TPWD 1971 F-6-R-18 #1427: Fisheries Investigations - Region 5-B: Job No. III Trotline Study

Marion Toole D-J Coordinator ”/6" FINAL REPORT As required by FEDERAL AID IN FISHERIES RESTORATION ACT TEXAS Federal Aid Project Non Fw6wR-l8 FISHERIES INVESTIGATIONS - REGION 5-B Job N00 III Trotline Study Project Leader: Roger L, McCabe James U0 Cross Executive Director Parks and Wildlife Department Austin, Texas J. M. Beall Director, Current Operations June 8, 1971 SUMMARY Project personnel researched the literature, interviewed,trotline fisher— men, and conducted actual experimental trotlining and bait trapping on Lake Corpus Christi to procure information on trotlining. A literature search revealed that trotlining was the least effective fishing method in terms of average catch per man-hour. According to two creel census, trotline fishermen averaged .15 and .17 fish per man-hour, respectively. Fishermen interviews provided data on the individuals doing trotline fishing, their methods, and their equipment. The fishermen were male resi- dents of the state. Their lines averaged 189 feet in length and contained a mean number of 40 hooks each. Experimental trotlining by project personnel yielded 118 fish in 54,590 hook-bait-hours for an average catch of .00216 fish per hookwbaitwhour. All trap types and baits were selective for trotline bait Species. The catch consisted of 95.97 per cent trotline bait Species, 2.77 per cent rough fish,and 1.26 per cent game fish. FINAL REPORT State Texas Project No. F~6wR-18 Project Title: Fisheries Investigations w Region 5wB _ Job No. III Job Title: Trotline Study Period Covered: January 1, 1970 to December 31. 1970 Background: Trotlining is a widespread fishing technique employed by both sport and commercial fishermen. Lake Corpus Christi is a popular trotline fishing lake in South Texas which provides a suitable area for studying the sport. Cure rently, a hook interval regulation, limiting the distance between hooks to no less than three feet, is the only law governing trotline fishing on this lake. Unfortunately, there is little available scientific data upon which to base management regulations. More information regarding the effects of this form of fish harvesting is essential. During the course of this study (January 1, 1968 through December 31, 1970), project personnel have researched the literature, interviewed trote line fishermen and conducted experimental trotlining and bait trapping. Literature pertaining to trotlining is scarce, consisting-mainly of nonsci~ entific articles in outdoor magazines and saltwater oriented research publi— cations. Fishermen interviews furnished information about the individuals involved in trotline fishing, their methods, and their equipment. Experimental trotlining and bait trapping by project personnel furnished data on materials, methods, and yields. Bait trapping exhibited a high degree of selectivity toward trotline bait species. Objectives: To study the trotline fishery of Lake Corpus Christi. 1. To conduct a literature search for publications pertaining to trot- lining. 2. To gather trotline fishing information through the use of fishermen interviews at Lake Corpus Christi. 3. To obtain data on actual trotline yields from Lake Corpus Christi. 4. To determine the feasibility of trapping live bait (Cichlasoma cyanoguttatum (Filippi), Lepomis spp. (Rafinesque))for use on trotlines. Procedures: Project personnel examined bibliographies and a list of unpublished Federal Aid Reports furnished by the Denver Public Library and utilized departmental facilities to procure information regarding trotlining. Fisherm men interviews were conducted using a form designed specifically to obtain data concerning trotline fishing and fishermen, their methods and equipment, their preferred locations, as well as baits and catches. Experimental trotlining on Lake Corpus Christi was initiated on May 29, 1969, and continued through July 29, 1970. Trotlines of various construction were fished at different locations in a variety of habitat types. Seven 105mfoot trotlines were used, cash containing a different hook Size ranging from 2/0 to 8/0. Eagle Claw, Kirby, O'Shaughnessey, and Limerick hooks were arranged in sequence with each line containing 20 hooks. Staging (drop or hook) lines were from 12 to 26 inches in length. Hook interval length (distance between hooks) was either 3, 4, or 4% feet. Fourteen bait types were fished in various combinations with hook sizes. Trotline clips and/or swivels were used to attach staging lines to main lines. Trotlines were set by tying one end of the main line to an object at or above the water surface and sinking the other end, thus enabling baits to be fished at a variety of depths. Experimental bait trapping was conducted in conjunction with experimental trotlining, using traps constructed of oneehalf of an inch square mesh hardw ware cloth (see Job Progress Report F~6-R~l6), designed specifically to trap deep-bodied, laterally compressed, Rio Grande perch-and sunfish. Traps were baited with milo, cob corn, range cubes, cottonseed cubes, or cottonseed I cake in-various Combinations and set in different locations on_the lake in suitable habitat. Findings: Literature pertaining to the subject of trotlining is scarce and consists mainly of nonwscientific articles in outdoor magazines and technical publi— cations concerning saltwater research. According to a lQ-month-creel census by Alvin Flury (September 1953 through June 1954) on Lake Corpus Christi, trotline fishermen comprised 61 per cent of the fishermen contacted. They expended 79 per cent of the manwhours (manwhours calculated by multiplying the number of men fishing, times the number of hours the line was set), were 77 per cent successful and caught 68 per cent of the fish recurded. Fisher“ men contacted in this census caught one fish every 6.53 manmhours for an average of .15 fish per manuhour and used mainly cut fish, white naptha laundry soap, and sunfish for bait. A creel census of eight Texas lakes by William H. Brown, published in the March 1957 issue of the Texas Game and Fish magazine, states that trotlines caught .17 fish per manmhour. On the basis of the data presented in this article, trotlining was the least efm fective method of sport fishing in terms of average catch per manmhour. Findings: (Con.) A total of 71 trotline fishermen was interviewed by project personnel. These fishermen were male residents of the state between the ages of 14 and 74. Trotline parties on Lake Corpus Christi contained an average of 4 perv sons fishing 3.4 trotlines. Trotlines usually were constructed of nylon from 20 to 750 feet in length. Mean length per trotline was 189 feet. Hook size preference varied from 1/0 to 9/0 with some trotliners using several hook sizes. Each trotline contained an average of 40 hooks. The length of staging lines varied from 8 to 26 inches. Fishermen checked their lines every 10.94 hours and rebaited 46 per cent of their hooks on each run. Trotlines were left in water for lengths of time ranging from one day to an indefinite period. Fishermen indicated no parties ular preference between midwlake (open water) and nearwshore fiShing locations. Preferred seasons, weather and water conditions were Similar to those con~ sidered optimum by rodwandwreel fishermen. Mean depth of the water fished was 16.8 feet while actual depths fished varied from 3 to 40 feet. Hooks were set at an average depth of 11 feet, with individual sets ranging from surface to 40 feet. ' Fishermen interviewed specified 22 preferred bait types (Table 1). Rio Grande perch was the most popular bait for flathead catfish (Pylodictis olivaris (Rafinesque) ) (Table 1). Cut bait, bar soap, and shrimp were the preferred baits for channel catfish (Ictalurus punctatus (Rafinesque) ), while bar soap, cut bait, Rio Grande perch, and sunfish were their favorite baits for blue catfish (I. furcatus (LeSueur) ) (Table 1). Experimental trotlining by project personnel.yielded 118 fish (Table 2) in 54,590 hookubait~hours (hookmbait—hours are calculated by multiplying the number of baited hooks times the number of hours fished) for an average catch of .00216 fish per hookmbaitwhour (Table 3). Results are expressed in hookw bait—hours instead of manmhours because manwhours fail to take into conw sideration the number of hooks fished. The most efficient bait was beef kidney which caught .00618 fish per hookmbaitmhour followed by shrimp, blood bait, sunfish, and fisherman's bait soap (Table 3). Several baits (cheese bait, heart, Rio Grande perch and Mexican tetra (Astyanax mexicanus (Filippi) ) failed to catch any fish. Obviously, some of the baits are more productive than the results indicate; otherwise, they could not maintain their popularity among the fishermen interviewed (Table 1). Hook size 2/0 accounted for the most fish while size 6/0 caught the most by weight (Table 4). Fish were caught at an average depth of 4.7 feet, while the mean depth of the water where fish were caught was 13.7 feet. There was no substantial difference in the hooking abilities of the different hook makes tested. Swivels were more effective than trotline clips as a means of attaching staging lines to main lines. Trotline clips were more susceptible to rust than brass swivels and occasionally broke as a result. In addition, trotline clips frequently become entangled with the main line. Table'l' Fishermen Interview Bait Preference ' S relies". WE... : : ""31ué" '”"Chanfiéi _ Flathead LargemouthII--_-I . _ _ CathiS_ . . Cfati-Sh . Hatfis .. .I . . . ' _ . . . . . Blood bait Crayfish Cut_bait Dough bait Dry gar Frogs GoldfiSh ”Grasshopper Heart Kidney Liver Minnows Mussels Pork skin Rio Grande perch Salamander Shrimp Soap Spleen Sunfish Tripe Worms +—| ~01bewa t—I N a—leHowl—I-DHNomH-Dr—IHNI—H—Ioomm NH WNNNf-‘N :l—‘ Some fishermen interviewed cited numerous bait preferences accounting for the large number of responses. Table 2 Experimental Trotlining Catch M Channel catfish Blue catfish Flathead catfish Largemouth bass w Yellow bullhead Freshwater drum Spotted gar Table 3 Number of Fish Caught per Hook-Baithour by Bait Type Nb.‘ . . . .. _ ... . ... .... _ ._ ....n._.. _._.. of FiSh per- _Bait_T_ye __ ‘ ;H00k*Bait5HrS°. lyNumber of Fish .. HookrBsit-Hour.. BloOd bait Cheese bait Cut bait Dried'liver aFel's soap _Fisherman's bait soapj ¥Fresh liver - Heart Kidney Live shad ,Rio Grande perch ,Shrimp :lSunfish :Mexican tetra w.us oo.Nm mm.mm AN.NH mN.mH NH.mH sm.ou . . . . WWOGDO. - “amuse rune mo .uB owmum>¢ .nmyuwcmyxoom.........muosno-..... .v.awuodnov... unusco swam; . mnqm.xoom Hum .umuuHmMIJOOm ugwsmo .oz ugmsmo .02 new uswsmo H ufiwfloz Scans: mNHm xoom mp floumo wdfidfiauone Heuamfiflnomxm q mHLmH Table 5 Catch of Traps in Lake Corpus Christi _ Common Name _ _ _ Scientific_Name_ Number_ Trotline Bait Fish Bluegill Lepomis macrochirus (Rafinesque) 507 Redear sunfish Lepomis microloBhus (Gunther) 94 Longear sunfish Lepomis megalotis (Rafinesque) - 75 Warmouth . Lepomis gulosus (Cuvier) . 40 Golden Shiner _ Notemigonus crysoleucas (Mitchill) 24 Rio Grande perch ' Cichlasoma cyanoguttatum (Baird & Girard) 21 Green sunfish : Lepomis cyanellus (Rafinesque) _ l Redbreast sunfish Lepomis auritus (Linnaeus) : __1 763 Game Fish . Channel catfish Ictalurus punctatus (Rafinesque) 6 White bass ' Morone chrysops (Rafinesque) 2 Largemouth bass - Micropterus_salmoides (Lacepede) 9 White crappie - Pomoxis annularis (Rafinesque) . __§ ' 22 Rough Fish Carp Cyprinus carpio (Linnaeus) 8 Gizzard shad 3 Dorosoma cepedianum (LeSueur) __2 - 10 ---—‘--&---—n-n--u--- -wfi___-m_mu-c--___-|_mz___—m._-___—__c—m_umumm_m__l —__-_-¢-_—ww 795