21 resultados para Victor Horsley
Resumo:
CDRS Research Highlights, 2004. Plants. Social Sciences. Vertebrates. Invasive Species Total Control Plan. Terrestrial Invertebrates. Project Isabela. Marine Sciences.
Resumo:
Gonadal morphology and reproductive biology of the Black Anglerfish (Lophius budegassa) were studied by examining 4410 specimens collected between June 2007 and December 2010 in the northwestern Mediterranean Sea. Ovaries and testes presented traits common among fishes of the order Lophiiformes. Spawning occurred between November and March. Size at first maturity (L50) was 33.4 cm in total length (TL) for males and 48.2 cm TL for females. Black Anglerfish is a total spawner with group-synchronous oocyte development and determinate fecundity. Fecundity values ranged from 87,569 to 398,986 oocytes, and mean potential fecundity was estimated at 78,929 (standard error of the mean [SE] 13,648) oocytes per kilogram of mature female. This study provides the first description of the presence of 2–3 eggs sharing the same chamber and a semicystic type of spermatogenesis for Black Anglerfish. This new information allows for a better understanding of Black Anglerfish reproduction—knowledge that will be useful for the assessment and management of this species.
Resumo:
The overall goal of this assessment was to evaluate the effects of nutrient-source reductions that may be implemented in the Mississippi River Basin (MRB) to reduce the problem of low oxygen conditions (hypoxia) in the nearshore Gulf of Mexico. Such source reductions would affect the quality of surface waters—streams, rivers, and reservoirs—in the drainage basin itself, as well as nearshore Gulf waters. The task group’s work was divided into addressing the effects of nutrient-source reductions on: (1) surface waters in the MRB and (2) hypoxia in the Gulf of Mexico.
Resumo:
This compilation of references to works which synthesize information on coastal topics is intended to be useful to resource managers in decision making processes. However, the utility must be understand in terms of its limited coverage. The bibliography is not inclusive of all the published materials on the topics selected. Coverage is clearly defined in the following paragraph. The time span of the bibliography is limited to references that were published from I983 to 1993, except for a last-minute addition of a few 1994 publications. All searches were done in mid- to late-1993. The bibliography was compiled from searches done on the following DIALOG electronic databases: Aquatic Sciences and Fisheries Abstracts, BlOSlS Previews, Dissertation Abstracts Online, Life Sciences Collection, NTlS (National Technical lnformation Service), Oceanic Abstracts, Pollution Abstracts, SciSearch, and Water Resources Abstracts. In addition, two NOAA electronic datases were searched: the NOAA Library and lnformation Catalog and the NOAA Sea Grant Depository Database. Synthesis of information is not an ubiquitous term used in database development. In order to locate syntheses of required coastal topics, 89 search terms were used in combinations which required 10 searches from each file. From the nearly 6,000 citations which resulted from the electronic searches, the most appropriate were selected to produce this bibliography. The document was edited and indexed using Wordperfect software. When available, an abstract has been included. Every abstract was edited. The bibliography is subdivided into four main topics or sections: ecosystems, coastal water body conditions, natural disasters, and resource management. In the ecosystems section, emphasis is placed on organisms in their environment on the major coastlines of the U.S. In the second section, coastal water body conditions, the environment itself is emphasized. References were found for the Alaskan coast, but none were found for Hawaii. The third section, on natural disasters, emphasizes environmental impacts resulting from natural phenomena. Guidelines, planning and management reports, modelling documents, strategic and restoration plans, and environmental economics related to sustainability are included in the fourth section, resource management. Author, geographic, and subject indices indices are provided. The authors would like to thank Victor Omelczenko and Terry Seldon of the NOAA Sea Grant Office for access to and training on the NOAA Sea Grant Depository Database. We are grateful also to Dorothy Anderson, Philip Keavey, and Elizabeth Petersen who reviewed the draft document.
Resumo:
Prior to introduction of non-native fish species into Lakes Victor i a, Kyoga and Nabugabo, the three lakes suppor ted diverse fish fauna representing 13 families consisting of six cichlid genera and fifteen non-cichlid genera. There were about 50 non-cichlid species and over 300 cichlids consisting of mainly haplochromines (Graham 1929, worthington 1929, Greenwood 1960). Many of the species were commercially and scientifically important and provided a rich variety of protein source to choose from. Following introduction of the Nile perch and several tilapiines species, most of the native species were drastically reduced and some have apparently disappeared. The few remaining species appear to be restricted in distribution due to the presence of the Nile perch. They are mainly confined to refugia such as marginal macrophytes, rocky outcrops and small satellite lakes which are separated from the areas of introduction by swamps