Northern Pacific Coast Research Articles

CHLOROQUINE-RESISTANT PLASMODIUM VIVAX MALARIA IN PERU

Reports from several sites in South America suggest the presence of isolated cases of chloroquine-resistant Plasmodium vivax malaria. To investigate the possibility of chloroquine-resistant P. vivax in Peru, we conducted 28-day in vivo drug efficacy trials at three sites in the Amazon region and one site on the northern Pacific Coast between 1998 and 2001. A total of 242 patients between the ages of 2 and 60 years were enrolled (177 from the Amazon region and 65 from the northern coast). All subjects received directly observed therapy with chloroquine, 25 mg/kg, over a three-day period. On enrollment, 49% had a documented fever and 96% had a history of fever; their geometric mean parasite density was 5,129 parasites/microL. A total of 212 (88%) of the 242 subjects completed their 28-day follow-up. Four of the 177 patients from the Amazon region had a recurrence of P. vivax parasitemia on days 21 and 28 after treatment was initiated. Two of these patients had chloroquine-resistant infections, based on polymerase chain reaction-single-stranded conformational polymorphism genotyping and chloroquine-desethylchloroquine blood levels, which were > or = 97 ng/mL at the time of the reappearance of parasitemia. None of the subjects studied on the northern Pacific Coast had recurrent parasitemia.

Skeletal tumor formations in the massive coral Pavona clavus

Skeletal tumor formations in the massive coral Pavona clavus were investigated for 3 yr on the northern Pacific coast of Costa Rica in a reef composed almost exclusively of this species. A field survey of tumor incidence showed that more than half of the population presented this phe- nomenon and that frequencies increased with depth. Up to 37 tumors per colony were recorded, and the largest tumor size was 37.5 m 2 , covering the whole colony surface area. Tumors and healthy skeletons and tissues were studied by scanning and transmission electron microscopy, histology, in situ alizarin marking for growth rates, and x-ray radiographs of skeletal slabs. Macroscopic and microscopic analyses of skeletons revealed the presence of 3 types of tumors (Types I to III). No cyto- logical changes or intracellular infection by parasitic agents were recorded. The only cellular change observed was the reduced numbers of zooxanthellae in tumorigenic tissues. Tumors begin their growth as a single polyp and develop for scores of years without any sign of cellular necroses. Tumors grew faster than healthy parts; however, their skeletal density was lower, with a higher Mg content making it less resistant to bioerosion. Two yr of in situ isogeneic and allogeneic contacts between healthy and tumor fragments revealed no infection or transfer of the tumor to the healthy tissue, even following isogeneic fusion combinations of healthy versus tumor fragments. We suggest that the ter- minology often used to characterize tumors in hard corals ('tumor', 'neoplasm', 'hyperplasia') does not reflect the pathogenesis and etiology of this phenomenon. The terms 'skeletal tumor' or 'calicoblastic epithelioma' seem more fitting for this de novo genesis.

NEW EOCENE DECAPODS (THALASSINIDEA and BRACHYURA) FROM SOUTHERN CALIFORNIA

Abstract A new decapod fauna has been recovered from Eocene rocks of San Diego County, California. Decapod faunas of Eocene age have been rare from California, although they are well described from the northern Pacific coast. Three new species, including Neocallichirus rhinos, Ctenocheles secretanae, and Minohellenus inexpressus, and two new genera and species, Acanthoportunus buchanani and Vegarthron santiago, are reported from this new fauna. A new genus has been erected to accommodate Portunites triangulum and Portunites granulifer; both are herein referred to Maeandricampus, new genus. Callianassa matsoni Rathbun has been reassigned to Neocallichirus. Portions of the cephalothorax and abdomen of a species of Ctenocheles are described from fossils for the first time. Orbitoplax weaveri, previously known from Eocene rocks of California and Oregon, is reported from the Eocene Mission Valley Formation and the Ardath Shale for the first time. In addition, one specimen of a stomatopod of indeterminate genus...

Environmental factors as determinants of malaria risk. A descriptive study on the northern coast of Peru.

We conducted a series of studies on the northern Pacific coast of Peru to determine environmental risk factors for malaria. We report in this paper the results of both a descriptive study of incidence and a prevalence survey of malaria. Both studies showed that the area was at low risk for malaria. The malaria incidence rate was 40/1000 p.a. during the study period, and the prevalence of infection was 0.9% (95% CI: 0.4-1.7) before and 1.4% (95% CI: 0.8-2.2) after the high incidence period. However, the risk of malaria varied according to season, village and even house within a single village. Incidence rates increased from February (2.6/1000 p.a.) to May (12.9/1000 p.a.) and decreased during the second part of the year. Most of the cases were clustered in four villages that constituted only 21% of the total population of the area. Houses where multiple cases were recorded were often located near a source of water. Our observations suggested that environmental factors, and particularly the presence of water for irrigation around villages and houses, played a major role in determining the risk of malaria. These observations were extended through an entomological study and a case-control study, to be published elsewhere.

New Eocene Decapods (Thalassinidea and Brachyura) from Southern California

A new decapod fauna has been recovered from Eocene rocks of San Diego County, California. Decapod faunas of Eocene age have been rare from California, although they are well described from the northern Pacific coast. Three new species, including Neocallichirus rhinos, Ctenocheles secretanae, and Minohellenus inexpressus, and two new genera and species, Acanthoportunus buchanani and Vegarthron santiago, are reported from this new fauna. A new genus has been erected to accommodate Portunites triangulum and Portunites granulifer; both are herein referred to Maeandricampus, new genus. Callianassa matsoni Rathbun has been reassigned to Neocallichirus. Portions of the cephalothorax and abdomen of a species of Ctenocheles are described from fossils for the first time. Orbitoplax weaveri, previously known from Eocene rocks of California and Oregon, is reported from the Eocene Mission Valley Formation and the Ardath Shale for the first time. In addition, one specimen of a stomatopod of indeterminate genus is noted. The Eocene decapod fauna from California, now containing eighteen genera, has elements common to the northern Pacific coast of North America as well as taxa known only from California; thus, the area appears to have been suited for decapods adapted to a wide variety of temperature and other environmental conditions. Several genera appear to have evolved within the region, whereas others may have been introduced from the Atlantic or Tethys region via the Central American Seaway. The number of Pacific amphitropical genera continues to increase; two portunid genera discussed here display such a pattern, adding to the four already reported for Cretaceous and Tertiary rocks of the region.

Accumulation of paralytic shellfish toxins in the scallop Patinopecten yessoensis caused by the dinoflagellate Alexandrium catenella in Otsuchi Bay, Iwate Prefecture, northern Pacific coast of Japan

: The survey on scallop toxicity in association with causative dinoflagellates was conducted when the cultured scallops Patinopecten yessoensis were found to accumulate paralytic shellfish toxins in late November of 1997 at Otsuchi Bay, Iwate Prefecture, Japan. Alexandrium catenella was observed in high density at the beginning of the survey. The cell density of A. catenella decreased and completely disappeared in early December. The scallop toxicity also decreased with decrease of the cell density of A. catenella. The toxin profile of the scallop was similar to that of natural and cultured cells of A. catenella isolated from the Bay, showing that scallop toxicity is due to A. catenella. This is the first case in which paralytic shellfish toxins were confirmed in scallops during a bloom of A. catenella in Sanriku coast of Iwate Prefecture.

Effects of food concentration and availability on the incidence of cloning in planktotrophic larvae of the sea star Pisaster ochraceus.

A decade ago, cloning was first observed in the planktotrophic larvae of sea stars obtained from plankton tows. However, no controlled experimental studies have investigated what factors may regulate this remarkable phenomenon. In the present study we offer the first documentation of cloning in the planktotrophic larvae of Pisaster ochraceus from the northern Pacific coast. This species was used as a model system to investigate three factors that may influence the incidence of asexual reproduction (cloning) in planktotrophic sea star larvae. In an initial experiment, larvae were reared under nine combinations of three temperatures and three food (phytoplankton) concentrations. Larvae reared at 12-15 degrees C and fed the highest food concentrations grew larger than the other larvae and produced significantly more clones. In a second experiment, qualitatively different algal diets were fed to larvae reared under the conditions found to be optimal in the initial experiment. Up to 24% of the larvae consuming a mixed phytoplankton diet of Isochrysis galbana, Chaetocerous calcitrans, and Dunaliella tertiolecta cloned, and significantly more clones were produced by these larvae than by those fed monospecific diets. Our experiments indicate that cloning generally occurs after larvae have attained asymptotic body length and only when food is abundant and of high quality. Since larval mortality is considered to be extremely high for marine invertebrates with planktotrophic larvae, production of clones under optimal conditions of temperature and food may serve to increase larval populations when the environment is most conducive to larval growth.

Mangrove Distribution during the Holocene in Tribugá Gulf, Colombia1

Abstract Neotropical mangrove ecosystems have undergone drastic changes in terms of extension and floristic composition during Plio–Pleistocene times. It is unclear if the northern Pacific coast of Colombia has been occupied continuously by mangroves during the last 5000 years, or if their presence is a recent phenomenon. Two basic questions were asked: (1) is the establishment of mangroves recent?; and (2) what were the dominant floral taxa during the late Holocene? In the Gulf of Tribuga, northern Colombian Pacific, 22 sediment cores were drilled to a maximum depth of 2 m in a diverse suite of mangrove substrates and positions relative to the shoreline. Data were gathered from sedimentological descriptions, palynological analyses, and radiocarbon dating of these cores. During the last 4500 years, mangroves in the southern area of the Tribuga Gulf have remained floristically stable and dominated by Rhizophora. The abundant presence of Acrostichum aureum is recent, probably related to human activities. In...

Molecular epidemiology of enzootic rabies in California.

Molecular characterization of rabies virus has been used to trace spillover transmission from reservoir species to non-reservoir animals and humans (molecular epidemiology), and to monitor emergence of specific strains of the virus into new species and geographic areas (molecular surveillance). To characterize the enzootic strains of rabies virus in California wildlife for epidemiological investigation of transmission to non-reservoir animals and humans. Molecular characterization was performed on rabies strains from 213 bats, 276 terrestrial animals and one human case, by RT-PCR amplification of the viral nucleocapsid (N) gene followed by Dde I digestion and restriction endonuclease analysis (REA). Brain material from 88 terrestrial animals and 74 bats was stained with a panel of 20 monoclonal antibodies (MABs) directed against the N protein. In order to characterize rabies from very small quantities of brain tissue a nested RT-PCR was developed and evaluated for sensitivity of rabies detection. Enzootic terrestrial rabies in California is confined to the Central Valley, the western slope of the Sierra Nevada, and the Central and Northern Pacific Coast Ranges. No terrestrial reservoirs were identified south of the Tehachapi Mountains or east of the Sierra Nevada. Bat strains accounted for rabies in terrestrial animals in these regions. Among terrestrial rabies strains REA identified ten genotypes that segregated geographically and were associated with skunk and fox populations from distinct locations. Co-circulation of three genotypes occurred in Placer County, which had the highest incidence of rabies in skunks. In regions with terrestrial enzootic rabies, the strain from that region accounted for 73% of spillover cases. Bat strains accounted for the remaining 27%. Among terrestrial animals MABs identified three predominant patterns. In rabies strains from bats REA identified ten major and two minor patterns primarily associated with genus and species of bat. Sharing of strains between species was observed. An additional sixteen unclassified REA bat patterns were observed in only one or two individuals of various species. MABs identified four major patterns in bats associated with genus and species of bat with considerable variability. The bat strains most frequently detected in spillover cases throughout California were from the California myotis (Myotis californicus) and Mexican free-tailed bat (Tadarida brasiliensis). Nested RT-PCR increased the detection level of rabies virus 100,000-fold, to 0.03 TCID50.

Eocene and Oligocene Otay-Type Waxy Bentonites of San Diego County and Baja California: Chemistry, Mineralogy, Petrology and Plate Tectonic Implications

AbstractOtay-type waxy bentonites of San Diego County are illite-smectite (I-S) with 85% dioctahedral smectite mixed with dioctahedral illite showing a Reichweite of 0. Primary or secondary waxy bentonite exposures are found in all Eocene and Oligocene formations of southwest San Diego County and western Baja California north of Ensenada. Primary waxy bentonites formed when hot volcanic ash fell into quiet marine or brackish coastal water. The transformation from glass to bentonite occurred within hours or days but consolidation of the bentonite into its waxy consistency took longer. Primary waxy bentonite consists of 95 wt% I-S with the remainder consisting of volcanic glass shards, sanidine fourling twins, hexagonal biotite crystals and amorphous manganese oxides and hydroxides. Secondary waxy bentonite is primary waxy bentonite that was mixed with nonvolcanic detritus either before consolidation or after consolidation and subsequent erosion. The hydrophobic character of primary waxy bentonite allows it to reflect, accurately, the chemistry and petrology of the original volcanic material. Chemical analysis of primary waxy bentonites shows that the original lava was subduction-related and exhibited petrologic variations nearly identical to those of the modern Cascades of the northern Pacific coast of the lower United States. Primary and secondary waxy bentonites as well as smectites derived from the weathering of volcanic ash that fell outside the waxy bentonite-producing environments are the previously unrecognized products of extensive Eocene and Oligocene subduction-related volcanic activity. Baja California exposures of waxy bentonite demonstrate pre-Pliocene subduction tectonics that gave way to rifting tectonics.

DNA Sequence and RFLP Analysis of Pleurotopsis longinqua from Three Disjunct Populations

The known distribution of Pleurotopsis longinqua is restricted to southeastern Australia, New Zealand, Patagonia, and the northern Pacific coast of North America. Previous studies demonstrated that isolates from all of these areas were sexually compatible (i.e., were the same biological species). Intercompatibility studies, however, did not provide information about genetic (evolutionary) relationships among the disjunct populations. Restriction fragment patterns of the nuclear ribosomal ITS1-5.8S-ITS2 were compared for isolates from each geographical region to estimate genetic divergence. Only one enzyme, Taq I, discriminated between different collections. To further examine genetic divergence, the ITS1-5.8S-ITS2 region was sequenced for one collection from each geographical area. Only four base-pair differences were observed among isolates from New Zealand, Argentina and Washington State. The remarkable similarity of these collections suggests that the current disjunct distribution is not very old.

DNA sequence and RFLP analysis of Pleurotopsis longinqua from three disjunct populations

The known distribution of Pleurotopsis longinqua is restricted to southeastern Australia, New Zealand, Patagonia, and the northern Pacific coast of North America. Previous studies demonstrated that isolates from all of these areas were sexually compatible (i.e., were the same biological species). Intercompatibility studies, however, did not provide information about genetic (evolutionary) relationships among the disjunct populations. Restriction fragment patterns of the nuclear ribosomal ITS1-5.8S-ITS2 were compared for isolates from each geographical region to estimate genetic divergence. Only one enzyme, Taq I, discriminated between different collections. To further examine genetic divergence, the ITS1-5.8S-ITS2 region was sequenced for one collection from each geographical area. Only four base-pair differences were observed among isolates from New Zealand, Argentina and Washington State. The remarkable similarity of these collections suggests that the current disjunct distribution is not very old.

THE ECOLOGY OF BODY SIZE IN A SEED BEETLE, STATOR LIMBATUS: PERSISTENCE OF ENVIRONMENTAL VARIATION ACROSS GENERATIONS?

tica). IV. Pattterns of fluctuating asymmetry and selection against asymmetry. Evolution 48:658-670. M0LLER, A. P., AND A. POMIANKOWSKI. 1994. Fluctuating asymmetry and sexual selection. Pp. 269-281 in T A. Markow, ed. Developmental instability: its origins and evolutionary implications. Kluwer Academic Publishers, Dordrecht, The Netherlands. MULVEY, M. G., P. KELLER, AND G. K. MEFFE. 1994. Singleand multiple-locus genotypes and life-history responses of Gambusia holbrooki reared at two temperatures. Evolution 48:1810-1819. PALMER, A. R. 1994. Fluctuating asymmetry analyses: a primer. Pp. 355-564 in T. Markow, ed. Developmental instability: its origins and evolutionary implications. Kluwer Academic Publishers, Dordrect, The Netherlands. PALMER, A. R., AND C. STROBECK. 1992. Fluctuating asymmetry as a measure of developmental stability: implications of nonnormal distributions and power of statistical tests. Acta Zool. Fennica 191:57-72. PALMER, A. R., C. STROBECK, AND A. K. CHIPPINDALE. 1994. Bilateral variation and the evolutionary origin of macroscopic asymmetries. Pp. 201-218 in T. A. Markow, ed. Developmental instability: its origins and evolutionary implications. Kluwer Academic Publishers, Dordrecht, The Netherlands. PARSONS, P. A. 1990. Fluctuating asymmetry: an epigenetic measure of stress. Biol. Rev. (Cambridge) 65:131-145. RICE, W. R. 1989. Analyzing tables of statistical tests. Evolution 43:223-225. SMITH, L. H. 1994. Fluctuating asymmetry and developmental stability in Cambrian and Ordovician trilobites. GSA Abstract with Programs 27:A373. SOKAL, R. R., AND F J. ROHLF. 1981. Biometry. 2d ed. Freeman, New York. STRATHMANN, M. F 1987. Reproduction and development of marine invertebrates of the northern Pacific Coast. Data and methods for the study of eggs, embryos, and larvae. Univ. of Washington Press, Seattle. STRATHMANN, R. R., L. FENAUX, AND M. F STRATHMANN. 1992. Heterochronic developmental plasticity in larval sea urchins and its implications for evolution of nonfeeding larvae. Evolution 46:972-986. WATSON, P. J., AND R. THORNHILL. 1993. Fluctuating asymmetry and sexual selection. Trends Ecol. Evol. 9:21-25.

Native Women of the Northern Pacific Coast: An Historical Perspective, 1830-1900

Contact with whites often heralded a contraction of native women’s roles and brought about a corresponding decline in their status. Yet the experiences of the Nishga and Tsimshian women of the northern Pacific coast during the fur trade and mission eras defy such generalizations. These women continued their traditional productive activities while assuming expanded roles as traders and workers at the Hudson’s Bay Company fort, and later took employment as inside workers in the newly established canneries. Nor did missions seriously erode their status, for the continuing economic independence and power of Nishga and Tsimshian women meant that they were not compelled to accept the narrow domestic roles and notions of female submissiveness promoted by the missionaries.

Radiocarbon test of earthquake magnitude at the Cascadia subduction zone

THE Cascadia subduction zone, which extends along the northern Pacific coast of North America, might produce earthquakes of magnitude 8 or 9 ('great' earthquakes) even though it has not done so during the past 200 years of European observation1–7. Much of the evidence for past Cascadia earthquakes comes from former meadows and forests that became tidal mudflats owing to abrupt tectonic subsidence in the past 5,000 years2,3,6,7. If due to a great earthquake, such subsidence should have extended along more than 100 km of the coast2. Here we investigate the extent of coastal subsidence that might have been caused by a single earthquake, through high-precision radiocarbon dating of coastal trees that abruptly subsided into the intertidal zone. The ages leave the great-earthquake hypothesis intact by limiting to a few decades the discordance, if any, in the most recent subsidence of two areas 55 km apart along the Washington coast. This subsidence probably occurred about 300 years ago.

Developments in Coal in 1989

In 1989, 5424 United States mines in 26 states produced a record 981.8 million tons of coal, an increase of 3.4% from a revised 949.7 million tons produced in 1988. Of this coal, the Eastern coal province produced 47.1%, the western coal provinces (Northern Great Plains, Rocky Mountain, Pacific Coast, and Alaska) produced 32.5%, the Interior coal province produced 14.6%, and the Gulf coal province produced 5.8%. This production distribution is almost identical to that of 1988. Wyoming produced 171.1 million tons of coal from 2 coal provinces, leading the United States for the second consecutive year. Kentucky again ranked a close second with 170.5 million tons of coal from 2 coal provinces. West Virginia again was third with 151.83 million tons, Pennsylvania again was fourth with 71.8 million tons, and Illinois again was fifth with 60.4 million tons. These 5 states produced 63.7% of United States coal production in 1989 compared to 63.4% in 1988. In rank, the total U.S. coal production was 0.3% anthracite, 69% bituminous, 21.7% subbituminous, and 9% lignite. By age, 62% was Pennsylvanian, 30% was Tertiary, and 8% was Cretaceous. The percentage distribution of the production by age is unchanged from 1988. Bituminous coal's share of the production in 1989 increased 3.7% from 1988 at the expense of subbituminous, due to significantly increased production in eastern Kentucky, West Virginia, and Indiana. Lignite production for montan wax extraction has been taking place on a small scale for many years at 1 mine in the Ione field in California and is included for the first time in this report. In Canada in 1989, 29 mines produced 70.51 million MT of coal, a decrease of 0.2% from 1988. The 3 western provinces (Alberta, British Columbia, and Saskatchewan) accounted for 94.3% of Canada's coal production in 1989, a 0.1% decrease from a revised 94.4% in 1988. By rank, 55% was bituminous, 29.7% subbituminous, and 15.3% lignite.

Reproduction and Development of Marine Invertebrates of the Northern Pacific Coast. Data and Methods for the Study of Eggs, Embryos, and Larvae. Megumi F. Strathmann

<i>Reproduction and Development of Marine Invertebrates of the Northern Pacific Coast. Data and Methods for the Study of Eggs, Embryos, and Larvae</i>. Megumi F. Strathmann

Developments in Coal in 1988

In 1988, 6,109 United States mines in 26 states produced a record 948.8 million (short) tons of coal, an increase of 0.2% from a revised 930.9 million tons produced in 1987. Of this coal, the Eastern coal province produced 47.3%, the western coal provinces (Northern Great Plains, Rocky Mountain, Pacific Coast, and Alaska) produced 32.2%, the Interior coal province produced 14.7%, and the Gulf coal province produced 5.8%. For the first time, Wyoming led the United States by producing 163.6 million tons of coal. Kentucky ranked second with 161.2 million tons, West Virginia was third with 144.9 million tons, Pennsylvania was fourth with 71.8 million tons, and Illinois was fifth with 59.9 million tons. In rank, the total U.S. coal production was 0.4% anthracite, 65.3% bituminous, 25.4% subbituminous, and 8.9% lignite. By age, 62% was Pennsylvanian, 30% was Tertiary, and 8% was Cretaceous. Large-scale lignite production was started for the first time at 1 mine in Arkansas. The increase in coal production and the decrease in the number of coal mines indicates increased coal-mining efficiency in the United States in 1988. A major factor in this greater efficiency was large-scale surface mining of increased quantities of lignite and subbituminous coal in the western and Gulf coal provinces, where coal commonly contains less than 1% sulfur. In Canada in 1988, 29 mines produced 70.5 million MT of coal, a record high and an increase of 15.6% from 1987. The 3 western provinces (Alberta, British Columbia, and Saskatchewan) accounted for 94.3% of Canada's coal production. In rank, 54.6% was bituminous, 28.2% subbituminous, and 17.2% lignite.

Developments in Coal in 1987

In 1987, United States mines in 26 states produced a record 930.58 million (short) tons of coal, an increase of 3.3% from a revised 900.5 million tons produced in 1986. Of this coal, the Eastern coal province produced approximately 48.3%, the western coal provinces (Northern Great Plains, Rocky Mountain, Pacific Coast, and Alaska) produced 29.3%, the Interior coal province produced 16.6%, and the Gulf coal province produced 5.7%. In rank, 0.6% was anthracite, 66.4% was bituminous, 24.6% was subbituminous, and 8.4% was lignite. There were no significant percentage changes in production by coal rank or by coal province from 1986. Operators of 2,335 coal mines in Kentucky led the United States by producing 177.26 million tons of coal. Wyoming ranked second with 146.5 million tons, West Virginia was third with 137.67 million tons, Pennsylvania was fourth with 66.8 million tons, and Illinois was fifth with 60.7 million tons. Canada produced 61.2 million metric tons.

Developments in Coal in 1986

In 1986, according to data from state agencies, United States mines in 26 states produced 897.9 million (short) tons of coal, a slight decrease of 0.2% from the revised 900 million tons produced in 1985. Of this coal, the Eastern Coal province produced 48.5%, the Northern Great Plains, Rocky Mountain, and Pacific Coast provinces and Alaska produced 29.2%, the Interior Coal province produced 16.7%, and the Gulf Coal province produced 5.6%. In rank, 0.4% was anthracite, 66.2% was bituminous, 24.9% was subbituminous, and 8.5% was lignite. Operators of 2,465 coal mines in Kentucky led the nation by producing 165.6 million tons of coal. Wyoming ranked second with 135.7 million tons, West Virginia was third with 130.8 million tons, Pennsylvania was fourth with 73.2 million tons, Illinois was fifth with 62.6 million tons, Texas was sixth with 48.5 million tons, Virginia was seventh with 41.8 million tons, Ohio was eighth with 34.7 million tons, Montana was ninth with 33.7 million tons, and Indiana was tenth with 31.9 million tons. A 3.6% decrease in Wyoming's coal production was the first decrease in 18 years. Development of the nation's first underground hydraulic coal mine progressed in Colorado. Surface mines produced 59% of United States coal production in 1986.