Succession of pelagic copepod species in coastal waters off northern Chile: the influence of the 1997–98 El Niño

A 2-year time series (17-d interval) of zooplankton, sampled from June 1996 through January 1998, along with oceanographic data, allowed the study of species abundances and diversity during non-El Niño and El Niño conditions at Mejillones (23° S), northern Chile. A total of 28 species was identified, of which the most abundant were the calanoids Paracalanus parvus, Calanus chilensis, Acartia tonsa, and Centropages brachiatus, the cyclopoid Oithona similis, and the poecilostomatoids Oncaea conifera and Corycaeus typicus. El Niño Southern Oscillation (El Niño) was first detected in the area in May 1997 and persisted until March 1998. We divided the time series into two parts: non-El Niño and El Niño conditions. The number of species significantly increased during El Niño conditions, but total abundance of copepods was greater during non-El Niño conditions. Although some expatriate species appeared during El Niño, such as the harpacticoid Microsetella norvegica and Eucalanus subtenuis, the diversity index of Hulburt was not significantly different between the two periods. Despite the dramatic alteration of oceanographic conditions during the El Niño period, we concluded that the community of pelagic copepods was not subject to drastic changes either in total abundance or in structure.     

Effects of El Niño-related Drought on Freshwater and Brackish-water Fishes in Suriname, South America

Droughts associated with the El Niño-Southern Oscillation (ENSO) affected fishes of brackish-water lagoons, freshwater swamps and a rainforest creek in Suriname, South America. The mean rainfall in the period August to February in 22 El Niño years was 76.6% of the mean rainfall in the same months of non-El Niño years. In the period 1900–1999, three out of four years in which an extreme drought (rainfall less then 60% of the mean value) occurred were El Niño years. The recent 1997/1998 ENSO event caused the second most severe drought in a 100-year record. Drying up of brackish-water lagoons, freshwater swamps and rainforest creeks was observed during El Niño-related droughts. In the lagoons ariid catfish died first, followed by snook, tilapia, mullet and tarpon, respectively. Landings of lagoon fish were positively correlated with rainfall in the period August–February. During the El Niño-related drought we observed failure of reproduction in three species of callichthyid armoured catfish in both coastal freshwater swamps and a rainforest creek in the interior. In the El Niño year 1997/1998, the no flow period of the rainforest creek was extended by four months beyond the long dry season and the dissolved oxygen levels in the dry-season pools dropped to 1.27mg O₂l^–1 (as compared to 4.53mg O₂l^–1 under running water conditions). Other fish species of the rainforest creek also showed decreased reproductive success in the El Niño year. We suggest that the stochastic effects of El Niño-related drought may be an important non-equilibrium component in the ecology of neotropical inland fish communities.     

Response on scallop culture to enhanced nutrient supply by experimental fertilisation of a landlocked bay

The effect of an enhanced nutrient supply to coastal waters of a landlocked bay, Hopavågen in Central Norway, on the phytoplankton production and biomass, and on growth of scallops (Pecten maximus) was studied in 1997–1999. Nitrogen, silicon and phosphorous (N:Si:P = 16:8:1, atomic) were added daily between May and October in 1998 at a level of 0.4 mg P m^–3 day^–1. The concentration of nutrient addition was doubled in 1999 during the same period. High addition of nutrients (1999) resulted in a significantly higher phytoplankton biomass in the summer period, expressed as chlorophyll a content, than without nutrient (1997) and low nutrient (1998). The respective mean chlorophyll a levels were 2.4 in 1999, 1.6 in 1998 and 1.2 g l^–1 in 1997. The mean primary production during the summers generally increased with the addition of nutrients from an average level of 320 mg carbon m^–2 day^–1 in 1997 to 1200 mg carbon m^–2 day^–1 in 1999. Scallops placed at 10 m depth in Hopavågen showed an increase in growth rate of the outer scallop shell in the period July–September from 0.16% day^–1 in 1997 to 0.53% day^–1 in 1998. Scallops grown in an unfertilised control station in the fjord outside Hopavågen had a significantly lower growth rate than those grown in the fertilised water of Hopavågen. The results showed decreased growth rate with increasing shell sizes. However, for all size groups studied a higher growth rate of the scallops was observed when nutrients were added to the bay. The tissue dry weight content of scallops grown in Hopavågen was 2–4 times higher than in the control scallops.     

Chemical characteristics,with particular reference to phosphorus,of the rivers draining into Lake Naivasha,Kenya

The loss of phosphorus from the catchment of Lake Naivasha, Kenya, was 0.2 kg ha^–1 ann^–1, 76% of it particulate in a `normal' year of wet and dry periods. It rose to a mean of 1.8 kg ha^–1 ann^–1, 90% of which was particulate, in the months following the extreme rainfall which followed the 1997–1998 El Niño event in the Southern Atlantic. Total and particulate phosphorus were positively correlated with suspended solids and with discharge, and conductivity was negatively correlated with discharge. The magnitude of losses pose both threats to the water quality of Lake Naivasha and to the sustainable soils resources of the catchment.     

A possible relationship between outbreaks of the oriental migratory locust (Locusta migratoria manilensis Meyen) in China and the El Niño episodes

We investigated the statistical relationship between outbreaks of the oriental migratory locust (Locusta migratoria manilensis Meyen) in the Huang Ho and Huai Ho regions of China and El Niño episodes during 1905–1959, and discussed how El Niño affects locust outbreaks. The outbreaks of the locust mostly occurred 1–2 years after the El Niño episodes. El Niño was suggested to affect the locust outbreaks by changing the precipitation and air temperature in Northern China.     

Coral survivors of the 1982–83 El Niño-Southern Oscillation,Galápagos Islands,Ecuador

Reef Sites

Coral survivors of the 1982–83 El Niño-Southern Oscillation, Galápagos Islands, Ecuador     

The impact of El Niño events on populations of mesopelagic hydromedusae

For over 10 years, the midwater ecology group at MBARI has compiled video and accompanying physical data with the ROV Ventana operating in mesopelagic depths of Monterey Bay, CA in order to elucidate patterns in midwater ecology. Two El Niño events have occurred during this time period, in 1991–92 and in 1997–98. The oceanographic metric of spiciness combines temperature and salinity data into one sensitive measurement. Although temperature and salinity measurements alone revealed no clear patterns, clear signals of spiciness were observed that corresponded to water mass intrusions into the deep waters of the bay during the two El Niño events. During these events, some seldom-seen species were observed in high numbers in the midwater, while historically common species became rare. During non-El Niño years, the leptomedusa Mitrocoma cellularia(A. Agassiz, 1865) was common in the surface waters (0–50 m) of Monterey Bay, but it was not abundant at depth, while the trachymedusa Colobonema sericeum Vanhöffen, 1902 was found in relatively high numbers at mesopelagic depths. During the last two El Niño events, M. cellulariawas observed in higher numbers at mesopelagic depths, whereas C. sericeum was scarce. M. cellularia was found in a wider range of temperatures, salinities, and dissolved oxygen values than was C. sericeum. Transport and tolerance hypotheses are proposed to explain differences in the presence and numerical density of the medusae.     

Ocean color observations of a surface water transport event: Implications for Pseudo-nitzschia on the Washington coast

A persistent patch of high biomass water, associated with the Juan de Fuca Eddy, is often observed in surface chlorophyll a images off the southwest coast of Vancouver Island, Canada. Outbreaks of toxic Pseudo-nitzschia spp. along the Washington, USA, coast are believed to correlate with the transport of waters from Juan de Fuca Eddy southward to Washington beaches. A time series of Sea-viewing Wide Field-of-view Sensor (SeaWiFS) satellite ocean color images from late May 1999 of coastal waters off Washington and Vancouver Island, processed for surface chlorophyll a concentration and spectral remote sensing reflectance, captured a transport event where water from the Juan de Fuca Eddy was transported onto the Washington shelf. Strong upwelling-favorable winds appeared to deform the patch over an 8-day period and move it southward into Washington coastal waters with surface velocities of approximately 8–16 km d⁻¹. SeaWiFS and sea surface temperature imagery showed the local phytoplankton response to wind-driven coastal upwelling restricted to a narrow (10–15 km) region along the Washington coast. Although we did not observe transport of high biomass water originating in the Juan de Fuca Eddy to Washington beaches in May 1999, transport of Pseudo-nitzschia cells could occur following a rapid shift to downwelling-favorable conditions. Tracking the trajectory of surface waters from the Juan de Fuca Eddy by remote sensing could be used to trigger conditional sampling for domoic acid along the Washington coast.     

A comparative analysis of the relationship between phytoplankton standing crops and environmental parameters in four eutrophic prairie reservoirs

An analysis was performed with multivariate statistical methods of the relationship between chlorophyll a concentrations and eighteen physico-chemical parameters measured over a six year period in four eutrophic Nebraska reservoirs. In the reservoirs with relatively clear water early in the growing season, physical factors (Secchi depth, turbidity, temperature) and non-nutrient chemical factors (alkalinity, hardness, C. O. D.) were significantly related to chlorophyll a concentrations, but macronutrients (nitrogen and phosphorus) were not. In the reservoir with persistent abiogenic turbidity, chemical factors including nitrogen and phosphorus were significant but physical factors were not. Six models based upon intercorrelations between measured parameters and chlorophyll a are evaluated for their usefulness in accounting for chlorophyll a variance. The best model accounts for 67–70 percent of the total variation in chlorophyll a in the four reservoirs.     

Eutrophication of the salt valley reservoirs, 1968–73 I. The effects of eutrophication on standing crop and composition of phytoplankton

A study was carried out over a period of six years to determine the effects of eutrophication upon standing crop and composition of the phytoplankton in four recently constructed flood control reservoirs in Nebraska. Water samples collected weekly during June, July, and August from 1968–73 were analyzed for chlorophyll a, phytoplankton composition, and phytoplankton abundance. Total volume of phytoplankton was calculated from appropriate dimensions and formulae. Inorganic turbidity in one reservoir was an important factor regulating the size and composition of the phytoplankton standing crop. In that reservoir diatoms were the most important component of the phytoplankton community during those years in which inorganic turbidity was greatest. When inorganic turbidity declined, blue-green algae became dominant.In the clear-water reservoirs chlorophyll a, phytoplankton number, and phytoplankton volume were significantly correlated with reservoir age, with the oldest containing chlorophyll a concentrations up to 247 mg/m³ and mean phytoplankton volumes up to 329 mm³/l, values sufficient to place it in the hypereutrophic category. The reservoirs had 2–6 times more chlorophyll a present at the end of the study than at the beginning, with the increase being greatest in the newest reservoir. Phytoplankton volume was significantly correlated with chlorophyll a in all the reservoirs.Blue-green algae quickly became established as community dominants in the reservoirs, making up over 80 percent of the phytoplankton volume in the newest reservoir by the second year of its existence. In the other clear-water reservoirs, blue-greens usually constituted over 95 percent of the total phytoplankton volume in summer. three genera, Microcystis, Aphanizomenon, and Anabaena, were responsible for virtually the entire standing crop of blue-greens in all the reservoirs.     

The use of dialysis culture in a study of chlorophyll budget in a brackish lagoon,Japan

Growth rates of the entire phytoplankton community of a brackish lagoon in northeastern Japan were estimated by measuring increasing chlorophyll a content in dialysis bags during the summer and early autumn of 1986. The chlorophyll a contents of lagoon water fluctuated between 20 and 200 mg m^–3. At lower densities of phytoplankton (20–50 mg chl. a m^–3), growth rates (the rate of increase of chlorophyll a) exceeded 1 turnover per day, while at higher densities (more than 50 mg chl. a m^–3), the growth rate decreased rapidly. Tidal exchanges of chlorophyll a showed net exports of chlorophyll a from the lagoon to adjacent waters. The exchange rate of chlorophyll a was estimated to be 0.65 d^–1. At about 140 mg m^–3 of chlorophyll a concentration, the increase of chlorophyll in the lagoon water compensated for tidal export. Only a small proportion of primary production was consumed by zooplankton in the lagoon. There were also net exports of ammonium and phosphate from the lagoon. Nutrient flux from sediment exceeded the phytoplankton requirement and was the major source of the ammonium and phosphate exports from the lagoon. The low inorganic N/P atom supply ratio in the lagoon suggests that nitrogen is a major nutrient limiting phytoplankton growth.     

A comparison of genetic diversity between the Galápagos Penguin and the Magellanic Penguin

The Galápagos Penguin (Spheniscusmendiculus) is a United States federallylisted endangered species with populations onthe Galápagos Islands of Fernandina andIsabela. Although the waters around theislands are normally productive, lowproductivity during El Niño years resultsin high adult penguin mortality and lowrecruitment in following years. We usedmicrosatellite markers developed for Spheniscus penguins to study the long termgenetic effects of serial bottleneck events inthe Galápagos Penguin, and compared thisvariation to that of its congener, theMagellanic penguin (Spheniscusmagellanicus). The observed heterozygosityfor the Galápagos Penguin was 3%,significantly lower than the 46%heterozygosity of the Magellanic Penguin. Thislow level of heterozygosity is directly relatedto its low effective population size. Whilethis population has survived long term,presumably without high levels of geneticvariation, we feel that the greater frequencyof El Niño events, coupled with increasedhuman impacts such as introduced disease, oildischarge, and competition with fisheries, mayput the species in particular danger ofextinction.     

Dynamics of seston constituants in the Ariège and Garonne rivers (France)

Water contents of suspended matter, algal pigments, particulate organic carbon and particulate phosphorus were measured in the rivers Garonne (2 sites) and Ariège (1 site) throughout an annual cycle. The general trend of the parameters was similar at the three sites. Depending on the sites, the period of algal growth (chlorophyll a + phaeopigments > 25 µg l^–1), lasted from two to six weeks in August–September. The algal peaks reached 50 to 90 µg 1^–1 of total pigments. High contents of particulate organic carbon (> 2 mg 1^–1) occurred at the end of summer (coinciding with algal growth), and during the November and May floods. In summer 50–75 % of the suspended matter was organic, in spring this was 10 times less. The high linear correlation between particulate organic carbon and pigment contents (r = 0.87; P = 0.0001) suggested an algal origin of at least part of the particulate carbon. Algal carbon was minor in the annual fluxes of particulate carbon (25 to 39% depending on the sites), but relatively high in comparison with other rivers. The mean particulate phosphorus content calculated over the year was 24 µg l^–1 ; it varied from 15 µg l^–1 during the high water period to 28 µg 1^–1 during the low water period. Likewise the percentage of particulate phosphorus in the suspended matter varied from 0.17 to 0.40. A negative linear correlation existed between particulate phosphorus content and specific discharge (r = – 0.46; P = 0.0001).The very marked seasonal trend of the parameters and the interactions led us to differentiate two modes of the rivers' functioning: a hydrologic phase and a biological phase. The hydrologic phase (high water) was dominated by the processes of erosion and transfer over the whole catchment area and the flood plain, while the biological phase was characterized by a high primary production in the river bed.     

La Reservarea de la Lobomicosis Comentarios a un Trabajo del Dr. Carlos Peña sobre dos Casos Colombianos

REsumen El autor comenta un trabajo delDr. C. Peña (Mycopath. & Mycol. appl., 33 (3–4)313–320) sobre 2 casos de lobomicosis, cuya región de origen aparentemente no concuerda con las características climatológicas que él ha hipotéticamente fijado para la reservárea de la infección: temperatura promedio anual superior a los 24° C, pluviometría superior a los 2000 mm, ausencia de verano ecológico. En realidad, según el autor, en los departamentos de Santander del Norte y de Boyacá (Colombia) existen áreas, hacia el lago de Maracaibo y cerca del rio Magdalena, respectivamente, que presentan dichas características. Las reserváreas de la paracoccidioidosis y de la lobomicosis no coinciden. Es importante trazar de cada paciente estudiado la trayectoria residencial-ocupacional de manera precisa y completa.

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Summary An article byDr. C. Peña (Mycopath. & Mycol. appl., 33(3–4) 313–320) on two cases of lobomycosis from Colombia, is commented. Apparently, the regions from which the patients had got the infection do not offer climatic features that, according to a previous hypothesis of the author, correspond to the reservarea of lobomycosis: annual medium temperature above 24° C, annual medium rainfall above 2000 mm, absence of any ecological summer.It is the contention of the author, that actually within the broad limits indicated byDr. Peña there are areas suitable to be arranged among provinces of reservarea of lobomycosis, id est, in the Departamento de Santander del Norte an area towards the Lake of Maracaibo, and in the Departamento de Boyacá narrow area near the Magdalena river.The importance is stressed of tracing a clear-cut and thorough occupational-residential trajectory, during the anamnestical study of each patient presenting an infection whose reservarea is to be studied.

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Trabajo realizado en la Sección de Micología Médica, Instituto de Medicina Tropical, Caracas, Venezuela (Director: Prof. Dr.Félix Pifano C.) El autor es Profesor Titular de la Cátedra de Microbiología (Jefe: Prof. Dr.Leopoldo Briceño Iragorry).     

Contrasting demographies and persistence of rare annual plants in highly variable environments

Spatial and temporal variation in critical life history traits differ markedly between two co-occurring, rare and endangered annual plants, Gilia tenuiflora arenaria and Chorizanthe pungens pungens, that have restricted, but overlapping geographic distributions in coastal habitats of central California, USA. Environmental variation was extreme during the 6-year study (1997–2002), with the greatest differences between an intense wet, warm El Niño year (1998), followed by a very dry, cool La Niña (1999). Both species have similar increases in adult survival and seed set with wetter, warmer weather in spring, but they differed in other traits: more Gilia germinated in years with high rainfall and temperature, while more Chorizanthe germinated in dry, cooler years; Gilia abundance increased with the number of years since the previous large El Niño event, while Chorizanthe abundance declined; and Gilia abundance was independent of the previous year’s seed set, while Chorizanthe density was directly related to the previous year’s seed set. The strong negative associations of Chorizanthe abundance with warm, wet weather and with time since the previous El Niño probably reflect the particular sequence of annual weather patterns from 1997 through 2002, especially the extremes in 1998 and 1999. Since it germinates readily in most years under a wide range of winter conditions and does not develop a long-lived seed bank, Chorizanthe seedling abundance reflects recent additions and depletions of its seed bank, rather than prevailing weather, per se. In contrast, Gilia seeds may remain in the seed bank for many years, until relatively rare winter conditions trigger significant germination. These species-specific demographies enhance persistence and coexistence of these species, but the mechanisms differ from each other and from those described for annuals in other highly variable environments.     

Weather changes associated with hospitalizations for cardiovascular diseases and stroke in California, 1983–1998

Poisson regression models were used to evaluate associations between temperature, precipitation, days of extreme heat, and other weather changes (lagged 7 days), as well as El Niño events, with hospitalizations for acute myocardial infarction, angina pectoris, congestive heart failure, and stroke in three California regions. Temperature changes were defined as a 3 °C decrease in maximum temperature or a 3 °C increase in minimum temperature. Temperature and precipitation were analyzed separately for normal weather periods and El Niño events, and for both weather periods combined. Associations varied by region, age, and gender. In Los Angeles, temperature changes resulted in small changes in hospitalizations. Among San Francisco residents 70+ years of age, temperature changes increased hospitalizations for nearly all outcomes from 6% to 13%. Associations among Sacramento residents were similar to those in San Francisco: among men 70+ years of age, temperature changes increased hospitalizations by 6%–11% for acute myocardial infarction and congestive heart failure, and 10%–18% for stroke. El Niño events were consistently and significantly associated with hospitalizations only in San Francisco and Sacramento, and then only for angina pectoris (increasing hospitalizations during El Niño events). These exploratory analyses merit further confirmation to improve our understanding of how admissions to hospitals for cardiovascular disease and stroke change with changing weather. Such an understanding is useful for developing current public health responses, for evaluating population vulnerability, and for designing future adaptation measures.     

Egg production rates of eight calanoid copepod species during summer 1997 off Newport, Oregon, USA

Measurements of hydrography, water transparency, chlorophyll (Chl) a and egg production rates (EPRs) by females of Calanus marshallae Frost, Calanus pacificus Brodsky, Eucalanus californicus Johnson, Epilabidocera longipedata Sato, Pseudocalanus mimus Frost, Centropages abdominalis Sato, Acartia longiremis Lilljerborg and Paracalanus parvus (Claus) were estimated at weekly intervals between 17 July and 2 September 1997. Production of eggs was determined in 24 h incubations to examine the effects of environmental variability on EPR, to detect the possibility of food limitation of EPR, and to evaluate the hypothesis that growth rates of females are size dependent. During the study, an anomalous downwelling event occurred, possibly in response to the 1997 El Niño, which allowed us to determine how El Niño events affect EPRs of coastal copepods. The larger copepods Calanus marshallae, Calanus pacificus and Centropages abdominalis showed the highest egg production and specific growth rates during the period of active upwelling (18 July-13 August, water temperatures 8-13C, Chl a concentration 4.7-16.2 l^-1 and water transparency 3-5 m). After 27 August, the 1997-98 El Niño arrived off Oregon, creating a downwelling situation. Upwelling winds ceased, the thermocline intensified, temperature and transparency increased (to >18°C and 16 m), and Chl a declined to <2 g l^-1. Densities of the common coastal species declined greatly as well. Paracalanus parvus became the dominant species, and Eucalanus californicus, Epilabidocera longipedata and Corycaeus anglicus became common in our samples. EPRs for the larger boreal copepods (Calanus and Centropages) declined greatly during El Niño;; the smaller copepods, Pseudocalanus mimus, A.longiremis and Paracalanus parvus, showed low but relatively constant egg production and specific growth rates during both upwelling and downwelling events. Over the entire study period, only three species produced eggs at its maximum rate (24-28 eggs female^-1 day^-1), Pseudocalanus mimus which averaged 4 eggs day^-1. All other species had EPRs that were two or five times below their maximum EPR. Thus, EPRs were not related to body size, contrary to our expectations. Hatching success was variable among species. Values as low as 20-40% were found for all species at least once during the study period, suggesting that occasionally a substantial portion of egg production may not be viable.      

Predicting the summer chlorophylla concentration in a reservoir based on the environmental conditions of the preceding spring

From a monthly survey over a ten-year period (1983–1992) of the Ishitegawa Reservoir, Japan, two multiple regression equations describing the mean chlorophylla (Chl-a) concentration at 0.5 m depth during July, August and September (C _S ) and the maximum Chl-a concentration in the photic zone, including its subsurface maximum during this period (C _M ), were obtained. The conductivity at 0.5 m depth in May and the mean air temperature during May or during May and June were used as independent variables. These equations were calculated using seven years of data (1983–1988 and 1992). From 1989 to 1991 two impermeable plastic-coated sheet fences were installed across the upper end of the reservoir along the top 5 m of water column. The equations were used to determine the effectiveness of this flow regulation on the summer Chl-a concentration. In 1989 and 1991, when the fences were in place from June to August, no effects were found on the observed C _S and C _M values. In 1990, when the fences had been in place since October 1989, the observed values were lower than the predicted values.     

Surface distribution of size-fractionated chlorophyll a and participate organic matter in the Strait of Magellan

The surface distribution of chlorophyll a (chl a) from size-fractionated phytoplankton and of particulate organic matter was studied along the Strait of Magellan during late austral summer (February 20th to March 2nd, 1991), in order to contribute an outline of the ecological characteristics of its pelagic compartment. Sampling of surface water was carried out at 2.5 mile intervals, yielding 152 sampling points for chl a and 104 for particulate organic carbon (POC). The Strait appeared as a system strongly controlled by land forcing. Its phytoplankton community was dominated by the picoplanktonic fraction along its entire length, with mean chl a concentrations of 0.74 and 1.17 g dm^–3 for pico- and total phytoplankton, respectively. The microphytoplankton never exceeded 0.02 g dm^–3. POC concentrations, with a maximum of 242.5 and a mean of 144.8 g dm^–3, were mainly of autotrophic origin, as indicated by a mean POC:chl a ratio of 138.4.     

High Complexity Food Webs in Low-diversity Eastern Pacific Reef–Coral Communities

Community-wide feeding interrelationships in a low-diversity coral reef off the Pacific coast of Panamá (Uva Island reef) demonstrate complex pathways involving herbivore, strong corallivore, and carnivore interactions. Four trophic levels with 31 interguild links are identified in a generalized food web, and documented feeding interrelationships with 287+ species links are portrayed in a coral–corallivore subweb. The importance of trophic groups changes greatly with time, from unknown causes over annual to decadal-scale periods, and during very strong El Niño–Southern Oscillation events such that intermittent intense herbivory by echinoids (Diadema) and corallivory by gastropod mollusks, the crown-of-thorns sea star Acanthaster, hermit crabs, and fishes result in high levels of coral mortality and bioerosion of reef substratum. Intraregional differences in species composition and abundances affecting food-web interactions are briefly described for nonupwelling (Uva Island) and upwelling areas (Pearl Islands) in Panamá. Seasonal upwelling in the Pearl Islands results in high plankton productivity, which likely augments production in invertebrates, fishes, marine mammals, and seabirds, but these pathways still remain largely unquantified. The corallivore Acanthaster is absent from upwelling centers in Panamá and from upwelling and nonupwelling areas in the southern and central Galápagos Islands, and the highly destructive, facultative corallivore Eucidaris galapagensis occurs only in the latter offshore islands and at Cocos Island. Relatively recent declines in the abundances of manta rays, sharks, and spiny lobsters are correlated with, but not necessarily causally linked to, increasing fishing activities in the late 1970s to early 1980s. The extent to which the complex yet highly unstable Uva Island food web is representative of other eastern Pacific coral reef ecosystems remains to be investigated.