Jarvis etal poster_aifrb_2010_29_sep2010
1
SPAWNING-RELATED MOVEMENTS OF BARRED SAND BASS IN SOUTHERN CALIFORNIA: INTERPRETATIONS FROM TWO DECADES OF TAG AND RECAPTURE DATA E. T. Jarvis, C. Linardich, and C. F. Valle California Department of Fish and Game (CDFG), 4665 Lampson Ave., Suite C, Los Alamitos, CA 90720 L.G. Allen 0 5 10 15 20 25 30 35 40 Venice B each ElSegundo M anhattan R eef Redondo Beach H orseshoe K elp H untington Flats H untington Flats N ew portB ay San C lem ente San O nofre O ceanside South C arlsbad San D iego B ay Tijuana K elp Tagged fish (% ) 1960s (n=4,725) 1990s (n=3,944) 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. CDFG tagging efforts were augmented by 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. Funding was supported in part by the Los Angeles County Fish and Game Commission and the Federal Aid in Sport Fish Restoration Act Grant #F-50- R-20). MAJOR FINDINGS Figure 2. Percent of barred sand bass tagged and percent of tags returned by site and tagging period. 1) Tagging locations with appreciable tagging effort (≥ 3% of tags) had tag return rates between 3 and 35%, with the exception of two sites (Fig. 2). Tagging locations included sand flats, reefs, and bays along the coast of southern California and one location in Baja California, Mexico (Fig. 1). Fish were captured by hook-and-line or trawl, measured to the nearest mm total length (TL), externally tagged with spaghetti or T-bar tags, and released. Rewards were offered for recaptures of tagged fish; recapture information included date, location, TL, and tag ID number. Records were assigned a fishing site code, and distance traveled was measured as the linear distance between tag and recapture locations. Records were also assigned spawning season codes based on capture month (Nov.–Mar. = non-spawning, Apr.–May = early spawning, Jun.–Aug. = peak spawning, Sept.–Oct. = late spawning). Fish caught in early and late spawning season were excluded from analyses to reduce variability arising from individuals that may not have been spawning. For decades, recreational fishers have targeted well-known barred sand bass spawning aggregation sites during the summer (Fig. 1; Love et al. 1996). Since 2000, barred sand bass CPUE by party boats has declined by 65% to below the 30- yr average (CDFG unpub. data), causing concern for potential harvest impacts and identifying the need to learn more about barred sand bass spawning movements. Throughout the 1960s and 1990s, CDFG biologists conducted tag and recapture studies of barred sand bass in southern California, enabling us to document the spawning-related movements of barred sand bass for the first time. Our objectives were to examine these data for trends in 1) residency at spawning locations, 2) movement to and from spawning locations, and 3) spawning site fidelity. Studying these trends may help us identify the specific aggregation behavior utilized by barred sand bass (transient or resident behavior), thus increasing our ability to manage this valuable resource. BACKGROUND AND OBJECTIVES Figure 1. Map of barred sand bass tagging locations in southern California. Grey polygons denote historical spawning aggregatio n locations. 2) Spawning residency at Huntington Flats was estimated by the frequency of returns over time; most same-year returns (82%, n = 141) were recaptured within a 35-d period, with secondary peaks in returns at 28 and 56 days at liberty (Fig. 3). D ays atliberty (7 d bins) 7 14 21 28 35 42 49 56 63 70 77 84 91 98 105 112 119 Frequency oftag returns (% ) 0 5 10 15 20 25 30 Figure 3. Frequency of tag returns over time for fish tagged during peak spawning season (Jun- Aug) at Huntington Flats and recaptured there within the same year. 6) Most of the fish that were tagged during peak spawning season and recaptured during subsequent peak spawning seasons were caught at the same location (80%, n = 132; Fig. 6). Figure 6. Recapture matrix of barred sand bass tagged during peak spawning season (Jun-Aug) and recaptured in subsequent peak spawning seasons. 3) Many non-spawning season recaptures appeared resident to their peak spawning tagging locations; however, migrant fish moved an average of 13 ± 8 km away, and movement was generally northward (Fig. 4). Figure 4. Recapture distances of barred sand bass tagged during peak spawning season (Jun-Aug) and recaptured during non- spawning season (Nov-Mar). 4) A positive correlation existed between fish size (TL) and migration distance to non-spawning season recapture locations (Fig. 5). Figure 5. Fish size (TL) versus migration distance from peak spawning season (Jun-Aug) tagging locations to non-spawning season (Nov-Mar) recapture locations. S -- 51.5 1 Oceanside S 1.5 42.8 8 Barn Kelp S 0.9 32.8 5 San Onofre S 1.6 31.4 4 San Mateo Point S -- 29.0 1 San Clemente S -- 24.1 1 Middle Kelp S -- 24.1 1 Capistrano Beach S 1.3 20.4 6 Dana Point S 1.1 18.5 2 Salt Creek S -- 12.9 1 S. Laguna Beach S 1.9 10.2 3 N. Laguna Beach S -- 1.6 1 Crystal Cove S 1.1 2.4 2 Corona Del Mar -- 1.5 0.5 19 Newport Bay N 0.0 8.0 3 Santa Ana River Jetty N 2.2 17.6 13 Huntington Flats N -- 24.1 1 Horseshoe Kelp Dir. SD Avg. Distanc e (km) N Peak Spawning Recapture Location Table. 1. Average recapture distances of barred sand bass tagged in Newport Bay during non-spawning season (Nov- Mar) and recaptured during peak spawning season (Jun- Aug). 5) Fish tagged at Newport Bay during non-spawning season and recaptured during peak spawning season moved an average of 17±5 km, and movement was generally southward (Table 1). Totallength (m m) 175 350 525 M igration distance (km ) 0 10 20 30 40 50 Barred sand bass individuals appear to 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). Due to recent barred sand bass catch declines and the susceptibility of transient aggregate spawning populations to over-harvesting, a precautionary management measure may be necessary for barred sand bass until a harvest guideline can be developed. R ecapture distance (km ) 0 1-5 6-10 11-15 16-20 21-25 26-30 31-35 N o.offish 0 1 2 3 4 5 30 40 1960s 1990s Tagging location (N to S) % of tagging effort % of tags returned Typical recapture rates using standard tag and recapture methods are 3 to 10% (Lowe and Bray 2006). Despite differences in tagging effort across sites, we report relatively high return rates across sites, suggesting an adequate representation of the large-scale spawning-related movements of barred sand bass in so. California. The trend in spawning site returns suggests a spawning residency of 7-35 d for migrant fish. We found this trend was true even after fish were grouped by tagging month (June, July, or August). Secondary peaks in tag returns may correspond with the 28-d lunar cycle, as lunar synchronicity in spawning has also been observed with other aggregate spawners (Zeller 1998, Starr et al. 2007). Barred sand bass displayed both migratory and resident behavior, which has also been observed at Catalina Island (Mason and Lowe 2010). It appears spawning aggregations contain migrants from several locations in addition to resident fish. Furthermore, migrants from the same non-spawning residence may not necessarily migrate to the same spawning location. Individual variation in migration distances may be related to fish size. Individuals recaptured at the same location during subsequent peak spawning seasons 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. Domeier, M.L., and P.L. Colin. 1997. Tropical reef fish spawning aggregations: defined and reviewed. Bull. Mar. Sci., 60:698-726. Love, M.S., A. Brooks, and J.R.R. Ally. 1996. An analysis of commercial passenger fishing vessel fisheries for kelp bass and barred sand bass in the southern California Bight. Calif. Fish Game, 82:105-121. Lowe, C.G., and R.N. Bray. 2006. Movement and activity patterns. Pp. 524-553 in The Ecology of California Marine Fishes (L.G. Allen, M.H. Horn, and D.J. Pondella, eds.), University of California Press, 670 pp Mason, T.J. and C.G. Lowe. Home range, habitat use, and site fidelity of barred sand bass within a southern California marine protected area. Fish. Res, 106:93-101. Starr, R.M., E. Sala, E. Ballesteros, and M. Zabala. 2007. Spatial dynamics of the Nassau grouper, Epinephelus striatus, in a Caribbean atoll. Mar. Ecol. Prog. Ser., 343:239-249. Zeller, D.C. 1998. Spawning aggregations: patterns of movement of the coral trout Plectropomus leopardus as determined by ultrasonic telemetry. Mar. Ecol. Prog. Ser., 162:253-263. 35-d spawning residency of migrant fish? Secondary peaks in returns . . . spawning aggregation pulses? Residents? Migrants? r s (57) = 0.31, p = 0.02 • 8,634 fish tagged; 11% return rate (82% of recaptures from the 1960s) • 91% of tagged fish were bigger than size at 100% maturity (> 270 mm TL), and the average size was 321 ± 51 mm TL • Tagging effort was concentrated at Horseshoe Kelp and Huntington Flats during peak spawning (42%) and Newport Bay during non-spawning (9%) • Max recapture distance was 92 km (Los Alamitos to Oceanside) METHODS DISCUSSION POINTS CONCLUSIONS REFERENCES ACKNOWLEDGEMENTS
Transcript of Jarvis etal poster_aifrb_2010_29_sep2010
SPAWNING-RELATED MOVEMENTS OF BARRED SAND BASS IN SOUTHERN CALIFORNIA: INTERPRETATIONS FROM TWO DECADES OF TAG AND RECAPTURE DATA
E. T. Jarvis, C. Linardich, and C. F. Valle
California Department of Fish and Game (CDFG), 4665 Lampson Ave., Suite C, Los Alamitos, CA 90720
L.G. Allen
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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. CDFG tagging efforts were augmented by 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. Funding was supported in part by the Los Angeles County Fish and Game Commission and the Federal Aid in Sport Fish Restoration Act Grant #F-50-R-20).
MAJOR FINDINGS
Figure 2. Percent of barred sand bass tagged and percent of tags returned by site and tagging period.
1) Tagging locations with appreciable tagging effort (≥ 3% of tags) had tag return rates between 3 and 35%, with the exception of two sites (Fig. 2).
Tagging locations included sand flats, reefs, and bays along the coast of southern California and one location in Baja California, Mexico (Fig. 1).
Fish were captured by hook-and-line or trawl, measured to the nearest mm total length (TL), externally tagged with spaghetti or T-bar tags, and released. Rewards were offered for recaptures of tagged fish; recapture information included date, location, TL, and tag ID number.
Records were assigned a fishing site code, and distance traveled was measured as the linear distance between tag and recapture locations.
Records were also assigned spawning season codes based on capture month (Nov.–Mar. = non-spawning, Apr.–May = early spawning, Jun.–Aug. = peak spawning, Sept.–Oct. = late spawning).
Fish caught in early and late spawning season were excluded from analyses to reduce variability arising from individuals that may not have been spawning.
For decades, recreational fishers have targeted well-known barred sand bass spawning aggregation sites during the summer (Fig. 1; Love et al. 1996).
Since 2000, barred sand bass CPUE by party boats has declined by 65% to below the 30-yr average (CDFG unpub. data), causing concern for potential harvest impacts and identifying the need to learn more about barred sand bass spawning movements.
Throughout the 1960s and 1990s, CDFG biologists conducted tag and recapture studies of barred sand bass in southern California, enabling us to document the spawning-related movements of barred sand bass for the first time.
Our objectives were to examine these data for trends in 1) residency at spawning locations, 2) movement to and from spawning locations, and 3) spawning site fidelity.
Studying these trends may help us identify the specific aggregation behavior utilized by barred sand bass (transient or resident behavior), thus increasing our ability to manage this valuable resource.
BACKGROUND AND OBJECTIVES
Figure 1. Map of barred sand bass tagging locations in southern California. Grey polygons denote historical spawning aggregation locations.
2) Spawning residency at Huntington Flats was estimated by the frequency of returns over time; most same-year returns (82%, n = 141) were recaptured within a 35-d period, with secondary peaks in returns at 28 and 56 days at liberty (Fig. 3).
Days at liberty (7 d bins)
7 14
21
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42
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105
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Fre
quency
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tag r
etu
rns
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0
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30Figure 3. Frequency of tag returns over time for fish tagged during peak spawning season (Jun-Aug) at Huntington Flats and recaptured there within the same year.
6) Most of the fish that were tagged during peak spawning season and recaptured during subsequent peak spawning seasons were caught at the same location (80%, n = 132; Fig. 6).
Figure 6. Recapture matrix of barred sand bass tagged during peak spawning season (Jun-Aug) and recaptured in subsequent peak spawning seasons.
3) Many non-spawning season recaptures appeared resident to their peak spawning tagging locations; however, migrant fish moved an average of 13 ± 8 km away, and movement was generally northward (Fig. 4).
Figure 4. Recapture distances of barred sand bass tagged during peak spawning season (Jun-Aug) and recaptured during non-spawning season (Nov-Mar).
4) A positive correlation existed between fish size (TL) and migration distance to non-spawning season recapture locations (Fig. 5).
Figure 5. Fish size (TL) versus migration distance from peak spawning season (Jun-Aug) tagging locations to non-spawning season (Nov-Mar) recapture locations.
S--51.51OceansideS1.542.88Barn KelpS0.932.85San OnofreS1.631.44San Mateo PointS--29.01San ClementeS--24.11Middle KelpS--24.11Capistrano BeachS1.320.46Dana PointS1.118.52Salt CreekS--12.91S. Laguna BeachS1.910.23N. Laguna Beach
S--1.61Crystal CoveS1.12.42Corona Del Mar--1.50.519Newport BayN0.08.03Santa Ana River Jetty
N2.217.613Huntington FlatsN--24.11Horseshoe Kelp
Dir.SD
Avg. Distance
(km)NPeak Spawning Recapture Location
Table. 1. Average recapture distances of barred sand bass tagged in Newport Bay during non-spawning season (Nov-Mar) and recaptured during peak spawning season (Jun-Aug).
5) Fish tagged at Newport Bay during non-spawning season and recaptured during peak spawning season moved an average of 17±5 km, and movement was generally southward (Table 1).
Total length (mm)
175 350 525
Mig
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0
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30
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50
Barred sand bass individuals appear to 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).
Due to recent barred sand bass catch declines and the susceptibility of transient aggregate spawning populations to over-harvesting, a precautionary management measure may be necessary for barred sand bass until a harvest guideline can be developed.
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401960s 1990s
Tagging location (N to S)
% of tagging effort % of tags returned
Typical recapture rates using standard tag and recapture methods are 3 to 10% (Lowe and Bray 2006). Despite differences in tagging effort across sites, we report relatively high return rates across sites, suggesting an adequate representation of the large-scale spawning-related movements of barred sand bass in so. California.
The trend in spawning site returns suggests a spawning residency of 7-35 d for migrant fish. We found this trend was true even after fish were grouped by tagging month (June, July, or August). Secondary peaks in tag returns may correspond with the 28-d lunar cycle, as lunar synchronicity in spawning has also been observed with other aggregate spawners (Zeller 1998, Starr et al. 2007).
Barred sand bass displayed both migratory and resident
behavior, which has also been observed at Catalina Island (Mason and Lowe 2010). It appears spawning aggregations contain migrants from several locations in addition to resident fish. Furthermore, migrants from the same non-spawning residence may not necessarily migrate to the same spawning location. Individual variation in migration distances may be related to fish size.
Individuals recaptured at the same location during subsequent peak spawning seasons 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.
Domeier, M.L., and P.L. Colin. 1997. Tropical reef fish spawning aggregations: defined and reviewed. Bull. Mar. Sci., 60:698-726.
Love, M.S., A. Brooks, and J.R.R. Ally. 1996. An analysis of commercial passenger fishing vessel fisheries for kelp bass and barred sand bass in the southern California Bight. Calif. Fish Game, 82:105-121.
Lowe, C.G., and R.N. Bray. 2006. Movement and activity patterns. Pp. 524-553 in The Ecology of California Marine Fishes (L.G. Allen, M.H. Horn, and D.J. Pondella, eds.), University of California Press, 670 pp
Mason, T.J. and C.G. Lowe. Home range, habitat use, and site fidelity of barred sand bass within a southern California marine protected area. Fish. Res, 106:93-101.
Starr, R.M., E. Sala, E. Ballesteros, and M. Zabala. 2007. Spatial dynamics of the Nassau grouper, Epinephelus striatus, in a Caribbean atoll. Mar. Ecol. Prog. Ser., 343:239-249.
Zeller, D.C. 1998. Spawning aggregations: patterns of movement of the coral trout Plectropomus leopardus as determined by ultrasonic telemetry. Mar. Ecol. Prog. Ser., 162:253-263.
35-d spawning residency of migrant fish?
Secondary peaks in returns . . . spawning aggregation pulses?
Residents?
Migrants?
rs(57) = 0.31, p = 0.02
• 8,634 fish tagged; 11% return rate (82% of recaptures from the 1960s)
• 91% of tagged fish were bigger than size at 100% maturity (> 270 mm TL), and the average size was 321 ± 51 mm TL
• Tagging effort was concentrated at Horseshoe Kelp and Huntington Flats during peak spawning (42%) and Newport Bay during non-spawning (9%)
• Max recapture distance was 92 km (Los Alamitos to Oceanside)
METHODS
DISCUSSION POINTS
CONCLUSIONS
REFERENCES
ACKNOWLEDGEMENTS
