Fishing gear selectivity in relation to their manufacture and to the management of fisheries of the Nile perch, the Nile tilapia, and Rastrineobola argentea (Mukene) in Lakes Victoria and Kyoga

The fisheries of Lakes Victoria and Kyoga have changed from the native tilapiine species and are now dominated by two introduced species; Nile perch and Nile tilapia, and one native species; Rastrineobola argentea (mukene). Because of the differences in the size of the species, it may be necessary to change the type and sizes of nets used.

Rapid assessment of the fish biodiversity of the Mburo-Nakivali wetland systems and Opeta-Bisina wetland systems, Uganda

There are 46 different fish species in the Lake Kyoga basin with some of them endemic. The Nile Perch (Lates niloticus) was introduced into the main Lake Kyoga, Nakuwa and Bisina in the late 1950s to increase the fish production. The Nile Perch profileration in lakes Kyoga and Nakuwa led to the almost complete elimination of many native fish species such as Orechromis esculentus and variabilis, Mormyrus kanumme, Schilbe mystus and several Haplochromines species. Lakes Mburo, Kachera, Nakivali and Kijjanebalora are part of the complex system of lakes separated from Lake Victoria by extended swamps known as the Koki lakes, some of the satellite lakes in the Lake Victoria basin. The fisheries of these lakes are important as they contribute to government efforts of increasing food security, poverty reduction and conservation of natural resource base. These lakes are important biodiversity areas because some of these lakes have been found to contain the native tilapiine Oreochromis esculentus (Ngege), absent or threatened with extinction in the main Lakes Victoria and Kyoga. It’s also important to note that this species is only unique to the Victoria and Kyoga lake basins (Graham, 1929, Worthington, 1929). The values of some of these lake fisheries are however, threatened by human activities such as over exploitation, introduction of exotics especially water hyacinth that is already present in River Rwizi and habitat degradation among others.

Nabugabo lakes and their current conservation status

Fish species diversity in Lake Nabugabo, Uganda, has declined following establishment of the introduced fish species in the lake. Most of the native fish species have disappeared and the lake is now dominated by the introduced Nile perch, Lates niloticus and the Nile tilapia Oreochromis niloticus. The dominant native fish species include Synodontis afrofischeri, Schilbe intermedius, Rastrineobola argentea and Brycinussadleri. Some of the native fish species that have disappeared from Lake Nabugabo were reported to occur in lakes Kayugi and Kayanja, which are adjacent to Lake Nabugabo but separated from it by extensive papyrus swamps. The Nabugabo lakes are satellite water bodies in the Lake Victoria basin, which is known to have experienced fish species changes due to the introduction of the Nile perch Lates niloticus during the 1960s.The Nabugabo lakes comprising of Lake Nabugabo main, and the smaller lakes Kayanja and Kayugi were investigated between 2000 and 2002 with experimental gill netting to evaluate the potential of these lakes in conservation of fish species diversity. Results show that some native fish species especially Oreochromis esculentus, and Oreochromis variabilis and the haplochromine cichlid Prognathochromis venator that have disappeared from Lake Nabugabo still occur in Lakes Kayanja and Kayugi. Inshore habitats with macrophyte cover were also found to be important habitats for the endangered native fish species in the Nabugabo lakes. These lakes and inshore habitats need to be protected to conserve the endangered native fish species and to reduce further decline in fish species diversity.

A manual of previously recorded non-indigenous invasive and native transplanted animal species of the Laurentian Great Lakes and coastal United States

This manual presents geographic information by state of occurrence, and descriptions of the socio-economic impact created by the invasion of non-indigenous and native transplanted animal species in the Laurentian Great Lakes and the coastal waters of the United States. It is not a comprehensive literature review, but rather is intended as a primer for those unfamiliar with the socio-economic impacts of invasive aquatic and marine animals. Readers should also note that the information contained in this manual is current as of its publication date. New information and new species are routinely being added to the wider literature base. Most of the information was gathered from a number of web sites maintained by government agencies, commissions, academic institutions and museums. Additional information was taken from the primary and secondary literature. This manual focuses on socio-economic consequences of invasive species. Thus, ecological impacts, when noted in the literature, are not discussed unless a connection to socio-economic factors can be made. For a majority of the species listed, either the impact of their invasion is not understood, or it is not published in sources surveyed. In the species summaries, sources of information are cited except for information from the U.S. Geological Survey’s (USGS) Nonindigenous Aquatic Species Database http://nas.er.usgs.gov. This website formed the base information used in creating tables on geographic distribution, and in many of the species summaries provided. Thus, whenever information is given without specific author/source and date citation, it has come from this comprehensive source. (PDF contains 90 pages)

Developing aquaculture of Small Native Species (SNS) in Bangladesh: village level agroecological change and the availability of SNS

Small native species (SNS) of fish are important source of protein and income for rural people in Bangladesh. A rapid rural appraisal study was carried out to explore the recent changes in the availability of SNS in relation to agroecology and related issues. Village residents noted that the availability of SNS had declined drastically due to habitat loss related to agricultural intensification and due to the restriction of access to the remaining habitats in the course of aquaculture development. Their perception was that poor people had gained from the intensification of agriculture in terms of rice consumption but had lost in terms of reduced access to fish and other animal products.

Deleterious effects of non-native species introduced into Lake Victoria, East Africa

Lake Victoria, in East Africa, has suffered from introductions and invasions of non-native species such as Lates niloticus, various tilapiine species, and Eichornia crassipes since the 1950s. These have had a devastating effect on the natural biological communities. This paper reviews the effects of the introductions on ecology, environment, fisheries and the local human population.

Assessment of contaminant body burdens and histopathology of fish and shellfish species frequently used for subsistence food by Alaskan Native communities

Subsistence food items can be a health concern in rural Alaska because community members often rely on fish and wildlife resources not routinely monitored for persistent bioaccumulative contaminants and pathogens. Subsistence activities are a large part of the traditional culture, as well as a means of providing protein in the diets for Tribal members. In response to the growing concerns among Native communities, contaminant body burden and histopathological condition of chum and sockeye salmon (Oncorhynchus keta and Oncorhynchus nerka) and the shellfish cockles and softshell clams (Clinocardium nuttallii and Mya arenaria) were assessed. In the Spring of 2010, the fish and shellfish were collected from traditional subsistence harvest areas in the vicinity of Nanwalek, Port Graham, and Seldovia, AK, and were analyzed for trace metals and residues of organic contaminants routinely monitored by the NOAA National Status & Trends Program (NS&T). Additionally, the fish and shellfish were histologically characterized for the presence, prevalence and severity of tissue pathology, disease, and parasite infection. The fish and shellfish sampled showed low tissue contamination, and pathologic effects of the parasites and diseases were absent or minimal. Taken together, the results showed that the fish and shellfish were healthy and pose no safety concern for consumption. This study provides reliable chemistry and histopathology information for local resource managers and Alaska Native people regarding subsistence fish and shellfish use and management needs.

Study of white spot disease in four native species in Persian Gulf by histopathology and PCR methods

After serious disease outbreak, caused by new virus (WSV), has been occurring among cultured penaeid shrimps in Asian countries like China since 1993 and then in Latin American countries, during June till July 2002 a rapid and high mortality in cultured Penaeus indicus in Abadan region located in south of Iran with typical signs and symptoms of White Spot Syndrome Virus was confirmed by different studies of Histopathology, PCR, TEM, Virology. This study was conducted for the purpose of determination of prevalence(rate of infection)/ROI and grading severity (SOI) of WSD to five species: 150 samples of captured shrimps and 90 samples of cultured ones; Penaeus indicus, P. semisulcatus, P. merguiensis, Parapenaopsis styliferus, and Metapenaeus affinis in 2005. 136 of 240 samples have shown clinical and macroscopical signs & symptoms including; white spots on carapase (0.5-2 mm), easily removing of cuticule, fragility of hepatopancreas and red color of motility limbs. Histopathological changes like specific intranuclear inclusion bodies (cowdry-type A) were observed in all target tissues (gill, epidermis, haemolymph and midgut) but not in hepatopancreas, among shrimps collected from various farms in the south and captured ones from Persian Gulf, even ones without clinical signs. ROI among species estimated, using the NATIVIDAD & LIGHTNER formula(1992b) and SOI were graded, using a generalized scheme for assigning a numerical qualitative value to severity grade of infection which was provided by LIGHTNER(1996), in consideration to histopathology and counting specific inclusion bodies in different stages(were modified by B. Gholamhoseini). Samples with clinical signs, showed grades more than 2. Most of the P. semisulcatus and M. affinis samples showed grade of 3, in the other hand in most of P. styliferus samples grade of 4 were observed, which can suggest different sensitivity of different species. All samples were tested by Nested PCR method with IQTm 2000 WSSV kit and 183 of 240 samples were positive and 3 1evel of infection which was shown in this PCR confirmed our SOI grades, but they were more specified.

Study of parasites native and introduced species of fish in Caspian Sea

Seven native and introduced species of fish in south east Caspian Sea coast examined for parasite infestation during 2004-2006. Native fishes include Barbus capito, Carassius auratus, Cyprinus carpio, Rutilus frisii kutum, Rutilus rutilus, Stizostidion lucioperca, Alosa caspia persica, 24 ecto and endo parasites were found in different organs of 7 species of fishes of them 2 of the metazoan 12 species of crustacean Lernaea cyprinacea , Lamproglena pukhella nematodea and cestodea parasite were found and identified to species and genus including: Asymphylodora kubanicums, Caryophylaeus fimbericep, Rhabdochona hellichii, Contracecum sp. (larvae), Pronoprymna, Aspidogaster limacoides, Raphidascaris acus, Caryophylaeus laticeps, Rhabdochona hellichi, Clinostomum complanatum, Hysterothylacium sp., Rhipidocotyle illense of the metzoan 9 monogen species were found and identified to species and genus level including Dactylogyrus frisii, Dactylogyrus nybelini, Dactylogyrus extensus, Gyrodactylus sp, Dactylogyrus baueri, D. formosus, Gyrodactylus sprostonae, Gyrodactylus sp, Mazaocraes alosae. One psecies of digenea parasites belonging to Diplostomatidea family comprised Diplostomum Spathaceum. In comprise infestation parasite of fish species Cyprinus carpio, Rutilus frisii kutum with 25 precent and Stizostidion lucioperca with 5 percent showed the highest and lowest in infection between fishes in comprise ecological region rivers with 45 percent and Estuary 16 percent showed the highest and lowest percent of parasite Infection.