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):  
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 ◽  
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):  
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):  
North Carolina ◽  
International Symposium ◽  
Maximum Size ◽  
Large Fish ◽  
Blue Catfish ◽  
Conservation Ecology ◽  
Size Limit ◽  
Catch And Release ◽  
The North ◽  
Gill Net

<em>Abstract</em>.—Blue catfish <em>Ictalurus furcatus </em>were introduced into North Carolina reservoirs in the mid-1960s and have recently become a popular target for anglers pursuing large catfish. In 2008, the North Carolina Wildlife Resources Commission enacted a maximum size limit for blue catfish at Badin Lake and Lake Norman where only one fish greater than 813 mm could be harvested daily. Surveys indicated that few fish larger than 813 mm were present in either system and that the time to reach the size limit was 12 years in Badin Lake and 20 years in Lake Norman, on average. Although few large fish were present in either system, tournament anglers at Lake Norman kept larger fish in a higher proportion than found in gill-net surveys or harvested during a recent creel survey. Modeling results suggested that the regulation would have little or no impact on increasing the number of large catfish in either population. However, the regulation will protect some rare fish that grow to the maximum size limit and potentially allow recapture opportunities if catch-and-release mortality is low.

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):  
International Symposium ◽  
Relative Abundance ◽  
Wildlife Conservation ◽  
Age And Growth ◽  
Mortality Data ◽  
Blue Catfish ◽  
Sampling Methodology ◽  
Conservation Ecology ◽  
Slow Growing ◽  
Annual Mortality

<em>Abstract</em>.—Management of blue catfish <em>Ictalurus furcatus</em> populations is an emerging focus for state fish and wildlife agencies as catfish anglers have shown a growing interest in trophy fishing. As blue catfish sampling methodology has improved, management of blue catfish fisheries has become a greater priority in some states. The Oklahoma Department of Wildlife Conservation (ODWC) has collected abundance, age and growth, and mortality data on blue catfish from 14 reservoirs statewide. Electrofishing surveys indicated that blue catfish populations are dominated by slow-growing fish less than 400 mm total length (TL) and average 24% total annual mortality. In addition, relative abundance of ≥762 mm TL blue catfish in the angler creel (8%) greatly exceeds that in population samples (<1%). In 2009, ODWC recommended a statewide regulation limiting harvest of blue catfish greater than 762 mm TL to one fish per day while maintaining the daily limit of 15 fish per day. The proposal met with moderate opposition through the regular regulation review process but was approved by the Oklahoma Wildlife Commission. Legislative opposition to the proposal subsequently developed, and a resolution was introduced to rescind the regulation but ultimately failed. A regulation restricting blue catfish harvest to 15 fish daily with only 1 fish ≥762 mm TL went into effect on January 1, 2010.

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):  
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.

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