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

2011 ◽  
Keyword(s):  
International Symposium ◽  
Ictalurus Punctatus ◽  
Channel Catfish ◽  
High Abundance ◽  
Sampling Effort ◽  
Conservation Ecology ◽  
Standard Work ◽  
Second International

<em>Abstract</em>.—Baited, tandem hoop nets are increasingly being used to sample channel catfish <em>Ictalurus punctatus</em> populations in reservoirs. However, there have been no published studies to address the effect of soak duration on precision of catch. The effect of soak duration on precision of channel catfish catch in baited, tandem hoop nets was evaluated in three Texas reservoirs. Precision of channel catfish catch was inconsistent among reservoirs when one-night soak durations were used but improved with two-night and three-night soak durations. Although catch precision was similar for two- and three-night soak durations, sampling effort could be doubled using two-night rather than three-night soak durations during a standard work week if a manager did not prefer to leave gear unattended during a weekend. Thus, we recommend use of baited, tandem hoop-net series with two-night soak durations to sample high-abundance channel catfish populations in reservoirs.

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

2011 ◽  
Keyword(s):  
International Symposium ◽  
Ictalurus Punctatus ◽  
Channel Catfish ◽  
Fish Density ◽  
State Agencies ◽  
Retention Efficiency ◽  
Conservation Ecology ◽  
Factors Influencing ◽  
The Mean ◽  
High Fish

<em>Abstract</em>.—In recent years, several state agencies have adopted the use of baited, tandem-set hoop nets to assess lentic channel catfish <em>Ictalurus punctatus</em> populations. Some level of escapement from the net is expected because an opening exists in each throat of the net, although factors influencing rates of escapement from hoop nets have not been quantified. We conducted experiments to quantify rates of escapement and to determine the influence of throat configuration and fish density within the net on escapement rates. An initial experiment to determine the rate of escapement from each net compartment utilized individually tagged channel catfish placed within the entrance (between the two throats) and cod (within the second throat) compartments of a single hoop net for overnight sets. From this experiment, the mean rate (SE) of channel catfish escaping was 4.2% (±1.5) from the cod (cod throat was additionally restricted from the traditionally manufactured product), and 74% (±4.2) from the entrance compartments. In a subsequent experiment, channel catfish were placed only in the cod compartment with different throat configurations (restricted or unrestricted) and at two densities (low [6 fish per net] and high [60 fish per net]) for overnight sets to determine the influence of fish density and throat configuration on escapement rates. Escapement rates between throat configurations were doubled at low fish density (13.3 ± 5.4% restricted versus 26.7 ± 5.6% unrestricted) and tripled at high fish density (14.3 ± 4.9% restricted versus 51.9 ± 5.0% unrestricted). These results suggest that retention efficiency is high from cod compartments with restricted throat entrances. However, managers and researchers need to be aware that modification to the cod throats (restrictions) is needed for hoop nets ordered from manufacturers. Managers need to be consistent in their use and reporting of cod end throat configurations when using this gear.

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

2011 ◽  
Keyword(s):  
International Symposium ◽  
Channel Catfish ◽  
Capture Efficiency ◽  
Ictalurus Furcatus ◽  
Blue Catfish ◽  
Conservation Ecology ◽  
Incidental Capture ◽  
Coastal Rivers ◽  
Second International

<em>Abstract</em>.—Use of trotlines to collect data on catfish populations can lead to incidental capture of endangered turtles. We evaluated the effectiveness of Zote© soap as a way to prevent capture of turtles on trotlines fished in coastal rivers of Mississippi and compared capture efficiency of cut bait and Zote© soap in research ponds. More than 11,000 hooks baited with Zote© soap were fished overnight in six coastal rivers of Mississippi, resulting in the capture of zero turtles, 193 blue catfish <em>Ictalurus furcatus</em>, and 462 channel catfish <em>I. punctatus</em>. Direct comparisons with other baits were not conducted in the coastal rivers because capture of a single endangered turtle would have resulted in revocation of our sampling permit. Therefore, comparisons of cut bait and Zote© soap were conducted in research ponds. The fi rst trial fished 440 hooks each of cut bait and Zote© soap. Cut bait and Zote© soap collected one and zero turtles, respectively, while each bait captured 48 channel catfi sh. The second trial fished 120 hooks each of cut bait and Zote© soap. Cut bait and Zote© soap collected two and zero turtles, respectively, and 15 and 8 channel catfish, respectively. A Mann–Whitney U-test indicated no signifi cant difference between bait type in number of catfish or turtles captured in either trial. While statistical differences in turtle catch between bait types were not found, preventing any capture of endangered turtles in the field is a high priority and our results indicated that use of Zote© soap provides the best method for eliminating turtle capture on trotlines in coastal rivers of Mississippi.

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

2011 ◽  
Keyword(s):  
United States ◽  
Body Condition ◽  
Ictalurus Punctatus ◽  
Channel Catfish ◽  
Aeromonas Hydrophila ◽  
Condition Index ◽  
The United States ◽  
Southern United States ◽  
Conservation Ecology ◽  
Columnaris Disease

<em>Abstract</em>.—U.S. Game and Fish agencies and farm-pond owners throughout the United States use commercially produced channel catfish <em>Ictalurus punctatus </em>fingerlings transported from the southern United States for supplemental stocking. We conducted six trials to examine whether pathogen load, body condition, and select environmental factors influence fingerling survival following transport and cage stocking. Fingerlings were sampled prior to stocking and weekly for the following 3 weeks. Weights and lengths were measured, and a relative condition index was used to quantify body condition. Skin scrapings and gill clippings were examined microscopically for pathogens, and posterior kidney was assayed for <em>Aeromonas hydrophila</em>. Mortality was either less than 10% (four trials) or catastrophic (two trials). A Columnaris disease epizootic was associated with ~50% mortality in one trial, and a red sore disease epizootic was associated with ~80% mortality in another. Body condition or other pathogens, present initially or acquired in study ponds, were not associated with high mortality. The first week appears to be critical for the survival of channel catfish fingerlings following transport.

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

2011 ◽  
Keyword(s):  
International Symposium ◽  
Freshwater Fishes ◽  
Valid Species ◽  
Conservation Ecology ◽  
Species Inventory ◽  
Distributed Order ◽  
Second International

<em>Abstract</em>.—Catfishes are a broadly distributed order of freshwater fishes with 3,407 currently valid species. In this paper, I review the different clades of catfishes, all catfish families, and provide information on some of the more interesting aspects of catfish biology that express the great diversity that is present in the order. I also discuss the results of the widely successful All Catfish Species Inventory Project.

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

2011 ◽  
Keyword(s):  
United States ◽  
Experimental Design ◽  
Natural Resource ◽  
Ictalurus Punctatus ◽  
Efficient Method ◽  
Channel Catfish ◽  
Southeastern United States ◽  
Conservation Ecology ◽  
Soybean Cake ◽  
Sunflower Cake

<em>Abstract</em>.—Many U.S. natural resource agencies stock catfish (Ictaluridae) into small impoundments to provide recreational fishing opportunities. However, effective standardized methods for sampling catfish in small impoundments have not been developed for wide application, particularly in the southeastern United States. We evaluated the efficiency of three bait treatments (i.e., soybean cake, sunflower cake, and no bait) of tandem hoop nets in two North Carolina small impoundments during the fall of 2008 and spring of 2009 in a factorial experimental design. The impoundments were stocked with catchable-size channel catfish <em>Ictalurus punctatus</em> at contrastingly low (5.5 fish/ha) and high (90.0 fish/ha) rates prior to our sampling. Nets baited with soybean cake consistently sampled more channel catfish than any other treatment. Channel catfish catch ranged as high as 3,251 fish per net series during the fall in nets baited with soybean cake in the intensively stocked impoundment and was up to 8.5 and 15.3 times higher during the fall than in the spring in each impoundment. Nets baited with soybean cake sampled significantly (12 and 24 times) more channel catfish than those with no bait in the two impoundments. These trends did not occur among other catfish species. Nonictalurid fish and turtle catch was higher during spring compared to that of fall, corresponding with low channel catfish catches. Our results indicate that tandem hoop nets baited with soybean cake during the fall is a more efficient method for sampling channel catfish compared to nets baited with sunflower cake or no bait in spring or fall. Our findings validate this technique for application in southeastern U.S. small impoundments to assess catfish abundance to guide management and evaluate the success of catfish stocking programs.

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

2011 ◽  
Keyword(s):  
Ictalurus Punctatus ◽  
Channel Catfish ◽  
Age Estimation ◽  
Aging Process ◽  
Processing Time ◽  
Statistical Analyses ◽  
Total Processing Time ◽  
Conservation Ecology ◽  
Processing Times ◽  
Accuracy And Precision

<em>Abstract</em>.—Otoliths and pectoral spines are common calcified structures used to age channel catfish <em>Ictalurus punctatus</em>. Several studies have assessed accuracy and precision of these structures; however, results have been conflicting. Additionally, information on processing times required to prepare and assign ages to these structures is lacking. Therefore, our objective was to assess bias, precision, and processing time of otoliths and pectoral spines used for age estimation of channel catfish. Otoliths (<EM>N</EM> = 603) and spines (<EM>N</EM> = 3,397) were collected from channel catfish during 2007–2009 to assess bias and precision. A subsample of these structures was used to estimate and compare processing times. Otoliths displayed greater precision and less reader bias compared to pectoral spines. Age-specific bias was observed for pectoral spines in relation to otoliths, with pectoral spines greatly underestimating ages for age-11 and older channel catfish. Total processing time was greater for otoliths (12.26 min ± 1.09 [SE]) compared to pectoral spines (11.01 min ± 0.07 [SE]). These results provide managers with information to make decisions on which structure to use for age estimation of channel catfish given a known bias and precision desired for statistical analyses and amount of time allotted for the aging process.

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

2011 ◽  
Keyword(s):  
International Symposium ◽  
Mail Survey ◽  
Attitude Scale ◽  
Policy Formation ◽  
Large Fish ◽  
Conservation Ecology ◽  
Related Attitude ◽  
Second International

<em>Abstract</em>.—Previous research indicates that hand grabbling does not negatively affect catfish populations in Mississippi, but hand grabbling is restricted to a season to control harvest of large fish. We conducted a mail survey from October to December 2008 to compare Mississippi hand grabbler and rod-and-reel catfish angler sociodemographics, fishing characteristics, participation patterns, and catch-related attitudes. A catch-related attitude scale was used to measure angler’s evaluation of catching fish in four constructs (catching something, catching numbers, catching large fish, and retaining fish). Results indicated that hand grabblers had stronger attitudes toward catching large fish, but rod-and-reel catfish anglers had stronger attitudes toward catching numbers. We explained that possible differences in catch-related attitudes and other characteristics were due to hand grabblers being a more specialized subworld of catfish anglers. Understanding differences in characteristics and processes through which these subworlds differed can assist with policy formation, especially if competition over resources (e.g., large, trophy catfishes) intensifies.

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

2011 ◽  
Keyword(s):  
Ictalurus Punctatus ◽  
Channel Catfish ◽  
River Estuary ◽  
Current Status ◽  
Catch Per Unit Effort ◽  
Delaware River ◽  
Conservation Ecology ◽  
Delaware River Estuary ◽  
Variable Recruitment ◽  
Native White

<em>Abstract</em>.—In the Delaware River estuary, native white catfish <em>Ameiurus catus</em> have appeared to decline as the introduced channel catfish <em>Ictalurus punctatus</em> has become more abundant. To determine the current status of these populations and the habitats they use, I surveyed four zones of the Delaware River estuary from April to November 2007. Hoop nets (<EM>N</EM> = 497) were set in main-stem river, lower tributary, and middle tributary habitats. Upper tributary habitats near the head of tide were angled. Our findings indicated that the ratio of channel catfish to white catfish was less than documented in the early 1990s. Channel catfish and white catfish were found throughout the study area, during all seasons. Channel catfish catch per unit effort was significantly greater in the river than in tributary habitats. Relative condition differed seasonally among zones and zone groups. Both species had unstable age structures, indicating variable recruitment. Variable recruitment may account for past differences in ratios of channel catfish to white catfish. Channel catfish in this study lived longer (22 years) when compared to channel catfish collected in other nearby river systems. Few brown bullhead <em>A. nebulosus</em> and no yellow bullhead <em>A. natalis</em> or flathead catfish <em>Pylodictis olivaris </em>were collected.

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