An annotated checklist of the fish fauna of the river systems draining the Kahuzi-Biega National Park (Upper Congo: Eastern DR Congo)

The Kahuzi-Biega National Park (KBNP), situated mainly in the Eastern Highlands Ecoregion of the Upper Congo basin, is drained by the Lowa and Ulindi rivers, and some western affluents of Lake Kivu. In this study, the first list of the fish diversity of these systems is provided based on museum collections and complemented, for the Lowa River system and the western Lake Kivu affluents, with recently collected specimens (2013–2017). A total of 118 species are reported from the Lowa basin, 22 from the Ulindi basin and seven from these Lake Kivu affluents. Within the Lowa and Ulindi, respectively, five and one species, all cichlids, have been introduced. Currently, 51 species are reported from within the park, only two of which have been reported from the highlands, i.e., Amphilius kivuensis from the Luha, the source of the Luka River, and Clarias liocephalus from the headwaters of the Lake Kivu’ affluents. With a total of 30 species, Cyprinidae is by far the largest family, representing 25% of the total species diversity of the Lowa basin. It is followed by Mormyridae with 13 species (11%), Alestidae and Mochokidae with 10 species each (8%), Clariidae and Amphiliidae with eight species (7%), and Distichodontidae with six species (5%). Seven new species for science were discovered and 11 species were found to be endemic to the Lowa system. Although further exploration is needed, this underscores the importance of the KBNP in protecting the fish fauna of the Lowa basin but also highlights the park's limited coverage of the fish fauna of the Lowa basin.     

Ostracods (Ostracoda,Crustacea) from two freshwater lakes near Maarssen,The Netherlands

Summary In Lake Maarsseveen I (with the lowest trophic level) 15 ostracod species were collected, whereas 9 species were found in Lake Maarsseveen II.Physocypria kliei Schäfer, 1934, andCypridopsis obesa Brady and Robertson, 1869, are new to the Dutch fauna.     

Length‐weight relationship of three fish species from the Poyang Lake,China

The paper reports the length–weight relationships of 3 species from the Poyang Lake, the largest freshwater lake freely connect to the Yangtze River, China. A total of 1,207 specimens were collected seasonally (January, April, September and November, 2010) using various types of fishing gear nets (mesh size: 1–12 cm) and stationary lift nets (mesh size: 0.7–4.4 cm). For each species, the sample size, length range, weight range, LWR, 95% confidence intervals of a and b, and coefficient of correlation were determined. Length‐weight relationships for 1 species were unknown to FishBase, and new maximum lengths are recorded for 2 species.     

Echiuropus bekmanae n.sp. (Crustacea, Amphipoda, Carinogammaridae) from Lake Baikal, retrieved by a new deep-water sampling device

Lake Baikal is well known for its exceptional diversity of gammarid amphipods, with 95% of endemics from its 270 described species representing about 20% of the world freshwater fauna. Echiuropus (Asprogammarus) bekmanae n.sp. was collected by an `autonomous trap system', a sampling device thoroughly described here. Although not necrophagous itself, this new species was found in two baited trap samples (at 750 and more than 1600 m) from 1995 and 1996. This rather small (13 mm) deep water species is the eighth species of the subgenus Asprogammarus, of the Baikal endemic genus Echiuropus. Diagnoses of the subgenus and the closer species are given.     

Omega-3 Fatty Acids in Fish from the Laurentian Great Lakes Tribal Fisheries

Dietary fish must be assessed for benefits and risks to formulate risk management strategies. This article demonstrates that Laurentian Great Lakes (GL) freshwater species are good sources of omega-3 fatty acids using new data from a small sample (n = 7) of Lake Superior siscowet lake trout (Salvelinus namaycush siscowet) and five other GL fish species’ data. For Lake Superior (LS) siscowets, the saturates, mono-unsaturates, and poly-unsaturates composed 20.1, 40.7, and 39.1% of total lipid weight, respectively. Omega-3 poly-unsaturates (PUFAs) in these fish were more than twice the omega-6 (omega 3/6 ratio = 2.4). The LS lake trout data were combined with earlier LS data collected during the 1980s for eight other species and from five species of Lake Erie fish. All the GL freshwater species were compared with seven other published marine and freshwater fish studies from other global regions. PUFAs were compared based on latitude and marine versus freshwater origin. Differences between marine and freshwater species in omega-3 fatty acid were less at higher latitudes. GL freshwater fish species can be a good source of beneficial fats like marine fish and must be accounted in effective risk communications involving persistent bioaccumulative toxicants in dietary fish.     

Molecular phylogenetic investigations of the Viviparidae (Gastropoda: Caenogastropoda) in the lakes of the Rift Valley area of Africa

The freshwater gastropod family Viviparidae is nearly cosmopolitan, but absent from South America. On the African continent, two genera are recognized; the widespread Bellamya and the monotypic Neothauma, which is confined to Lake Tanganyika. Most of the African Bellamya species are confined to the major lakes of the Rift Valley area in Africa, i.e. Lake Albert, Lake Malawi, Lake Mweru, and Lake Victoria. The phylogenetic analyses of mitochondrial (COI and 16S) and nuclear (H3, 18S and 28S) DNA inferred three major lake-clades; i.e. Lake Victoria/Kyoga/Albert, Lake Malawi and Lake Mweru/Bangweulu. The endemic B. rubicunda from Lake Albert and B. unicolor from Lake Kyoga were inferred to be part of the Lake Victoria clade. Bellamya capillata as identified by shell characters was polyphyletic in gene trees. The monophyletic Bellamya species radiation in Lake Malawi was most nearly related to the Lake Victoria/Kyoga/Albert-clade. Taxa from the Zambian lakes, Mweru and Bangweulu, were inferred together and placed ancestral to the other lakes. Neothauma tanganyicense was inferred as the sister-group to the Zambian Bellamya. Within the lake-clades the endemic radiations show very low genetic diversities (0–4.1% in COI), suggesting much faster morphological divergence than molecular divergence. Alternatively, Bellamya in Africa constitutes only a few species with several sub-species or eco-phenotypic morphs. The African viviparids were inferred to be the sister-group to a clade comprising Asian species, and the relatively low genetic diversity between the clades (12.6–15.5% in COI) makes a recent Miocene dispersal event from Asia to Africa much more likely than an ancient Gondwana vicarience distribution.     

东太湖鱼类群落结构特征及其与环境因子的关系

基于2019年4月、7月和10月的调查数据,用多元分析方法研究了围网拆除后东太湖鱼类群落结构的变化,及其与主要环境因子的关系。共调查到鱼类4目10科31属39种,其中鲤形目鱼类占69.23%。按不同生态类型东太湖鱼类主要为定居性鱼类、中上层鱼类以及肉食性和杂食性鱼类。优势种为鲫（Carassius auratus）、大鳍鱊（Acheilognathus macropterus）和（Hemiculter leucisculus）等。鱼类的种类数、渔获量、丰富度指数和多样性指数在监测月份间均差异显著（P＜0.05）,均为4月 > 7月 > 10月。鱼类个体呈现小型化,鱼类物种多样性处在一般水平。等级聚类分析（Cluster）结果表明,除10月份的1号点和3号点外,各样方间的相似度在46.75%以上。单因子相似性分析（ANOSIM）和相似性百分比分析（SIMPER）也表明,4月和10月的鱼类群落物种组成差异显著,平均相异性为59.41%。丰度/生物量曲线（ABC）分析表明,东太湖鱼类群落结构处于中度干扰状态。冗余分析（RDA）表明,总磷对主要鱼类变化的解释量为21.0%,是重要的解释因子（蒙特卡罗检验P＝0.036）。而总磷、pH、溶解氧等是目前影响东太湖鱼类群落的主要环境因子。     

The genus Argulus (Crustacea: Branchiura) in Africa: two new species,A. fryeri and A. gracilis,the previously undescribed male of A. brachypeltis Fryer and the identity of the male described as A. ambloplites Wilson

Two new species of Argulus Müller, 1785 (Crustacea: Branchiura) are described from Africa. A. fryeri n. sp., parasitic on an unknown fish species collected from Lake Turkana, Kenya, is characterised by: deep antero-lateral depressions which delimit a pronounced frontal region; robust, square second maxillae ornamented with numerous small, simple scales; and the shape of the respiratory areas. The most distinctive features of A. gracilis n. sp., parasitic on Auchenoglanis occidentalis var. tanganicanus collected from Lake Tanganyika, are the anterior spines on the first antennae and the shape of the respiratory areas. A. brachypeltis Fryer, previously known only from the female, is characterised by: a narrow, elongate body with foreshortened carapace lobes; small, slender terminal spines on the first antennae; and short terminal segments on the second maxillae with minute claws. The identity of the male described as A. ambloplites Wilson is discussed and renamed A. confusus nom. nov.     

Occurrence of the endangered species Nitellopsis obtusa (Charales,Charophyceae) in western Japan and the genetic differences within and among Japanese populations

Nitellopsis obtusa (Charales, Charophyceae) are widely distributed from Europe to Asia; however, this species has been recorded in only the five lakes in central Honshu in Japan. This species was thought to be extinct in Japan, but was rediscovered in limited areas of Lake Kawaguchi in central Honshu. More recently, we discovered more Japanese populations of N. obtusa in Lake Biwa in western Honshu, and it became clear that the species had a broader distribution in Japan than originally believed. In addition, although only male or female thalli have been collected at each lake, both male and female thalli were found from Lake Biwa. This is the first report of a potentially sexual population of N. obtusa in Japan. The DNA sequences of three chloroplast DNA markers, including both coding and non‐coding regions, were identical in all specimens from Lake Kawaguchi and Lake Nojiri (Central Honshu), and differed from those of Lake Biwa and German specimens. Although Japanese and German specimens were genetically similar, Japanese specimens displayed considerable genetic diversity according to locality.     

Heterotrophic flagellates, centrohelid heliozoa and filose amoebae from marine and freshwater sites in the Antarctic

Heterotrophic flagellates, centrohelid heliozoa and filose amoebae were recorded from cultures derived from water collected at marine and freshwater sites in the Antarctic. Marine samples were collected in the vicinity of Prydz Bay, southeast Antarctica and freshwater samples from Sombre Lake on Signy Island and Crooked and Druzhby Lakes in the Vestfold Hills. Thirty-five species were identified. One new species, Kiitoksia kaloista (Protista incertae sedis), is described. The other species have been previously reported from other geographic locations, providing no evidence for endemism in protozoan species found in Antarctica. Received: 23 September 1996 / Accepted: 28 December 1996     

The calanoid copepods of the Nile system

At least 11 or 12 calanoid taxa occur in the Nile system. One species is typical of the river and of Lake Chad (Th. galebi); two are restricted to Lake Victoria (Th. galeboides, T. stuhlmanni), but both might be only subspecies to more widespread species. One is restricted to Lakes Edward and George (T. worthingtoni) but is a little known species. No calanoids are on record from Lakes Albert and Kyoga, while the species reported from Lake Turkana (T. banforanus) is out of range, and almost certainly represents an erroneous record. Among the remaining species, four are East-African, ranging from the southern tip of the continent to the Ethiopian plateau and the Nile valley (P. schultzei, Th. mixtus, T. kraepelini, T. cf orientalis), while two are Sahelian species that span Africa from east to west (M. mauretanicus, T. processifer et ssp.).Two new synonyms are introduced. One new subspecies (T. processifier friedae) is described from the Ethiopian plateau. It is suggested that Tropodiaptomus orientalis (Brady, 1886), the type species of its genus, should not be considered a nomen dubium, but should be redescribed on its type female(s) and on topotypical males from Sri Lanka.     

Four new species of Gomphocythere (Crustacea, Ostracoda) from Lake Tanganyika, East Africa

Four new species of the ostracod genus Gomphocythere are described from Lake Tanganyika (East Africa): Gomphocythere downingi n. sp. G. coheni n. sp., G. wilsoni n. sp., and G. woutersi n. sp. All species are endemic to the lake and are found within a variety of substrates and depths. The addition of these four new species brings the total number of endemic Gomphocythere species in Lake Tanganyika to nine. Other Gomphocythere species are known from water bodies throughout East and South Africa and in the Levant. Brooding is an important, but not a unique, preadaptation for the persistence and taxic prolific speciation of this lineage in Lake Tanganyika.     

Insect emergence from a shallow southern West German lake,with special reference to the parasitic host-associated water mite larvae

Insect emergence was studied with floating box traps in the littoral of Lake Mindelsee from July 1st until September 30th, 1984. The material was collected every 48 h. Out of the total catch of 6897 specimens per m², 75.1 % belonged to the Chironomidae, 4,9% to the Chaoboridae, 15,4% to the Ephemeroptera and 3,2% to the Trichoptera. Endochironomus sp., Lauterborniella agrayloides, Polypedilum pullum (Chironomidae) and Oocetis testacea (Trichoptera) are reported for the first time from Lake Mindelsee. The seasonal course of the total emergence showed two distinct peaks: one at the end of July, the other at the beginning of September. Diurnal emergence was studied on two occasions, in July and in August. Most of the insects emerged during dusk and dawn. Species composition and degree of water mite infection of the collected nematocerans were studied. Host range and specific attachment sites of the different water mite taxa could only be established on the genus or family-level, with the exception of the most common water mite species Hydrodroma despiciens. In addition to its main host Chaoborus flavicans, this mite species infested 16 chironomid species with Corynoneura sp., Cryptocladopelma viridula, Pseudochironomus prasinatus and Tanytarsus lactescens as new records. The larvae of Hydrodroma despiciens were attached almost exclusively to the thorax of the imagines. Chaoborus flavicans, and within the Chironomidae Procladius sp. of the subfamily Tanypodinae, showed the highest average mite load. Species of the subfamily Chironominae were also heavily infested (e.g. Microtendipes sp., infestation rate 76 % with a maximum mite load of 18). Within the representatives of the subfamily Orthocladiinae however, only low infestation rates occurred with maximum one larva per host. Finally, problems like the synchronization of the life-cycles of hosts and parasites and strategies of coexistence between the different water mite taxa parasitizing one host are discussed.     

New species and new records of diatoms from Lake Fuxian,China

Abstract One new species, four newly recorded genera, and two newly recorded species of diatoms are described from China. They are Sellaphora fuxianensis sp. nov. Li, Sellaphora Mereschkowsky, Karayevia Round & Bukhtiyarova, Placoneis Mereschkowsky, Fallacia Stickle & Mann, Placoneis prespanensis Levkov, Krstic & Nakov, and Fallacia lucinensis (Hustedt) D. G. Mann. All taxa were collected from Lake Fuxian in Yunnan Province, China. These species were observed with light and scanning electron microscopes, and their taxonomic characters are discussed.     

Collapse of Lake Whitefish Coregonus clupeaformis (Mitchill, 1818) species pair in Como Lake,Ontario

Lake Whitefish (Coregonus clupeaformis) species pairs exist in a small number of northern temperate lakes in North America. Sympatric populations of dwarf and normal‐sized whitefish represent a continuum of morphological and genetic divergence among these lakes. In this study, we used morphological and age data to assess the status of the Lake Whitefish species pair in Como Lake, Ontario (Canada). Whitefish were collected with gill‐nets from spawning shoals during the fall of 2012 and 2014 and compared with archived (circa 1989) dwarf and normal‐sized specimens. Our study indicates that the two previously collected forms have been replaced by a single form with a different morphology and age structure. In comparison to archived specimens, contemporary Lake Whitefish were larger, deeper‐bodied and older; with more gill rakers, lateral line scales, smaller eyes and a wider interorbital width. We hypothesize that the recent invasion of Como Lake by Spiny Waterflea (Bythotrephes longimanus) has affected whitefish growth rates and changed the ecosystem conditions that previously maintained the species pair.     

Abundance and distribution of fish in the lower Mnembo River, Malawi-Mozambique

Endorheic Lake Chilwa is one of the most productive lakes for fisheries in Africa. High human population densities and agricultural practices in the Chilwa catchment have been linked to observed declines of the annual fish catch in the lake. The Mnembo River is a major inflow into Lake Chilwa which has received little scientific study to date. In 2003/2004, fish diversity, abundance and distribution were monitored monthly at three sites in the Mnembo River. Twelve fish species were collected, a subset of the fourteen fish species present in Lake Chilwa. Although Barbus spp. were the most abundant species sampled in the Mnembo, total biomass was higher for Labeo cylindricus (6709 and 10,434 g, respectively). Total biomass of Pareutropius longifilis (1741 g) and Brycinus imberi (1174 g) were also high in the river. Catches of Barbus and Labeo were highly correlated (r = 0.763). Compared with other inflows into Lake Chilwa (Likangala and Domasi), the Mnembo River appears to be less adversely influenced by human populations, with high abundance of Barbus and strong presence of the riverine species Labeo, Pareutropius and Brycinus.     

不同类型景观水体浮游动物群落差异及其影响因素

探明不同类型景观水体中环境敏感型浮游动物群落特征差异及影响因素对景观水体生物多样性维持和水生生态系统保护十分重要。于2014年5月在上海选取具代表性的8个景观水体共设置35个采样点进行浮游动物采样调查,并同步测定水体环境指标。本次调查采集并鉴定浮游动物40种,其中轮虫29种,枝角类7种,桡足类4种。基于浮游动物群落组成进行聚类分析,所有采样点聚为四种景观类型:天然湖泊(淀山湖)、人工湖泊(滴水湖)、AAAA级公园水体(共青森林公园和古猗园)和普通综合性公园水体(世纪公园、和平公园、长风公园和车镜公园)。两种公园水体浮游动物种类较为丰富,多样性较高,各自约有40%的种为生境特有种,而淀山湖特有种仅1种(为猛水蚤),滴水湖3种均为蛭态类。物种相似性方面,大型天然淀山湖与人工滴水湖相似性最高(37.5%),普通公园水体次之(33.3%),与AAAA公园水体相似度最低(20%)。后两者间的相似性较高(27.8%),且两者与滴水湖的相似度均较低(18.5%和12.0%)。四类水体仅有3个共有种/类群:角突臂尾轮虫(Brachionus angularis)、螺形龟甲轮虫(Keratella co...     

Where ichthyofaunal provinces meet: the fish fauna of the Lake Edward system,East Africa

Based on literature, museum collections and three recent expeditions, an annotated species list of the Lake Edward, East Africa, drainage system is presented, excluding the endemic haplochromines. A total of 34 non-Haplochromis species belonging to 10 families and 21 genera are recorded from the system. Three of these are endemic and two others have been introduced in the region. Six species are new records for the Lake Edward system. A species accumulation curve indicates that we probably covered most of the non-Haplochromis species in the area sampled during the recent expeditions, but undetected species might still be present in the Congolese part of the system, which is poorly sampled. A comparison of the species list with those of neighbouring basins confirmed the placement of the Lake Edward system within the east-coast ichthyofaunal province.