Pacific Central-American Coastal Large Marine Ecosystem: A Review
Igor Belkin University of Rhode Island PCAC LME Countries PCAC LME Eastern Tropical Pacific LME total area:
MEXICO GUATEMALA EL SALVADOR PCAC LME HONDURAS LME total area: 1,996,659 km2 NICARAGUA COSTA RICA PANAMA Eastern Tropical Pacific COLOMBIA Each dot corresponds to a grid cell, 0.25 latitude by 0.25 longitude. At the Equator, cells are 28 km x 28 km ECUADOR PERU Sea Surface Temperature
(Fiedler and Talley, 2006) Sea Surface Salinity (Fiedler and Talley, 2006) (Kessler, 2006; drifter data)
Surface Currents (Kessler, 2006; drifter data) Surface Currents: Spring vs. Fall
(Wyrtki, 1965) CC: California Current (CC) NEC: North Equatorial Current NECC: North Equatorial Countercurrent SEC: South Equatorial Current CRC: Costa Rica Coastal Current ITCZ:Intertropical Convergence Zone. Dashed lines around the NECC show its varying extent. Vertical Structure of Zonal Currents (Kessler, 2006)
Mean meridional sections of temperature (white contours) and zonal current (color shading, where red is eastward and blue westward; cm/s). At 125W and 110W, directly measured currents are shown within 8 latitude; elsewhere the currents are geostrophic. Seasonal Variations of Geostrophic Currents
Red colors indicate high dynamic heights (0/450 m), blue low; units = dyn. cm. Kessler (2006) Long-Term Variability of Sea Surface Temperature SST change in LMEs from 1957 through 2012
Belkin (2015) PACIFIC CENTRAL- AMERICAN COASTAL Long-Term Variability of SST
Between 1957 and 2012, the PCAC LME has warmed by 0.27C, thus belonging to Category 4 (slow warming LME). The thermal history of this LME was non-monotonous. The coolingphase culminated in two minima, in 1971 and 1975, both associatedwith major La Nias, after which SST rose by approximately 1C overthe next 30 years. The absolute minimum of 1975 was synchronous with absoluteminima in two other East Pacific LMEs: California Currentand Gulf ofCalifornia. The warming phase was accentuated by two sharp peaks, in and 1997, both associated with major El Nios. Similar warm eventswere observed in other East Pacific LMEs (Humboldt Current, Gulf ofCalifornia, and California Current). All significant maxima and minimaof SSTobserved in PCAC LMEare associated with El Nios and La Niasrespectively. CALIFORNIA CURRENT GULF OF CALIFORNIA GULF OF MEXICO CARIBBEAN SEA HUMBOLDT CURRENT CALIF. CURR. GULF of CALIF. GULF of MEXICO PACIFIC CENTRAL CARIB.SEA HUMBOLDT CURR. SST Fronts From Satellite Data (Belkin, 2005) (OReilly, 2015; satellite data)
Chlorophyll-a (OReilly, 2015; satellite data) (OReilly, 2015; satellite data)
Primary Productivity (OReilly, 2015; satellite data) Chlorophyll-a and Primary Productivity
(OReilly, 2015) The annualChlorophyll-aconcentration (CHL) cycle has a maximum peak (0.343 mg m-3) in March and a minimum (0.230 mg m-3) during August. The average CHL-a is mg m-3. Maximumprimary productivity(490 g C m-2 y-1) occurred during 2000 and minimumprimary productivity(336 g C m-2y-1) during 1998. There is a statistically insignificant increasing trend in Chlorophyll of 15.2% from 2003 through 2013. The averageprimary productivityis 407 g C m-2 y-1, which places this LME in Group 4 of 5 categories (with 1 = lowest and 5= highest). Fish Catch Anchoveta Engraulis ringens
Anchoveta Cetengraulis mysticetus Fish Catch Penaeid shrimp Penaeus monodon Yellowfin tuna Thunnus albacares Pacific sardine Sardinops sagax Pacific thread herring Opisthonema libertate The Pacific Central-American Coastal LME is rich in both pelagic and demersal fisheries resources. The most valuable fisheries in the region are offshore tunas and coastal penaeid shrimps, whose landed bycatch is usually not reported. More than 50% of the reported shelf catches consists of small coastal pelagic species such as anchoveta (Engraulis ringensandCetengraulis mysticetus), Pacific sardine (Sardinops sagax) and Pacific thread herring (Opisthonema libertate), most of which are used for fishmeal and fish-oil. (Sea Around Us Project, 2014)
Annual Catch (Sea Around Us Project, 2014) Conclusions The Pacific Central American LME is one ofthe most complex LMEs in the World Ocean Long-term warming so far was rather slow The only regime shift - after La Nina 1975 Effects of El Ninos and La Ninos are strong Primary productivity is stable Fishing yields declined since the 1990s Acknowledgments: Ken Sherman Jay OReilly THANK YOU!