important and diverse roles throughout human history. Once exploited to near extinction, many species in the United States (U.S.) have recovered dramatically under the Marine Mammal Protection Act (MMPA). The U.S. National Marine Fisheries Service (NMFS) has jurisdiction to administer the MMPA for cetaceans and most pinnipeds. While most take is now prohibited, NMFS still dedicates significant time and resources to protecting and conserving marine mammals. As human populations continue to grow and exploit marine environments, opportunities for human-marine mammal interactions (HMMI) have increased. Resources may fail to keep up with growing needs for conservation investments, so that many agencies struggle to adequately meet social and legal requirements. Methods: This study evaluated NMFS’ approach to addressing HMMI through a mixed-methods (semi-structured interviews, quantitative questionnaire, and facilitated workshops) expert elicitation analysis of resource allocation (i.e., staff time) and priorities of NMFS Science Center (SC) and Regional Office (RO) staff across five geographic regions to understand how employee time is allocated, the degree to which employee time allocation is aligned with self-reported job descriptions, and employee perceptions of actions or investments which would improve their ability to mitigate HMMI. Results and Discussion: SC staff reported spending more time on Biological and Administrative tasks , while RO staff allocated more time to Policy, Social science , and Outreach tasks . SC employees spent less time on Biological tasks than specified by their perceived job descriptions, suggesting resource constraints. Participants identified Biological research and monitoring as top priorities, followed by Policy tasks . Identified actions included increasing research capacity, enhancing enforcement, expanding social science expertise, and improving outreach programs. The study reveals mismatches between mandated activities and available resources, suggesting strategic reallocation or increased funding may benefit the agency in effectively addressing growing HMMI challenges.

Frontiers in Marine Science↗

Microbial consortia of gorgonian corals from the Aleutian islands

Gorgonians make up the majority of corals in the Aleutian archipelago and provide critical fish habitat in areas of economically important fisheries. The microbial ecology of the deep-sea gorgonian corals Paragorgea arborea, Plumarella superba , and Cryogorgia koolsae was examined with culture-based and 16S rRNA gene-based techniques. Six coral colonies (two per species) were collected. Samples from all corals were cultured, and clone libraries were constructed from P. superba and C. koolsae . Cultured bacteria were dominated by the Gammaproteobacteria , especially Vibrionaceae , with other phyla comprising <6% of the isolates. The clone libraries showed dramatically different bacterial communities between corals of the same species collected at different sites, with no clear pattern of conserved bacterial consortia. Two of the clone libraries (one from each coral species) were dominated by Tenericutes , with Alphaproteobacteria dominating the remaining sequences. The other libraries were more diverse and had a more even distribution of bacterial phyla, showing more similarity between genera than within coral species. Here we report the first microbiological characterization of P. arborea, P. superba , and C. koolsae .

Alaska↗

Historic population estimates for bottlenose dolphins (Tursiops truncatus) in Aragua, Venezuela indicate monitoring need

This study reports historic capture-mark-recapture survival and abundance estimates of common bottlenose dolphins ( Tursiops truncatus ) based on photo-identification surveys of coastal Venezuela (along the Aragua coast between Turiamo Bay and Puerto Colombia). We used the most recent data available: dolphins identified by unique dorsal fin marks during wet and dry season surveys conducted from 2004 to 2008. Dolphin encounter histories were analyzed in the Closed Capture Robust Design framework, with the top model including random movement, constant survival, and capture-recapture probabilities that varied by secondary periods. Survival of marked adults was estimated at 0.99 (95% CI = 0.97 to 1.00). Population estimates for all adults (marked and unmarked) averaged 31 animals (SD = 13.8), and for all dolphins (all adults and calves), 41 animals (SD = 17.2). Coastal bottlenose dolphins face numerous threats, including ship strikes, oil spills, conflict with recreational and industrial fisheries, other negative human interactions, biotoxins, chemicals, noise, freshwater discharge, and coastal development. Further, small populations are, in general, at increased risk due to reduced resiliency and recovery potential when exposed to such threats and to expected environmental and demographic stochasticity. These historic estimates of abundance and survival are critical for establishing a reference state and indicate a need for ongoing monitoring of the small dolphin population while the Aragua coast is still, as of yet, relatively little impacted by humans. Should coastal development increase (as is the global trend) and/or environmental catastrophes (e.g., harmful algal blooms, hurricanes, and oil spills) occur, these historic estimates will be essential for assessing impacts and guiding management and conservation interventions. Our results show year-round dolphin presence and highlight the Venezuelan coastal–oceanic landscape as an area of both future research and conservation importance.

Aragua↗

Methods for evaluating riparian habitats with applications to management

Riparian area planning and management is a major national issues today--something that should have been the case a century ago. A century of additive effects of land use has resulted in major impacts on many riparian stream habitats and their fisheries, wildlife, and domestic livestock use. Before scientists can evaluate the influences of various land and water uses on riparian environments, they must first understand these environments. This means being able to detect and measure with confidence the natural and artificial variation and instantaneous conditions of the riparian habitat. These conditions must then be related to the production capability of riparian habitat and any extraneous factors affecting this production potential.

Report↗

Mortality of smelt, Osmerus mordax (Mitchill), in Lakes Huron and Michigan during the fall and winter of 1942-1943

The mortality that nearly exterminated the huge stocks of smelt in Lakes Huron and Michigan during the fall and winter of 1942&ndash;1943 appears to have originated in central Lake Huron in the Saginaw Bay area in late September or early October 1942. The mortality spread rapidly northward reaching the Drummond Island area about the latter part of October and the St. Ignace region of the Straits of Mackinac near the end of the month. In the latter part of October smelt died also in the Canadian waters of Lake Huron including North Channel and Georgian Bay but exact details as to time and course are lacking. There is some evidence that the epidemic had not reached the Ontario shore of central Lake Huron by late May 1943. Spreading through northern Lake Michigan the mortality had penetrated as far south as Grand Traverse Bay by November 19 and as far west as Point Aux Barques, Michigan, by November 26, 1942. Smelt were reported to be dying in Lake Charlevoix, Michigan, in early February 1943, and in Green Bay toward the middle of that month. The mortality did not reach Crystal Lake where in contrast to Lake Charlevoix a dam barred the passage of fish from Lake Michigan. At the time of the 1943 spring spawning run (April) only a few scattered survivors remained from the vast populations. After consideration of possible causes, it was concluded that the mortality could be explained only as resulting from a communicable disease (bacteria or virus). This explanation alone is in harmony with the following facts: the mortality was progressive, spreading from one area into adjacent areas over a period of at least 4 1/2 months and under a great diversity of habitat conditions; only smelt were affected but within the species death overtook fish of all sizes from 2 inches on and all ages of both sexes, mature and immature; the mortality penetrated Lake Charlevoix where the passage of fish to and from Lake Michigan was possible but did not reach Crystal Lake where the passage from Lake Michigan was barred by a dam; the epidemic did not reach other inland lakes where free and easy access from the Great Lakes was impossible nor did it extend to Lakes Superior, Erie, and Ontario. Considered at first as a nuisance and a threat to the native fishes of the Great Lakes, the smelt ultimately became a fish of primary importance to commercial fishermen, sportsmen, and others. In Green Bay, the center of the commercial fishery, smelt became the dominant commercial species, yielding more than 4 million pounds in some years. Almost all of the commercial production was from nets set under the ice. The take by amateurs and others who dipped smelt from streams during the spawning run was even greater, amounting to as much as 5 1/2 million pounds in a single year in the State of Michigan alone (the yield in Wisconsin may have been nearly as great). The mortality of smelt was a severe blow to the nation's war-time food-production program. It is estimated that in 1943, in which year elaborate preparations had been made for the efficient utilization of the spawning-run production, the mortality reduced the output of smelt by about 13 million pounds. The total loss through the present (1946) season can be set in the neighborhood of 50 million pounds. The first indication of a recovery of the smelt came in 1945 when a small amount was produced commercially in Green Bay and numerous light runs occurred in streams tributary to Lakes Huron and Michigan. The general level of abundance in 1945, however, is believed to have been less than 10 per cent of that of &ldquo;pre-mortality&rdquo; years. Such information as is available for 1946 suggests considerable further improvement in this year. Given good survival of young, it is anticipated that a large rise in the abundance of smelt can occur in 1947 and that by 1948 or 1949 the size of the populations should no longer be influenced by the number of spawners available in preceding years. The smelt from the Escanaba area of Green Bay were without exception significantly longer and heavier in 1944 and 1945 than were fish of corresponding age captured in the same region in 1941. Furthermore, three of four comparisons indicated significantly greater size in 1945 than in 1944. This improvement in growth rate is believed to have been associated with the reduction in the smelt population brought about by the 1942&ndash;1943 mortality.

Transactions of the American Fisheries Society↗

Virus diseases of the salmonidae in the western United States. I. Etiology and epizootiology

The history of fish diseases in western United States shows an increasing awareness that viruses could cause epizootics in fish. Fishery biologists bunked first, for protozoan and metazoan parasites, then for bacteria, and if none could be identified assumed that the mortalities were attributable to nutritional deficiency, Microbiologists in general were cognizant of virus diseases in other animals and investigators of fish diseases were alert to the possibility that piscine epizootics could be of similar cause. In 1950 an epizootic occurred in sockeye salmon (Gncorhynchus norkm) that was shown to have a viral etiologic agent. In recent years, with increasing frequency, we have been able to demonstrate a virus utiology for epizootics and panzootics in trout and salmon in several states in the West. FIGURE 1 is a map showing the location of epizootics of infectious pancreatic necrosis (IPN), Sacramento River chinook disease (SRCD), Oregon sockeye disease (OSD), and Columbia River sockeye disease (CRSDJ. The pathology and immunopathology of these are discussed in detail in other reports. The present report was initiated as a review of the literature concerning the diseases and to present in brief a description of their etiologic agents.

Annals of the New York Academy of Sciences↗

Investigation of a largescale common murre (Uria aalge) mortality event in California in 2015

From August through December 2015, beachcast bird survey programs reported increased deposition of common murres ( Uria aalge ) on central and northern California beaches, but not on southern California beaches. Coastal wildlife rehabilitation centers received more than 1,000 live, stranded, and debilitated murres from Sonoma County to San Luis Obispo County during August–October. Approximately two-thirds of admitted birds were after-hatch-year birds in emaciated body condition and in various stages of molt, with extremely worn plumage. Necropsies were done on a sample ( n =35) of birds to determine the probable cause of death of beachcast carcasses. Most birds examined during necropsy were emaciated, with starvation the most likely cause of death. Birds were also tested for underlying infectious diseases at the US Geological Survey National Wildlife Health Center (NWHC) and harmful algal bloom toxins at the University of California, Santa Cruz and the National Oceanographic and Atmospheric Administration's Northwest Fisheries Science Center. Twenty-four out of 29 tested birds had detectable levels of domoic acid, and no indication of infectious disease was found. Emaciation is thought to be the cause of death for these birds, with a large warm water anomaly and harmful algal bloom playing a secondary detrimental role.

California↗

Acute Toxicity of the Lampricides TFM and Niclosamide to Three Species of Unionid Mussels

The sea lamprey (Petromyzon marinus), a jawless parasitic eel-like fish native to the Atlantic Ocean (fig. 1), was accidentally introduced into the Great Lakes in the early 20th century through the construction of shipping canals. A member of the Petromyzonidae family, the primitive parasite has been identified as a major cause of the collapse of the Great Lakes fishery in the 1940s and 1950s. The lampricides 3-trifluoromethyl-4-nitrophenol (TFM) and 2'5-dichloro-4'-nitrosalicylanilide (niclosamide) have been used to control larval sea lampreys in tributaries of the Great Lakes since the early 1960s. The lampricide TFM is the main compound used to keep sea lamprey populations in check while niclosamide is used primarily in combination with TFM as a cost-saving measure. The addition of niclosamide at a ratio of 1% to TFM will reduce the amount of TFM required for effective treatment by about 40%.

Open-File Report↗

Fort Collins Science Center-Fiscal year 2009 science accomplishments

Public land and natural resource managers in the United States are confronted with increasingly complex decisions that have important ramifications for both ecological and human systems. The scientists and technical professionals at the U.S. Geological Survey Fort Collins Science Center?many of whom are at the forefront of their fields?possess a unique blend of ecological, socioeconomic, and technological expertise. Because of this diverse talent, Fort Collins Science Center staff are able to apply a systems approach to investigating complicated ecological problems in a way that helps answer critical management questions. In addition, the Fort Collins Science Center has a long record of working closely with the academic community through cooperative agreements and other collaborations. The Fort Collins Science Center is deeply engaged with other U.S. Geological Survey science centers and partners throughout the Department of the Interior. As a regular practice, we incorporate the expertise of these partners in providing a full complement of ?the right people? to effectively tackle the multifaceted research problems of today's resource-management world. In Fiscal Year 2009, the Fort Collins Science Center's scientific and technical professionals continued research vital to Department of the Interior's science and management needs. Fort Collins Science Center work also supported the science needs of other Federal and State agencies as well as non-government organizations. Specifically, Fort Collins Science Center research and technical assistance focused on client and partner needs and goals in the areas of biological information management and delivery, enterprise information, fisheries and aquatic systems, invasive species, status and trends of biological resources (including human dimensions), terrestrial ecosystems, and wildlife resources. In the process, Fort Collins Science Center science addressed natural-science information needs identified in the U.S. Geological Survey Science Strategy (http://www.usgs.gov/science_strategy), including understanding and predicting change in ecosystems, climate variability and change, energy development and land management, the role of the environment and wildlife in human health, freshwater ecosystems, data integration, and evolving technologies. Several science projects were expanded in Fiscal Year 2009 to meet these evolving needs.

Open-File Report↗

Updated decision analysis to inform multi-species salmonine management in Lake Michigan

The recreational fishery for salmonine species in Lake Michigan (lake trout, Chinook salmon, coho salmon, steelhead, and brown trout) is largely maintained through stocking. Decisions about how many of each species to stock require an understanding of how to maintain a sustainable balance of predators (salmonine species) to prey (alewife) in the lake. The current models used to make these decisions can estimate the ratio of Chinook salmon to alewife in the lake. However, the Lake Michigan Committee’s new stocking strategy aims to incorporate the other salmonine species into this predator-prey ratio. We used structured decision making to evaluate potential stocking strategies. We worked with fishery stakeholders and members of the Lake Michigan Committee, conducted participatory modeling to forecast outcomes of stocking scenarios using updated information on fish movement and feeding, and evaluated the risk of these stocking strategies. Most of the stocking practices we evaluated resulted in a high risk of large declines in alewife abundance, negatively affecting future salmon fisheries. The forecasts were substantially more pessimistic than those resulting from a similar analysis conducted a decade earlier, apparently due to more recent alewife assessments indicating lower alewife productivity (recruits per spawner). Alewife recruitment dynamics is an area of substantial uncertainty, with apparently large consequences for management; decision makers on Lake Michigan would benefit from greater understanding of alewife recruitment dynamics to reduce this uncertainty when accounting for risks.

Lake Michigan↗

Environmental Assessment for a Marine Geophysical Survey of Parts of the Arctic Ocean, August-September 2010

According to the United Nations Convention on the Law of the Sea (UNCLOS), individual nations? sovereign rights extend to 200 nautical miles (n.mi.) (370 km) offshore or to a maritime boundary in an area called the continental shelf. These rights include jurisdiction over all resources in the water column and on and beneath the seabed. Article 76 of UNCLOS also establishes the criteria to determine areas beyond the 200 n.mi. (370 km) limit that could be defined as ?extended continental shelf,? where a nation could extend its sovereign rights over the seafloor and sub-seafloor (As used in UNCLOS, ?continental shelf? refers to a legally defined region of the sea floor rather than a morphological shallow-water area adjacent to continents commonly used by geologists and hydrographers.). This jurisdiction provided in Article 76 includes resources on and below the seafloor but not in the water column. The United States has been acquiring data to determine the outer limits of its extended continental shelf in the Arctic and has a vested interest in declaring and receiving international recognition of the reach of its extended continental shelf. The U.S. collaborated with Canada in 2008 and 2009 on extended continental shelf studies in the Arctic Ocean. The U.S. Coast Guard (USCG) Cutter Healy worked with the Canadian Coast Guard ship Louis S. St. Laurent to map the continental shelf beyond 200 n.mi. (370 km) in the Arctic. Each icebreaking vessel contributed different capabilities in order to collect data needed by both nations more efficiently in order to save money, avoid redundancy, and foster cooperation. Generally, the Healy collects bathymetric (sea-floor topography) data and the Louis S. St. Laurent collects seismic reflection profile data. The vessels work in concert when ice conditions are heavy, with one vessel breaking ice for the ship collecting data. The Canadian Environmental Assessments for these projects are available on line at http://www.ceaa.gc.ca/052/details-eng.cfm?pid=38185 (2008) and http://www.ceaa.gc.ca/052/details-eng.cfm?pid=46518 (2009). The U.S. Geological Survey (USGS) and Geological Survey of Canada (GSC) are undertaking a similar partnership again for 2010 in a limited area of U.S. waters during the period between ~10 and 16 August. The survey vessels will then proceed to international or Canadian waters where surveying will proceed until ~3 September, when the two icebreakers will separate to conduct independent work. The survey area of the joint work will be bounded approximately by 145? to 158? W longitude and 71? to 84? N latitude in water depths ranging from ~2,000 to 4,000 m (fig. 1). Ice conditions are expected to range from open water to 10/10 ice cover. The Louis S. St. Laurent will join accompanying vessel Healy in or near the survey area around 10 August to begin the joint survey work. As its energy source, the seismic system aboard Louis S. St. Laurent will employ a 3-airgun array consisting of three Sercel G-airguns. Two guns will have a discharge volume of 500 in3 and the third a discharge volume of 150 in3 for a total array discharge volume of 1,150 in3. The seismic survey will take place in water depths 2,000?4,000 m. This airgun array is identical to the system used in the 2008 and 2009 field programs by the Geological Survey of Canada. The USGS requested that the National Marine Fisheries Service (NMFS) issue an Incidental Harassment Authorization (IHA) to authorize the incidental, that is, not intentional, harassment of small numbers of cetaceans and seals should this occur during the seismic survey in U.S. waters. USGS is also consulting with the U.S. Fish and Wildlife Service (USFWS) regarding concerns about disturbance to walruses and polar bears. Through informal consultation with the Office of Protected Resources with the National Oceanic and Atmospheric Administration (NOAA), USGS proposes that no ESA-listed marine species?bowhead, fin, humpback or sperm whale?w

Open-File Report↗

Tagging methods for estimating population size and mortality rates of inland striped bass populations

Striped bass Morone saxatilis in inland reservoirs play an important role ecologically and in supporting recreational fishing. To manage these populations, biologists need information about abundance and mortality. Abundance estimates can be used to assess the effectiveness of stocking programs that maintain most reservoir striped bass populations. Mortality estimates can indicate the relative impact of fishing versus natural mortality and the need for harvest regulation. The purpose of this chapter is to evaluate tagging studies as a way of obtaining information about abundance and mortality. These approaches can be grouped into three broad categories: tag recapture, tag return, and telemetry. Tag-recapture methods are typically used to estimate population size and other demographic parameters but are often difficult to apply in large systems. A fishing tournament can be an effective way of generating tagging or recapture effort in large systems, compared to using research sampling only. Tag-return methods that rely on angler harvest and catch and release can be used to estimate fishing (F) and natural (M) mortality rates and are a practical approach in large reservoirs. The key to success in tag-return studies is to build in auxiliary studies to estimate short-term tagging mortality, short- and longterm tag loss, reporting rate, and mortality associated with catch and release. F and M can also be estimated using telemetry tags. Advantages of this approach are that angler nonreporting does not bias estimates and fish with transmitters provide useful ecological data. Cost can be a disadvantage of telemetry studies; thus, combining telemetry tags with conventional tag returns in an integrated analysis is often the optimal approach. In summary, tagging methods can be a powerful tool for assessing the effectiveness of inland striped bass stocking programs and the relative impact of fishing versus natural mortality

American Fisheries Society Symposium↗

Habitat Suitability Index Models and Instream Flow Suitability Curves: American shad

INTRODUCTION The American shad, an anadromous species, is the largest member of the herring family (Clupeidae) and is native to North America (Talbot and Sykes 1958; Hildebrand 1963; Walburg and Nichols 1967). Historically, the commercial fishery for American shad on the Atlantic coast was widespread and intense; in 1896 the estimated catch was 22.7 million kg (50 million lb). By 1960, however, the estimated catch had dropped to slightly more than 3.6 million kg (8 million lb), according to Walburg and Nichols (1967). Pollution, overfishing, and dams constructed across streams that prevent shad from reaching their spawning grounds have caused partial or total depletion of stocks (Hildebrand 1963). Several programs aimed at restoring American shad to their former range have been initiated by Federal and State agencies.

FWS/OBS↗

Use of eyeballs for establishing ploidy of Asian carp

Grass carp Ctenopharyngodon idella, silver carp Hypophthalmichthys molitrix, and bighead carp H. nobilis are now established and relatively common in the Mississippi and Atchafalaya rivers. Commercial fishers of Louisiana's large rivers report recurrent catches of grass carp, and the frequency of bighead carp and silver carp catch is increasing. Twelve black carp Mylopharyngodon piceus were recently captured from the Mississippi and Atchafalaya River system, and 10 were analyzed for ploidy. By using the methods described herein, all 10 fish were determined to be diploid. Such correct identifications of ploidy of feral Asian carp species, as well as other species, would provide science-based information constructive for meeting reporting requirements, tracking fish movements, and forecasting expansion of species distribution. To investigate the postmortem period for sample collection and to lessen demands on field operations for obtaining samples, a laboratory study was performed to determine the length of time for which eyeballs from postmortem black carp could be used for ploidy determinations. Acquiring eyes rather than blood is simpler and quicker and requires no special supplies. An internal DNA reference standard with a documented genome size, including erythrocytes from diploid black carp or Nile tilapia Oreochromis niloticus, was analyzed simultaneously with cells from seven known triploid black carp to assess ploidy through 12 d after extraction. Ploidy determinations were reliable through 8 d postmortem. The field process entails excision of an eyeball, storage in a physiological buffer, and shipment within 8 d at refrigeration temperatures (4??C) to the laboratory for analysis by flow cytometry. ?? Copyright by the American Fisheries Society 2007.

North American Journal of Fisheries Management↗

A review of standardization in Mississippi’s multidecadal inland fisheries monitoring program

Standardizing data collection, management, and analysis processes can improve the reliability and efficiency of fisheries monitoring programs, yet few studies have examined the operationalization of these tasks within agency settings. We reviewed the Mississippi Department of Wildlife, Fisheries, and Parks, Fisheries Bureau’s inland recreational fisheries monitoring program—a 30+-year effort to standardize field protocols, data handling procedures, and automated analyses through a custom-built computer application, the Fisheries Resources Analysis System (FRAS). Drawing on quantitative summaries of sampling trends and qualitative interviews with fisheries managers, we identified key benefits, challenges, and opportunities associated with the Bureau’s standardization efforts. Standardized procedures improved sampling consistency, data reliability, and operational efficiency, enabling the long-term tracking of fish population and angler metrics across more than 270 managed waterbodies. However, challenges related to analytical transparency and spatiotemporal comparisons persist. Simulations indicated that under current conditions, 5.8, 22.9, and 37.1 years would be required to sample (boat electrofishing) 50%, 75%, and 95% of the Bureau’s waterbodies at least once, respectively; these figures should translate to other agencies, assuming similar resource availability per waterbody. The monitoring program has reduced manual processing effort and enhanced staff capacity for waterbody-specific management, yet several opportunities remain to improve efficiency and utility. These include expanding FRAS functionalities for trend visualization, integrating mobile field data entry to reduce transcription errors, linking monitoring results with management objectives, and enhancing automated report generation for management support. Strengthening these elements could not only streamline workflows but better position agencies to apply standardized data in adaptive management embedded into the monitoring program.

Mississippi↗