Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

The variability of algae density at the surface level of soil in a coffee plantation in the Central Plateau of Costa Rica (1130 m altitude was studied from June 1980 to July 1981. One hundred twenty or one hundred sixty samples were taken each time. The major chemical and physical characteristics of the soil were determined and ecological information for macrovegetation was collected. The highest algae count was obtained during the initial period of the 1981 rainy season (529 313 ± 288 875 cells/g dry soil). During the dry season the number of algae declined greatly and in April 1981 it was 9578 ± 5 693 cells/g dry soil. The dominant group of algae was Chlorophyta due to the great soil acidity. The Bacillariophyta populations were very small and Cyanophyta were encountered only in three months the study, The factors which limit full development of algae during the remainder of the rainy season are discussed.

Desde mayo de 1980 hasta abril de 1981 se estudió algunas características biométricas, dimorfismo sexual y rendimiento en carne en Anadara tuberculosa en Punta Morales, Costa Rica. Las muestras se separaron en 3 grupos de tallas (1: 42-47,5 mm; 2: 48-53,5 mm; 3: 54-59 mm). No se encontró dimorfismo sexual en cuanto a las variables longitud-peso. Se estimó que el crecimiento es alométrico. El mejor modelo que explicó el peso fresco fue el cuadrático, siendo la longitud el parámetro más adecuado. Se encontró que el porcentaje de carne por peso fue mayor en los ejemplares de la talla 1 (20,34%) y menor en los de la talla 3 (16,31 %) con un promedio para las tres tallas de 18,26%.

Observations on the biology of Cichlasoma macracanthum (Jordan & Evermann, 1896) from the Chiquimulilla Channel, on the Pacific coast of Guatemala, were made from March to August 1980. Stomach contents suggest that this species is a benthic omnivore. The principal food items were plant and animal detritus and secondarily fishes, crustacea, macrophytes and insects. Size fluctuated between 70 and 189 mm TL with three age groups for males and females.

A model was formulated to estimate the carrying capacity (animal weight/area) and area of ponds in intensive culture of freshwater fish, managed with artificial feed. The model is based on a non-stationay mass balance of oxygen in the water, depending on the following parameters: water flow, ratio of oxygen concentration in the affluent and effluent pond, oxygen consumption per unit of animal weight, pond volume and water temperature. It was applied to the culture of rainbow trout.

The average size of the discarded fish in the shrimp by-catch ichthyofauna of Costa Rica was compared with that of the Gulf of México and Gulf of California fisheries. The high diversity, small size and limited commercial value, suggest an industrial use of the studied species as the best option. Local conditions suggest that fish meal production could be a feasible alternative for the industrial processing of the discarded by-catch.

Current biogeographic patterns of the 12 genera of the gardening ant tribe Attini are examined. Six of the genera are more concentrated in the southern subtropics of South America, and the true leaf-cutting ants, Atta and Acromyrmex, markedly so. No pattern of taxonomic diversity following phylogeny emerges, and the hypothesis that leaf-cutting ants evolved in the tropical rain-forest cannot be assumed to be confirmed. The taxonomic diversity of attine ants on Caribbean islands was examined in terms of biogeographic theory. Island surface area and distance from the mainland were important in predicting species numbers present, yet these two factors only explained less than 50% of the observed taxonomic diversity.

Several physicochemical and biotic factors were studied to better understand the distribution of land and semi-acuatic turtles in the Valle Central Region, Costa Rica: Kinosternon scorpioides, Rhinoclemys pulcherrima, Rhinoclemys funerea, Chelydra serpentina. Biometric characteristics of the species collected in their habitats were measured in situ.

Ovules of Bixa orellana L. are crassinucellate, bitegmic and have a micropyle formed by both integuments. Ovular position varies during development. Survival of the chalazal m egaspore results in monosporic gametophyte. Fertilization is porogamous, and syngamy and triple fusion seem to occur simultaneously. The proembryo seems to be a massive coenocyte; later, it becomes cellular. The embryo is spatulate and the radicle is antitropous. Germination takes place through a chalazal canal next to the hilum. The outer integument contains the pigment bixine.

This is the first comprehensive report on hallucinatory, edible and poisonous mushrooms of Costa Rica. A total of 67 species is reported of which 4 are hallucinatory, 55 are edible and 8 are poisonous. A search based on information obtained from national health centers between 1972 and 1977, includes total number of intoxications per year, number of cases by age, sex and geographic distribution.

Approximately 5,500 fishes weighing more than 62 Kg and representing 61 species were captured at four-week intervals at a mangrove and a beach site at Punta Moreles, Gulf of Nicoya, Costa Rica, from May 1980 to April 1981. Day and night samples were taken equelly. Anchoa panamensis comprised 23% of the total number of individuals, whereas Mugil curema acounted for 21% of total biomass.Capture trends were similar for numbers of species and individuals and total biomass throughout the study. The only significant capture data difference was between mangrove (greater) and beach habitats in terms of numbers. Large numbers of juvenile engraulids, atherinids and gerreids were correlated negatively with lower salinity from August to October. The mullet, Mugil curema, apparently favors higher salinities of the dry season and accounts for the increase in biomass at the beginning and end of the study. In spite of these seasonal differences, H’ diversity varied little, with a mean of 2.72 for numbers and 2.98 for biomass.Percentage similarity (PS) values between sites, times and sampling periods were generally low but only rarely significantly so. The moderately low seasonal change in PS values coupled with a stable and high annual H’ diversity indicate that the littoral fish populations are not presently adversely stressed by environmental contamination input into the Gulf of Nicoya.