Eastern Tropical Pacific Oceanography and Ecosystems Paul Fiedler Southwest Fisheries Science Center Marine Mammal and Turtle Division
Oceanography Background shading is mean surface temperature ranging from to 18 to 29 ° C (dark to light). National Oceanic and Atmospheric Administration | NOAA Fisheries | Page 2
Ecosystems Biogeochemical Provinces : Longhurst, A. R. 2007. Ecological Geography of the Sea, 2 nd ed. National Oceanic and Atmospheric Administration | NOAA Fisheries | Page 3
Ecosystems Eastern boundary currents • California, Peru Currents • Coastal upwelling • High primary production • Clupeid fisheries National Oceanic and Atmospheric Administration | NOAA Fisheries | Page 4
Ecosystems Cold tongue • South Equatorial Current, Southeast trade winds • Equatorial upwelling • El Niño • CO 2 source National Oceanic and Atmospheric Administration | NOAA Fisheries | Page 5
Ecosystems Warm pool • North Equatorial Countercurrent • Intertropical Convergence Zone • Warm, highly stratified • Low productivity • Oxygen minimum layer • Yellowfin tuna fishery • Costa Rica Dome National Oceanic and Atmospheric Administration | NOAA Fisheries | Page 6
Ecosystems Coastal • CRCC • Coastal eddies • Gap winds • Coral reefs • Seabird, turtle nesting National Oceanic and Atmospheric Administration | NOAA Fisheries | Page 7
What is the Costa Rica Dome? Townsend Cromwell (1958 , Thermocline topography, horizontal currents and ridging in the eastern tropical Pacific. IATTC Bulletin): “…attention is drawn to the shallow thermocline off Costa Rica near 10°N, 90°W, persistent the year round… This area will be referred to as the Costa Rican Thermal Dome , …” Monthly thermocline depths < 35m 1990-2009 National Oceanic and Atmospheric Administration | NOAA Fisheries | Page 8
Oxygen minimum layer Oxygen saturation (%) at 150m depth (World Ocean Atlas 2013). • Affect distribution of plankton and fish • Oxygen minimum layers are expanding National Oceanic and Atmospheric Administration | NOAA Fisheries | Page 9
U. S. National Marine Fisheries Service interest: Dolphins impacted by the yellowfin tuna purse-seine fishery SWFSC Cetacean and Ecosystem Surveys • 10 survey years (1986 -2006), August-November • 2166 sea days • 15,253 sightings National Oceanic and Atmospheric Administration | NOAA Fisheries | Page 10
Biodiversity of SWFSC sightings in eastern tropical Pacific Number of species in three taxa that occur in the eastern tropical Pacific (ETP), with the global number of species per taxon and the IUCN conservation status for ETP species. From S. L. Martin. 2014. "Ecosystem-based management for the oceanic commons: Applying the concepts of ecosystem services, indicators, and trade-offs to make informed decisions." Ph.D. diss. Scripps Institution of Oceanography, UCSD. National Oceanic and Atmospheric Administration | NOAA Fisheries | Page 11
Dolphins National Oceanic and Atmospheric Administration | NOAA Fisheries | Page 12
Whales National Oceanic and Atmospheric Administration | NOAA Fisheries | Page 13
Seabirds Masked Booby Juan Fernandez Petrel Black Storm-petrel Tahiti Petrel National Oceanic and Atmospheric Administration | NOAA Fisheries | Page 14
Sea Turtles • Olive Ridley ~ 2 million are resident (nest and feed) • Nest only: Leatherback, Green, Hawksbill • Feed only: a few juvenile Loggerheads National Oceanic and Atmospheric Administration | NOAA Fisheries | Page 15
Summary • Oceanography – variety of oceanic and coastal processes • Ecosystems – moderately productive and diverse • Top predators are widespread – cetaceans, seabirds, turtles Al Jackson, Trevor Joyce, Lisa Ballance, Robert Pitman, Jeff Seminoff, Summer Martin National Oceanic and Atmospheric Administration | NOAA Fisheries | Page 16
Science and Management Questions 1) What are the interconnections at the eastern end of the equatorial current system? 2) Are the Papagayo (and Tehuantepec) eddies important biological hotspots that carry nutrients and organisms to the ocean interior? How does the biological community evolve? 3) How does the shallow oxygen minimum layer affect zooplankton and higher organisms living in the epipelagic or surface layer? 4) Is there any evidence of ecosystem regime shifts? 5) How does the eastern tropical Pacific support such a diverse community of top predators? 6) Do the IUCN/Key Biodiversity Area criteria work for cetaceans? 7) Is the Costa Rica Dome a biodiversity hotspot, or just a center of overlap? 8) How will climate change affect oceanography and ecosystems? Compile existing data on historical spatial-temporal variability as a baseline. National Oceanic and Atmospheric Administration | NOAA Fisheries | Page 17
Biodiversity Species richness for cetaceans, seabirds, micronekton larvae, and sea turtles on SWFSC surveys. From S. L. Martin. 2014. "Ecosystem-based management for the oceanic commons: Applying the concepts of ecosystem services, indicators, and trade-offs to make informed decisions." Ph.D. dissertation. Scripps Institution of Oceanography, UCSD. . National Oceanic and Atmospheric Administration | NOAA Fisheries | Page 18
El Niño The warm phase of the El Niño-Southern Oscillation cycle of ocean-atmosphere interaction. National Oceanic and Atmospheric Administration | NOAA Fisheries | Page 19
Surface chlorophyll (phytoplankton biomass) Climatologies of monthly data, 1997-2010, from GlobColour Project (European Service for Ocean Colour, http://www.globcolour.info). National Oceanic and Atmospheric Administration | NOAA Fisheries | Page 20
Surface winds Figure 3.3. Surface wind vectors and divergence (negative is convergence), March and September climatologies 1999-2009 (Risien and Chelton 2008, http://cioss.coas.oregonstate.edu/scow). National Oceanic and Atmospheric Administration | NOAA Fisheries | Page 21
Precipitation Figure 3.4. Precipitation rate, March and September climatologies (CPC Merged Analysis of Precipitation Enhanced, http://www.esrl.noaa.gov/psd/data/ gridded/data.cmap.html). National Oceanic and Atmospheric Administration | NOAA Fisheries | Page 22
Gap winds Figure 3.5. Wind vectors and curl (related to rotation, colors), January climatology 1999-2009 (Risien and Chelton, 2008, http://cioss.coas.oregonstate.edu/scow). Three prominent wind jets with associated anticyclonic (negative) and cyclonic (positive) wind curl are, from northwest to southeast, Tehuantepec, Papagayo, and Panama. National Oceanic and Atmospheric Administration | NOAA Fisheries | Page 23
Thermocline National Oceanic and Atmospheric Administration | NOAA Fisheries | Page 24
Sea Turtles, cont. Leatherback (a.k.a. Laúd, Baula) National Oceanic and Atmospheric Administration | NOAA Fisheries | Page 25
Pelagic ecosystem model Ecopath model of the eastern Pacific pelagic ecosystem. (Olson & Watters 2003. IATTC Bulletin.22(3)). National Oceanic and Atmospheric Administration | NOAA Fisheries | Page 26
Ocean depth National Oceanic and Atmospheric Administration | NOAA Fisheries | Page 27
Tuna fishery Average annual distributions of the purse-seine catches of yellowfin, by set type, 2008-2012. The sizes of the circles are proportional to the amounts of yellowfin caught in those 5° by 5° areas. (IATTC Fishery Status Report No. 12, 2013) National Oceanic and Atmospheric Administration | NOAA Fisheries | Page 28
Fisheries in the eastern tropical Pacific Total catch (black lines) and total estimated market value (green lines) for the top 10 commercially fished species groups in the ETP across all gear types and countries. Note that there are differences in the vertical axis scales across species groups. Data source: IATTC and NMFS public data. From S. L. Martin. 2014. "Ecosystem-based management for the oceanic commons: Applying the concepts of ecosystem services, indicators, and trade-offs to make informed decisions." Ph.D. disseertation. Scripps Institution of Oceanography, UCSD. National Oceanic and Atmospheric Administration | NOAA Fisheries | Page 29
International Agreements • Agreement on the International Dolphin Conservation Program (AIDCP) To reduce incidental dolphin mortalities in the tuna purse-seine fishery, to seek ecologically sound means of capturing large yellowfin tunas not in association with dolphins, and to ensure the long-term sustainability of the tuna stocks. • Inter -American Tropical Tuna Commission (IATTC) To study the biology of the tunas and related species, to determine the effects that fishing and natural factors have on their abundance, and to recommend conservation measures so that the stocks of fish can be maintained at levels which will afford maximum sustainable catches. • Inter-American Convention (IAC) for the Protection and Conservation of Sea Turtles To promote the protection, conservation and recovery of sea turtle populations and of the habitats on which they depend. National Oceanic and Atmospheric Administration | NOAA Fisheries | Page 30
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