Abstract.--During the 1960s and 1990s, the California Department of
Fish and Game tagged 8,634 barred sand bass in southern California, and
972 fish (11%) were recaptured. Tag returns suggest barred sand bass are
transient aggregate spawners that form spawning aggregations consisting
of both resident and migrant individuals. Spawning residency at a
historic spawning location was estimated by the frequency of returns
over rime; most same-year returns (82%, n = 141) were recaptured within
a 7 to 35-day period. The maximum recapture distance was 92 km. The
average ([+ or -] SD) non-spawning season recapture distance from peak
spawning season tagging locations was 13 [+ or -] 8 km, and movement was
generally northward. A positive relationship existed between fish size
(TL) and migration distance to non-spawning season recapture locations.
Fish tagged at a presumed non-spawning season residence were primarily
recaptured south of the tagging location during peak and late spawning
season; the average migration distance was 17 [+ or -] 15 km. Recaptures
in subsequent years showed a high degree of spawning (80%, n = 135) and
non-spawning (73%, n = 11) site fidelity. This is the first
documentation of the spawning-related movements of barred sand bass and
will be important for informing management decisions regarding this
popular sport fish.
Introduction
Barred sand bass, Paralabrax nebulifer, continues to be a highly
sought-after sport fish in southern California. In the early 1900s,
barred sand bass was landed in both the commercial and recreational
fisheries; however, due to limited demand in the commercial fishery and
scarcity of the resource during the 1950s, commercial take was banned in
1953 and a 12-in (305 mm) minimum size limit was implemented for the
recreational fishery in 1959 (Collyer 1949, Young 1969). Since the
1960s, barred sand bass ranked among the top 10 sport fish in the
commercial passenger fishing vessel (CPFV) fleet in southern California,
and total annual catches in the recreational fishery averaged nearly two
million fish per year (Allen and Hovey, 2001; PSMFC 2010). From 2001 to
2005, "heavy annual landings" (e.g., ~700 tons) were also
reported in the commercial fishery of Baja California, Mexico
(Aburto-Oropeza et al. 2008).
Catch and effort in the southern California recreational fishery is
highest during peak spawning season (June to August) when barred sand
bass form large spawning aggregations over sort bottom habitat in depths
of 20 to 40 m (Turner et al. 1969; Feder et al. 1974; Love et al.
1996a,b). Based on the exceptionally high landings of barred sand bass
during summer months, it is possible these aggregations consist of
thousands of fish, although underwater video documentation has never
been reported. For decades, anglers have targeted well-known barred sand
bass spawning aggregation sites including Ventura Flats, inner Santa
Monica Bay, Huntington Flats, San Onofre, and Silver Strand in San Diego
(Love et al. 1996a; Figure 1). However, since the high in 2000, barred
sand bass CPFV catch-per-unit-effort (CPUE) has declined by 65% (CDFG
unpublished data) to below the 30-yr average, causing concern regarding
the vulnerability of the population to future harvest impacts.
[FIGURE 1 OMITTED]
Fish species that are targeted during their spawning aggregations
are especially susceptible to overexploitation because harvest effects
may not be immediately evident (Sadovy and Domeier 2005). This is due to
a condition of hyperstability, in which catch rates (and aggregation
densities) remain deceptively high until the population reaches a
critical minimum level. Once this occurs, spawning aggregations at
historic sites may cease to exist, even after a population rebound
(Domeier and Colin 1997; Sadovy and Domeier 2005). Commercial fishing on
spawning aggregations in the Caribbean resulted in the disappearance of
about one-third of historical spawning aggregations of the Nassau
grouper, Epinephelus striatus, and a negative impact on the trophic
levels of the surrounding ecosystem (Sadovy and Domeier 2005). It is
unclear whether recent barred sand bass catch declines are indicative of
an already exploited stock because no spawning biomass estimates exist.
Nevertheless, a better understanding of barred sand bass spawning
behavior and spawning movements will help to make informed management
decisions.
Although the timing and location of barred sand bass spawning
aggregations in southern California is well-documented, little else is
known about their spawning-related movements. After peak spawning,
considerably fewer barred sand bass are caught over sand flats and
catches typically resume inshore in bays or near low relief natural or
artificial reefs, but not in such high numbers (Love et al. 1996a).
Fishery-independent data also demonstrate seasonal differences in barred
sand bass densities (Froeschke et al. 2005; Martin and Lowe 2010). These
seasonal trends suggest barred sand bass exhibit transient spawning
aggregation behavior, in which large aggregations format specific,
predictable locations at higher than average densities for a period of
several weeks to months (Domeier and Colin 1997). Transient spawning
aggregations are characterized by individuals that may (or may not)
migrate relatively long distances, whereas resident spawning
aggregations form near or within home ranges, occur year-round, and
persist for only hours or days. Clearly, knowledge of the origins and
destinations of barred sand bass spawning migrations and understanding
the degree of site fidelity to historic aggregation locations will have
important management implications for this species.
Throughout the 1960s and 1990s, biologists with the California
Department of Fish and Game (CDFG) conducted tag and recapture studies
of barred sand bass in southern California and Baja California, Mexico.
The recapture information from these two time periods enables us to
document the historical spawning-related movements of barred sand bass
for the first time. Specifically, our objectives of this study are to
examine these historical data for trends in 1) residency at spawning
locations, 2) movement to and from spawning locations, and 3) spawning
and non-spawning site fidelity.
Methods
Tagging Events
During the 1960s and 1990s, barred sand bass were tagged along the
coast of southern California and at one location in Baja California,
Mexico (Figure 1). Tagging locations included sand flats, reefs, and bay
habitat. During both tagging periods, fish were captured by
hook-and-line, measured to the nearest mm total length (TL), externally
tagged with spaghetti or T-bar tags, and released. In the 1990s, fish
were also captured by bottom trawl, and upon release, tagged fish
suffering from barotrauma were recompressed to depth using weighted,
inverted milk crates. Loran or GPS coordinates of the tagging sites were
recorded (1990s); otherwise, a site name or geographic landmark was
provided. In addition, depth (m) and release condition were recorded for
some but not all fish. Rewards for recaptures of tagged fish were
offered during both tagging periods. Recapture information included
date, location, TL (mm), and tag ID number. In the 1990s, recapture
depth (m) and Loran or GPS coordinates were also provided when
available.
Analyses
Ail historical barred sand bass tag and recapture data were
archived into a relational database. To standardize tagging effort
across the two tagging periods, reported locations for all records were
assigned a fishing site code based on historical southern California
CPFV sport fish surveys (Ally et al. 1990). Site codes (N = 252) were
inclusive of nearly every nearshore and coastal mainland and island area
in southern California, enabling assignments of specific fishing sites
even when only geographic landmarks were reported. Days at liberty,
recapture distance (estimated or actual km), and general direction of
movement were calculated and incorporated into the database. We used
two-sample Kolmogorov-Smirnoff tests to compare distributions of tagged
fish length structure, depth of capture of tagged fish, and days at
liberty between the two tagging periods. Recapture distances were
measured as linear distances between approximate or exact tagging and
recapture locations. The lack of high spatial resolution (e.g., GPS
coordinates), especially in the 1960s, probably underestimates the
actual linear distance between fish tag and recapture events. However,
because out goal was to investigate large-scale movements between
fishing sites (rather than fine-scale movements within fishing sites),
this underestimate becomes negligible. Spawning season codes were also
assigned to each tag and recapture record based on capture month
(Nov.-Mar. = non-spawning season, Apr. May = early spawning season,
Jun.-Aug. = peak spawning season, Sept.-Oct. = late spawning season).
Where noted, early and late spawning season recaptures were excluded
from analyses to limit variability resulting from individuals that may
not have been demonstrating spawning-related movements. In this paper we
report recapture rates and return rates. Recapture rates refer to the
number offish recaptured at a given site divided by the total number of
fish recaptures. Return rates refer to the number of fish recaptured at
a given site divided by the total number of fish tagged at that site.
Spawning Season Residency
To investigate the residence time of individuals at spawning
grounds, we selected fish tagged at Huntington Flats during peak
spawning season and recaptured at Huntington Flats within the same year.
This location was chosen because of the high return rate and because it
is a well-known spawning aggregation location. We plotted the percent
frequency of tag returns over days at liberty (in 7-day bins) for each
group of fish tagged in June, July, and August, and overall. We assumed
if spawning season residency of migrant fish did not vary widely among
individuals, then the frequency of tag returns should drop off after a
similar length of time, regardless of tagging month. This period of rime
was assumed to represent spawning residence rime of migrant individuals
and coincided with a drop in percent returns to less than 5%. We also
reported the locations and recapture distances of fish that were
recaptured away from Huntington Flats during the same peak spawning
season.
Movement to Non-spawning Season Locations
Movement from peak spawning season tagging locations to
non-spawning season recapture locations was assumed to be movement from
spawning grounds to non-spawning season residences. To estimate the
proximity of non-spawning season residences to spawning grounds, we
grouped non-spawning season recapture distances for fish tagged during
peak spawning season into 5-km bins. Average non-spawning season
recapture distances were calculated for each tagging location to
determine whether non-spawning season migration distances (= linear
recapture distances) varied by spawning location. We then tested for a
relationship between TL and migration distance using a Spearman Rho rank
test.
Movement to Spawning Locations
We examined peak spawning season recaptures of fish tagged in
Newport Bay during the non-spawning season to identify if and where
Newport Bay residents migrate to spawn. This location was chosen due to
the high return rate and because most non-spawning season tagging events
were at this location. Spawning migration distances from Newport Bay to
spawning grounds were reported and tested for a relationship with TL
using a Spearman Rho rank test. We also looked for seasonal patterns in
site fidelity to Newport Bay by creating a recapture plot of fish tagged
in Newport Bay (Nov.-May) from the years 1964 to 1973.
Spawning and Non-spawning Season Site Fidelity
To investigate annual site fidelity of barred sand bass to specific
peak spawning season tagging locations (i.e., presumed spawning grounds)
we considered fish that were only tagged during peak spawning season and
recaptured during subsequent peak spawning seasons. We constructed a
matrix of the number of fish recaptured by tagging location and
recapture location, with tag and recapture locations arranged from north
(N) to south (S). A higher number of recaptures that occur along a
series of corresponding tag/recapture locations within the matrix (i.e.,
where recapture location = tag location) indicated a higher degree of
spawning site fidelity than an arrangement of non-corresponding
tag/recapture locations or few corresponding tag/recapture locations
within the matrix. To investigate non-spawning season site fidelity, we
examined trends in percent site fidelity to Newport Bay (% returns to
Newport Bay) across seasons and over subsequent non-spawning seasons.
Again, we focused on this location due to the high return rate and
because most non-spawning season tagging events were at this location.
Results
Tagging Effort
From 1962 to 1976 there were 4,687 barred sand bass tagged from
Santa Barbara to San Diego Bay. Tagging was primarily at Huntington
Flats (38%), Newport Bay (21%), Venice Beach (5%), San Onofre (5%), and
El Segundo (4%; Table 2). Most fish were tagged during peak spawning
season (72%) and non-spawning season (17%); early and late spawning
season comprised 5 and 6% of tagged fish. Newport Bay accounted for 91%
of the non- and early spawning season tagged fish (n = 737 and 179).
Most fish at other locations were tagged during peak spawning season:
Huntington Flats (98%), Venice Beach (100%), San Onofre (99%), and El
Segundo (92%). Between 1989 and 1999, there were 3,947 barred sand bass
tagged from Santa Barbara to Baja California, Mexico, including Santa
Catalina Island. In the 1990s, 74% of fish were captured by
hook-and-line. The distribution of tagging depths between line-caught
and trawl-caught barred sand bass did not significantly differ
([D.sub.max] = 0.310, p > 0.05; Table 1). Fish in the 1990s were
primarily tagged at Huntington Flats (32%), Horseshoe Kelp (12%),
Manhattan Reef (10%), Ventura (9%), Tijuana Kelp (8%), Redondo Beach
(6%), and San Diego Bay (6%; Table 2). Most fish were tagged during peak
spawning season (76%) and non-spawning season (17%); early and late
spawning season comprised 5 and 1% of tagged fish. Eighty-five percent
of fish tagged during non-spawning season were tagged at Manhattan Reef
(92%, n = 358) and Redondo Beach (97%, n = 198). Tagging effort (= mean
fish tagged per day and mean tagging months per year) was similar
between the two tagging periods (Table 1).
Ninety-one percent of tagged fish were of mature size (Table 1),
and the average size of fish tagged at all sites was bigger than the
size at 100% maturity (~270 mm TL; Figure 2). Sites with fewer than 80%
mature tagged fish were San Onofre (64%), San Diego Bay (63%), and South
Carlsbad (54%). Length frequency (LF) distributions of tagged fish
significantly varied between the 1960s and 1990s ([D.sub.max] = 0.310, p
< 0.05); most large fish were tagged in the 1990s at Ventura and
Tijuana Kelp (Figure 2). There was a significant positive linear
relationship between TE and depth of capture ([r.sup.2] = 0.14, p =
0.001).
Recaptures
There were 972 recaptures; 82% were from the 1960s (Table 1).
Overall, 96% were of mature size (Table 1). In the 1960s, return rates
ranged between 1 and 35% among sites with appreciable tagging effort (N
[greater than or equal to] 100 fish, average = 18 [+ or -] 11% SD; Table
2). Of these, percent returns were high ([greater than or equal to] 5%)
with the exception of San Clemente (1%). Forty-five percent of all
recaptures in the 1960s were caught at Huntington Flats and Newport Bay
(Table 2). In the 1990s, return rates ranged between 1 and 6% among
sites with appreciable tagging effort (average = 3 [+ or -] 2% SD);
sites with the lowest percent returns were Redondo Beach, San Diego Bay,
and Ventura (Table 2). Fifty-eight percent of recaptures in the 1990s
were caught at Huntington Flats and Horseshoe Kelp (Table 2). Although
the maximum days at liberty were similar between the two tagging periods
(Table 1), there was a significant difference in the distribution of
recaptures over time between the 1960s and the 1990s ([D.sub.max] =
0.310, p < 0.001). The 1990s had fewer long term recaptures than the
1960s, with the majority of fish recaptures (75%, n = 128) caught within
just 63 days at liberty compared with 315 days in the 1960s. Overall,
the maximum recapture distance was 92 km S (Los Alamitos to Oceanside).
It is not clear how many recaptured fish were released versus how many
were kept.
Spawning Season Residency
We identified 172 Huntington Flats same-year returns (1960s: n =
117, 1990s: n = 55). Overall, 82% of returns were recaptured within a 7
to 35-day period (Figure 3). Although the numbers of tagged fish were
higher for fish tagged in July (n = 1,760) than fish tagged in June (n =
350) and August (n = 808), the return rate was highest for June-tagged
fish (14%), compared to only 5% for July- and August-tagged fish.
Regardless of tagging month, the frequency of tag returns decreased to
less than 5% within a 35-day period, and there was an overall 75%
decrease in tag returns between 35 and 42 days at liberty (Figure 3). At
28 days, we observed a peak in June- and August-tagged returns and an
inflection in the decline of returns for fish tagged in July. After 35
days, the overall frequency of tag returns remained low (< 5%) with
the exception of a second peak at 56 days (Figure 3). Maximum days at
liberty was highest for August- (119 days) and June-tagged fish (77
days), compared to 56 days for July-tagged fish.
Fifteen fish tagged at Huntington Flats during peak spawning season
were recaptured at a different location during the same peak spawning
season; recapture locations for these migratory fish included Horseshoe
Kelp (n = 9), Seal Beach (n = 1), Santa Ana River Jetty (n = 3), Corona
Del Mar (n = 1), and Dana Point (n = 1). Most of these migratory fish
(13 of 15) were tagged in July. Of these, eight were recaptured in July
and seven were recaptured in August.
Movement to Non-spawning Season Locations
Non-spawning season recapture distances varied among and within
sites. Fifty-nine barred sand bass were tagged during peak spawning
season and recaptured during non-spawning season (1960s, n = 50; 1990s,
n = 9). Sixty-four percent of fish were recaptured within l km of the
tagging site; the rest showed a normal distribution around 15 km (Figure
4). In the 1960s, the overall average ([+ or -] SD) non-spawning season
recapture distance was 4 [+ or -] 7 km, but fish recaptured away from
the tagging location had an average recapture distance of 13 [+ or -] 8
km. In the 1990s, eight of nine fish were recaptured away from the tag
site; the average non-spawning season recapture distance was 19 [+ or -]
14 km. There was a positive relationship between fish size (TL) and
migration distance to non-spawning season recapture locations
([r.sub.s](57) = 0.31, p = 0.02; Figure 5a).
Carlsbad and Huntington Flats tag locations had the highest number
of tag returns during non-spawning season, but fish tagged at Huntington
Flats showed higher variability in recapture distances (Table 3). The
farthest movement between peak and non-spawning season was from Ventura
to Carbon Canyon (40 km S) and from Tijuana, Mexico to La Jolla (35 km
N). The farthest non-spawning season recapture location from Huntington
Flats was the Palos Verdes Peninsula (29 km N). Most non-spawning season
recapture locations were north of peak spawning season tagging locations
(Table 3).
Movement to Spawning Locations
Fish tagged in a presumed non-spawning season residence (Newport
Bay) during non-spawning season were primarily recaptured outside of
Newport Bay during peak spawning season. We identified at least 16
different peak spawning season recapture sites that were typically
located south of Newport Bay; the average ([+ or -] SD) distance was 17
[+ or -] 15 km (Table 4, Figure 6). The farthest recapture location from
Newport Bay was Oceanside (52 km S). In contrast to the results reported
above (Figure 5a), no correlation was found between TL and spawning
migration distance from Newport Bay ([r.sub.s](71) = 0.23, p = 0.05;
Figure 5b).
Spawning and Non-spawning Site Fidelity
One-hundred sixty-nine fish were tagged during peak spawning season
and recaptured during subsequent peak spawning seasons (1960s, n = 162;
1990s, n = 7). Eighty-nine percent were recaptured after 1 yr at
liberty, 8% after 2 yr, and 2% after 3 yr. Overall, 80% were caught back
at the same tagging location. The average recapture distance ([+ or -]
SD) for the 20% that were recaptured elsewhere was 18 [+ or -] 16 km.
Overall, the recapture matrix plot identified a high degree of breeding
site fidelity as indicated by the arrangement of recaptures along
corresponding tag/recapture locations (Figure 7). Tagging locations with
the highest measure of breeding site fidelity were Huntington Flats,
Venice Beach, San Onofre, Carlsbad, and Twintrees. We also identified
two fish that were twice recaptured in subsequent peak spawning seasons
at the same locations (Twintrees and Huntington Flats, Table 5).
Of fish tagged in Newport Bay during non-spawning season, there
were 170 tag returns. Two fish were recaptured twice at Newport Bay;
once during the respective non-spawning tagging season and again during
a subsequent non-spawning season (Table 5). Percent site fidelity was
highest during non-spawning (86%, n = 36) and early spawning seasons
(97%, n = 37) and lowest during peak (23%, n = 16) and late spawning
(29%, n = 5) seasons. Including the two fish that were recaptured twice,
there were 15 fish recaptured during subsequent non-spawning seasons. Of
these, 73% were recaptured back at Newport Bay, and the other four fish
were either recaptured at Laguna Beach (11 km S, n = 3) or San Clemente
(31 km S, n = 1).
Discussion
Typical recapture rates using standard tag and recapture methods in
the marine environment is 3 to 10% (Lowe and Bray 2006), making it
difficult to attain fish movement information without significant
spatial and temporal sampling effort. Even with adequate sampling
coverage, spatial and temporal differences in fishing effort can
potentially yield biased results. In this paper, we report an 11%
overall recapture rate consisting of several hundred fish and, with few
exceptions, we report relatively high return rates across sites (Table
2). Thus, although certain limitations are inherent in tag and recapture
studies, we believe these historical data enabled us to provide an
adequate characterization of the large-scale spawning-related movements
of barred sand bass in southern California.
Our results indicate that barred sand bass individuals display a
high degree of spawning site fidelity, may migrate up to tens of
kilometers, and may reside at spawning grounds for several weeks. These
findings suggest barred sand bass, like other serranids, form transient
spawning aggregations (Domeier and Colin 1997). Although more tagged
fish displayed resident behavior, our results could potentially be
biased toward fish resident to spawning grounds because other locations
may not have been fished as intensely during non-spawning season.
However, it is also possible that spawning movements were completely
missed or that some fish were tagged in locations outside of spawning
areas and did not migrate to spawn. Mason and Lowe (2010) reported that
a portion of acoustically monitored adult barred sand bass at Santa
Catalina Island, CA, showed year-round site fidelity to their home
ranges, whereas others were not detected in these areas during spawning
season. This type of "polymorphic movement behavior" has also
been described for other transient aggregate spawners (Zeller 1998; Egli
and Babcock 2004; Semmens et al. 2010).
[FIGURE 2 OMITTED]
[FIGURE 3 OMITTED]
Movement to and from Spawning Locations
Non-spawning residences were generally north of spawning grounds,
implying migration directionality. Moreover, our data suggest spawning
aggregations are not comprised of migrants from the same location.
Indeed, fish tagged at Newport Bay did not migrate to the same (or to
the nearest) spawning grounds. Zeller (1998) reported that coral trout,
Plectropomus leapardus, showed differences in spawning migration
distance, where fish with overlapping home ranges did not necessarily
make excursions to the same spawning grounds. Red hind, Epinephelus
guttatus, another serranid demonstrating transient spawning behavior,
also showed variability in spawning migration distance (e.g., 1.8 32.3
km; Nemeth et al. 2007).
[FIGURE 4 OMITTED]
Spawning migration distance was related to body condition and
size-at-age/maturity in Atlantic cod (Gadus morhua; Jorgensen et al.
2008), where fish that migrated longer distances were generally older,
bigger fish with higher overall fitness. Although the relationship
between barred sand bass TL and spawning migration distance was somewhat
inconclusive, we cannot rule out bioenergetics as a possible explanation
for individual variability in migration distance, as maturity and
fitness were not determined for tagged fish.
Migration distance also varied by peak spawning season tagging
location. This could be due to variability in the numbers of returns
across sites or distinct differences among sites. Nemeth et al. (2007)
attributed differences in migration distance and functional migration
area (i.e., the area inclusive of home ranges and spawning ground) to
differences in shelf area and fish length between spawning sites, where
the site demonstrating a smaller functional migration area and shorter
migration distances contained a smaller shelf area and aggregations of
smaller fish.
Spawning Season Residency
Barred sand bass return rates at Huntington Flats suggested a
spawning residence time within a 7 to 35-day period. Nemeth et al.
(2007) reported a similar spawning residency period for tagged red hind
recaptured on their spawning grounds (e.g., 7 d 2 mo); however, diver
surveys of the same study indicated fish densities fluctuated during
spawning season and were influenced by lunar phase and gender. We were
unable to account for gender-specific movements or movement between
tagging and recapture events. Nevertheless, we attribute the secondary
peaks in spawning location tag returns at 28 and 54 days at liberty to
pulses of immigration and emigration or pulses of aggregation formation,
which may correspond with the 28-day lunar cycle. Spawning aggregations
of coral trout and Nassau grouper occurred in pulses, and spawning
residence times at aggregation sites were relatively short (e.g., 4-14
d; Zeller 1998; Starr et al. 2007). For these tropical species, the
pulses were related to specific monthly lunar phases, such as the full
moon (Nassau grouper) or the new moon (coral trout). In contrast,
spawning aggregation formations of dusky grouper, E. margmatus, a
temperate serranid, pulsed at relatively longer intervals (e.g., 2-4 wk)
without specific lunar synchronicity (Herue et al. 2006).
[FIGURE 5 OMITTED]
[FIGURE 6 OMITTED]
[FIGURE 7 OMITTED]
Fish tagged in June or August demonstrated longer-term residency
(i.e., longer maximum days at liberty) at the spawning grounds than fish
tagged in July, suggesting densities of migrant fish are highest in
July. This timing is in agreement with seasonal trends in barred sand
bass fishing effort and CPUE (CDFG unpublished data). Although the
abbreviated residency rime of July-tagged fish could be related to
intense fishing pressure in July, our data indicate otherwise. First,
the higher return rate of June-tagged fish relative to July-tagged fish
indicated fish tagged in July were less available for recapture, despite
there being many more fish tagged in July. Nemeth et al. (2007) reported
a very similar pattern in monthly tag return rates of red hind at their
spawning locations during spawning season. However, unlike this study,
returns were only the result of sampling effort because spawning
locations were closed to fishing during spawning season. Second, barred
sand bass that were recaptured away from Huntington Flats during the
same peak spawning season provided evidence of emigration from the
spawning grounds.
Emigration during peak spawning season suggested barred sand bass
may utilize multiple spawning locations during peak spawning season.
Alternatively, peak spawning season emigrants may represent individuals
that had already returned to their non-spawning residences after
spawning at Huntington Flats. With the exception of Horseshoe Kelp, the
other emigration sites (e.g., Seal Beach, Santa Ana River Jetty, Dana
Point) are hot well-recognized as barred sand bass spawning aggregation
locations. Fine-scale movement studies of other serranids report strong
spawning site fidelity to a single spawning location (Zeller 1998; Starr
et al. 2007).
Spawning and Non-spawning Season Site Fidelity
Most fish tagged during peak spawning season were recaptured at the
same location during subsequent peak spawning seasons. These individuals
may represent year-round residents or repeat migrants. In either case,
the high percent of peak spawning returns that these fish comprised
(80%) demonstrates a high degree of spawning site fidelity. The mere
persistence of barred sand bass spawning aggregations over time (e.g.,
decades) also implies a strong degree of site fidelity. Tradition may
play a primary role in spawning site selection over annual reassessment
of resources, especially if resources are relatively unchanging from one
year to the next (Warner 1988, 1990). Due to annual differences in
tagging effort across tagging locations, it was not possible to
accurately quantify long-term inter-annual variability in spawning site
fidelity by tagging location. The few recaptures not displaying site
fidelity may have reflected individual variability in the timing of
spawning-related movements, movement among aggregation sites, or a
degree of annual reassessment.
We also identified individuals that demonstrated non-spawning site
fidelity to Newport Bay. Fish tagged and recaptured during non-spawning
season in Newport Bay may have represented fish that remained there
year-round or migrated to spawn and returned in the winter. Although
barred sand bass prefer sand/rock ecotone habitat to 30 m depth (Feder
et al. 1974; Johnson et al. 1994; Mason and Lowe 2010), adults have been
shown to utilize bay habitat throughout the year (Pondella et al. 2006).
Nevertheless, a portion of adult barred sand bass tagged in Newport Bay
migrated to locations outside of the bay during spawning season.
Although it is unknown whether these migrant recaptures would have
returned to Newport Bay after peak spawning season, the seasonal pattern
in site fidelity reported at this location is highly suggestive. Indeed,
barred sand bass acoustically tracked and monitored at Catalina Island
were shown to display home ranging behavior and an ability to home
(Mason 2008; Mason and Lowe 2010). Coral trout and Nassau grouper have
also demonstrated site fidelity to non-reproductive areas in addition to
spawning site fidelity (Zeller 1998; Starr et al. 2007).
Recapture Rates
There was a striking difference in recapture rate between the 1960s
(17%) and 1990s (4%). Given that tagging effort and numbers of tagged
fish did not dramatically differ between the two tagging periods,
recapture rates may have been influenced by changes in barred sand bass
availability or the willingness of fishers to report tag returns.
Generally, high recapture rates in open systems reflect relatively lower
population sizes due to the higher probability of encountering the same
fish at a later date. This may explain the higher number of long-term
recaptures in the 1960s dataset. Barred sand bass were scarce during the
1950s (a cold water period) and encountered more frequently along the
coast "in and subsequent to periods of warmer waters" (Young
1969; Feder et al. 1974). Indeed, CPFV barred sand bass catch values
were nearly four times greater in the 1990s than in the 1960s despite
only a doubling of fishing effort (CDFG unpublished data). Furthermore,
kelp bass and barred sand bass larvae densities were also lower during
the cool regime (1950s-1970s) and higher in the warm regime
(1980s-1990s; Moser et al. 2001). Although it appeared that barred sand
bass populations increased in the 1990s relative to the 1960s, barred
sand bass stock-recruitment relationships and the effects on these
relationships by natural and anthropogenic influences remain unknown.
Management Implications
Our data strongly suggest barred sand bass are transient aggregate
spawners that show a high degree of spawning site fidelity. Thus,
well-known spawning aggregation locations may comprise a large portion
of the total annual reproductive output in southern California and
enable spawning biomass estimates for stock assessment purposes.
However, accurate biomass estimates at these locations may be difficult
to attain without knowledge of whether barred sand bass aggregations
flux with new or returning migrants over the course of the spawning
season. In the midst of recent catch declines, a precautionary approach
to management may be an important consideration until a harvest
guideline can be developed. Measures taken to protect stocks of
transient aggregation spawners include marine protected areas (MPAs),
seasonal bans, and seasonal area closures (Sadovy and Domeier 2005).
However, recent California MPA proposals for the south coast study
region (i.e., Pt. Conception to the U.S./Mexico border) are not
inclusive of known barred sand bass spawning aggregation locations (CDFG
2010), and seasonal bans or seasonal area closures may not be feasible
to implement due to overlap among popular recreational fishing grounds.
Alternatively, barred sand bass, which appears to have a relatively long
spawning residency period (this study) and is capable of daily spawning
(Oda et al. 1993), may benefit from a reduction in the current bag limit
(10 fish). Further consideration of barred sand bass movement patterns,
life history traits, and feasibility concerns will help to define
additional management alternatives to protect the resource.
Acknowledgements
CDFG lead investigators for the barred sand bass tagging studies in
the 1960s and 1990s were P. "Bud" Young and J.R. Raymond Ally,
respectively. Over the two tagging periods, CDFG tagging efforts were
augmented by [and listed in no particular order] R. Izor (Izorline
International), Orange County Marine Institute, County Sanitation
Districts of Orange County, Los Angeles Rod and Reel Foundation, and
many other individual volunteers. We thank L.G. Allen, C. Lowe, T.
Mason, M. McKinzie and one anonymous reviewer for their critical review
of the drafts of this manuscript. Funding was supported in part by the
Los Angeles County Fish and Game Commission and the Federal Aid in
Sportfish Restoration Act (also known as the Dingell-Johnson Act; Grant
#F-50-R-20).
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Table 1. Tag and recapture summary statistics for barred sand bass
tagged in southern California, historical California Department of
Fish and Game tagging project (1960s and 1990s).
Tag and recapture results 1960s 1990s
Tagged fish 4,687 3,947
Tagging effort
days 174 153
Avg ([+ or -] SD) fish/day 27 [+ or -] 32 26 [+ or -] 58
Avg ([+ or -] SD) mo/yr 4 [+ or -] 3 6 [+ or -] 3
Capture method
hook-and-line 100% 74%
bottom trawl -- 26%
Avg ([+ or -] SD) capture
depth (m)
overall -- 15 [+ or -] 17
hook-and-line -- 22 [+ or -] 7
bottom trawl -- 25 [+ or -] 12
Avg ([+ or -] SD) TL (mm) 306 [+ or -] 38 337 [+ or -] 72
% mature ([greater than
or equal to] 270) 89% 93%
% legal size ([greater than
or equal to] 305) 41% 70%
Recaptures 801 171
Recapture rate
overall 17% 4%
hook-and-line 17% 5%
bottom trawl -- 3%
Avg ([+ or -] SD) recapture
depth (m) -- 23 [+ or -] 9
Avg ([+ or -] SD) TL (mm) 326 [+ or -] 43 343 [+ or -] 46
% mature ([greater than
or equal to] 270) 96% 98%
% legal size ([greater than
or equal to] 305) 68% 86%
Days at liberty
Avg ([+ or -] SD) 200 = 197 90 [+ or -] 187
Max 1,211 1,258
Recapture distance (km)
Avg ([+ or -] SD)--All fish 6 [+ or -] 12 7 [+ or -] 9
Avg ([+ or -] SD)--Only movers 18 [+ or -] 15 10 [+ or -] 9
Max 92 76
Table 2. Numbers of barred sand bass tagged, percent of tags
returned, numbers recaptured (= Recaps), and percent of total
recaptures by site in southern California, historical California
Department of Fish and Game tagging project (1960s and 1990s). Sites
arranged north to south.
1960s
% of Tags % of Total
Site Name Tags Returned Recaps Recaps
Santa Barbara 2 50 1 <1
Ventura -- -- -- --
Carbon Canyon -- -- 2 <1
Malibu -- -- 1 <1
Topanga Canyon 63 6 4 <1
Santa Monica 1 100 3 <1
Venice Beach 237 13 24 3
El Segundo 202 5 7 1
Manhattan Reef -- -- 2 <1
Redondo Beach 37 22 9 1
Torrance Beach -- -- 1 <1
Palos Verdes
Peninsula -- -- 3 <1
Horseshoe Kelp 10 0 8 1
Long Beach 98 11 7 1
Seal Beach -- -- 2 <1
Huntington Flats 1,772 13 235 29
Santa Ana River
Jetty -- -- 6 1
Newport Harbor 999 22 125 16
Corona Del Mar 1 0 5 1
Crystal Cove 7 14 4 <1
North Laguna Beach 33 15 19 2
South Laguna Beach 109 35 31 4
Aliso Beach 12 0 3 <1
Salt Creek 32 41 24 3
Dana Point 6 33 17 2
Capistrano Beach -- -- 1 <1
San Mateo Point 136 19 25 3
San Clemente 143 1 7 1
Middle Kelp 44 43 10 1
San Onofre Power
Plant 229 28 61 8
Box Canyon -- -- 7 1
Barn Kelp 120 27 38 5
Las Flores 11 27 4 <1
Oceanside 157 8 5 1
South Carlsbad 104 31 44 3
Twintrees 106 14 12 1
Round Kelp -- -- 1 <1
Encinitas Pt. -- -- 1 <1
Moonlight Beach 7 14 0 0
La Jolla 1 0 0 0
Mission Bay 2 0 0 0
Point Loma -- -- -- --
San Diego Bay 4 0 0 0
North Island/
Coronado Area -- -- -- --
Silver Strand -- -- -- --
Imperial Beach 2 0 0 0
Santa Catalina
Island -- -- -- --
Tijuana Kelp -- -- -- --
1990s
% of Tags % of Total
Site Name Tags Returned Recaps Recaps
Santa Barbara 11 0 0 0
Ventura 350 1 1 1
Carbon Canyon 11 9 1 1
Malibu 42 5 1 1
Topanga Canyon 18 0 0 0
Santa Monica 18 0 2 1
Venice Beach -- -- -- --
El Segundo 2 0 1 1
Manhattan Reef 388 4 7 4
Redondo Beach 204 2 7 4
Torrance Beach -- -- -- --
Palos Verdes
Peninsula 4 0 0 0
Horseshoe Kelp 707 5 15 9
Long Beach 4 0 4 2
Seal Beach 1 0 2 1
Huntington Flats 1,258 6 82 49
Santa Ana River
Jetty 5 20 3 2
Newport Harbor 3 0 0 0
Corona Del Mar 1 0 1 1
Crystal Cove -- -- -- --
North Laguna Beach -- -- -- --
South Laguna Beach -- -- -- --
Aliso Beach -- -- -- --
Salt Creek -- -- -- --
Dana Point 28 11 4 2
Capistrano Beach -- -- -- --
San Mateo Point 45 2 0 0
San Clemente -- -- -- --
Middle Kelp 4 0 0 0
San Onofre Power
Plant 7 0 1 1
Box Canyon 1 0 3 2
Barn Kelp 21 10 1 1
Las Flores 17 18 0 0
Oceanside 17 0 3 2
South Carlsbad -- -- -- --
Twintrees -- -- -- --
Round Kelp -- -- -- --
Encinitas Pt. -- -- -- --
Moonlight Beach -- -- -- --
La Jolla -- -- -- --
Mission Bay 65 2 1 1
Point Loma 2 0 3 2
San Diego Bay 230 1 0 0
North Island/
Coronado Area 6 0 0 0
Silver Strand 63 6 4 2
Imperial Beach 99 3 7 4
Santa Catalina
Island 12 8 9 5
Tijuana Kelp 300 4 4 2
Table 3. Recapture distances (= Recap Dist, km) of barred sand bass
tagged during peak spawning season (Jun-Aug) and recaptured during
non-spawning season (Nov-Mar), historical California Department of
Fish and Game tagging project (1960s and 1990s). Dir. = direction of
recapture location from tagging location (north versus south along
the southern California coastline).
Avg
Recap
Peak Spawning Season Dist Non-spawning Season
Tag Location N (km) SD Recapture Location
Ventura 1 40.0 -- Carbon Canyon
Santa Monica 1 -- -- Santa Monica
Venice Beach 2 7.5 10.6 Venice Beach
Malibu
Redondo Beach 3 0.2 0.3 Redondo Beach
Horseshoe Kelp 2 27.0 -- Redondo Beach
Unknown
Huntington Flats 14 5.1 8.7 Huntington Flats
Long Beach
Palos Verdes Peninsula
Santa Ana River Jetty
Unknown
Newport Bay 1 8.9 -- North Laguna Beach
Crystal Cove 1 -- -- Crystal Cove
South Laguna Beach 3 4.7 4.0 South Laguna Beach
Dana Point
Newport Bay
Salt Creek 1 -- -- Salt Creek
Dana Point 1 -- -- Dana Point
San Mateo Point 3 0.0 0.0 San Mateo Point
Middle Kelp 5 3.6 5.1 Middle Kelp
Aliso Beach
North Laguna Beach
San Onofre 7 3.3 5.2 San Onofre
Salt Creek
Unknown
Barn Kelp 1 -- -- Unknown
Carlsbad 11 0.6 1.4 Carlsbad
Twintrees
Twintrees 1 -- -- Twintrees
San Diego Bay 1 -- -- San Diego Bay
Coronado 1 6.0 -- La Jolla
Imperial Beach 1 8.0 -- Point Loma
Tijuana Kelp 1 35.0 -- La Jolla
Distance
from Tag
Peak Spawning Season Location
Tag Location N (km) Dir.
Ventura 1 40.0 S
Santa Monica 1 -- --
Venice Beach 1 -- --
1 24.1 N
Redondo Beach 3 -- --
Horseshoe Kelp 1 27.0 N
1 -- --
Huntington Flats 8 0.0 --
3 11.3-19.3 N
1 29.0 N
1 8.0 S
1 -- --
Newport Bay 1 8.9 S
Crystal Cove 1 -- --
South Laguna Beach 1 -- --
1 11.3 S
1 11.3 N
Salt Creek 1 -- --
Dana Point 1 -- --
San Mateo Point 3 -- --
Middle Kelp 3 -- --
1 11.3 N
1 17.7 N
San Onofre 4 -- --
2 16.1 N
1 -- --
Barn Kelp 1 -- --
Carlsbad 10 0.6 --
1 4.8 S
Twintrees 1 0.0 --
San Diego Bay 1 -- --
Coronado 1 0.0 N
Imperial Beach 1 8.0 N
Tijuana Kelp 1 35.0 N
Table 4. Average recapture distances (= Recap Dist, km) of barred
sand bass tagged in Newport Bay during non-spawning season (Nov-Mar)
and recaptured during peak spawning season (Jun-Aug), historical
California Department of Fish and Game tagging project (1960s). Dir.
= direction of recapture location from tagging location (north versus
south along the southern California coastline).
Peak Spawning Season Avg Recap
Recapture Location N Dist (km) SD Dir.
Horseshoe Kelp 1 24.1 -- N
Huntington Flats 13 17.6 2.2 N
Santa Ana River Jetty 3 8.0 0.0 N
Newport Bay 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
Middle Kelp 1 24.1 -- S
San Clemente 1 29.0 -- S
San Mateo Point 4 31.4 1.6 S
San Onofre 5 32.8 0.9 S
Barn Kelp 8 42.8 1.5 S
Oceanside 1 51.5 -- S
Table 5. Tag and recapture dates and locations of barred sand bass
recaptured on two separate occasions, historical California
Department of Fish and Game tagging project (1960s).
1st recapture 1st recapture
Tagging location Tag date location date
Twintrees 7/26/1968 Twintrees 8/7/1969
Newport Bay 12/13/1964 Newport Bay 5/15/1965
Newport Bay 12/13/1964 Newport Bay 2/27/1965
Laguna Beach 8/23/1968 Unknown * 10/8/1968
Newport Bay 5/31/1964 Corona Del Mar 7/2/1964
Middle Kelp 8/30/1968 Salt Creek * 9/21/1968
Laguna Beach 9/17/1968 Unknown * 10/8/1968
Huntington Flats 6/25/1968 Huntington Flats 6/28/1968
Salt Creek 9/19/1968 Salt Creek * 9/21/1968
Recapture Days at 2nd recapture
Tagging location distance (km) liberty location
Twintrees 0.00 376 Twintrees
Newport Bay 0.00 153 Newport Bay
Newport Bay 0.00 76 Newport Bay
Laguna Beach -- 46 Laguna Beach
Newport Bay 1.60 33 Laguna Beach
Middle Kelp 6.40 22 Newport Bay
Laguna Beach -- 21 Newport Bay
Huntington Flats 0.00 3 Huntington Flats
Salt Creek 0.00 2 San Onofre
2nd recapture Recapture Days since 1st
Tagging location date distance (km) recapture
Twintrees 9/2/1970 0.00 391
Newport Bay 11/10/1965 0.00 179
Newport Bay 5/19/1965 0.00 81
Laguna Beach 7/10/1969 12.90 275
Newport Bay 9/30/1964 16.10 90
Middle Kelp 9/29/1968 0.00 8
Laguna Beach 2/10/1969 0.00 125
Huntington Flats 7/26/1968 0.00 28
Salt Creek 5/16/1969 35.40 237
* Asterisks denote fish that were released in Newport Bay following
weigh-in at a fishing tournament.