Jarvisetal bsb movements_01_mar10
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Transcript of Jarvisetal bsb movements_01_mar10
SPAWNING-RELATED MOVEMENTS OF BARRED SAND BASS, PARALABRAX 1
NEBULIFER, IN SOUTHERN CALIFORNIA: INTERPRETATIONS FROM TWO DECADES 2
OF HISTORICAL TAG AND RECAPTURE DATA. 3
E.T. Jarvis, C. Linardich, and C.F. Valle. California Department of Fish and Game, Marine 4
Region, Los Alamitos, CA, 90720. 5
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Abstract 6
During the 1960s and 1990s, the California Department of Fish and Game tagged 8,634 7
barred sand bass in southern California. Tag and recapture data suggest migrant individuals reside 8
at spawning grounds for approximately one month. Although 64% of non-spawning season 9
recaptures occurred within 1 km of the spawning location, the average (± SD) recapture distance of 10
migrant fish was 13 ± 8 km. Fish size (TL) was weakly correlated with “migration” distance from 11
spawning locations (rs(57) = 0.31, p = 0.02). Spatial and temporal trends in recaptures suggest a 12
high degree of spawning and non-spawning season site fidelity. 13
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Introduction 14
Barred sand bass, Paralabrax nebulifer, continues to be one of the most sought-after sport fish 15
in southern California. In the early 1900s, barred sand bass were landed in both the commercial 16
and recreational fisheries; however, due to limited demand in the commercial fishery and scarcity 17
of the resource during the 1950s, commercial take was banned in 1953 and a 12 in (30.5 cm) 18
minimum size limit was implemented in 1959 (Collyer 1949; Young 1969). Since the 1960s, 19
barred sand bass have ranked among the top 10 sport fish caught by commercial passenger fishing 20
vessels (CPFVs = party boats) in southern California, with total annual catches averaging nearly 21
two million fish per year between 1980 and 2003* (Allen and Hovey 2001; PSMFC 2010a). 22
Although no commercial fishery currently exists for barred sand bass in California, “heavy annual 23
landings” of barred sand bass have been reported in the commercial fisheries of Baja California, 24
Mexico, and the Gulf of Mexico in recent years (Aburto-Oropeza et al. 2008). 25
In southern California, fishing effort for barred sand bass by both party and private boaters is 26
highest during peak spawning season (June to August). In recent years, approximately 77% of the 27
June, July, and August barred sand bass harvest was taken by party/charter boats (PSMFC 2010b). 28
Well-known spawning aggregation sites include the Ventura Flats, inner Santa Monica Bay, 29
Huntington Beach Flats, San Onofre, and Silver Strand in San Diego. According to California 30
Department of Fish and Game (CDFG) CPFV logbook data, Huntington Beach Flats ranks the 31
highest in numbers of barred sand bass caught in the past 40 years (CDFG unpublished data). 32
From 1961 to 2008, barred sand bass CPFV catch-per-unit-effort (CPUE = barred sand bass 33
kept/angler*hr) increased to a high in 2000, and has recently decreased to the lowest CPUE since 34
*Data reported were collected by the Marine Recreational Statistics Survey (MRFSS), which was replaced in 2004 by the California Recreational Fisheries Survey (CRFS). Catch estimates after 2003 were not included because data from these two surveys are not comparable.
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1985 (CDFG unpublished data), causing concern regarding the vulnerability of the population to 35
future harvest impacts. 36
Fish species that are targeted during their spawning aggregations are especially susceptible to 37
overexploitation because harvest effects may not be immediately evident (Sadovy and Domeier 38
2005). Furthermore, overexploitation of an aggregate spawner can result in the complete absence 39
of spawning aggregation formations at historic sites (Domeier and Colin 1997; Sadovy and 40
Domeier 2005). Consequences of this occurring in the barred sand bass fishery might include 41
negative ecological impacts, as well as severe economic impacts to the sport fishing industry in 42
southern California. 43
Barred sand bass is one of three temperate serranine fishes (sea basses), including kelp 44
bass, Paralabrax clathratus, and spotted sand bass, Paralabrax maculatofasciatus, that participate 45
to varying degrees in aggregate spawning behavior (Hovey and Allen 2000; Erisman and Allen 46
2006; Miller and Allen 2006). Barred sand bass breeding aggregations are reported to occur over 47
sand flats in depths of 20 to 40 m (Turner 1969; Feder et al. 1974; Love et al. 1996), and based on 48
the exceptionally high landings of barred sand bass during the summer, it is possible that these 49
aggregations consist of thousands of fish. However, underwater video documentation of these 50
aggregations has never been reported. Following peak spawning, considerably fewer barred sand 51
bass are caught over the sand flats and catches typically resume inshore in bays or near low relief 52
natural or artificial reefs, but not in such high numbers (Love et al. 1996). These catch trends may 53
suggest transient spawning aggregation behavior, in which large aggregations form at specific, 54
predictable locations at higher than average densities for a period of several weeks to months 55
(Domeier and Colin 1997). Transient spawning aggregations are characterized by having 56
individuals that migrate relatively longer distances to breed than “resident” aggregate spawners, 57
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but it is still unclear to what degree this may occur with barred sand bass. Knowledge of the 58
origins and destinations of barred sand bass spawning migrations, and understanding whether all or 59
some of the adult population participates in spawning aggregations will be important for effective 60
management of this species. 61
In the 1960s and 1990s, biologists with the California Department of Fish and Game (CDFG) 62
tagged nearly 9,000 barred sand bass in southern California. The recapture information from these 63
two time periods enables us to document the historical spawning-related movements of barred 64
sand bass for the first time. Specifically, our objectives of this study are to examine these 65
historical data for trends in 1) residency at spawning locations, 2) movement to and from spawning 66
locations, and 3) breeding site fidelity. 67
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Methods 69
Tagging Effort 70
During the 1960s and 1990s, barred sand bass were tagged along the coast of southern 71
California and at one location in Baja California, Mexico (Figure 1). Tagging locations included 72
sand flats, reefs, and bay habitat. During both tagging periods, fish were captured by hook-and-73
line, measured to the nearest mm total length (TL), externally tagged with spaghetti or T-bar tags, 74
and released. In the 1990s, fish were also captured by bottom trawl, and upon release, tagged fish 75
suffering from barotrauma were recompressed to depth using milk crates. Loran or GPS 76
coordinates of the tagging sites were recorded; otherwise, a site name or geographic landmark was 77
provided. In addition, depth (m) and release condition were recorded for some but not all fish. 78
Rewards for recaptures of tagged fish were offered during both tagging periods. Recapture 79
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information included date, location, TL (mm), and tag ID number. In the 1990s, recapture depth 80
(m) and Loran or GPS coordinates were also provided when available. 81
Analysis 82
All historical barred sand bass tag and recapture data were archived into a relational 83
database for analysis. To standardize tagging effort across the two tagging periods, locations for 84
all records were assigned a fishing site code based on historical southern California CPFV sport 85
fish surveys (Ally et al. 1990). Spawning season codes were also assigned to each tag and 86
recapture record based on capture month (Nov.–Mar. = non-spawning season, Apr.–May = early 87
spawning season, Jun.–Aug. = peak spawning season, Sept.–Oct. = late spawning season). Days at 88
liberty, recapture distance (estimated or actual km), and general direction of movement were 89
calculated and incorporated into the database. Recapture distances were measured as linear 90
distances between approximate or actual tagging and recapture locations. In this paper we report 91
recapture rates and return rates. Recapture rates refer to the number of fish recaptured at a given 92
site divided by the total number fish recaptures. Return rates refer to the number of fish recaptured 93
at a given site divided by the total number of fish tagged at that site. 94
Spawning season residency 95
To investigate the residence time of individuals at spawning locations, we selected fish 96
tagged at Huntington Beach Flats during peak spawning season and recaptured at Huntington 97
Beach Flats within the same year (peak spawning season through December). This location was 98
chosen because of the high return rate and due to the relatively high historical catch numbers of 99
barred sand bass. For each group of fish tagged in June, July, and August, we plotted the 100
cumulative number of tag returns over time (days at liberty), as well as the frequency of recaptures 101
over time. Each trend line was examined for the point in time after which the rate of tag returns 102
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decreased; this point was assumed to represent the minimum residence time. We also report the 103
locations and recapture distances of fish that were recaptured away from Huntington Beach Flats 104
during the same peak spawning season. 105
Movement to non-spawning season locations 106
Movement from peak spawning season tagging locations to non-spawning season recapture 107
locations was assumed to be movement from spawning grounds to non-spawning season 108
residences. To estimate the proximity of non-spawning season residences to spawning grounds, 109
we grouped non-spawning season recapture distances for fish tagged during peak spawning season 110
into 5 km bins. We then calculated the average non-spawning season recapture distances from 111
each tagging location to determine whether non-spawning season “migration” distances varied by 112
spawning location. Finally, we tested for a relationship between fish length (TL) and “migration” 113
distance to non-spawning season residences using a Spearman Rho rank test. 114
Movement to spawning locations 115
We examined peak spawning season recaptures of fish tagged in Newport Bay during the 116
non-spawning season to identify if and where Newport Bay residents migrate to spawn. Spawning 117
“migration” distances from Newport Bay to spawning grounds were reported and also tested for a 118
relationship with fish length (TL) using a Spearman Rho rank test. Lastly, we looked for seasonal 119
patterns in site fidelity to Newport Bay by creating a recapture plot of fish tagged in Newport Bay 120
(Nov.-May) for the years 1964 to 1973. 121
Spawning and non-spawning season site fidelity 122
To investigate annual site fidelity of barred sand bass to specific peak spawning season 123
tagging locations (i.e., presumed spawning grounds) we considered fish that were only tagged 124
during peak spawning season and recaptured during subsequent peak spawning seasons. We 125
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constructed a matrix of the number of fish recaptured by tagging location and recapture location, 126
with tag and recapture locations arranged from N to S. A higher number of recaptures that occur 127
along a series of corresponding tag/recapture locations within the matrix (i.e., where recapture 128
location = tag location) indicates a higher degree of spawning site fidelity than an arrangement of 129
non-corresponding tag/recapture locations or few corresponding tag/recapture locations within the 130
matrix. 131
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Results 133
Tagging Effort 134
From 1962 to 1976 barred sand bass were tagged from Santa Barbara to San Diego Bay (Table 135
1, Figure 2a). Most of this tagging effort occurred in the 1960s. Thirty-eight percent were tagged 136
at Huntington Beach Flats during peak spawning season (Jun.–Aug.), while 21% were tagged in 137
Newport Bay during the non-spawning season and early spawning season (Nov.–May). Tagging 138
at other locations primarily occurred during peak spawning season. Between 1989 and 1999, 139
barred sand bass were tagged from Santa Barbara to Baja California, including Santa Catalina 140
Island (Table 1, Figure 2b); 20 of these locations had also been visited in the 1960s. In the 1990s, 141
50% of fish were tagged at Huntington Beach Flats (32%) and Horseshoe Kelp, mostly during 142
peak spawning season. Most fish were captured by hook-and-line, while others were captured by 143
trawl (Table 1). Tagging effort (= average number of fish tagged per day and average number of 144
tagging months per year) was similar between the two tagging periods (Table 1), although in the 145
1990s, most of the tags were out within the first four years, versus six years in the 1960s. 146
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Demographics of tagged barred sand bass 147
Length frequency distributions of tagged fish were similar at locations with the highest 148
numbers of tagged fish (Manhattan Reef, Horseshoe Kelp, Huntington Beach Flats, and Newport 149
Bay, Figure 3). On average, fish tagged in the 1990s were larger than fish tagged in the 1960s 150
(Table 1), although this trend was likely influenced by the larger fish tagged in Ventura and 151
Mexico in the 1990s (Figure 3). The majority of fish tagged in Ventura were captured by trawl, 152
with no difference in capture depth between line-caught and trawl-caught barred sand bass (Table 153
1). There was a weak but significant positive linear relationship between capture depth and TL (r2 154
= 0.14, p = 0.001). 155
Most tagged fish were greater than the size at 100% maturity (~ 270 mm); however, the 156
proportion of legal sized (= 305 mm) barred sand bass was higher in the 1990s than the 1960s 157
(Table 1). In the 1990s, the proportion of tagged adults decreased from 88% in the non-spawning 158
season to 59% in the late spawning season; likewise, the proportion of tagged legal fish decreased 159
from 65% to 38%. This trend was also apparent for fish tagged in the 1960s, but was less 160
pronounced. 161
Recaptures 162
Despite similar tagging effort between the two tagging periods, recaptures were more 163
numerous in the 1960s than the 1990s (Table 1, Figure 4a,b). In the 1960s, locations with the 164
highest recapture rates were Huntington Beach Flats (29%) and Newport Bay (16%; Figure 4a). 165
Return rates at these locations were 13% (n = 231) and 22% (n = 224), respectively. In the 1990s, 166
Huntington Beach Flats again had the highest number of recaptures (49%; Figure 4b); however tag 167
returns at this site were relatively low (6%) compared to the 1960s. The 1990s had fewer long 168
term recaptures (> 90 days at liberty) than the 1960s, with the majority of recaptures (75%) 169
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occurring within just 63 days at liberty compared with 315 days in the 1960s (Figure 5). Although 170
the maximum days at liberty were similar between the two tagging periods (Table 1), there was a 171
significant difference in the average number of days at liberty between the 1960s and the 1990s 172
(student t-test, t = 7.156, p = 0.000; Table 1). Overall, the majority of recaptures occurred within 173
close proximity (< 10 km) to the site of tagging, although one recapture occurred 92 km S (Los 174
Alamitos to Oceanside). It is not clear how many recaptured fish were released versus how many 175
were kept. 176
Spawning season residency 177
We identified 117 Huntington Beach Flats same-year returns in the 1960s and 55 in the 178
1990s. The rate of returns for fish tagged during peak spawning season decreased after 179
approximately 34 days at liberty, regardless of tagging month (Figure 6). This period accounted 180
for 73, 93, and 80% of June-, July-, and August-tagged fish returns, respectively. Subsequently, 181
return rates of July-, and August-tagged fish both decreased by 88%. In contrast, the decrease in 182
the return rate for June-tagged fish was more gradual (40%). This gradual decrease was attributed 183
to a subsequent increase in the frequency of June-tagged fish returns that occurred between 46 and 184
55 days at liberty (Figure 6); these returns occurred during the month of August. The maximum 185
number of days at liberty was greatest for August- (119 days) and June-tagged fish (77 days), 186
compared to only 56 days for July-tagged fish. 187
Fifteen fish tagged at Huntington Beach Flats during peak spawning season were 188
recaptured at a different location during the same peak spawning season; recapture locations for 189
these migratory fish included Horseshoe Kelp (n = 9), Seal Beach (n = 1), Santa Ana River Jetty (n 190
= 3), Corona Del Mar (n = 1), and Dana Point (n = 1). Most of these migratory fish (13 of 15) 191
were tagged in July. 192
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Movement to non-spawning season locations 193
Non-spawning season recapture distances were variable among individuals, with some 194
suggesting resident behavior and others demonstrating migratory behavior. There were 59 barred 195
sand bass that were tagged during peak spawning season and recaptured during non-spawning 196
season (1960s, n = 50; 1990s, n = 9). The frequency distribution of recapture distances revealed 197
an interesting trend, with 64% of fish being recaptured within 1 km of the tagging site; the 198
remainder showed a normal distribution around 15 km (Figure 7). In the 1960s, the overall 199
average (±SD) non-spawning season recapture distance was 4 ± 7 km, but fish recaptured greater 200
than 1 km away from the tagging location had an average recapture distance of 13 ± 8 km. In the 201
1990s, eight of nine fish were recaptured greater than 1 km away from the tag site; the average 202
non-spawning season recapture distance was 19 ± 14 km. Fish size (TL) showed a weak, positive 203
correlation with non-spawning season “migration” distance (rs(57) = 0.31, p = 0.02). 204
Carlsbad and Huntington Beach Flats tag locations had the highest number of recaptures 205
occurring during non-spawning season, but fish tagged at Huntington Beach Flats showed higher 206
variability in recapture distances (Table 2). The farthest non-spawning season recapture distances 207
occurred between Ventura and Carbon Canyon (40 km S) and Tijuana, Mexico and La Jolla (35 208
km N). The farthest non-spawning season recapture location from Huntington Beach Flats was the 209
Palos Verdes Peninsula (29 km N). Most non-spawning season recapture locations were located 210
north of peak spawning season tagging locations (Table 2). 211
Movement to spawning locations 212
Fish tagged in a presumed non-spawning season residence (Newport Bay) during non-213
spawning season were primarily recaptured outside of Newport Bay during peak spawning season 214
(Table 4). We identified at least 15 different peak spawning season recapture sites that were 215
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typically located south of Newport Bay by an average (±SD) distance of 17 ± 15 km (Table 3). No 216
fish were tagged in Newport Bay during non-spawning season in the 1990s; however, a fish tagged 217
in San Diego Bay during non-spawning season was recaptured during peak spawning season off 218
the coast of San Onofre (75 km N). In contrast to the correlation results reported above, no 219
correlation was found between fish size (TL) and “migration” distance from Newport Bay to 220
spawning grounds (rs(71) = 0.23, p = 0.05). 221
Spawning and non-spawning season site fidelity 222
Several fish were tagged during peak spawning season and recaptured during subsequent 223
peak spawning seasons (1960s, n = 162; 1990s, n = 7). Eighty-nine percent of these recaptures 224
occurred after 1 yr at liberty, 8% after 2 yr, and 2% after 3 yr. Of the 169 recaptures, 80% 225
occurred back at the same tagging location. The average recapture distance (±SD) for the 20% 226
that were recaptured elsewhere was 18 ± 16 km. Overall, the recapture matrix plot identified a 227
high degree of breeding site fidelity as indicated by the arrangement of recaptures occurring along 228
corresponding tag/recapture locations (Figure 8). Tagging locations with the highest measure of 229
breeding site fidelity appeared to be Huntington Beach Flats, Ocean Park Venice, San Onofre 230
Power Plant, Carlsbad, and Twintrees; however, these return rates may be biased by differences in 231
fishing and tagging effort across sites. We also identified two fish that were twice recaptured in 232
subsequent peak spawning seasons at the same locations (Twintrees and Huntington Beach Flats, 233
Table 4). 234
Annual trends in Newport Bay recaptures revealed fish were still present and/or had left 235
and returned to Newport Bay during subsequent non-spawning and early spawning seasons (Figure 236
9). Two fish were twice recaptured at Newport Bay over subsequent non-spawning seasons (Table 237
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4). Fish recaptures outside of Newport Bay typically occurred during the middle of peak spawning 238
season through late spawning season (Figure 9). 239
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Discussion 241
Spawning season residency 242
The spawning residency of migrant barred sand bass at Huntington Beach Flats appears to 243
be approximately one month. This is within the reported spawning residency for other fishes (4 – 244
80 days; Robichaud et al. 2003; Bendal et al. 2005; Douglas et al. 2009). For some species, 245
spawning residency may vary by year and by sex, but we were unable to test this for barred sand 246
bass. Nevertheless, individual barred sand bass with shorter-term residency (e.g., up to one 247
month) likely represent migratory individuals, while fish demonstrating longer-term residency 248
(e.g., up to four months) likely represent fish whose home ranges are located within or near to 249
Huntington Beach Flats. Fish tagged in June or August (the beginning and end of peak spawning 250
season) demonstrated longer-term residency to the spawning grounds than fish tagged in July, 251
suggesting the peak in spawning migrations occurs in July. This timing is in agreement with the 252
month of highest catch numbers and fishing effort for barred sand bass in the southern California 253
CPFV fishery (CDFG unpublished data). Moreover, the majority of fish that were recaptured 254
away from Huntington Beach Flats during peak spawning season were tagged in July. Finally, the 255
expected peak in immigration/emigration rates and associated fishing pressure was apparent in the 256
frequency of June-tagged returns over time. For example, return rates of June-tagged fish 257
decreased after a month and then subsequently increased again before leveling off. We attribute 258
this initial decrease to a peak in immigration to the spawning grounds occurring some time in July, 259
while the subsequent increase and leveling off in return rates is likely associated with a peak in 260
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emigration from the spawning grounds, followed by an associated decrease in fishing pressure 261
there. 262
Due to the use of standard tag and recapture methods, we were unable to quantify diel site 263
fidelity at spawning locations. Barred sand bass individuals may use neighboring reefs to “rest” or 264
forage between spawning events or may travel to and from other nearby spawning locations during 265
this period. Actively tracked coral trout, Plectropomus leopardus, an aggregate spawning 266
Epinephelid (= Serranidae in part; Smith and Craig 2007), were shown to make multiple trips 267
between their home ranges and nearby spawning sites (< 1 km) during the spawning season (Zeller 268
1998). Zeller (1998) also reported that in some cases, visits to spawning grounds occurred 269
multiple times during the day or lasted from two to three days. Several large artificial reefs and 270
structures located near Huntington Beach Flats include Bolsa Chica Artificial Reef (2.7 km W), oil 271
platforms Eva (2.7 km NW), Emma (2.3 km NE), and Esther (6.7 km NW), and the Los Angeles 272
Federal Breakwater (11.8 km NW). Data collected by the California Seafloor Mapping Program 273
(CSMP) reveal patches of hard substrate (i.e., smaller patch reefs or structures) also exist within 274
the Huntington Beach Flats area (CSUMB 2009). Increases of barred sand bass densities during 275
peak spawning season have been observed on SCUBA at Platform Eva (Martin 2008) and the Los 276
Angeles Federal Breakwater (Froeschke et al. 2005). The degree to which these reefs/structures 277
may act as reproductive staging areas for migratory individuals, resting/foraging areas during peak 278
spawning season, or even distinct spawning areas, remains unknown. 279
Movement to and from spawning locations 280
Movement to and from spawning locations is perhaps one of the more interesting and yet 281
least known behaviors of barred sand bass. Our results further suggest that some barred sand bass 282
individuals migrate to spawn, while others are year-round residents. Mason (2008) demonstrated 283
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that a portion of acoustically monitored adult barred sand bass at Santa Catalina Island, CA, 284
exhibited year-round site fidelity to their home ranges, while others were not detected in these 285
areas during spawning season. This type of “polymorphic movement behavior” has been 286
described for other aggregate spawners including coral trout, Nassau grouper, Epinephelus 287
striatus, and snapper, Pagrus auratus (Colin 1992; Zeller 1998; Egli and Babcock 2004). 288
Not every fish migrated to the same location after spawning season. Likewise, barred sand 289
bass that shared a non-spawning season residence (Newport Bay) did not necessarily migrate to the 290
same spawning grounds. Zeller (1998) reported that coral trout with overlapping home ranges did 291
not necessarily make excursions to the same spawning grounds, regardless of spawning ground 292
proximity to home ranges. Spawning migration distance has been strongly linked to body 293
condition, size-at-age/maturity, and fishing pressure in Atlantic cod (Gadus morhua; Jørgensen et 294
al. 2008); fish that migrate longer distances are generally older, bigger fish with higher overall 295
fitness. Although a relationship between fish size (TL) and “migration” distance in this study was 296
inconclusive, we can not rule out bioenergetics as a possible explanation for the observed 297
variability in migration distances, as maturity and fitness were not determined for tagged fish. 298
Moreover, it is impossible to know for certain the accuracy of the reported fish tag and recapture 299
locations or if some fish were early or late spawners/migrators. These caveats, in addition to the 300
possibility that a portion of the adult barred sand bass population simply doesn’t spawn (i.e., 301
practices “skipped spawning”), may explain the variability in reported migration distances 302
(Jørgensen et al. 2005). 303
Spawning and non-spawning season site fidelity 304
Most fish tagged during peak spawning season were recaptured at the same location during 305
subsequent peak spawning seasons. Whether these individuals represent year-round residents or 306
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repeat migrants, barred sand bass appear to show a high degree of breeding site fidelity. 307
Historically, breeding site fidelity was studied extensively in salmonids, but less so in other fishes. 308
With the advent of more sophisticated tracking methods (e.g. electronic tags), breeding site fidelity 309
in fishes has been increasingly documented (Hunter et al. 2003; Block et al. 2005; Douglas et al. 310
2009). Tradition (or learned behavior) has been shown to play a primary role in spawning site 311
selection over annual reassessment of resources, especially if resources are relatively unchanging 312
from one year to the next (Warner 1988, 1990). Due to annual differences in tagging effort across 313
tagging locations, it was not possible to accurately quantify long-term inter-annual variability in 314
spawning site fidelity by tagging location. Recaptures that occurred at different locations in 315
subsequent years may reflect individual variability in the timing of spawning-related movements, 316
movement among aggregation sites, or a certain degree of annual reassessment. 317
We also identified individuals that demonstrated site fidelity to a non-spawning season 318
tagging location (Newport Bay). Bays are noted as habitat for young-of-the year (YOY) and 319
juvenile barred sand bass (Feder et al. 1974; Valle et al. 1999; Allen et al. 2002), while adults 320
prefer sand/rock ecotone habitat to 30 m depth (Feder et al. 1974; Johnson et al. 1990; Mason 321
2008). In San Diego Bay, YOY barred sand bass were shown to develop there throughout their 322
life history and adults utilized the bay habitat throughout the year (Pondella et al. 2006). In this 323
study, a fish that was tagged and recaptured during non-spawning season in Newport Bay may 324
represent a fish that remained there year-round or one that migrated to spawn and returned in the 325
winter. Our data indicate that a portion of adult barred sand bass in Newport Bay migrate to 326
locations outside of the bay during spawning season. This identifies Newport Bay as an important 327
non-spawning season residence for barred sand bass, as well as an important source of migrants to 328
various spawning locations outside of the bay. Although it is unknown for certain whether the 329
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migrant recaptures in this study would have returned to Newport Bay following peak spawning 330
season, the overall pattern in recaptures is highly suggestive. 331
Recapture rates 332
The most striking difference between the two tagging periods is the recapture rate: 17% in 333
the 1960s compared to 4% in the 1990s. A typical range of recapture rates using standard tag and 334
recapture methods is 3 to 10% (Lowe and Bray 2006). Given that tagging effort and numbers of 335
tagged fish did not dramatically differ between these two time periods, recapture rates may have 336
been influenced by changes in barred sand bass availability, in addition to advances in fishing 337
technology (e.g., fish finders, GPS), the willingness of fishers to report tag returns, and an 338
increased knowledge of spawning aggregation sites. In general, high recapture rates in open 339
systems reflect relatively lower population sizes due to the higher probability of encountering the 340
same fish at a later date. This may explain the higher number of long-term recaptures in the 1960s 341
dataset. CPFV barred sand bass catch values were nearly four times greater in the 1990s than in 342
the 1960s despite only a doubling of fishing effort (CDFG unpublished data). Historical Fish and 343
Game publications report that barred sand bass were scarce during the 1950s (a cold water period) 344
and occurred more frequently along the coast “in and subsequent to periods of warmer waters” 345
(Young 1969; Feder et al. 1974). Kelp bass and barred sand bass larvae densities were also lower 346
during the cool regime (1950s – 1970s) and higher in the warm regime (1980s – 1990s), especially 347
during the 1980s (Moser et al. 2001). While it appears that barred sand bass populations may have 348
increased in the 1990s relative to the 1960s, barred sand bass stock-recruitment relationships and 349
the effects on these relationships by natural and anthropogenic influences remain unknown. 350
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Management implications 351
Currently, a sustainable level of harvest for barred sand bass is unknown because no 352
biomass estimates exist. Due to concerns over barred sand bass catch declines in recent years and 353
the uncertainty in the status of the population, barred sand bass may require further fishery 354
protection beyond current minimum size limits and bag limits. Information gathered on the 355
spawning-related movements of barred sand bass may be useful for identifying further protection 356
measures. For instance, an aggregate spawner that demonstrates multiple spawning events over a 357
relatively long spawning residency period would likely benefit from a series of temporary fishing 358
closures during the peak in fishing effort. Non-spawning residences that are shown to supply 359
migrant spawners to spawning aggregation sites may be important sites to consider for seasonal 360
protection of barred sand bass. Further consideration of barred sand bass movement patterns and 361
life history traits, in addition to important feasibility concerns, may help to define additional 362
alternatives to protect barred sand bass until a harvest guideline can be developed. 363
364
Acknowledgements 365
CDFG lead investigators for the barred sand bass tagging studies in the 1960s and 1990s 366
were P. “Bud” Young and J.R. Raymond Ally, respectively. Over the two tagging periods, CDFG 367
tagging efforts were augmented by [and listed in no particular order] R. Izor (Izorline 368
International), Orange County Marine Institute, County Sanitation Districts of Orange County, Los 369
Angeles Rod and Reel Foundation, and many other individual volunteers. We thank L.G. Allen 370
and T. Mason for their critical review of the drafts of this manuscript. Funding was supported in 371
part by the Los Angeles County Fish and Game Commission and the Federal Aid in Sportfish 372
Restoration Act (also known as the Dingell-Johnson Act; Grant #F-50-R-20). 373
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Important Serranid Fishes from the Gulf of California: Ecology, Fisheries, and Conservation. 376
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24
Table 1. Tag and recapture summary statistics for barred sand bass tagged in southern California, 478
historical California Department of Fish and Game tagging project (1960s and 1990s). 479
Tag and recapture results 1960s 1990sTagged fish 4,687 3,947Tagging effort days 174 153 fish/day 27 ± 32 26 ± 58 Avg (±SD) (mo/yr) 4 ± 3 6 ± 3Capture method hook-and-line 100% 74% bottom trawl -- 26%Avg (±SD) capture depth (m) overall -- 15 ± 17 hook-and-line -- 22 ± 7 bottom trawl -- 25 ± 12Avg (±SD) TL (mm) 306 ± 38 337 ± 72 % mature 89% 93% % legal size 41% 70% Recaptures 801 171Return rate overall 17% 4% hook-and-line 17% 5% bottom trawl -- 3%Avg (±SD) recapture depth (m) -- 23 ± 9Avg (±SD) TL (mm) 326 ± 43 343 ± 46 % mature 96% 98% % legal size 68% 86%Days at liberty Avg (±SD) 200 ± 197 90 ± 187 Max 1,211 1,258Recapture distance (km) Avg (±SD) - All fish 6 ± 12 7 ± 9 Avg (±SD) - Only movers 18 ± 15 10 ± 9 Max 92 76
480
25
Table 2. Recapture distances (km) of barred sand bass tagged during peak spawning season 481
(Jun-Aug) and recaptured during non-spawning season (Nov-Mar), historical California 482
Department of Fish and Game tagging project (1960s and 1990s). Dir. = direction of recapture 483
location from tagging location. 484
485
26
Table. 3. Recapture distances (km) of barred sand bass tagged in Newport Bay during the non-486
spawning season (Nov-Mar) and recaptured during peak spawning season (Jun-Aug), historical 487
California Department of Fish and Game tagging project (1960s). Dir. = direction of recapture 488
location from tagging location. 489
490
Recapture distance (km)
Peak Spawning Season Recapture Location N Avg Stdev Dir.
Horseshoe Kelp 1 24.1 -- W
Huntington Beach Flats 13 17.6 2.2 W
Santa Ana River Jetty 3 8.0 0.0 W
Newport Harbor 19 0.5 1.5 --
Corona Del Mar 2 2.4 1.1 S
Crystal Cove 1 1.6 -- S
North Laguna Beach 3 10.2 1.9 S
South Laguna Beach 1 12.9 -- S
Salt Creek 2 18.5 1.1 S
Dana Point 6 20.4 1.3 S
Capistrano Beach 1 24.1 -- S
San Mateo Point 4 31.4 1.6 S
San Clemente 1 29.0 -- S
Middle Kelp 1 24.1 -- S
San Onofre Power Plant 5 32.8 0.9 S
Barn Kelp 8 42.8 1.5 S
Oceanside 1 51.5 -- S
27
Table 4. Tag and recapture dates and locations of barred sand bass recaptured on two separate occasions, historical California 491
Department of Fish and Game tagging project (1960s). 492
493
494
* Asterisks denote fish that were released in Newport Harbor following weigh-in at a fishing tournament.495
28
List of Figures 496
497
Figure 1. Map of barred sand bass tagging locations in southern California, historical California 498
Department of Fish and Game tagging project (1960s and 1990s). 499
500
Figure 2. Numbers of barred sand bass tagged by the California Department of Fish and Game 501
in southern California during the a) 1960s and b) 1990s. 502
503
Figure 3. Length-frequency distributions of barred sand bass by tagging location, historical 504
California Department of Fish and Game tagging project (1960s and 1990s). 1960s and 1990s 505
sites are represented by grey and white bars, respectively. Only locations where at least 100 506
tagged individuals are listed. The vertical lines represent minimum size of legal take (305 mm). 507
508
Figure 4. Numbers of tagged barred sand bass recaptured during the a) 1960s and b) 1990s, 509
historical California Department of Fish and Game tagging project (1960s and 1990s). 510
511
Figure 5. Numbers of barred sand bass recaptured by days since tagged for fish tagged in the a) 512
1960s and b) 1990s, historical California Department of Fish and Game tagging project (1960s 513
and 1990s). 514
515
Figure 6. Cumulative number of barred sand bass recaptures (dots) and frequency of recaptures 516
(bars) by days since tagged for fish tagged during each month of peak spawning season (June, 517
29
July, August) at Huntington Beach Flats, CA and recaptured within the same year at the same 518
location, historical California Department of Fish and Game tagging project (1960s and 1990s). 519
520
Figure 7. Recapture distances for barred sand bass tagged during peak spawning season (Jun-521
Aug) and recaptured during non-spawning season (Nov-Mar), historical California Department 522
of Fish and Game tagging project (1960s and 1990s). 1960s = dark bars, 1990s = grey bars. 523
524
Figure 8. Recapture matrix plot of barred sand bass tagged during peak spawning season and 525
recaptured in subsequent peak spawning seasons, historical California Department of Fish and 526
Game tagging project (1960s and 1990s). Shaded, darker boxes occurring along the diagonal 527
line indicate a higher degree of breeding site fidelity. 528
529
Figure 9. Recapture plot of barred sand bass tagged in Newport Bay, California during non-530
spawning season (Nov-Mar, shaded areas), historical California Department of Fish and Game 531
tagging project (1960s). Recaptures occurring within 90 d of tagging were excluded. Recapture 532
locations are arranged north to south (top to bottom).533
30
534
Figure 1. 535
31
536
537 Figure 2. 538
32
539 Figure 3. 540
33
541
542 Figure 4 543
34
544 Figure 5. 545
35
546 547 Figure 6. 548
36
549 Figure 7. 550
37
551 Figure 8. 552
38
553 Figure 9. 554