Conservation, Ecology, and Management of Catfish: The Second International Symposium

2011 ◽  
Keyword(s):  
Size Structure ◽  
Management Strategies ◽  
Age Groups ◽  
Missouri River ◽  
Population Characteristics ◽  
Fish Length ◽  
Natural Mortality ◽  
Conservation Ecology ◽  
Flathead Catfish ◽  
Tag Loss

<em>Abstract</em>.—Few studies have been conducted on angler exploitation rates or angler harvest size selectivity for flathead catfish <em>Pylodictis olivaris</em>. However, exploitation of a narrow range of age groups or sizes could affect flathead catfish population characteristics and fisheries, and management strategies may be needed to enhance fisheries if selective angler exploitation is severe. Almost 3,000 flathead catfish (305–1,209 mm total length [TL]) were marked with Carlin dangler reward tags over a 3-year period in a 92-km section of the Missouri River in northwest Missouri. Corrected angler exploitation (accounting for angler nonreporting, tag loss, and natural mortality) ranged from 4.1% to 9.6%. Angler harvest rates of flathead catfish varied by fish length. Tagged fish 305–380 mm TL were harvested in lower proportion than expected. Fifty-six percent of all fish tagged were in this size-group vested in higher proportion (50% of total) than relative abundance (27%) would suggest, as were flathead catfish ≥ 508 mm TL (17% of total tagged and 23% of total harvested). Angler exploitation rates of flathead catfish from the Missouri River did not seem excessive (<10%). However, 77% of flathead catfish harvested by anglers were less than 508 mm TL, and given that logistic regression predicted that flathead catfish between 450 and 650 mm TL had the highest probability of being harvested by anglers, harvest restrictions protecting fish less than 650 mm TL would likely shift the population size structure towards larger-sized individuals, if that was a management goal.

Conservation, Ecology, and Management of Catfish: The Second International Symposium

2011 ◽  
Keyword(s):  
International Symposium ◽  
Size Structure ◽  
River System ◽  
Population Characteristics ◽  
Blue Catfish ◽  
Growth And Survival ◽  
Conservation Ecology ◽  
Flathead Catfish ◽  
Management Actions ◽  
Catch Rates

<em>Abstract</em>.—Catfish are popular recreational fish in Alabama, and management interest has been rising. We hypothesized that tailwater habitat more closely resembling lotic conditions would provide more suitable conditions for catfishes compared to impounded habitats. We examined and compared population characteristics, including abundance, age and size structure, growth, and survival of blue catfish <em>Ictalurus furcatus</em>, channel catfish <em>I. punctatus</em>, and flathead catfish <em>Pylodictis olivaris</em> between tailwater and reservoir habitats in a section of the Coosa River in 2001–2002. Coosa River system tailwater habitats appear to generally provide higher quality environments for abundance and growth of catfishes than reservoir habitat, although results were often not consistent among species. We found no differences for many comparisons of stock descriptors between tailwater and reservoir habitat. We found that blue catfish were larger (48 mm total length larger) and flathead catfish electrofishing catch rates were higher (13 fish/h greater) in tailwater areas. Catfish populations in the Coosa River were characterized by slow growth and high longevity, findings in accord with other recent otolith-based age analyses from populations in the Southeast. All species had moderate to high annual survival (57–88%), likely indicating light exploitation levels. Catfish populations in this section of the Coosa River appear robust, and the tendency for these dam tailwaters to have higher quality catfish populations may warrant management actions to enhance/sustain these fisheries.

Conservation, Ecology, and Management of Catfish: The Second International Symposium

2011 ◽  
Keyword(s):  
Management Strategies ◽  
Missouri River ◽  
Rapid Expansion ◽  
Movement Behavior ◽  
Radio Tracking ◽  
Blue Catfish ◽  
Spawning Period ◽  
Annual Cycles ◽  
Conservation Ecology ◽  
Flathead Catfish

<em>Abstract</em>.—Flathead catfish <em>Pylodictis olivaris</em> and blue catfish <em>Ictalurus furcatus</em> thrive in large rivers and constitute large sport fisheries. Defining a spatial scale for new management strategies has become increasingly important due to rapid expansion of the sport fishery. To investigate life history characteristics, migratory pathways, and space use, we used telemetry to monitor the movement behavior of flathead catfish and blue catfish during two complete annual cycles. Individuals were sampled from a 97-km reach of the lower Missouri River and surgically implanted with transmitters during April 2006 (<EM>N</EM> = 77) and again in April and July of 2007 (<EM>N</EM> = 80). Acoustic tracking by boat and radio tracking by helicopter were used on the Missouri, Lamine, Chariton, Little Chariton, and Grand rivers during 2006–2008. The proportion of individuals that used a tributary during the putative spawning period (May 15–July 15) increased from 10% (8 of 77) in 2006 to 18% (14 of 80) in 2007. Flood conditions in May 2007 may have contributed to this increase. Between April 2006 and May 2007, the majority of flathead (51%) and blue catfishes (55%) moved less than 100 river kilometers from where they were tagged. The maximum linear range during 2006–2007 was 347.6 river kilometers for blue catfish and 751.9 river kilometers for flathead catfish. Seasonal structure to annual movements was evident with periods of both restricted movement (December–March; July–September) and migratory behavior (March–June; October–December). The variability in observed behaviors provides a substantial basis for managers to identify and protect distant habitats that are used by adult catfish for spawning, feeding and growth, and overwintering.

Conservation, Ecology, and Management of Catfish: The Second International Symposium

2011 ◽  
Keyword(s):  
International Symposium ◽  
Size Structure ◽  
Pylodictis Olivaris ◽  
Social Event ◽  
Conservation Ecology ◽  
Party Size ◽  
Catch And Release ◽  
Flathead Catfish ◽  
Creel Survey ◽  
Total Effort

<em>Abstract</em>.—Hand grabbing for catfish has been practiced in Mississippi for many years; however, few studies have addressed this fishing technique. Ross Barnett Reservoir is a<em> Abstract</em>.—Hand grabbing for catfish has been practiced in Mississippi for many years; however, few studies have addressed this fishing technique. Ross Barnett Reservoir is a 13,360-ha impoundment located in central Mississippi that supports a substantial hand grabbing fishery. A roving creel survey was conducted during the 2007 and 2008 Mississippi hand grabbing season (May 1–July 15). Objectives were to estimate catch, harvest, and effort of hand grabbers and to solicit information concerning techniques used by these anglers. A total of 37 parties was interviewed, consisting of 150 total anglers. Seventy percent of the parties interviewed targeted flathead catfish <em>Pylodictis olivaris</em>. Ninety-five percent of the parties used a probe, and all parties fished boxes located at depths of 1–2 m. Average party size was four anglers, indicating that hand grabbing is a social event. For 2007 and 2008, anglers spent an estimated 4,424 and 5,259 h hand grabbing, respectively. An estimated 3,313 and 2,589 catfish were harvested in 2007 and 2008, respectively. Based on size structure of harvested catfish, hand grabbing anglers at Ross Barnett Reservoir do not appear to be size-selective. Most anglers were harvest-oriented, with catch-and-release estimates making up only 12% and 9%, respectively. Future creel surveys should be directed at the total effort allocated toward catfishing, in an effort to determine the effect of hand grabbing on Ross Barnett Reservoir.

Conservation, Ecology, and Management of Catfish: The Second International Symposium

2011 ◽  
Keyword(s):  
International Symposium ◽  
Body Condition ◽  
Relative Abundance ◽  
Habitat Restoration ◽  
Missouri River ◽  
Natural State ◽  
Pylodictis Olivaris ◽  
Conservation Ecology ◽  
Flathead Catfish ◽  
Growth Increments

<em>Abstract</em>.—An assessment of the flathead catfish <em>Pylodictis olivaris</em> population in the Missouri River bordering Nebraska was conducted between 1997 through 2008. The Missouri River was divided into four sections based on physical and geomorphologic uniqueness (upper unchannelized, lower unchannelized, upper channelized, and lower channelized). Two sections were sampled annually, and each section was sampled on alternate years. Boat electrofishing collected 12,846 fish in 83.5 h from 701 sampling stations. Most flathead catfish sampled (98%) were less than 510 mm total length (quality length), with significantly more fish captured in channelized than unchannelized reach. Fish from channelized sections also had higher mean total lengths and larger growth increments but were in poorer body condition than those from unchannelized sections. Low relative abundance of flathead catfish in the upper unchannelized section and scarcity of large individuals were attributed to poor habitat conditions. Habitat restoration along with restoring natural riverine processes would return the river to a more natural state and would not only benefit flathead catfish, but other native Missouri River fishes as well.

Conservation, Ecology, and Management of Catfish: The Second International Symposium

2011 ◽  
Keyword(s):  
International Symposium ◽  
Pylodictis Olivaris ◽  
Blue Catfish ◽  
Conservation Ecology ◽  
Flathead Catfish ◽  
Tag Loss ◽  
Reward Value ◽  
Exploitation Rate ◽  
Time Correction ◽  
Regulation Changes

<em>Abstract</em>.—The Missouri Department of Conservation suspected that blue catfish <em>Ictalurus furcatus </em>and flathead catfish <em>Pylodictis olivaris </em>were being heavily exploited by anglers in 22,539-ha Harry S. Truman Reservoir in west-central Missouri. A reward tag study was initiated in 2004 to determine angler exploitation rates for both species. Three hundred blue catfish ≥ 482 mm total length (TL) and 194 flathead catfish ≥ 508 mm TL were equipped with transbody Carlin dangler reward tags in 2004 and 2005, respectively. All reward tags displayed a reward value of US$50. A 5-year post-tagging estimate of annual exploitation (<em>u</em>) was calculated with a 25% annual correction for angler nonreporting and a one-time correction for tag loss. The estimated annual exploitation rates for blue catfish ranged from 25.5% to 33.4% with a mean of 28.8%. The estimated cumulative exploitation rate (<EM>U</EM>) at 5-years post-tagging was 81.7% for all sizes of tagged blue catfish and 92.4% for tagged blue catfish ≥ 610 mm TL. The estimated annual exploitation rates for flathead catfish ranged from 0% to 3.9% with a mean of 1.8%. The estimated cumulative exploitation rate at 5-years post-tagging for flathead catfish was 8.8%. These exploitation rates indicate that blue catfish are being heavily exploited while flathead catfish are not. Of all the reward tagged blue catfish that were reported by anglers, 7% were reported as released while 22% of the reported flathead catfish were released. These results are being used to examine possible regulation changes to protect the blue catfish fishery at Truman Reservoir.

Conservation, Ecology, and Management of Catfish: The Second International Symposium

2011 ◽  
Keyword(s):  
Age Estimation ◽  
Early Life ◽  
Age Groups ◽  
Early Life History ◽  
Blue Catfish ◽  
Conservation Ecology ◽  
Flathead Catfish ◽  
Daily Increments ◽  
Daily Ring ◽  
Management And Conservation

<em>Abstract</em>.—We validated methods for estimating daily age of age-0 blue catfish <em>Ictalurus furcatus</em> and flathead catfish <em>Pylodictis olivaris</em>. Larvae of each species were reared in the laboratory and were sampled approximately every 10 d over a 4-month period. Five individuals of each species were randomly selected for daily age estimation from each of nine age-groups, ranging from 40 to 119 d posthatch for blue catfish and 20–121 d posthatch for flathead catfish. Mean daily ring count and known age were related for both species, indicating that daily ring deposition occurred in the otoliths of these fishes. Daily increment counts were accurate through 60 d posthatch for blue catfish and through 72 d posthatch for flathead catfish, with mean deviance of estimated age within 1 d of the known age. For both species, daily increments could be enumerated for older fish; however, accuracy decreased with age. We encourage researchers to utilize our aging technique to estimate hatch dates, the timing and frequency of hatching, and early growth rates of catfishes in wild populations. Such early life history information will be valuable in enhancing the management and conservation of important catfish populations.

Conservation, Ecology, and Management of Catfish: The Second International Symposium

2011 ◽  
Keyword(s):  
Mississippi River ◽  
Radio Telemetry ◽  
Linear Range ◽  
Population Characteristics ◽  
Fish Length ◽  
Long Distance ◽  
Seasonal Movement ◽  
Flathead Catfish ◽  
Significant Difference ◽  
High Degree

<em>Abstract</em>.—A radio-telemetry study was initiated in August 2004 to determine extent and timing of flathead catfish <em>Pylodictis olivaris</em> movements in the Iowa River, Iowa. Between 2004 and 2007, 56 flathead catfish were radio-tagged in the Iowa River between the Mississippi River and the lowermost dam at Iowa City, Iowa. Fish tagged for this study were collected during prespawn/spawn (mid-April to mid-July) and summer/fall (late-July to mid-October) periods at three sites. Radio-tagged fish were tracked through September 2009; fish included in our analyses were located 3–31 times and were tracked for 92–1,554 d. While some fish remained near original tagging locations, others made long distance movements associated with overwintering and spawning. Total linear range varied from 0.5 to 120 km with a mean of 42.4 ± 6.1 (mean ± SE) km, and there were no significant correlations between total linear range and fish length or age. There was no significant difference in total linear range of fish related to tagging period. However, seasonal movement patterns indicated that timing of sampling may affect population characteristics observed at the reach level in the Iowa River. Fish tracked for multiple years exhibited a high degree of fidelity for seasonal locations, particularly during summer/fall and overwintering periods. In addition to telemetry results, harvest of radio-tagged fish in the English and Mississippi rivers indicates that a larger scale than the reach, or Iowa River main stem, should be considered in management of flathead catfish in the Iowa River.

scholarly journals Population Characteristics of Yellow Perch in a Central Appalachia Hydropower Reservoir

2018 ◽  
Vol 9 (2) ◽  
pp. 486-495
Author(s):  
Corbin D. Hilling ◽  
Nate D. Taylor ◽  
Stuart A. Welsh ◽  
Dustin M. Smith
Keyword(s):  
West Virginia ◽  
Yellow Perch ◽  
Size Structure ◽  
Management Strategies ◽  
Relative Weight ◽  
Population Characteristics ◽  
Diet Shift ◽  
Management Decisions ◽  
Ontogenetic Diet Shift ◽  
Hydropower Reservoir

Abstract Estimates of population characteristics of sport fishes inform fisheries management decisions and provide feedback on management strategies. Cheat Lake provides an unusual fishery in West Virginia because the hydropower reservoir supports a Yellow Perch Perca flavescens population. We estimated age structure, size structure, condition, total instantaneous mortality, growth, and summer diet for Cheat Lake Yellow Perch based on electrofishing collections in 2012. From 302 individuals, we observed a maximum age of 9 y. Maximum age, average size, and growth of females in the sample exceeded those of males. Cheat Lake Yellow Perch scored low on the relative weight index, but generally exhibited faster growth than other populations, even when compared by sex. Estimated annual survival was 0.63 (95% CI = 0.51–0.78), which is comparable to other exploited populations. These data support the presence of an ontogenetic diet shift from consumption of zooplankton to macroinvertebrates and fishes as Yellow Perch age. This study is the first evaluation we are aware of on Yellow Perch population characteristics in West Virginia, providing baseline data to enhance management decisions and direct future studies.

Conservation, Ecology, and Management of Catfish: The Second International Symposium

2011 ◽  
Keyword(s):  
Size Structure ◽  
Management Strategies ◽  
Northwestern Part ◽  
Blue Catfish ◽  
Conservation Ecology ◽  
Catch Data ◽  
Annual Survey ◽  
Gill Net ◽  
Glass Slides ◽  
Similar Survey

<em>Abstract</em>.—In Georgia, blue catfish <em>Ictalurus furcatus</em> are native in the Coosa River drainage in the northwestern part of the state. However, they were first detected outside this range during an annual gill net survey of Lake Sinclair conducted by the Georgia Department of Natural Resources in 1996, then again in a similar survey of Lake Oconee during 1997. Catch of blue catfish in annual surveys of Lake Oconee continued to increase, but demographics of the populations are unknown. We used annual survey data for the period 1989–2009 to identify trends in catch of blue catfish in the lake. Age and size structure of the blue catfish population in Lake Oconee was assessed based on catch data from the 2008 survey. Mean length for blue catfish captured (<em>n</em> = 121) was 330 mm (SD = 132 mm), and mean weight was 468 g (SD = 683.9 g); the largest fish was 740 mm and weighed 5078 g. Otoliths from the blue catfish collected were cross-sectioned, mounted on glass slides, and examined under a dissecting microscope, and annuli on each section were counted independently by two readers. Catch data indicated that blue catfish catch increased rapidly after 1997. Seven year-classes (2001–2007) were represented in the 2008 sample, and most fish were from the 2003 year-class (mean age: 3.7 years; SD = 1.4 years). These data document a rapidly expanding blue catfish population in Lake Oconee and could serve as the basis for developing management strategies in this reservoir system and others across North America where blue catfish are expanding their range.

scholarly journals Mobility Patterns in Different Age Groups in Japan during the COVID-19 Pandemic: a Small Area Time Series Analysis through March 2021

2021 ◽  
Author(s):  
Shuhei Nomura ◽  
Yuta Tanoue ◽  
Daisuke Yoneoka ◽  
Stuart Gilmour ◽  
Takayuki Kawashima ◽  
...  
Keyword(s):  
Care Delivery ◽  
Human Mobility ◽  
Age Groups ◽  
Virus Transmission ◽  
Initial Response ◽  
Health Care Delivery System ◽  
Population Characteristics ◽  
Mobility Patterns ◽  
Mobility Data ◽  
The Status

AbstractIn the COVID-19 era, movement restrictions are crucial to slow virus transmission and have been implemented in most parts of the world, including Japan. To find new insights on human mobility and movement restrictions encouraged (but not forced) by the emergency declaration in Japan, we analyzed mobility data at 35 major stations and downtown areas in Japan—each defined as an area overlaid by several 125-meter grids—from September 1, 2019 to March 19, 2021. Data on the total number of unique individuals per hour passing through each area were obtained from Yahoo Japan Corporation (i.e., more than 13,500 data points for each area). We examined the temporal trend in the ratio of the rolling seven-day daily average of the total population to a baseline on January 16, 2020, by ten-year age groups in five time frames. We demonstrated that the degree and trend of mobility decline after the declaration of a state of emergency varies across age groups and even at the subregional level. We demonstrated that monitoring dynamic geographic and temporal mobility information stratified by detailed population characteristics can help guide not only exit strategies from an ongoing emergency declaration, but also initial response strategies before the next possible resurgence. Combining such detailed data with data on vaccination coverage and COVID-19 incidence (including the status of the health care delivery system) can help governments and local authorities develop community-specific mobility restriction policies. This could include strengthening incentives to stay home and raising awareness of cognitive errors that weaken people's resolve to refrain from nonessential movement.

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