William A. Bussing

Freshwater Ecoregions of the World: A New Map of Biogeographic Units for Freshwater Biodiversity Conservation

ABSTRACT We present a new map depicting the first global biogeographic regionalization of Earths freshwater systems. This map of freshwater ecoregions is based on the distributions and compositions of freshwater fish species and incorporates major ecological and evolutionary patterns. Covering virtually all freshwater habitats on Earth, this ecoregion map, together with associated species data, is a useful tool for underpinning global and regional conservation planning efforts (particularly to identify outstanding and imperiled freshwater systems); for serving as a logical framework for large-scale conservation strategies; and for providing a global-scale knowledge base for increasing freshwater biogeographic literacy. Preliminary data for fish species compiled by ecoregion reveal some previously unrecognized areas of high biodiversity, highlighting the benefit of looking at the worlds freshwaters through a new framework.

Fish communities and environmental characteristics of a tropical rain forest river in Costa Rica

Inflorescences of Baclris gasipaes (a moooecioos neolropica1 pahn) present a strong prezigotic resource allocation toward masculinity on the inflorescence. Male reproductive effort (ERM. biomass) was 0.82 ± 0.11 g male flowers / g inflorescence. A high conelatioo between me total inflorescence biomass with female reproductive effort (ERF) (r= 0.76), indicates that plants wim bigger inflorescences allocate more resources to ihe female functioos. The pistillate flowers are situated preferentially in me inner pans of rachillas. Early ideas about evolution of protoginy, resource allocation and plant sexual systems are supported by these data.

Annotated checklist of the freshwater fishes of continental and insular Costa Rica: additions and nomenclatural revisions

Based on a combination of intensive literature review, electronic database searches, re-identification of museum specimens and fieldwork, we hereby provide an updated checklist of the freshwater fishes of continental and insular Costa Rica. This checklist, systematically arranged at the ordinal and familial level, includes nomenclatural revisions, distributional information, and when appropriate, cross-references on the basis of Bussing (1998). According to our results, the native Costa Rican freshwater fish fauna is composed by 250 species, divided into 119 genera, 49 families and 19 orders; increasing in 108 the number of species originally reported by Bussing (1998). By far, the vast majority of these species, according to their supposed tolerance to salinity, are peripheral (63.2%), followed by secondary freshwater fishes (23.6%); only 13.2% are primary freshwater fishes. 24 species in this checklist appear to be endemic to Costa Rica. In addition to the native fauna 8 exotic species are reported.

Ecological assessment of finfish as indicators of habitats in the Gulf of Nicoya, Costa Rica

Trawl samples of demersal fish populations within the Gulf of Nicoya, Costa Rica were conducted during February and July, 1979 and April, 1980 in an attempt to define basic abundance, diversity and distributional patterns. Seventeen day and three night samples produced 6 441 fishes of 107 species during the February cruise. Twenty day and two night samples produced 9 220 individuals of 131 species during the July cruise. Twenty day samples produced 14 151 individuals representing 125 species taken during the April cruise. A total of 214 species were collected during this study.The Gulf may be divided into three zones on the basis of the physical characteristics of the stations (water temperature, dissolved oxygen, salinity, depth and distance from the mouth of the Gulf). Few changes in the position of these zones occurred during the study period indicating a relatively stable estuarine configuration from a biological perspective.The Gulf of Nicoya area is under the influence of a wet and a dry season. No significant seasonal changes in the number, biomass, percent occurrence, diversity of partitioning by size class of fishes were observed.Two major types of fish distributional patterns were observed. Several species were ubiquitous and were found throughout the Gulf in varying abundances. Other species were restricted to either the upper or lower Gulf. Dominant groups in the upper Gulf include the sciaenids, sea catfishes (Ariidae) and flatfishes (Soleidae, Cynoglossidae andSyacium ovale). These fishes tend to inhabit the warmer, shallower, less saline waters of the upper Gulf. Flounders (bothidae), gobies (Bollmannia spp.), morays and congers (Hildebrandia nitens, Priodonophus equatorialis andMuraenesox coniceps) and several other species dominated the deeper, cooler, more saline lower Gulf.

Marine and estuarine fish diversity in the inner Gulf of Nicoya, Pacific coast of Costa Rica, Central America

A checklist of the marine and estuarine fishes of the inner part of the Gulf of Nicoya, Pacific coast of Costa Rica, Central America, was compiled by examining a museum fish collection, resulting in 72 families and 274 species. Of these species, 127 (46.4%) were marine species and 147 (53.6%) were estuarine-associated species. In terms of their life history and considering the habitat type classification, 188 (almost 70% of the total) were categorized as species inhabiting soft-bottom habitats, reflecting the large estuarine environment and rich fish diversity of the Gulf despite its relatively small area in the tropical Eastern Pacific region. Furthermore, the list contains 13 threatened species of IUCN Red List, which need further research to understand their abundance and their exposure to habitat loss in the Gulf. Further detailed studies on its fish fauna and habitat are needed to better understand and conserve biodiversity within the whole Gulf.

Occurrence of the tripodfish Bathypterois ventralis (Aulopiformes: Ipnopidae) in the Pacific coast of Costa Rica

UCR::Investigacion::Unidades de Investigacion::Ciencias Basicas::Centro de Investigacion en Ciencias del Mar y Limnologia (CIMAR)

Fishes from the Tusubres River basin, Pacific coast, Costa Rica: checklist, identification key and photographic album

UCR::Investigacion::Unidades de Investigacion::Ciencias Basicas::Centro de Investigacion en Ciencias del Mar y Limnologia (CIMAR)