Effect of Sample Duration on Catch Rate and Size Structure Data for Blue Catfish Collected by Low‐Frequency Electrofishing

2020 ◽  
Author(s):  
Daniel E. Shoup ◽  
Kristopher A. Bodine
Keyword(s):  
Structure Data ◽  
Size Structure ◽  
Low Frequency ◽  
Catch Rate ◽  
Blue Catfish ◽  
Sample Duration

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

2011 ◽  
Keyword(s):  
Size Structure ◽  
Low Frequency ◽  
Relative Standard Error ◽  
Limited Information ◽  
Blue Catfish ◽  
Frequency Distributions ◽  
Gill Nets ◽  
Pulsed Dc ◽  
Gill Net ◽  
Catch Rates

<em>Abstract</em>.—Despite increasing popularity of blue catfish <em>Ictalurus furcatus</em> with anglers, effective management of blue catfish has been hindered by limited information on appropriate sampling methods. We compared the efficiency, precision, and accuracy of low-frequency pulsed-DC electrofishing and experimental gill nets for use in estimating relative population abundance and size structure in 12 reservoirs. Electrofishing yielded greater catch rates and lower mean relative standard error (RSE) than gill nets. Similarly, the number of samples necessary to achieve a RSE = 0.25 was lower with electrofishing in most reservoirs. Gill-net catch per unit effort (CPUE) and electrofishing CPUE were strongly correlated (<EM>P</EM> < 0.01), and length-frequency distributions were also similar between gear types in many reservoirs examined. Where they differed, there was no consistent pattern, suggesting that differences were due to low precision (caused by low numbers of fish captured) rather than gear bias. Our analysis indicated that both low-frequency pulsed-DC electrofishing and gill netting effectively measured relative abundance of blue catfish. In most cases, electrofishing was more efficient at estimating CPUE and size structure (requiring fewer samples to achieve comparable precision); thus, we recommend using this gear when estimating these parameters for reservoir blue catfish populations.

Analysis of crab size structure and the fishing effort applied to a crab fishery in northwest Mexico

Crustaceana ◽  
2018 ◽  
Vol 91 (2) ◽  
pp. 225-237 ◽  
Author(s):  
César A. Heredia-Delgadillo ◽  
Guillermo Rodríguez-Domínguez ◽  
Raúl Pérez-González ◽  
Nicolás Castañeda-Lomas ◽  
Sergio G. Castillo-Vargasmachuca ◽  
...  
Keyword(s):  
Gulf Of California ◽  
Size Structure ◽  
Coastal Lagoons ◽  
Low Frequency ◽  
Fishing Effort ◽  
Double Ring ◽  
Northwest Mexico ◽  
Fishing Gears ◽  
Fishery Cooperatives ◽  
Ring Net

The fishing effort of a Sinaloa crab fishery in the Gulf of California in 2014 was analysed based on fishermen’s interviews, official catches and permits, and information from a sample of fishing logbooks from five fishery cooperatives operating in four coastal lagoons that contained the daily catch from individual fishing trips. Unauthorized gear, a double-ring net (DR), was used most frequently (>70% of the fishers) for crab fishing, although authorized single-ring nets and Chesapeake traps (CT) were also used with low frequency. The estimated fishing effort was 641 boats/day in the four coastal lagoons, which was 34% more than authorized, and 818 boats/day were employed in all of Sinaloa. A total of 57 479 fishing gears were estimated for the study area, which was 49.9% greater than the maximum authorized number, and 80 822 nominal fishing gears were estimated for the entire Sinaloa crab fishery, 14.15% more than the total gear limit (70 800). The size of the mesh used in the gear was smaller than the authorized limit of 76 mm, and >50% of the catches included crabs of unlawful size. It is argued that the effort must be regulated in terms of the number of vessels, per unit time, and not the number of gears. The information from this study demonstrates a failure to monitor compliance with current regulations and thus means that other strategies for the sustainable management of the fishery, such as co-management, should be tested.

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):  
Linear Models ◽  
Negative Relationship ◽  
Low Frequency ◽  
Catch Per Unit Effort ◽  
Blue Catfish ◽  
James River ◽  
Growth And Survival ◽  
Pulsed Dc ◽  
Class Strength ◽  
Stable Growth

<em>Abstract</em>.—Introduced blue catfish <em>Ictalurus furcatus</em> populations in tidal rivers of the Atlantic slope support important recreational and commercial fisheries, with the James River trophy fishery being nationally recognized. During the period 2001–2008, low-frequency (15 pulses/s) pulsed DC electrofishing was used to sample blue catfish in tidal fresh-oligohaline sections of the James, Mattaponi, Pamunkey, and Rappahannock River systems; 54,174 blue catfish were collected, and 4,660 of these were aged using otoliths. Mean catch per unit effort (CPUE) was generally high (ranging from 223 to 6,106 fish per hour). Trends of increasing CPUE through time occurred in the James (839–4,449 fish per hour) and Rappahannock (1,400–6,106 fish per hour) rivers, and differences in CPUE were detected among rivers. Temporal shifts in growth (mean length at age) were observed, with growth slowing for all ages in the Pamunkey River and slowing for older ages in the Mattaponi (ages 9–13) and Rappahannock (ages 8–12 and age 14) rivers. In the Pamunkey and Rappahannock rivers, a negative relationship existed between growth (mean length at age 10) and density (CPUE). Although density increased dramatically in the James River, growth remained stable. Growth varied among rivers; by the end of the study, mean total length at age 10 ranged from 416 mm in the Rappahannock River to 675 mm in the James River. Growth through age 15 fi t linear models, as opposed to the von Bertalanffy nonlinear curve. In three of the four populations, the maximum age sampled increased in each succeeding survey year, and the maturing of all four populations was reflected in concurrent increases in size distributions. Recruitment was variable, with coincident strong and weak year-classes occurring in all four populations—an implication that landscape-level environmental variables play a role in determining recruitment success. In three of the four populations, patterns in year-class strength persisted, with correlation of catch-curve residuals from surveys separated by time. Approximately 35 years poststocking in the James and Rappahannock rivers and 25 years poststocking in the Mattaponi River, these populations had not yet reached equilibrium. It is unknown what the dynamics of blue catfish abundance, growth, and survival will be in the long-term in these rivers, leaving uncertainty regarding the future of the fisheries the populations support, as well as unanswered questions related to potential effects on other species.

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.

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

2011 ◽  
Keyword(s):  
Low Frequency ◽  
The United States ◽  
Key Factors ◽  
Blue Catfish ◽  
Biological Variables ◽  
Natural Reproduction ◽  
Gill Net ◽  
Successful Establishment ◽  
Weak Negative Correlation ◽  
Catch Rates

<em>Abstract</em>.—The blue catfish <em>Ictalurus furcatus</em> is the largest ictalurid in the United States and is present in many reservoirs throughout Texas. While some populations are native, many fisheries are the result of introductions through stocking programs. These stockings can result in established fisheries while others fail to produce established populations. It is possible that a combination of physical, chemical, and biological variables produce an ideal environment for the successful establishment and survival of this species. The objective of this study was to identify the key factors that influence the success of blue catfish populations in Texas reservoirs. Thirty reservoirs distributed across Texas were sampled using gill nets and low-frequency electrofishing. Blue catfish abundance, condition, and natural reproduction were compared with multiple physicochemical and biological variables collected at each reservoir. Factor analysis indicated that both gill-net catch rates and low-frequency electrofishing catch rates were positively correlated to measures of primary productivity. The analysis also showed that gill-net catch rates increased with increasing reservoir surface area. The occurrence of natural reproduction showed a weak negative correlation to length of growing season. The results of this study provide further insight into the biology of blue catfish and provide managers with information that can be used to prioritize future stocking efforts.

A Study on the Fine Structure of the Lateral Line Organ of the Sea Eel

1973 ◽  
Vol 31 ◽  
pp. 648-649
Author(s):  
K. Hama
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Lateral Line ◽  
Low Frequency ◽  
Sensory Cells ◽  
Apical Surface ◽  
Voltage Electron ◽  
Sensory Epithelia ◽  
Low Frequency Vibration ◽  
Transmission Electron

The lateral line organs of the sea eel consist of canal and pit organs which are different in function. The former is a low frequency vibration detector whereas the latter functions as an ion receptor as well as a mechano receptor.The fine structure of the sensory epithelia of both organs were studied by means of ordinary transmission electron microscope, high voltage electron microscope and of surface scanning electron microscope.The sensory cells of the canal organ are polarized in front-caudal direction and those of the pit organ are polarized in dorso-ventral direction. The sensory epithelia of both organs have thinner surface coats compared to the surrounding ordinary epithelial cells, which have very thick fuzzy coatings on the apical surface.

Lectin Binding to Human Breast Tumor Cells

1976 ◽  
Vol 34 ◽  
pp. 34-35
Author(s):  
Robert E. Nordquist ◽  
J. Hill Anglin ◽  
Michael P. Lerner
Keyword(s):  
Carcinoma Cell ◽  
Ricinus Communis ◽  
Lectin Binding ◽  
Low Frequency ◽  
Breast Carcinoma Cell Line ◽  
Human Breast ◽  
Human Breast Tumor ◽  
Duct Carcinoma ◽  
Specific Antigens ◽  
Ricin Agglutinin

A human breast carcinoma cell line (BOT-2) was derived from an infiltrating duct carcinoma (1). These cells were shown to have antigens that selectively bound antibodies from breast cancer patient sera (2). Furthermore, these tumor specific antigens could be removed from the living cells by low frequency sonication and have been partially characterized (3). These proteins have been shown to be around 100,000 MW and contain approximately 6% hexose and hexosamines. However, only the hexosamines appear to be available for lectin binding. This study was designed to use Concanavalin A (Con A) and Ricinus Communis (Ricin) agglutinin for the topagraphical localization of D-mannopyranosyl or glucopyranosyl and D-galactopyranosyl or DN- acetyl glactopyranosyl configurations on BOT-2 cell surfaces.

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