distribution and abundance

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Distribution and abundance of copepod nauplii in the vicinity of a submarine canyon (NW Mediterranean)

Distribution and abundance of copepod nauplii in the vicinity of a submarine canyon (NW Mediterranean)

Abstract. Distribution and abundance of copepod nauplii in relation to oceanic features detected by in situ data in the vicinity of the Palamos Canyon (NW Mediterranean) was analyzed. Vertical trawls (60 -Jlrn mesh) and physical data (CTD and ADCP), were obtained in a spring period (May 1992 )� The vicinity of the canyon was dominated by the Liguro-Proven�a1-Catalan Current (slope current), influenced by the fresh water from of the Rhóne River runoffs, and perturbations of its flow induced by the submarine topography. High abundance of copepod nauplii were associated with the slope current waters and its intrusions into the canyon, showing an offshore-nearshore abundance gradient. The highest concentrations of copepod nauplii were found at the eastem margin of the slope current along of a shallow salinity front. Results showed that the spawning of dominant copepod species in the offshore zone could be related to retention areas, such as the salinity front, and to the biological enrichment of tbe slope curren! influenced by Rhóne river discharges during the rainy period and ice melting of the Proven�a1 mountains.
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Local abundance and regional distribution of tree species of forest fragments in Brazil: A test of models

Local abundance and regional distribution of tree species of forest fragments in Brazil: A test of models

In the present study, we examined data from 56 plots in seven forest fragments. Predictions of niche-based and metapopulation models were compared on three different spatial scales. Our aim was to investigate whether the patterns of distribution and abundance observed in differed among scales. On the smaller ones, we expected the environment heterogeneity to be also smaller and dispersal ability to be more homogeneous among species. If this held true, the chances of finding patterns in agreement with Hanski’s (1982) model would be improved. In contrast, on greater scales we expected a more pronounced influence of phenomena linked to the general geographic distribution of species, and therefore, a smaller chance of finding the patterns predicted by Hanski (1982).
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Distribution and abundance of the ascidian Ecteinascidia turbinata (Ascidiacea: Perophoridae)
in Cuba [Spanish]

Distribution and abundance of the ascidian Ecteinascidia turbinata (Ascidiacea: Perophoridae) in Cuba [Spanish]

Abstract: Distribution and abundance of the ascidian Ecteinascidia turbinata (Ascidiacea: Perophoridae) in Cuba. Permanently submerged mangrove roots (Rhizophora mangle) are the main habitat of the ascidian Ecteinascidia turbinata in Cuba. It was occasionally found on black coral (Antiphates caribeana) between 22 and 38 meters deep. This species exhibits a wide distribution in all the mangrove keys surrounding the Island of Cuba but does not occur in riparian or fringing mangroves. Populations of this species are abundant in Cuba: in 75 % of the 58 localities sampled the species was present and in 57 % more than 50 % of the roots held at least one colony. The highest colony densities were found in the northern coast of Pinar del Río province with values near one colony per lineal meter of mangrove root. We found the highest density (1.46 col/m) and greatest bio- mass at Jutías Key, with values between 25 and 660 g/m. The average of wet biomass in the studied mangroves was 73.63 g/m. Rev. Biol. Trop. 55 (1): 247-254. Epub 2007 March. 31.
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Distribution and abundance of stomatopods (Crustacea: Haplocarida) in Southern Sinaloa, México

Distribution and abundance of stomatopods (Crustacea: Haplocarida) in Southern Sinaloa, México

Abundance and distribution. A total of 54 specimens of stomatopods were collected during lhe SIPCa Project. The most abundant species w"re Squil/a biformis (23 specimens) and S. parva ( 1 4 specimens). Stomatopods are known to be dwelling crustaceans that live in holes in hard substrates (coral rubble and rocks) or in burrows dug in soft sediments (m ud and sand, sometimes mixed with gravel or shell fragrnents) (Reaka and Manning, 1981). There is little evidence as to whelher stomatopods lhat live on subtidal soft substrates reduce lheir activity outside burrows during night-time, or act indiscriminately, wandering around by day or night. The SIPCa specimens were aU col­ lected between 0 8 : 1 6 A.M. and 05:49 P.M.;
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Changes in the Abundance and Distribution of Black necked Swans (Cygnus melancoryphus) in the Carlos Anwandter Nature Sanctuary and Adjacent Wetlands, Valdivia, Chile

Changes in the Abundance and Distribution of Black necked Swans (Cygnus melancoryphus) in the Carlos Anwandter Nature Sanctuary and Adjacent Wetlands, Valdivia, Chile

Abstract.—Recently, the Carlos Anwandter Nature Sanctuary (Sanctuary) at the Cruces River, Chile, has under- gone important ecosystem changes. Brazilian waterweed (Egeria densa), the main food resource of Black-necked Swans (Cygnus melancoryphus), has greatly decreased in abundance. This disappearance may have affected the abun- dance of Black-necked Swans within the Sanctuary; however, the variation in the Black-necked Swan population is still poorly understood. Spatiotemporal variation in population abundance and feeding/breeding ecology of Black-necked Swans was analyzed in the Sanctuary and adjacent wetlands (non-protected areas outside the Sanctu- ary) from 2000 to 2010. Temporal fluctuations in Black-necked Swan abundance were recorded, with increases in population size from late December to early June and decreases from late June to late September. Five main feeding grounds that were devoid of Brazilian waterweed were identified. However, several other aquatic plants were recorded on these grounds, suggesting that these areas provide alternative food resources for Black-necked Swans. Changes in the reproductive timing of Black-necked Swans throughout the 10-year study were recorded; no reproductive events occurred between 2004 and 2006, and a shortened reproductive period occurred between 2006 and 2010. In addition, there were changes in the locations of the breeding grounds as well as in the number of nests and chicks recorded during the study period. These results revealed new patterns in Black-necked Swan population trends as well as their distribution in areas both inside and outside the Sanctuary. Thus, to ensure ef- fective conservation of this species requires the integration of protected areas within as well as non-protected areas outside the Sanctuary. Received 4 October 2012, accepted 15 May 2013.
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The vertical distribution and abundance of gastropods and bivalves from rocky
beaches of Cuastecomate Bay, Jalisco

The vertical distribution and abundance of gastropods and bivalves from rocky beaches of Cuastecomate Bay, Jalisco

The recent increase in human activities such as tourism and fishing along the shore- line of Jalisco has intensified the exploitation of natural resources. In Cuatecomate Bay, at the southeastern coast of Jalisco, several gas- tropod and bivalve species have been exploi- ted commercially for many years. Since the intertidal fauna of Jalisco has not been stu- died well, the present study is important be- cause it will provide a more complete unders- tanding of the vertical distribution patterns of abundance and diversity of most noticea- ble gastropod and bivalve populations found in the rocky beaches of this region. Special emphasis was devoted to identify possible af- finities between groups of species among sampling sites by computing two classifica- tion (cluster) analysis, in an effort to unders- tand the relationship between the certain bio- logical, morphological and sedimentological characteristics of the beach and the abundan- ce and species composition found in these beaches, and to make generalizations on this relationship in other similar localities along the tropical Mexican Pacific.
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Abundance and spatial distribution of coastal floating plastic marine debris in the Balearic Islands

Abundance and spatial distribution of coastal floating plastic marine debris in the Balearic Islands

Coastal ecosystems are continuously affected by anthropogenic threats such as urbanization, maritime activities, recreational and commercial activities, all of which have been prominent sources of plastic marine litter. During summer of July 2017, the spatial distribution of floating plastics at seven locations across the island using nearshore sea cleaning boats was assessed. One-hundred percent of the samples contained plastic items of varying sizes, ranging from macro- (> 25 mm), meso- (5-25 mm) and micro- plastics (< 5 mm), composed principally of fragments, films and filaments. Significant differences were found for the abundance and size differences of items between the sampling locations. All samples were collected within one kilometre of the coastline and both the abundance and weight was found to significantly increase closer to the coastline. Plastics smaller than 5 mm were the dominant size class and fragments composed of almost 60% of the items with the main colors being transparent and white. Low variability of polymers were found with polyethylene being the primary plastic polymer type. These preliminary results indicate there is high small scale variability of coastal marine plastic concentrations surrounding the Balearic Islands.
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Distribution, abundance and composition of coral reef zooplankton, Cahuita National Park, Limon, Costa Rica

Distribution, abundance and composition of coral reef zooplankton, Cahuita National Park, Limon, Costa Rica

Abstract: The zooplankton distribution, abundance and composition at Cahuita coral reef (Cahuita National Park, 9° 45' N and 82° 49 'W, Costa Rica) were studied in four stations from January to November 1984. The samples were collected monthly using a net witb 0.47m diameter opening and 280J.lm mesh. Copepods were predominant tbroughout tbe year (32-95%), followed by foraminiferans (1-34%), fish larvae and eggs «1-28%), crustacean larvae (2-13.8%) and chaetognatba (1- 6.5%). Mollusc and echinoderm larvae were also presento High densities of zooplankton were obtained in January, August and October, with peak abundance in May. Low densities were found in April and November. Sorne groups like Copepoda, Chaetognatha, crustacean larvae and Polychaeta showed significant differ­ enees in tbeir abundanees from station to station. Amphipoda, Urochordata, mollusc and echinoderm larvae as well as ichtbyoplankton showed no such differences. Comparing tbe rainy and dry season, a significant difference,-Was detect­ ed between holo- and merozooplankton abundanees; holozooplankton population dominated botb in number and diver­ sity. The lower diversity of larval forms is assumed to be a result of strong sedimentation and sediment resuspension. The variability of zooplankton abundance and its distribution are influenced by tbe current system tbat predominates in
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Abundance and distribution of small infauna in mangroves of Missionary Bay, North Queensland, Australia

Abundance and distribution of small infauna in mangroves of Missionary Bay, North Queensland, Australia

higher abundances of polychaetes in the mudflat. Alongi (1987a) recorded little variation in sediment properties (% silt, grain size, water content) at a mid- and low-intertidal site in Missionary Bay, which relate to my transect sites I and IV. However, he measured higher values of total organic matter as well as organic C and N at the mid-intertidal site, which would correspond with the distribution of oligochaetes and capitellids. Oligochaetes and capitellid polychaetes were most abundant at the mangrove sites and their occurrence is often related to muddy sediments rich in organic matter (Pearson and Rosenberg 1978). These findings from Missionary Bay are therefore in accordance with records of Schrijvers et al. (1995a), who found a correlation of macrobenthic oligochaetes with % mud and organic matter in mangrove sediments. Interactions between endo- and epifauna have rarely been studied in mangrove forests, therefore their effect on the abundance and distribution of small infauna cannot be fully assessed. Most mangrove crabs feed on leaves, microbes, detritus and carrion, while few species are classified as carnivore (see Alongi and Sasekumar 1992, Schrijvers et al. 1996). Juvenile penaeids prey upon small macrofauna (Robertson 1988). Small infauna could indeed provide a rich food source for juvenile fish and prawns, as they are easily accessible at the sediment surface where they occur in great numbers. Given the higher abundance of small than larger infauna, trophic interactions and food webs of mangrove ecosystems have to be further studied.
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Occurrence, distribution, abundance and diversity of fishes in the Gulf of Nicoya, Costa Rica

Occurrence, distribution, abundance and diversity of fishes in the Gulf of Nicoya, Costa Rica

The data used in this study were taken during three cruises in the Gulf of Nicoya. The first , February, 1 979 consisted of 20 collections from 1 7 stations (3 stations were duplicated as night stations). The sec­ ond cruise took place during July, 1 9 79 and consisted of 22 collections at 20 stations (2 stations were duplicated as night stations). During April, 1 980, a third cruise consisted of 20 day stations. The location of these stations (Fig. 1 ) was chosen to provide coverage of the majority of the Gulf. The addition of Stations 1 9, 20 and 2 1 , in the J uly and April cruises, was made to enhance the coverage of the upper gulf. Collections were made at each of the stations using a semi-balloon shrimp trawl (30 ft head rope and 3 7 ft foot rope at the mouth with 1 1 / 2 inch stretched mesh #9 thread body and 1 3/8 inch stretched mesh #1 8 thread bag). The net was towed at 1 -2 knots with the prevailing current for a period of 30 minutes. A cable length of 5 or 6 to 1 (length to depth) was used to e nsure that the trawl was fishing the bottom. If the net became fouled or faiÍed to function properly the haul was repeated. All fish captured were sorted to species whenever p ossible. Identifications were the r e s p o n s ab i l i t y o f López and Bussing, whereas Bartels and Price accounted for the ecological aspects of the study.
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Species composition, abundance and distribution of zooplankton in a tropical eutrophic lake: Lake Catemaco, México

Species composition, abundance and distribution of zooplankton in a tropical eutrophic lake: Lake Catemaco, México

dtmsity was observed along the sampling period (Fig. 4). Regarding spatial variations, although the analysis of the complete data djd not yield significant differences, densities of total zooplankton in· the stations placed at the central part ofthe lake appear to be higher than those placed in a more peripheral position (Fig. 5). Therefore, the Wilcox's non-parametric comparison for two paired samples was applied to the densities of the stations, clustering them within tbree groups: northern (stations 3, 4 and 9), central (2, 5, 8) and southern (1,6,7). This test showed no important differences in derisity between the northern and southern groups (z= 0.72, probability of equality, p = 47.24 %), but the central group differed from the northern (z=2.44, p = 1.48%) and the southern one (z= 1.9245, p= 5.42%). Station 7, located off the town of Victoria, showed the lowest density.
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Seasonal vertical distribution, abundance, biomass, and biometrical relationships of ostracods in Golfo Dulce, Pacific coast of Costa Rica

Seasonal vertical distribution, abundance, biomass, and biometrical relationships of ostracods in Golfo Dulce, Pacific coast of Costa Rica

organic matter, as well as a high sediment flow. The great amount of detritus in September is further evidence for the contribution of rivers, especially the Rincon River (Fig. 1). This leads to a strong decomposition through microbial activity. Another explanation could be the intro- duction of oceanic water mass. Richards et al. (1971) observed a rise in the oxygen isopleths until 10m with a marked north-south gradient, with higher oxygen concentrations in the direc- tion toward the open ocean (south). Although it was not observed for the rainy season, the thermocline showed a rise in the northern direction at this time (Jacob 1996). Mixed pro- cesses through tide currents produced the dif- ferences found. Surface salinity was on average lower than that reported previously (>31 PSU, Richard et al. 1971, Brenes & León 1988), a direct consequence of the heavy rains in the second half of the year. Recently, Quesada- Alpízar & Morales-Ramírez (2004) detected biannual events in the basin of the Golfo in the influx of cold, high salinity, and oxygen rich oceanic water masses, which might be related to the same forces driving the coastal upwelling system in the Gulf of Panamá.
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Phlebotominae sand flies in Paraguay . Abundance distribution in the Southeastern region

Phlebotominae sand flies in Paraguay . Abundance distribution in the Southeastern region

Phlebotominae were collected at ten sites along the Paraná river, in the departments of Misiones (Coratei) and Itapúa (Ayolas, San Cosme-Damián, Carmen del Paraná, Quiteria, Aguapey, Encarnación, Bella Vista, Capitán Meza, Mayor Otaño), Paraguay (Fig. 1). Two CDC miniature light traps were used in parallel per site, both with CO 2 (500 ml/ h), placed 1.5 m above the ground. Captures were carried out monthly during 24 h, from September 1993 to August 2001. Environmental characteristics of the sites are de- scribed in the discussion. Phlebotominae were processed and identified according to Young and Duncan (1994) and Marcondes (1996). Meteorological data were obtained from EBY Ituzaingó (Argentina). Fisher or χ 2 tests were used for
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The distribution and abundance of wetland ichthyofauna, and exploitation of the fisheries in the
     Godineau Swamp, Trinidad – Case study

The distribution and abundance of wetland ichthyofauna, and exploitation of the fisheries in the Godineau Swamp, Trinidad – Case study

Regulations within the fishery are of little consequence if external factors, such as agri- culture, drainage infrastructure, oil pollution, industrial and residential development that affect the integrity of the habitat and the fishery are not managed toward the same objective of maintaining a healthy wetland system. This can be achieved by screening all development and land use, proposed and existent, within the wetland and its watershed. Proposals should be reviewed through a consultative process with affected stakeholders. Public awareness and concern may put pressure on stakeholders to remediate habitats and implement pollution minimization procedures. Consideration of tra- ditional rights, environmental impacts and miti- gation of these impacts with a view to safeguard the rights of the stakeholders and the integrity of the wetland system should be the major factors in decision making for development and land use in and around the wetland area. This is in keeping with Trinidad and Tobago’s national
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Abundance, distribution and size structure of Diadema antillarum (Echinodermata:
Diadematidae) in South Eastern Cuban coral reefs

Abundance, distribution and size structure of Diadema antillarum (Echinodermata: Diadematidae) in South Eastern Cuban coral reefs

show a higher human activity. That informa- tion was obtained previously to the design of this study which is part of a broader research (Pina-Amargós 2008) carried out to evaluate the effectiveness of the Marine Reserve. Densities and test diameters of D. antillarum recorded from reef crests were compared among zones at each sampling time using a one way ANOvA and the Student-Newman-Keuls test for post- hoc comparisons. Density data were transformed using the forth root transformation as suggested by the log-mean vs. log-variance relationship (Taylor’s Law) for conformity to the assump- tions of normality and variance homogeneity. No statistical analyses were performed with densities recorded from reef slopes to prevent erroneous results caused by a high proportion of zero values. Because of obvious differences in Diadema densities between habitats, statistical comparison was unnecessary.
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Distribution and abundance of four caiman species (Crocodylia: Alligatoridae) in Jaú National Park, Amazonas, Brazil

Distribution and abundance of four caiman species (Crocodylia: Alligatoridae) in Jaú National Park, Amazonas, Brazil

We thank the following: Regina Oliveira invited us to work at JNP. Laércio Marajó dos Reis, Aldenora Lima de Queiroz, José Carlos Raposo, Carlos Sotero da Silva, Carola Reimann and Norma Chemin helped us in the fieldwork. Arnaldo Carneiro Filho gave to us files of the Landsat-TM images. Augusto S. Abe and Peter Brazaitis reviewed carefully our text, and two anonymous reviewers read criti- cally an early version of this paper. This research was supported by: Fundação Vitória Amazônica; Instituto Nacional de Pesquisas da Amazônia; Biodiversity Support Program - a consortium among World Wildlife Fund, The Nature Conservancy and World Resources Institute, financed by Usaid (Grant MS33); Fundação O Boticário de Proteção a Natureza (Projeto de Pesquisa 119/93A); Coordenação
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Copper in Deccan Basalts (India): review of the abundance and patterns of distribution

Copper in Deccan Basalts (India): review of the abundance and patterns of distribution

Out of the available data for the Deccan Trap, the normative character for 129 basalts is known. In Table 2 it is used to characterize the variation in copper abundance in term of different basalts types, and, at the same time, compared with the world average for the same type. Considering the arithmetic mean among the Deccan Trap, the highest Cu concentration is found in the quartz normative tholeiites (299 ppm) like in the case of basalts around the world. But the difference is larger than twice, the Deccan quartz tholeiites being richer in copper. In the world average, next in the order of decreasing abundance are olivine normative tholeiites (126 ppm) and the nepheline normative basalt poorest, with 47 ppm Cu only. However, surprisingly, in case of the Deccan Trap, nepheline normative basalt is next to quartz tholeiite in their copper abundance (122 ppm) which is nearly three times the world average for the same type (47 ppm).
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At sea abundance and distribution of skuas and jaegers (Charadriiformes: Stercorariidae) at coastal waters off central Chile

At sea abundance and distribution of skuas and jaegers (Charadriiformes: Stercorariidae) at coastal waters off central Chile

1987b). Jaegers chased mostly migratory species such as Franklin's gulls and Arctic terns, all boreal migrants. This is consistent with the observations that jaegers synchronize their migrations with those of their hosts and follow them during their migratory movements (Furness 1987a). However, parasitic jaegers were also able to take advantage of local species such as South American and Inca terns and Grey gulls. Jaegers kleptoparasitized only smaller birds (see Table 2), supporting the idea that size is an important factor influencing host species selection as smaller species are more vulnerable and prone to drop food items after being chased (Furness 1987a; Arcos 2000). Chilean skuas kleptoparasitized on both smaller and larger seabirds (e.g., Peruvian booby) but were also able to engage in multi- species flocks for feeding and resting, in accordance to their classification as ‘ opportunistic kleptoparasites ’ (Furness 1987b). Remarkably, Chilean skuas and Parasitic jaegers seem to be almost completely segregated in the species they associate with as only Inca terns were common hosts to both Stercorarius species, although with different purposes (see Table 2). Brown skuas were never seen associated to other species.
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Abundance, distribution within phorophytes and fruit production of the first population of

Abundance, distribution within phorophytes and fruit production of the first population of

Abstract. The phorophytes distribution was studied and the fruit production of the 46 Telipogon helleri (Orchidaceae) plants, recently registered in Mexico by Solano et al. (2011), was detailed. The coffee plantation was characterized, the life stages of every orchid plant (immature and adult), the vertical distribution (trunk, forks, branches, twigs) and the orientation they had in the phorophytes were determined. From T. helleri plants, the 97.83% are adults, what suggests there is recruiting limitation. A number of 10 T. helleri plants grew up over coffee bushes (21.74% of the total) and 36 of the same species occupied shade trees (78.26%). Considering coffee bushes and shade trees, the 73.92% of the population (34 plants) grew up in the trunk. The 78.26% of the plants was between 2.1-4 m of height. A quantity of 51 inflorescences with 181 flowers was assessed, from which the 23.76% formed fruits (43 fruits). Telipogon helleri still has a very incipient and located population, that is why it is essential to monitor it in order to see what its behavior might be in future and to evaluate its relationship with the rest of vascular epiphytes present in the coffe agroecosystem.
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Distribution and abundance of Syacium ovale larvae (Pleuronectiformes: Paralichthyidae) in the Gulf of California

Distribution and abundance of Syacium ovale larvae (Pleuronectiformes: Paralichthyidae) in the Gulf of California

Abstract: The spawning season of the tonguefish Syacium ovale (Günter 1864) was determined by an analysis of the distribution of preflexion stage larvae in the Gulf of California. The larvae were collected during eight oceanographic surveys between 1984 and 1987. The spawning of this species starts in early summer and ends at the beginning of fall, with the highest reproductive activity in mid summer. The central and southern regions of the Gulf are the most important reproductive area. Spawning is associated with high sea surface temperatures and low plankton biomass, both of which are characteristics of the tropical current that invades the study area during summer.
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