TPWD 1970 F-6-R-17 #1360: Fisheries Investigations - Region 5-3, Job No. III Trotline Study: Job Progress Report, Lake Corpus Christi

JOB PROGRESS REPORT 'é?2?ZZ;gf As required by FEDERAL AID IN FISHERIES RESTORATION ACT- TEXAS Federal Aid Project No. F—6-R-l7 FISHERIES INVESTIGATIONS ~ REGION 5—3 Job No. III Trotline Study Project Leader: Roger L. McCabe J. R. Singleton Executive Director Parks and Wildlife Department Austin, Texas Marion Toole Eugene A. Walker D-J Coordinator Director, Wildlife Services September 15, 1970 SUMMARY Although trotline fishing is a widespread and p0pular sport, there is little published information available upon which to base recommendations for regulating and improving the quality of this fishing method. During the sec- ond job segment, actual experimental trotlining was initiated by project per- sonnel and conducted in conjunction with fisherman interviews-and experimental bait trapping. While certain trends in the data have developed concerning the experimental trotline study and the fisherman interviews, no conclusions should be formulated at this time due to the insufficient quantity of infor- mation. Bait trapping has continued to be highly selective toward the trap- ping of desired bait fishes. JOB PROGRESS REPORT State Texas Project No.: F—6-R-l7 Project Title: Fisheries Investigations Region 5-B Job No.: III Job Title: Trotline Study _ Period Covered: January 1, 1969 to December 31, 1969 Background: Although trotlining is a major form of sport and commercial fishing, the amount of available published data pertaining to freshwater is quite limited. Since trotline fishing could exert a definite influence on a given fishery, more information regarding the means and methods, yields, and effects of this form of fish harvesting is needed. This report covers the second year of a pr0posed four-year trotline study being conducted at Lake Corpus Christi, in South Texas. Lake Corpus Christi is a p0pular trotline fishing lake and offers a suitable area for studying the sport. Presently a hook interval regulation is the only law governing trot- line fishing on this lake. The first segment of the study entailed literature research, fisherman interviews, and experimental bait trapping. Publications dealing with the subject of trotlining are very limited, and difficulty in contacting trotline fishermen resulted in fewer interviews and less data than were anticipated. Short-term bait trapping exhibited a high degree of selectivity for trotline bait species. Objectives: To continue gathering trotline fishing information through the use of fisherman interviews at Lake Corpus Christi. To obtain data on actual trotline yields from Lake Corpus Christi by use of experimental trotlines. To determine the feasibility of trapping bait for use on trotlines. Procedures: Fisherman interviews were continued in order to procure information pertaining to the individuals doing trotline fishing, their methods and equipment, their preferred locations, and their baits and catches. Creel censusing was intended for the second segment of the study, but was curtailed due to the time element involved and to the difficulty in con- fronting trotline fishermen. This procedure may possibly be resumed in the forthcoming segment if the obstacles can be eliminated. Experimental trotlining by project personnel was initiated on Lake Corpus Christi in May and continued monthly throughout the remainder of the year except during August and OctOber. Lines of various construction were used at different locations in a variety of habitat types. Seven 105-foot trotlines were used-with the staging (drop or hook) lines ranging from 12 inches to 24 inches in_length and the distance between the staging lines being either 3, 4, or 4% feet. Eagle Claw, Kirby, O'Shaughnessy, and Limerick hooks were used in sizes varying from 2/0 to 8/0. Eleven dif— ferent baits were used in various combinations with the hook sizes (Table l). The method by which the trotlines were set consisted of tying one end of the line to an object at or above the water surface and sinking the other end, thus enabling the baits to be fished in depths ranging from 12 inches to the maximum depth fished, 30 feet. Experimental bait trapping was continued in conjunction with the experi- mental trotlining using traps designed specifically to catch live Rio Grande perch (Cichlasoma cyanoguttatum) and sunfish (Lepomis spp.). Clover leaf and V-mouth bait traps were used containing milo, cob corn, range-cubes, cotton- seed cubes, or cottonseed cake in various combinations. The traps were set in different locations on the lake, wherever the-habitat was thought to be opti- mum and checked periodically. ' Findings: Nineteen trotline fishermen were interviewed during the second job seg- ment. Due to the low number of interviews obtained, the data were not of sufficient quantity to form conclusions so they are presented in the form of broad ranges of low and high extremes. The fishermen interviewed had from one to eight trotlines in the water ranging from 36 to 2,400 feet in length. The main lines were usually con- structed of nylon and set in water depths varying from 5 to 50 feet. Fisher- men indicated no preference between midmlake and nearmshore fishing locations. Hook size varied from 2/0 to 9/0, and most fishermen interviewed pre- ferred from 20 to 30 hooks per line while some had anywhere from 11 to 250. Hooks were fished at depths ranging from the surface down to 35 feet. The lengths of the staging lines varied from 10 to 24 inches. Trotlines were left in the water for lengths of time varying from one day to an indefinite period. Preferred seasons, weather, and water conditions were similar to those considered Optimum by rod-andmreel fishermen seeking other types of sport fishes. o o umw umuuomm o o mmmn Lunoammnma o o amwmumo mumsumam n ma Swamumo spam 0 Ma Lmflmumo Hmmnmso Fels. Soap Fisherman's Bait Soap Rio Grande Sunfish mmmH uflmm kn Humwuno mnmuoo mxmq EH “mm mmnwauonH mo comma H mHan Table 2 Catch of Traps Set in Lake Corpus Christi Common Name Trotline Bait Fishes Bluegill Longear sunfish Rio Grande perch Redear sunfish Warmouth Redbreast sunfish Game Fishgg Channel catfish White bass Largemouth bass _.un--—--___w-_*—_-+-—_-m-v_m Rough Fishes Gizzard shad Total - -—Im=.-L'—€-nw-abW-x-w-I-I-—__——---—__*D*I—-___—----—---_-£---- Scientific Name Number Lepomis macrochirus Lepomis megalotis - Cichlasoma cyanoguttatum Lepomis microlthus Chaenobryttus gulosus Lepomis auritus |—'-_-I-J-I—_—D___--I*-*_-_——---_ m_--—--m“------—---—-mn- Ictalurus punctatus Roccus chrysops Misreptergg salmoides Dorosomg_cepedianum A total of 16 different bait types were used by those fishermen inter— viewed. The most popular bait for flathead catfish (Pylodictis olivaris) was Rio Grande perch (Cichlasoma cyanoguttatum), while shrimp was preferred for channel catfish (Ictalurus punctatus). P & G bar soap, sunfish (Lepomis spp.), blood bait, and shrimp were the preferred baits for blue catfish (I. furcatus). A total of 26 channel catfish, 22 blue catfish, and l flathead catfish was caught by the fishermen interviewed. The fishermen interviewed were males between 21 and 67 years of age, residents of the state, and employed in a variety of occupations. Experimental trotlining was initiated by project personnel during the second job segment to obtain data on actual yields and to test the materials and techniques involved. Although there are insufficient data to formulate conclusions, certain tendencies have begun to develop. Project personnel caught a total of 70 fishes in 2,065.5 hours (Table l). The most Species were caught on live sunfish (Lepomis spp.) while the most individuals were taken on Fisherman's Bait Soap. Channel catfish and blue catfish were caught on most of the baits while flathead catfish, largemouth bass (Micropterus salmoides) and spotted gar (Lepisosteus oculatus) were taken only on live sunfish. Fish were taken at depths varying from 1 to 8 feet while the hooks were fished at depths ranging from several inches below the surface to 30 feet. Although no correlation between the depths at which fish were caught and sea- sonal variation in weather conditions can be made at this time, an effort will be made to do so in future segments. The largest number of fish were caught on hook size 2/0 while more pounds of fishes were taken on two of the larger sizes, 6/0 and 8/0. Strangely, hook size 7/0 was the least effective. As expected, the trend thus far indicated that small hooks will catch more and smaller fish while large hooks will hook fewer but larger fish. The bait trapping portion of the study was conducted to determine if preliminary trends would continue to indicate that bait fish consisting primarily of sunfish and occasionally Rio Grande perch could be selectively trapped. Both the clover leaf and Vwmouth type traps and all baits used proved to be highly selective towards the trapping of bait fish. The traps were set a total of 1,118 hours. The catch of 415 fish consisted of 92.35 per cent bait fish (Table 2) and 2.65 per cent game fish. /: /\ Prepared by: Ben S. Watson __ Approved: ’ Asst. Project Leader Coordinator Date: _ September 15, 1970 E1 in M. C. Dietz Inland Supervisor 4.,