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F660
 88-9

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ABSTRACT				3
INTRODUCTION				4-9
	Physical Description of the Salton Sea			4
	History of the Salton Sea Fishery			6
	Present Salton Sea Fishery			7
	Salton Sea Sportfish Regulations			9
	Study Objectives			9
METHODS				10-11
RESULTS AND DISCUSSION				11-43
	Area of Angler Origin			11
	Angler Types			11
	Average Duration of Angler Day			14
	Species Composition of Catch by Angler Type			14
		Boat Anglers		14
		Jetty Anglers		17
		Shore Anglers		17
	Catch Rates by Angler Category and Species			20
		Boat Anglers		20
		Jetty Anglers		20
		Shore Anglers		24
	Use, Catch, Effort and Success by Month			25
	Catch Composition by Species and Area			25
		Orangemouth Corvina		25
		Tilapia		29
		Bairdiella		29
		Sargo		29
	Sportfish Lengths and weights			36
		Orangemouth Corvina		36
		Tilapia		36
		Bairdiella		40
		Sargo		40
	Angling Quality Relative to Other California Sportfisheries			40
SUMMARY AND CONCLUSIONS				43-45
MANAGEMENT RECOMMENDATIONS				46
ACKNOWLEDGEMENTS				46
REFERENCES				47-50

An angler creel census was conducted at the Salton Sea, California, from October 1982 through September 1983, to determine catch-per-unit-effort, catch composition by area, angler type (shore, jetty, or boat), size of fish caught and area of angler origin. Census clerks interviewed 19,053 anglers who fished 70,756 hours and caught 103,301 sportfish at an average catch rate of 1.46 fish per hour.

The Mozambique mouthbrooder, Tilapia mossambica, made up 41% of the total sportfish catch, followed by bairdiella (croaker), Bairdiella icistia, and sargo, Anisotremus davidsoni, at 28% each, and orangemouth corvina, Cynoscion xanthulus, at 3%. The Tilapia catch represents the first reported California sportfishery for this genus. The redbelly tilapia, Tilapia zillii, was not found during this census, even though it a occassionally been seen in angler and Department of Fish and Game gill net catches during the late 1970's. Mean angler catch rates in fish per hour were 0.60 for tilapia, 0.41 for bairdiella and sargo, and 0.04 for corvina. Angler effort was highest from February through June. In terms of catch per hour, the data show that the Salton Sea sportfishery is one of California's highest quality fisheries.

Angler origin has changed little since 1966-69. A total of 75% of Salton Sea anglers came from outside of Imperial and Riverside counties, with Los Angeles County contributing the largest percentage (37%). Length measurements together with size-at-sexual maturity information for corvina caught by sport anglers suggest that a significant portion were removed prior to sexual maturity. Similar data for tilapia, bairdiella, and sargo do not indicate premature exploitation.
________________

^1/ Inland Fisheries Administrative Report No. 88-9. Edited by Arthur C. Knutson, Jr., Inland Fisheries Division, Sacramento.

^2/ Associate Fishery Biologist, Inland Fisheries, Region 5, 15378 Bird Farm Road, Chino, CA 91710.

The Salton Sea, located in the southeastern Riverside and Imperial counties, is California's largest inland water (Figure 1). It is 58 km long and 14 km to 22 km wide, encompassing approximately 930 km² of surface area and having 153 km of shoreline. The Sea lies in a desert basin (Salton Sink), which is 83 m below sea level and receives only 5 cm of rainfall per year (Hely et al. 1966). Information on the geologic and hydrologic history of the Salton Sink and its relationship to the Colorado River can be found in Hely et al. (1966) and Walker (1961).

The Sea's water surface elevation is maintained indirectly by the Colorado River through the transportation of water through the All American and Coachella canals for irrigation in the Coachella and Imperial valleys (Figure 1). Agricultural wastewater, which contains high salt concentrations, is collected and carried by gravity flow through an extensive drainage network which empties either directly into the Sea or into one of three major tributaries (Alamo, New, and Whitewater rivers) which in turn flow directly into the Sea (Figure 1). The U.S. Bureau of Reclamation (1981) estimates that the average annual precipitation at the Sea contributes 4.3 X 10⁷ m³ of water, or 2.5% of the total annual inflow, while agricultural wastewater accounts for 1.73 X 10⁹ m³ or 97.5% of the annual inflow. There is no outlet for water to leave the Sea other than through evaporation.

Since water may leave the Sea only by evaporation, salts accumulate rapidly. A 1966 hydrologic report (Hely et al. 1966) estimates that 4 million tons of minerals, predominantly sodium and chloride, flow into the Sea annually as a result of minerals that are leached from agricultural lands. At the time of the Sea's formation (1905-07), the salinity was approximately 4 parts per thousand (ppt) of total dissolved solids (TDS), but by 1936 it had risen to 43 ppt TDS due to increased agricultural use of surrounding desert lands (Hely et al. 1966). Due to varying amounts of agricultural drainage water entering the Sea and rainfall in the basin, the Sea's mineral content has fluctuated between 32 and 41 ppt TDS since 1942 (Black l983a). At present, the Sea's salinity is approximately 41 ppt TDS.

The water elevation and depth also have undergone wide fluctuations since the Sea's formation. In 1908, the elevation was approximately 60 m below sea level and the maximum depth 24 m (Hely et al. 1966). By 1925, the elevation had dropped to 76 m below sea level and the maximum depth to 9 m. Between 1948 and the present, the Sea's elevation has risen from 73 m below sea level to 69 m and the maximum depth increased from 11 m to 16 m. Elevation fluctuations have caused numerous flooding problems for adjacent landowners.

 

FIGURE 1. The Salton Sea and the areas sampled during 1982-83.

Several physical parameters contribute to the highly eutrophic nature of the Sea. The mean depth is only 8 m and the maximum depth is approximately 16 m. Walker (1961) reported that daily surface water temperatures range from a minimum of 10°C in the winter to a maximum of 36°C in the summer. An overabundance of mineral nutrients, primarily compounds of nitrogen and phosphorous, produce intense algal blooms (U.S. Dept. Interior Fed. Water Qual. Admin. 1970). The subsequent death and decomposition of large numbers of phytoplankton often cause temporary anoxic conditions in localized areas, especially waters deeper than 9 m (Walker 1961). When these conditions exist together with high winds that commonly occur at the Sea, the entire water column sometimes becomes anoxic and fish present in these areas often suffocate (U.S. Dept. Interior Fed. Water Qual. Admin. 1970). These fish kills occur with varying severity throughout the year and become public nuisances.

The earliest report of fish in the Sea was by Evermann (1916), who listed five freshwater Colorado River species: (i) carp, Cyprinus carpio; (ii) bonytail, Gila robusta; (iii) Razorback sucker, Xyrauchen texanus; (iv) rainbow trout, Salmo gairdneri, and (v) striped mullet, Mugil cephalus. Carp and mullet were reportedly the most an , no mention was made of any sportfishery by early authors (Evermann 1916; Thompson and Bryant 1920; Coleman 1929). By 1942, the salinity of the Sea had become 32 ppt TDS and all of the above-mentioned fish had disappeared from the Sea with the exception of mullet and carp (Dill and Woodhull 1942). They made the first mention of a sportfishery, saying that "there had been but little angling" since the close of the commercial mullet fishery in 1921. This statement probably refers to a mullet sportfishery since these authors reported that carp, catfish, and a few sunfish were present only at the mouths of the New and Alamo rivers. However, a commercial mullet fishery existed at the Sea from 1915-21 and 1943-53 (Walker 1961). The first mullet sportfishery was described by Walker (1961) as a fall and early winter snag fishery around the freshwater inlets.

As early as 1929, the California Department of Fish and Game (CDFG) introduced striped bass, Morone saxitilis, into the Sea but was unsuccessful in establishing a sportfishery (Anon. 1930). A total of 36 fish species were stocked by the CDFG between 1929 and 1956, 32 of which were collected at San Felipe, Baja California and planted in the Sea during the 1950-56 period (Walker 1961). This approach resulted in the establishment of three species which make up a major portion of the self-sustaining sportfishery that currently exists. They are the orangemouth corvina, Cynoscion xanthulus; sargo, Anisotremus davidsoni; and Bairdiella (croaker), Bairdiella icistia (Walker l961).

The CDFG attempted to document the early sportfishery in 1958, 1963-67, and 1969 Hulquist (1981). However, the effort expended was inadequate to estimate angler use and catch.

Partyboat catch logs for the 1962-72 period were examined by Black (1974) and he demonstrated that orangemouth corvina were the primary and almost exclusive species caught. The partyboat bairdiella catch was reported only when it was used as bait for catching corvina or when fishing for corvina was poor (Black 1974). Sargo was also reported only when corvina fishing was poor.

By the mid 1970's, occasional creel census' showed that a substrate-breeding cichlid, the redbelly tilapia, Tilipia Zillii, was present in the Sea. The origin of the redbelly, Tilipia Zillii was from CDFG-approved stockings into irrigation canals and drains by local water districts to control aquatic plant growth that impeded water flow to agricultural lands and drainage to the Sea (Pelzman 1973).

In 1979, it became apparent that another cichlid had established a breeding population in the Sea and also was providing a sportfishery. This fish is a maternal mouthbrooder whose identity has only recently been resolved through electrophoretic analysis and comparison with tilapia of known origin and identity. This tilapia is the mozambique mouthbrooder, Tilipia mossambica (W. Courtenay, Professor of Zoology, Florida Atlantic Uni., pers. commun. 1985). Its probable origin is from CDFG-approved stockings for, aquatic plant control in irrigation systems (canals and drains) of the Imperial, Palo Verde, and Bard valleys of California in the mid to late 1960's (St. Amant 1966; Hoover and St. Amant 1970) and in Yuma, Arizona in 1963 (Barrett 1983). A California sportfishery for both tilapia species has not been previously reported.

The desert pupfish, Cyprinodon macularius, is the only fish endemic to the Salton Sink -- all others are the result of introductions (Table 1). Several of these introduced species have nearly caused the extinction of the desert pupfish due to predation, competition for available habitat, and interference with spawning behavior (Black 1980; Matsui 1981; Schoenherr 1979). Known habitat for the desert pupfish includes desert springs within the Colorado River drainage (Miller 1943) and shoreline poo1s adjacent to the Salton Sea (Barlow 1958). The desert pupfish has been extirpated from nearly all of its former range within California, with the exception of San Felipe Creek, Salt Creek, and several irrigation drains and shoreline pools tributary to or part of the Salton Sea (Black 1980; G. Black and K. Nicol, Cal. Fish and Game, unpub. manus., 1987). The precarious status of this fish's prolonged existence is such that the State of California has listed it as an endangered species in order to provide protection (Calif. Fish & Game Comm. and Dept. of Fish and Game 1980). The pupfish was designated an endangered species by the U.S. Fish and Wildlife Service in 1986. (Federal Register 1986).

Walker (1961) reported on the probable origin of several nongame species introductions into the Salton Sea, including the threadfin shad, Dorosoma petenense, the longjaw mudsucker, Gillichthys mirabilis, and mosquitofish, Gambusia affinis affinis (Table 1).Another species, the sailfin molly, Poecilia latapinna became established in several irrigation drains in the mid-1950's as escapees from local tropical fish hatcheries (St.Amant, Associate Fishery Biologist,CDFG, pers. commun.1984). The sailfin molly has since expanded its range to include the Salton Sea (Moyle 1976). All four of these introduced nongame species are found in the nearshore waters with the latter three also present in the shoreline pools. The common carp is included in Table 1 because although it does not inhabit the main body of the Sea, I have found it regularly in gill nets set within the brackish waters of the New and Alamo river deltas. There is no known sportfishery for carp in the Sea, so I consider it to be a nongame species.

TABLE 1. Present Salton Sea Fish Fauna
Game fishes
Scientific name	Common name
Cynoscion xanthulus (Jordan & Gilbert)	Orangemouth corvina
Anisotremus davidsoni (Steindachner)	Sargo
Bairdiella icistia (Jordan & Gilbert)	Bairdiella/Croaker
Tilapia mossambica (Peters)	Mozambique mouthbrooder
Tilapia zillii (Cervais)	Redbelly tilapia
Nongame fishes
Cyprinodon macularius (Baird & Girard)	Desert pupfish
Gillichthys mirabilis (Cooper)	Longjaw mudsucker
Gambusia affinis affinis (Baird & Girard)	Mosquitofish
Dorosoma petenense (Gunther)	Threadfin shad
Poecilia latapinna (Le Sueur)	Sailfin molly
Cyprinus carpio Linnaeus	Common carp

The five introduced game fishes are listed in Table 1. The striped mullet was considered by Walker (1961) to be virtually extinct in 1961, and monthly Department gill-netting surveys from 1979-81 support the contention that this species is no longer present in the Sea. These surveys also demonstrated that the redbelly tilapia had extremely limited distribution within the Sea and that the Mozambique mouthbrooding tilapia was abundant throughout the Sea year-round and spawned in the nearshore waters.

Walker (1961) recommended "high rates of harvest" and no season closures for the three sport fish species present at that time. That management philosophy towards the Sea's sportfishery persists today. The only regulation on fish take is a bag limit of nine for orangemouth corvina.

This paper presents information on relative angler use, catch rates, species and size composition of the catch, and related characteristics of the sportfishery. The study was not designed to estimate total cach, effort or angler use for the entire Salton Sea. It is hoped that future work will be undertaken to make these quantitative estimates to fully demonstrate the value of this sportfishery. This information is necessary in order to provide information regarding economic worth of the fishery in relation to other economic values in the region. Specific objectives of this study were to: 

(1) assess angling quality for each sportfish species expressed as catch per unit of effort (CPUE);
(2) determine the size (length) at which these fish were recruited into the sportfishery;
(3) establish baseline fishery data for existing conditions; and
(4) determine whether angler county of origin has changed since the l960's.

The Sea has eight marinas with boat launching facilities, several fishing jetties, and numerous access points along its shoreline for shore fishing or launching car-top boats (Figure 1). Due to the large number of angler access points and inadequate funding for creel census clerks, it was decided that the roving creel census (Von Geldern and Tomlinson 1973) was the most appropriate method to realize the study objectives.

All areas could not be sampled adequately due to the travel time required to drive around (3 hours) or circumnavigate (5 hours) the Sea by boat. Weekend creel census efforts during the period 1963-69 (Hulquist 1981) showed that anglers fishing from North Shore Marina to Red Hill Marina represented all areas and could be adequately censused by two creel clerks. Therefore, eight sampling sites were chosen within this area for the census; all are located on the eastern side of the Sea. These areas included four marinas and three fishing jetties; from north to south, they were North Shore Marina, Salton Sea State Park Headquarters, Mecca Beach, Corvina Beach, Salt Creek, Bombay Beach, Niland Marina, and Red Hill Marina. All of the eight sampling locations provided fishing for shore anglers and all but one (Mecca Beach) allowed at least car&emdash;top boat access.

Sampling days were randomly chosen based on the ratio of weekend days and holidays to weekdays for each month. Four major holidays were excluded - - Christmas, New Years, Easter, and Thanksgiving. Sixteen sampling days were selected each month during the 12-month census (October 1982 through September 1983). Sampling days began approximately 0800 h and continued until 1700-1800 h during the late fall, winter, and early spring. Due to the extremely warm mid-day air temperatures in the late spring, summer, and early fall that reduced angling pressure, census days were divided into an early morning census from 0700 h until approximately 1200 h and a late afternoon census from about 1700 h to 2000 h. If the weather (wind or rain) did not permit censusing, then the missed sample day was replaced by another similar day (weekend day/holiday or weekday) during the same month. However, if the missed sample occurred near the end of the month, the sample was not always replaced. Night censusing was not done because local anglers indicated that little fishing effort occurred then.

Census clerks interviewed all anglers encountered. One clerk interviewed anglers in the four northern areas and the other clerk in the four southern areas on the same day. Clerks drove to the census locations and walked the shoreline or jetty. Each location was generally censused in the morning and again in the afternoon.

For each angler interviewed, the following information was recorded: (i) date; (ii) location; (iii) angler type (shore, jetty, boat); (iv) number of each fish species kept; (v) angler's sex; (vi) area of origin; (vii) angler's beginning fishing time; (viii) time of interview; (ix) whether the angler had completed fishing for the day, and (x) the number of anglers in the group. In addition, the total lengths (TL) of each orangemouth corvina, bairdiella, and tilapia and fork lengths (TL) of each sargo were recorded in millimeters (mm). Since anglers could be encountered more than once during a sampling day, each angler or angling party already censused that day who had not completed fishing was given a numbered identification card for subsequent interviews. For the same reason, each fish measured was given a caudal fin clip.

During the 1982-83 creel census, 75% of the almost 19,000 anglers interviewed lived outside of Riverside and Imperial counties (Table 2), which is an insignificant change in the past 15 years. Creel census interviews of approximately 12,500 Salton Sea anglers for 26 weekend days during the 1966-69 period showed that 78% of the anglers had permanent residences outside of Riverside and Imperial counties (Hulquist 1981). Hulquist (1981) reported that Los Angeles County anglers contributed the largest percentage of use (39%); followed by San Bernardino (15%), San Diego (14%), Riverside (12%), Imperial (10%), Orange (8%), other California counties (1%), and out of state (1%). Information from the 1982-83 census (Table 2) shows that there have not been any major changes in angler origin at the Sea since 1966-69. Increased percentage use was detected for California anglers residing further away than the six southern counties within a 2 to 3 hour drive of the Sea; 8% of the 1982-83 anglers were from these other California counties as compared to only 1% during 1966-69 (Hulquist 1981). The monthly percentage of total angler use by residents of the six southern counties is quite variable. For example, Los Angeles County residents contributed 29% of the total use in December of 1982 as compared to 55% in September of 1983.

Angler Types

All of the three angler types caught all four sportfish available in the Sea. Of the 19,053 anglers interviewed, 10,993, or 58%, were shore anglers (Figure 2). Shore angler use was the highest in April (1,729) and the lowest in August (406). Jetty anglers numbered 4,748, or 25% of the total. The most use occurred in February (656 anglers), while theleast use occurred in August (92 anglers). The 3,312 boat anglers made up 17% of the total anglers interviewed. This percentage is probably an underestimate of relative boat angler use because the roving land clerk had less chance of encountering a boat angler than the more stationary shore and jetty anglers. Creel clerks censused the most boat anglers in November (647) and April 1983 (640), and the least in July 1983 (26). Relative use by all angler groups is greatest during the fall, late winter, and early spring months (Figure 2), probably because of favorable climatic conditions rather than fishing quality.

TABLE 2. Area of Origin for Anglers Using the Salton Sea Creel Census - October 1982 through September 1983.
Area of Origin
	Los Angeles county		San Diego County		Riverside County		San Bernardino County		Imperial County
Months	No.	%	No.	%	No.	%	No.	%	No.	%
Oct.	977	44	259	12	361	16	275	12	105	5
Nov.	919	42	317	14	318	14	281	13	129	6
Dec.	315	29	136	13	196	18	132	12	84	8
Jan.	351	32	65	6	162	15	152	14	31	3
Feb.	590	31	203	11	308	16	173	9	132	7
Mar.	648	30	253	12	327	15	186	8	344	16
Apr.	862	33	434	16	430	16	333	13	218	8
May	681	37	236	13	292	16	241	13	111	6
June	578	40	149	10	262	18	161	11	140	10
July	371	38	104	11	282	29	99	10	94	10
Aug.	250	47	48	9	147	28	30	6	34	6
Sept.	502	55	56	6	184	20	75	8	50	5
Totals	7044	37	2260	12	3269	17	2138	16	1472	8

TABLE 2, cont. Area of Origin for Anglers Using the Salton Sea Creel Census - October 1982 through September 1983.
Area of Origin
	Orange County		Other Calif. counties		Out of state		Foreign country
Months	No.	%	No.	%	No.	%	No.	%	Totals
Oct.	67	3	106	5	55	2	0	0	2205
Nov.	92	4	75	3	45	2	14	<1	2190
Dec.	21	2	117	11	67	6	8	<1	1076
Jan.	26	2	246	22	59	5	3	<1	1095
Feb.	108	6	269	14	92	5	9	<1	1884
Mar.	68	3	267	12	75	3	11	<1	2179
Apr.	136	5	185	7	43	2	1	<1	2642
May	114	6	109	6	44	2	0	0	1828
June	62	4	75	5	8	<1	0	0	1435
July	15	2	16	2	0	0	0	0	981
Aug.	18	3	0	0	2	<1	0	0	529
Sept.	16	2	31	3	6	<1	0	0	920
Totals	743	4	1496	8	496	3	46	<1	*18,964

*This total differs from total number of anglers in Table 4 due to missing angler origin information for 89 anglers.

FIGURE 2. Number of boat, jetty, and shore anglers interviewed each month during Salton Sea creel census - October 1982 through September 1983.

Complete trip information was used to determine the average length of an angler day for each angler type (Table 3). Jetty anglers spent the most time fishing per day, an average of 5.0 h but the monthly averages were highly variable, from 2.4 to 6.7 h. Shore and boat anglers spent similiar time per completed fishing day, 4.2 h and 4.4 h, respectively, while monthly averages ranged between 3.1 h and 4.8 h, and between 2.8 h and 6.6 h, respectively.

Boat Anglers

Boat anglers caught 29,564 fish in 15,177 h of fishing, for a success rate of 1.95 fish per hour. Tilapia comprised 45% (13,263) of the total boat angler catch (Figure 3), 1/ and accounted for as much as 77% (November) and as little as 8% (March) of the total monthly catch. Peak tilapia catches occurred in October and November, when 2,624 and 6,857 fish were creeled, respectively. The lowest catches were recorded from July through September when less than 100 tilapia were caught each month, apparently because of decreased fishing pressure (Figure 2). Tilapia were the most numerous sportfish caught in 50% of the months sampled.

The second most numerous fish in the boat anglers' creel was sargo, which accounted for 8,683 fish and 29% of the overall catch (Figure 3). From December through April, sargo made up 35% to 57% of the monthly catch and for February, March, and April it was the most numerous of the four sportfish caught. The largest numbers of sargo were taken in October and November and February and March. Sargo were creeled in the lowest numbers from May through September when the fishing effort was the lowest (Figure 2).

The catch of bairdiella ranked third in the total catch by boat anglers -- 5,939 fish made up 20% of the total catch (Figure 3). The catch was very low during the months of November through January, when a total of only 231 bairdiella were creeled; bairdiella contributed to no more than 3% of the total sportfish catch in these months. Beginning in February and continuing through June there was an increasing catch, with the highest catches occurring in May (1,488 fish) and June (1,171 fish). During these two months, bairdiella comprised 58% and 59%, respectively, of the boat anglers' total sportfish catch.

The least abundant fish creeled by boat anglers was corvina, which numbered 1,679 and accounted for only 6% of the boat anglers' catch during the year (Figure 3). From October through January, corvina made up 1% or less of the total monthly catch of sportfish -- only 115 fish were sampled during this time period.

^1/ No redbelly tilapia were identified from the anglers catch during the census. It appears that they may no longer provide a sportfishery in the Sea. All subsequent references to tilapia in this report are for the T. mossambica, hereafter referred to as tilapia.

TABLE 3. Average Duration of Completed Angler Days by Angler Type and Month, 1982-83
Month	Angler Type	Days Fished		Total Hours Fished		Hours Fished Per Day
October	Shore	104		500		4.8
	Boat	240		1103		4.6
	Jetty	69		418		6.0
November	Shore	86		281		3.3
	Boat	350		1584		4.5
	Jetty	34		152		4.5
December	Shore	22		97		4.4
	Boat	99		405		4.1
	Jetty	25		59		2.4
January	Shore	36		163		4.5
	Boat	53		147		2.8
	Jetty	26		126		4.8
February	Shore	65		202		3.1
	Boat	130		459		3.5
	Jetty	54		274		5.1
March	Shore	56		258		4.6
	Boat	383		1753		4.6
	Jetty	111		570		5.1
April	Shore	50		215		4.8
	Boat	299		1425		4.3
	Jetty	21		98		6.7
May	Shore	34		224		4.4
	Boat	68		302		6.6
	Jetty	9		30		3.4
June	Shore	0
	Boat	12		60		5.0
	Jetty	0
July	No information recorded
August	No information recorded
September	Shore	43		120		3.2
	Boat	18		58		2.8
	Jetty	54		308		5.7
Totals	Shore	496		2062		4.2
	Boat	1652		7297		4.4
	Jetty	403		2036		5.0

FIGURE 3. Species composition (percent and numbers) of sportfish caught by boat anglers each month during Salton Sea creel census -- October through September 1983.

Boat anglers caught the most corvina in March (541) and April (518) when this fish comprised 20% of the catch each month. Only 79 corvina were censused from the boat anglers' creel during July through September, probably due to very low fishing pressure (Figure 2).

Jetty Anglers

Jetty anglers caught 36,014 fish in 18,156 h of angling, for an average success rate of 1.98 fish per hour. The most numerous fish caught by jetty anglers was sargo; 13,336 sargo comprised 37% of the sportfish kept by this angler group (Figure 4). Sargo ranked as the most abundant sportfish caught by jetty anglers during 50% of the months censused. They caught 1,000 or more sargo in seven of the 12 months; the highest catches were in February (2,075 fish), June (2,035 fish), and July (1,805 fish). The percentage of sargo in the monthly catch ranged from 16% (March) to 81% (November). The sargo catch by jetty anglers was more consistent throughout the year than that by boat anglers.

Bairdiella was the second most abundant fish caught by jetty anglers; 11,455 bairdiella contributed 32% of the total catch (Figure 4). Bairdiella totals were highest in March (2,809 fish), June (2,920 fish), and July. (2,063 fish) and were the most numerous sportfish in their catch during March and May. This fish made up 71% of the monthly catch in May. Only 45 (<3%) were censused from November through January. The low bairdiella catch during these months was also evident in the boat anglers' catch.

Tilapia ranked third in the jetty anglers' catch; 10,521 tilapia comprised 29% of the catch (Figure 4). Tilapia were the most abundant sportfish in the jetty anglers' catch during four of the months sampled (December, June, July and August); more than 1,000 tilapia were caught in December (1,839), June (2,953), and July (2,186). They made up as much as 63% (December) and as little as 5% (February) of the monthly catch. Except for January through April when tilapia catches were consistently low, the tilapia catches by jetty anglers were sporadic.

As for the boat sportfish catch, corvina were the least numerous fish taken by jetty anglers; the 702 corvina sampled represented only 2% of the censused sportfish catch by jetty anglers (Figure 4). Corvina comprised 1% or less of the sportfish catch for 9 of the 12 months sampled. The highest catches were recorded in June (301) and July (332).

Shore Anglers

Shore angler interviews revealed that they creeled 37,723 fish in 37,423 h of fishing for an average annual success rate of 1.01 fish per hour. A total of 18,300 tilapia comprised 49% of the catch (Figure 5). They were the most numerous sportfish in the shore anglers' catch in all but 3 of the 12 months sampled (March, April, and July) and made up 50% or more of the catch in half of the months censused. The lowest tilapia catches occurred from November through April -- this was also evident for jetty catches. The highest tilapia catches occurred from May through September, somewhat similar to jetty angler catches.

FIGURE 4. Species composition (percent and numbers) of sportfish caught by jetty anglers each month during Salton Sea creel census -- October 1982 through September 1983.

FIGURE 5. Species composition (percent and numbers) of sportfish caught by shore anglers each month during Salton Sea creel census -- October 1982 through September 1983.

Bairdiella ranked second in the shore anglers' catch, accounting for 11,640, or 31%, of the total catch (Figure 5). Shore anglers caught the most bairdiella from April through August, when 89% of the total annual catch was made; conversely, October through March accounted for only 11%. Similar high and low bairdiella catches were also exhibited in some of the monthly catches by boat and jetty anglers.

The third most numerous fish in the shore anglers' catch was sargo; 7,202 sargo comprised 19% of the total catch (Figure 5). Approximately 52% were caught during June and July. This is contrary to the boat and jetty anglers' peak catches during December through April.

As in the case of boat and jetty anglers, corvina were the least numerous fish creeled by shore anglers, accounting for only 1% (581 fish) of the catch sampled during the year (Figure 5). A total of 86% were caught during June and July, which were the same months when jetty anglers caught the most corvina.

Catch Rates by Angler Category and Species

Boat Anglers

For boat anglers, the catch rate was highest for tilapia, at 0.88 fish per hour over the 12 month period (Figure 6). This success rate was the highest reported by any of the three angler groups for any of the four sportfish caught in the Sea (Figures 6-8). Monthly catch rates for tilapia by boat anglers fluctuated widely; they ranged from a low of 0.08 fish per hour (March) to a high of 2.28 fish per hour (November).

The sargo catch rate was 0.58 per angler hour during the 12 month period (Figure 6). Monthly boat angler success rates ranged from 0.08 fish per hour (July) to 1.08 fish per hour (January), with the greatest success achieved during October through February.

Boat anglers averaged 0.39 bairdiella per hour during the census, with success rates ranging from 0.01 fish per hour (January) to 1.42 fish per hour (June) (Figure 6). Overall, boat anglers had more success catching bairdiella during the late spring and summer than during the winter and early spring.

Corvina were caught at an annual rate of only 0.10 fish per hour (Figure 6). However, boat anglers were more successful than jetty and shore anglers in catching corvina (Fi~gures 6-8). Monthly success rates ranged from 0.001 fish per hour (December) to 0.26 fish per hour (June); boat anglers were most successful during March through September.

Jetty Anglers

Jetty anglers were most successful at catching sargo, with an average catch per angler hour of 0.73 fish for the entire year (Figure 7). Monthly success rates ranged from 0.25 (May) to 1.41 (July). Overall, jetty anglers were more successful in catching sargo than either boat or shore anglers (Figures 6-8). The highest success rates were attained in January-February and June-July (Figure 7).

FIGURE 6. Boat angler catch per hour for Salton Sea sportfish during 1982-83 creel census.

FIGURE 7. Jetty angler catch per flour tor Salton Sea sportfish during 1982-83 creel census.

FIGURE 8. Shore angler catch per hour for Salton Sea sportfish during 1982-83 creel census.

Jetty anglers caught bairdiella at an average annual rate of 0.64 fish per angler hour (Figure 7), which was the highest bairdiella catch rate for any of the three angler categories (Figures 6-8). Jetty angler success rates for bairdiella fluctuated widely, ranging from less than 0.02 fish per hour (November-January) to 1.69 fish per hour (June). The highest monthly catch rates for bairdiella were in March and May through August. Boat anglers had the highest success in the capture of bairdiella during November, May, June, and August.

Tilapia ranked third in jetty angler catch success with an average annual catch rate of 0.54 fish per hour (Figure 7). Catch rates for tilapia varied widely, from 0.08 (February) to 1.72 (June) fish per hour and were highest in December and June through August. Of the three angler types, jetty anglers were least successful in catching tilapia.

Jetty anglers were least successful in catching corvina, averaging only 0.04 corvina per hour for the entire year (Figure 7). This rate of success ranked between that achieved by boat (0.10) and shore (0.01) anglers (Figures 6-8). Success rates varied from no success (December and January) to 0.26 corvina per angler hour (July). The highest catch rates occurred during June through August.

Shore Anglers

Of the four sportfish, tilapia were caught with the highest degree of success by shore anglers, at an annual rate of 0.58 tilapia per angler hour. Monthly rates ranged from 0.08 (April) to 1.31 (June) fish per hour (Figure 8). Success rates were highest in January, and June through September and are similar to jetty angler success rates (Figure 7).

Shore anglers were not as accomplished in catching bairdiella as boat and jetty anglers --they were caught at 0.31 fish per hour (Figure 8). Monthly bairdiella catch rates varied from 0.001 (January) to 1.07 (July) fish per hour. The lowest catch rates were from October through January, which is fairly consistent with the lowest catch rates for boat and jetty anglers. June and July were the months of greatest shore angler success and is similar to the peak months for boat and jetty anglers.

Sargo ranked third in average annual catch rate for shore anglers at 0.18 fish per hour (Figure 8), and was the lowest sargo catch rate for any of the three angler types. Catch rates fluctuated very little for the eight months from October 1982 through May 1983, when rates ranged from 0.04 to 0.16 sargo per hour. Shore angler catch rates were relatively constant compared to rates by boat and jetty anglers. Success rates were highest from June through August, as was the case for jetty anglers (Figures 6 and 7).

Shore anglers were the least successful of the three angler types in catching corvina at only was 0.01 fish per hour (Figure 8). Monthly rates varied from no success (January) to 0.09 corvina per hour in July. As for jetty anglers, the highest shore angler catch rates were in June and July (Figure 7).

Census clerks interviewed 19,053 anglers who fished 70,756 hours and caught 103,301 sportfish for an annual catch rate of 1.46 fish per angler hour (Table 4). sampling was conducted on 190 days, of which 133 were weekdays and 57 were weekends and holidays.

The majority of angling use (53%) and effort (54%) occurred from February through June (Table 4). A total of 45% of the angler use and 46% of the effort occurred during interviews conducted on weekends and holidays. More than half (56%) of the total catch was during June, July, October and November.

T. Mossambica made up 41% of the total catch by all anglers (Table 4). The months of June, July, October, and November were the best fishing months, with 64% of the tilapia caught then. Water temperatures as low as 120C caused a massive tilapia die-off during February and March of 1982 and probably was responsible for the extremely low catches (4%) during those months. Monthly tilapia catch rates ranged from 0.11 fish (March) to 1.16 (June) fish per hour; the annual catch rate was 0.60 fish per hour.

Bairdiella and sargo each made up 28% of the total sportfish catch (Table 4). A total of 80% of the bairdiella were caught during March through July, when bairdiella moved inshore to spawn (Walker 1961). The poorest catches (1%) occurred from November through January, when only 329 fish were censused.

Sargo catches showed no seasonal trend as was the case for bairdiella and tilapia. Highest catches were in February, June, July, and October; 14,841 sargo accounting for 51% of the catch. The fewest sargo were censused during May (852) and August (611) and together made up only 5% of the catch. Compared to the other sportfish, catch rates for sargo were relatively stable, fluctuating from 0.21 (May) to 0.72 (July) fish per angler hour.

The 2,962 corvina caught comprised only 3% of the total (Table 4). The highest catches of corvina occurred from March through July, when 87% were caught. Unusually high winds and rain probably reduced effort and resulted in meager catches in August and September. The high catch rates for these 2 months indicate that if the weather had been better, the effort and catches might have been substantially higher. Catch rates were highest from March through September, peaking in June (0.16) and July (0.17), and ranging from 0.04 to 0.17. The annual rate was 0.04 fish per hour. Black (1974) reported that partyboat anglers at the Sea from 1962-72 had most success from July through October each year. As with bairdiella, the increase in corvina take occurs during inshore spawning movement (CDFG, unpub. data).

Orangemouth Corvina

Monthly corvina catch rates showed no pattern with catch location (Table 5). Area 8 in the southern end of the Sea (Figure 1) had the highest angler success rate for corvina (0.085), while Areas 6 and 7, also in the southern part, had the lowest rates (0.012 and 0.006, respectively). Boat anglers accounted for 97% of the orangemouth corvina sampled at Area 8. In comparison, Area 2, the next best area for angler success in the catch of corvina, had only 36% of the corvina landed by boat anglers. Seventy-four percent of the total censused corvina catch came from Areas 2 and 8 (37% from each area).

TABLE 4. Summary of Salton Sea Angler Use, catch, and Effort by Month frau October 1982 through Septenter 1983.
Months	No. anglers	No. hrs. fished	No. fish	No. fish per angler hour	No. ORC 1/	ORC per angler hr.	No. TIL2/	TIL per angler hr.	No. BAR3/	BAR per angler hr.	No. SAR4/	SAR per Angler Hr.
Oct.	2,218	8286.75	11,492	1.39	81	0.01	5,973	0.81	2,063	0.32	3,375	0.53
Nov.	2,190	7827.25	11,017	1.41	59	0.01	7,754	0.86	261	0.03	2,943	0.43
Dec.	1,082	3717.75	5,124	1.38	8	0.002	3,214	0.86	52	0.02	1,850	0.51
Jan.	1,095	3658.00	4,916	1.34	1	0.0003	2,706	0.91	16	0.01	2,193	0.71
Feb.	1,884	6201.00	6,336	1.02	86	0.02	870	0.15	1,755	0.32	3,625	0.67
Mar.	2,180	7974.75	8,366	1.05	559	0.07	886	0.11	4,012	0.60	2, 909	0.40
Apr.	2,648	10082.75	5,436	0.54	537	0.06	1,559	0.23	1,556	0.15	1,784	0.26
May	1,846	7662.25	9,043	1.18	156	0.04	3,250	0.37	4,785	0.92	852	0.21
June	1,450	6394.00	21,430	3.35	735	0.16	8,368	1.16	8,000	1.38	4,327	0.68
July	1,000	3975.75	13,699	3.45	582	0.17	4,744	1.12	4,859	1.02	3,514	0.72
Aug.	536	1571.75	2,648	1.68	63	0.09	1,025	0.64	949	0.73	611	0.36
Sept.	924	3403.75	3,794	1.11	95	0.06	1,735	0.50	726	0.27	1,238	0.32
Total	19,053	70,756	103,301	1.46	2,962	0.04	42,084	0.60	29,034	0.41	29,221	0.41

^1/OCR = orangenouch corvina
^2/TIL = tilapia
^3/BAR = bairdiella
^4/SAR = sargo

TABLE 5. 1982-83 Orangemouth Corvina Catch and Catch Rates by Month and Area -- All Angler Categories
	Area 1				Area 2
Month	Sampled catch	Rank	Catch/hr	Rank	Sampled catch	Rank	Catch/hr	Rank
October	17	2	0.022	2	50	1	0.019	3
November	6	4	0.005	3	10	2	0.003	5
December	0	8	0	8	0	8	0	8
January	0	8	0	8	0	8	0	8
February	0	8	0	8	3	2	0.001	2
March	2	5	0.018	3	24	2	0.014	4
April	33	4	0.084	2	145	2	0.041	4
May	4	5	0.027	5	60	1	0.021	6
June	18	5	0.040	7	442	1	0.199	3
July	10	7	0.312	2	309	1	0.476	1
August	0	8	0	8	26	1	0.096	1
September	0	8	0	8	32	1	0.090	2
Totals	90	6	0.027	5	1101	1	0.049	2

TABLE 5. (cont.) 1982-83 Orangemouth Corvina Catch and Catch Rates by Month and Area -- All Angler Categories
	Area 3				Area 4
Month	Sampled catch	Rank	Catch/hr	Rank	Sampled catch	Rank	Catch/hr	Rank
October	0	8	0	8	3	4	0.017	4
November	0	8	0	8	1	6	0.001	6
December	0	8	0	8	0	8	0	8
January	0	8	0	8	0	8	0	8
February	0	8	0	8	0	8	0	8
March	0	8	0	8	4	4	0.013	5
April	1	6	0.037	5	47	3	0.174	1
May	0	8	0	8	14	4	0.152	2
June	15	6	0.075	6	125	2	0.078	5
July	9	8	0.057	4	182	2	0.259	3
August	0	8	0	8	2	5	0.005	3
September	8	4	0.038	4	31	2	0.024	6
Totals	33	7	0.034	4	409	3	0.039	3

TABLE 5. (cont.) 1982-83 Orangemouth Corvina Catch and Catch Rates by Month and Area -- All Angler Categories
	Area 5				Area 6
Month	Sampled catch	Rank	Catch/hr	Rank	Sampled catch	Rank	Catch/hr	Rank
October	7	3	0.030	8	1	1	<0.001	1
November	3	2	0.010	1	31	1	0.041	4
December	1	8	0.001	2	0	8	0	8
January	1	1	0.050	1	0	8	0	8
February	0	8	0	8	1	3	<0.001	3
March	5	3	0.030	2	2	5	0.006	6
April	4	5	0.008	6	0	8	0	8
May	0	8	0	8	28	3	0.150	3
June	54	4	0.110	4	2	8	0.020	5
July	22	3	0.039	7	22	3	0.043	5
August	4	4	0.037	3	5	3	0.032	4
September	5	5	0.031	5	1	7	0.007	7
Totals	106	4	0.013	6	93	5	0.012	7

TABLE 5. (cont.) 1982-83 Orangemouth Corvina Catch and Catch Rates by Month and Area -- All Angler Categories
	Area 7				Area 8
Month	Sampled catch	Rank	Catch/hr	Rank	Sampled catch	Rank	Catch/hr	Rank
October	0	8	0	8	3	4	0.003	5
November	0