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What have ecological studies of fishes in kelp forests

Theme numero uno:. How has application of broader ecological understanding contributed to our understanding of the ecology of kelp forest fishes?. What have ecological studies of fishes in kelp forests contributed to our broader ecological understanding?.

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What have ecological studies of fishes in kelp forests

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  1. Theme numero uno: How has application of broader ecological understanding contributed to our understanding of the ecology of kelp forest fishes? What have ecological studies of fishes in kelp forests contributed to our broader ecological understanding?

  2. longevity, fecundity reproductive modes life cycle distribution structure (size, age, genetic, spatial) dynamics structure (composition, abundance) diversity biogeography dynamics Life History Traits (species-wide, genetic, reproductive success) Population Attributes Community Attributes

  3. Larvae survive, grow, disperse, develop Pelagic Environment settlement reproduce Benthic Environment Adult Juvenile survive, grow, mature “Bipartite” life cycle of marine organism with pelagic larvae

  4. “CLOSED” POPULATIONS “OPEN” POPULATIONS Production Supply Production Supply Little or no exchange among populations Significant exchange among populations Supply Production Production Supply

  5. Temperate reef fish assemblages comprised of BOTH “open” and “closed” populations

  6. “CLOSED” “OPEN” 1:1 recruitment (births) (t+1) recruitment (settlement) adults (time = t) adults (time = t) 1:1 adults (t+1) adults (t+1) recruitment (births) recruitment (settlement) (time = t)

  7. Consequences of larval dispersal: (1) decouples local recruitment (replenishment) from local production (2) larval recruitment critical to replenishment of local populations • local replenishment reliant on recruitment of larvae • produced elsewhere (4) “open” spatial structure of local and regional populations But remember that “openness” is a function of: (1) spatial scale: openness decreases as scale of population increases (2) adult movement: openness decreases as movement increases • “retention”: openness decreases as likelihood that larvae return • to adult population increases

  8. Sources of spatial and temporal variation in recruitment Larval production: - reproductive mode - adult abundance - adult fecundity (eggs per female) size structure / sex ratio adult condition

  9. Reproductive modes of kelp forest fishes: (1) internal vs. external reproduction (2) internal vs. external eggs (3) external eggs: benthic or “broadcast” (i) internal fertilization, internal eggs: viviparity e.g., rays, sharks, surfperch, rockfish (ii) internal fertilization, external eggs: ovoviviparity e.g., skates, sharks (swell, horn), sculpins (iii) external fertilization (oviparity), broadcast eggs e.g., kelp bass, wrasses (senorita, sheephead) (iv) external fertilization (oviparity), benthic eggs e.g., greenlings, gobies, damselfishes, kelpfishes

  10. Consequences of reproductive modes: (1) behavior and social structure e.g., benthic eggs -- nest guarding, territoriality broadcast eggs -- spawning aggregations (2) Defines resources that influence population distribution and abundance e.g., competition for nest sites Also, some species are hermaphroditic e.g., kelp bass, wrasses (sequential, protogynous) gobies (sequential, protandrous)

  11. Sources of spatial and temporal variation in recruitment Larval production: - reproductive mode - adult abundance - adult fecundity (eggs per female) size structure / sex ratio adult condition – e.g., surf perch, El Nino

  12. Sources of spatial and temporal variation in recruitment Larval dispersal (direction, distance, delivery): - larval duration - larval behavior - oceanographic features - interaction among these Larval production: - timing of reproduction - location of reproduction

  13. Larval dispersal and delivery: larval duration (1) Longer larval duration  greater dispersal potential e.g., Shanks et al. 2003, Kinlan and Gaines 2003 (2) Larval duration  temporal variability in populations e.g., Schmitt, unpublished

  14. Pelagic duration – dispersal distance relationships 10000 invertebrates 1000 macroalgae fish 100 Predicted by passive dispersal 10 Dispersal Distance (km) 1 0.1 0.01 0.001 0.0001 0.01 0.1 1 10 100 1000 10000 Propagule Duration (hr) Shanks et al., Ecological Applications, 2003

  15. Larval duration midpoint (range) Species Larval duration of coastal fish species from western North America Shanks et al., Ecological Applications, 2003

  16. Pelagic-duration “Isolation by distance” 10000 1000 100 10 Dispersal Distance (km) 1 0.1 0.01 = 30 days 0.001 0.0001 0.01 0.1 1 10 100 1000 10000 Propagule Duration (hr) Estimates of larval fish dispersal distance Kinlan and Gaines 2003, Ecology 10’s to 100’s of km

  17. Larval dispersal and delivery: larval duration (2) Larval duration  temporal variability in populations e.g., Schmitt, unpublished high Temporal variation (CV) adult population size low short (0) high (2-4) intermed. ( < 1) larval duration (mo)

  18. Sources of spatial and temporal variation in recruitment Larval dispersal (direction, distance, delivery): - larval duration - larval behavior - oceanographic features - interaction among these Larval production: - timing of reproduction - location of reproduction

  19. Larval dispersal and delivery: larval behavior (1) Larval cues: (light, pressure, temperature, structure) e.g., Norris 1963, Ecology - Opal eye (Girella nigricans) - distribution among tide pools of different temp.s - lab experiments - coast-wide patterns of recruitment - hypothesized mechanisms: - internal waves - thermal / structural cues - upwelling

  20. Larval dispersal and delivery: larval behavior (2) Vertical distribution e.g., Larson et al. 1994, CalCOFI - vertical distribution of rockfish early and late larvae - upwelling - see Ammann, unpublished kelp bed late larvae early larvae depth pelagic juveniles sea floor offshore onshore

  21. Sources of spatial and temporal variation in recruitment Larval dispersal (direction, distance, delivery): - larval duration - larval behavior - oceanographic features - interaction among these Larval production: - timing of reproduction - location of reproduction

  22. Larval dispersal and delivery: oceanographic features (1) Large-scale episodic events e.g., Cowen 1985, J. Mar. Res. - Sheephead (Semicossyphus pulcher) - adult size distribution (Pt Conception - Cabo San Lucas) - back-calculated otoliths to estimate year and coast-wide patterns of recruitment - recruitment to north only during El Nino - poor recruitment to south during El Nino - currents run more northward only during El Nino Conclusion: currents carry larvae northward and replenish SB populations only during El Nino

  23. Sources of spatial and temporal variation in recruitment Larval dispersal (direction, distance, delivery): - larval duration - larval behavior - oceanographic features - interaction among these Larval production: - timing of reproduction - location of reproduction

  24. Olive rockfish Mid-water complex Long larval duration (3 - 4 months) Yellowtail rockfish Black rockfish Kelp rockfish Gopher rockfish Benthic complex Short larval duration (1-2 months) Black-&-yellow rockfish

  25. 70 50 30 10 Fish per 240 m3 20 16 12 8 4 0 El Nino La Nada La Nina (1998) (1999) (2000) Olive, Yellowtail and Black rockfish Mid-water complex Long larval duration (3 - 4 months) Kelp, Black-&-yellow, and Gopher rockfish Benthic complex Short larval duration (1-2 months)

  26. Mid - water Benthic Large - scale spatial patterns 454 454 Midwater Benthic Rockfish recruitment 2000 2001 2002 Patterns: strong interannual variability patterns of variation differ between species complexes poor recruitment to the south 100 100 0 0 0 0 100 100 1999 1999 2002 1999 1999 2002

  27. Kelp, Black-&-yellow, and Gopher rockfish 20 16 Fish per 240 m3 12 8 4 El Niño Normal 0 La Niña (1998) (1999) (2000) Kelp rockfish Relaxation Gopher rockfish Black-&-yellow rockfish Benthic complex Short larval duration (1-2 months)

  28. 70 Olive, Yellowtail and Black rockfish 50 Fish per 240 m3 30 10 El Niño Normal La Niña (1998) (1999) (2000) Mid-water complex Long larval duration (3 - 4 months) Upwelling Olive rockfish Yellowtail rockfish Black rockfish

  29. 14 13 12 Temperature (°C) 11 10 9 May June July August Year 2000 Mid-water complex n = 227 0.5 0.4 Number of fish per sampling unit 0.3 0.2 0.1 0.0 Benthic complex n = 363 0.5 0.4 Number of fish per sampling unit 0.3 0.2 0.1 0.0 May June July August (2) Smaller-scale, more frequent events (Ammann unpublished)

  30. Sources of spatial and temporal variation in recruitment Settlement: - larval cues - habitat structure - priority effects conspecific cues predation competition

  31. Settlement (post-settlement): habitat structure (1)Macrocystis (rockfishes in central California) e.g., Carr 1991, JEMBE - read about it later (2)Macrocystis vs. understory (southern California) e.g., Carr 1989, JEMBE - manipulated presence of giant kelp and monitored recruitment - recruitment of some species higher to kelp plots - recruitment of some species higher to understory

  32. Settlement (post-settlement): habitat structure (3)Macrocystis (kelp bass in southern California) e.g., Carr 1994, Ecology - positive correlation between recruitment and kelp density - demonstrated experimentally (4)Macrocystis (kelp surfperch in southern California) e.g., Anderson 1994, MEPS - manipulated presence of giant kelp canopy and monitored recruitment (5) Sea urchins (blue-banded goby in southern California) e.g., Hartney and Grorud 2002, Oecologia - manipulated presence of urchins and monitored recruitment

  33. Sources of spatial and temporal variation in recruitment Settlement: - larval cues - habitat structure - priority effects conspecific cues predation competition Very little information available!

  34. Sources of spatial and temporal variation in recruitment Early post-settlement: - survival - growth - movement predation competition

  35. Early post-settlement: predation Conspecific and interspecific resident effects e.g., Anderson 2001, Ecology - kelp surfperch (post-parturition) in So. California - manipulated presence of predators – kelp bass - mortality higher in presence of predators - mortality was density-dependent e.g., Steele, 1997b, Oecologia - manipulated presence of predators – kelp bass - reduced recruitment of blue-banded, not black-eyed goby e.g., Johnson, unpublished - juvenile kelp rockfish in central California - same patterns as Anderson above

  36. Early post-settlement: competition Conspecific and interspecific resident effects e.g., Steele 1997a, Ecology - black-eyed and blue-banded gobies in So. California - manipulated presence of adults of both - settlement of black-eyed (-) “influenced” in presence of adult conspecifics - settlement of black-eyed not influenced by presence of adult blue-banned - settlement of blue-banded (+) influenced in presence of adult conspecifics - settlement of blue-banded not influenced in presence of adult black-eyed

  37. Sources of spatial and temporal variation in recruitment - survival - growth - movement competition predation Late post-settlement: adult and juvenile interactions

  38. Late post-settlement: interspecificcompetition (1) Hixon 1980, Schmitt and Holbrook 1990, etc. - striped and black surfperch in So. California - two species exhibit depth stratified distributions - manipulated presence of either species - monitored change in depth distribution (2) Larson 1980, Ecological Monographs - black-and-yellow and gopher rockfish in So. Calif. - same as above for sibling surfperches (3) Hallacher and Roberts 1985, Env. Biol. Fishes - spatial and dietary partitioning of rockfishes within kelp forest

  39. Striped (+) Striped (--) Striped (+) Striped (+) Striped (+) Striped (+) Striped (+) Black (+) Black (--) Black (+) Black (+) Black (+) Black (+) Black (+) Black (+) Striped (+) nobody home Black (+) Late post-settlement: interspecificcompetition 1 2 3 reef: time: pre- manipulation post- Conclusion: striped perch competitively dominant: excludes (interference) black from shallow.

  40. Late post-settlement: intraspecificcompetition Territory size limits local density and pop. size (1) Garibaldi in So. California -- Clarke 1970 - map territory sizes and distribution - remove individual - monitored change in territory sizes and density (2) striped and black surfperch in So. California - Schmitt & Holbrook - same as above (3) black-and-yellow and gopher rockfish in So. Calif. - Larson 1980 a, b Marine Biology - same as above

  41. San Francisco Bay 40 80 120 160 0 Miles Kilometers 0 40 80 120 160 Monterey Bay Pt. Conception Biogeographic patterns: PISCO monitoring study: Distributed across: • oceanographic • conditions • reef habitat • marine reserves Objectives: • geographic patterns • temporal dynamics

  42. California Current California Pacific Ocean California Counter Current

  43. Rockfish-dominated Subtropical Canonical Discriminant 1 (16.2%) Kelp greenling, rainbow surfperch Canonical Discriminant 1 (33.2%) Spatial patterns of reef fish assemblages

  44. Latitudinal gradients in fish assemblages

  45. Latitudinal gradients in fish assemblages

  46. Temperate reef fish – habitat associations: (1)Macrocystis (southern California) e.g., Larson and DeMartini 1984, U.S. Fishery Bull. - compared fish assemblage in areas with and with giant kelp - cobblestone bottom off San Onofre - difference in relative abundance of species (2)Macrocystis vs. Nereocystis (central California) e.g., Bodkin 1986, U.S. Fishery Bull. - compared fish assemblages on either side of Piedras Blancas (Nereo. north, Macro. south) - difference in relative abundance of species

  47. Temperate reef fish – habitat associations: (3)Macrocystis (southern California) e.g., Ambrose and Swarbrick 1989, Bull. Mar. Sci. - compared fish assemblage in areas with and with giant kelp - included artificial reefs - little difference in relative abundance of species (4)Macrocystis (southern California) e.g., Holbrook et al. 1990,1994, Austr. J. Ecol., Am. Zool. - same as (3) above, no difference in species richness - planktivores and macro-invert eaters, reduced with kelp

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