Shallow-water Mysida (Crustacea: Mysidacea) of Bahrain (Arabian Gulf): species composition,abundance and life history characteristics of selected species

Mysida were collected from Tubli Bay and the eastern coastline of Bahrain during 1991–1992 incidental to a survey of penaeid prawns. These samples provided an opportunity to assess the species composition of mysids from a nearshore region of the Arabian Gulf—an area in which mysid fauna is poorly known. The 114 beam trawl samples yielded >29?000 mysids. Rhopalophthalmus sp. (>90%), Siriella brevicaudata (5%), Kainomatomysis foxi (1.2%), Siriella sp. A (0.9%) and Indomysis annandalei (0.6%) were the most abundant of 11 species identified. Basic life history variables (carapace length, life stage, brood size) were measured for these five taxa.     

Effects of artificial shading on distribution and abundance of juvenile chinook salmon ( Oncorhynchus tshawytscha )

The influence of artificial shade on the distribution and abundance of juvenile chinook salmon was studied in a side channel of the South Fork Salmon River, Idaho. Fish biomass and abundance were greater in shaded than in unshaded areas when compared to both cumulative incident light reaching the study sections during the 72-hour test runs and instantaneous incident light conditions at the end of the 72-hour test runs. Because conditions may be atypical at the time of instantaneous light measurement, we prefer cumulative incident light for relating light and shade conditions to daytime distribution (abundance and biomass) of juvenile chinook salmon.     

Variation in the life history and abundance of three popluations of Bruneau hot springsnails ( Pyrgulopsis bruneauensis )

Bruneau hot springsnail density, size class structure, recruitment, and mortality were measured monthly over approximately 2 years and compared to environmental variables at 3 hot spring sites in southwestern Idaho. Food resources (attached algae) and water chemistry were similar among sites, but temperature, population density, and size structure differed significantly. Density was highest at a warm, fairly constant temperature site. A cooler, highly variable temperature site and a site where temperatures frequently approached or exceeded thermal maxima tolerance limits had lower densities. Size class structure varied seasonally and distinctly among sites, with recruitment occurring year-round at temperatures < 36°C. Mortality affected different size classes at different sites, with smaller snails incurring greatest mortality at site 3 (highest temperature variability). Growth rates were positively correlated with temperatures up to 36° C. Mean snail size differed among sites and also appeared to be related to temperature, with the variable temperature sites having larger snails. Although these snail populations are found in a range of water temperatures, they appear best adapted to springs with mean temperatures between 32° and 33°C and low thermal variance.     

Life history variation in recently established populations of western mosquitofish ( Gambusia affinis )

We report life history characteristics for 4 recently established populations of western mosquitofish ( Gambusia affinis ). Mosquitofish from thermally stable habitats, Bonham and Garrett, were characterized by maturity at large sizes, high fat reserves, and large embryos. In contrast, females from a thermally unstable habitat, Wabuska, matured at small sizes and had low fat reserves and small embryos. Females from Parker, a site with no appreciable thermal input, matured at intermediate sizes and had low fat reserves as well as large embryos. These populations shared a common ancestor in 1937; therefore, these results suggest either phenotypic plasticity or rapid evolution.     

Micromammalian distribution and abundance in the Western Cape Province,South Africa,as evidenced by Barn owls Tyto alba (Scopoli)

The history of Western Cape mammalogy began almost 200 years ago with Thunberg () and has been augmented periodically ever since. The present paper follows Vernon () and Grindley et al. () in eliciting information from material in Barn owl Tyto alba (Scopoli) pellets. Analyses are based on identified and counted mandibles and maxillae. The Laminate vlei rat, Otomys laminatus Thomas and Schwann, and Krebs's fat mouse, Steatomys krebsii Peters, are shown to have wider distributions than were previously recorded. The Southern multimammate mouse, Mastomys coucha (A. Smith), is apparently expanding its range westwards, a move probably enabled by changes in vegetation due to farming practices. There appears to be some correspondence between proportional representation of some species and rainfall, either its amount per annum or its seasonality. Variation in alveolar length in Cape gerbils, Tatera afra (Gray), taken as a proxy for mean individual mass, suggests that mean size in this species may be influenced by rainfall seasonality. Although the Vlei rat, Otomys irroratus (Brants), is known to breed throughout the year, the present evidence indicates that in the West Coast National Park births peak in late spring and early summer, some two months after maximum rainfall. The Western Cape data support the concept that T. alba is a selective opportunist. Sample structure and co‐occurrence of species in individual pellets both show that in some cases the owls are more nearly opportunistic while in others they appear to be considerably more selective.     

Life history of Paraselenis (Spaethiechoma) dichroa (Germar, 1824) (Coleoptera: Chrysomelidae: Cassidinae) in natural conditions of Atlantic Forest from Brazil

Cassidinae Gyllenhaal? is the second largest subfamily of Chrysomelidae (Coleoptera), which presents characteristic morphology, biology and behaviour. The current study describes the life cycle of Paraselenis(Spaetiechoma) dichroa (Germar), ?determining biological and behavioural aspects as well as the action of natural enemies on populations, when the species has maternal care. The study was conducted between February and April 2015 in the National Forest of Passa Quatro, municipality of Passa Quatro, Minas Gerais state, Brazil. Daily observations were made (morning and afternoon) to evaluate the offspring of females on Ipomoea sp. and Merremia macrocalyx (O’Donell?) (Convolvulaceae), as well as the actions of natural enemies on the young. The eggs are deposited on the midrib and abaxial surface of leaves (n = 25). Egg clusters are pedunculated, arranged in groups and devoid of any cover. On average, each female produced 27.3 ± 5.6 (n = 16) eggs, with a mean incubation period of 12.7 ± 2.9 days (n = 10 females with their young). The larvae remained grouped in the leaves throughout development, except when they fed. They retained faeces and exuviae as a stacked faecal structure on their mobile urogomphi (caudal process) like a faecal shield. The mean number of larvae per female was 12.7 ± 10.1 (n = 19) and the larval period lasted 24.9 ± 4.5 days (n = 12). Pupation occurred on the stem of the plant (n = 16). On average there were 8.1 ± 8.5 individuals for pupae progeny (n = 14). The mean duration of the pupal stage was 10.4 ± 3.3 days (n = 5). Overall, 3% of adults emerged (n = 13 individuals), with a total cycle time of 41.3 ± 8.4 days (n = 6). Adults are sexually dimorphic in the elytral shape. Females remain with the offspring throughout development. The natural enemies of immatures were Emersonella pubipennis Hansson? (Hymenoptera: Eulophidae), Tachinidae (Diptera) and Stiretrus decastigmus (Herrich-Schaeffer?) (Heteroptera: Pentatomidae), Conura sp. Spinola? (Hymenoptera: Chalcididae) and Brachymeria sp. Westwood? (Hymenoptera: Chalcididae). The information presented here on the natural history of P. dichroa are important as they may serve as a starting point to understand evolutionary questions and multispecies interactions.     

Life cycle and geographic distribution of the gymnophallid Bartolius pierrei (Digenea) on the Patagonian coast,Argentina

The life cycle of the gymnophallid Bartolius pierrei Cremonte, 2001 Cremonte, F. 2001. Bartolius pierrei n. g. n. sp. (Digenea: Gymnophallidae) from Península Valdés, Argentina. Systematic Parasitology, 49: 139–147. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar] (Digenea) at Fracasso Beach (the type locality) (42°25′S, 64°07′W), Península Valdés, Argentina, was elucidated. This digenean uses the clam Darina solenoides (Mactridae) as both first and second intermediate host. The Kelp Gull, Larus dominicanus, and the Red Knot, Calidris canutus rufa, a Neotropical migratory bird, act as definitive hosts. A prevalence of infection of 92% was found in the Red Knot. The cercariae of B. pierrei did not parasitize other invertebrates, not even the tellinid clam Tellina petitiana, which shares the intertidal habitat with D. solenoides. This fact could be explained by the behaviour of the cercaria and its strategy for penetration. The cercariae enter directly in the extrapallial space of the clam by piercing the exposed mantle border. Tellina petitiana could not be invaded by B. pierrei cercariae because it does not expose the mantle border when feeding. Because the Red Knot does not feed on T. petitiana, this behaviour may constitute an adaptive strategy of the parasite. Under laboratory conditions, cercariae lived up to 2 days, metacercariae became infective in 50 days, and the adult life is considerd to be shorter than 3 days. The short adult life span in gymnophallids could be a result of adaptation to migratory birds. This fact would ensure parasite dispersion (i.e. by covering long distances in a short time) and inter-breeding with other Darina-infesting populations located far apart. Bartolius pierrei is an endemic parasite of the Magellan Region, distributed where its intermediate clam host is present, from San José Gulf in Península Valdés to the southern tip of South America.     

Timing, distribution, and abundance of kokanees spawning in a Lake Tahoe tributary

We counted kokanee spawners and carcasses every 1-7 days from mid-September through mid-November in 1991 and 1992 in Taylor Creek, a tributary to Lake Tahoe, California-Nevada. Less than 1% of the spawning run entered Taylor Creek before flow from Fallen Leaf Lake was increased on 2 October 1991; in 1992 the peak occurred on 30 September or 1 October after flows increased on 29 September. In both years spawners concentrated in the middle three of five stream reaches below the impassable Fallen Leaf Lake dam. From tab-and-recovery experiments, the average longevity of male spawners in the stream was 3.5 days in 1991 and 2.8 days in 1992, whereas the average female longevity was 2.0 days in 1991 and 2.3 days in 1992. Observed carcasses accounted for less than 10% of spawners counted, suggesting removal by scavengers or high predation on prespawners. An estimated 1928 males and 1309 females spawned in 1991, and 8021 males and 8712 females spawned in 1992. Our estimate of 3237 spawners in 1991 compared favorably to our estimate of 3520 ± 1474 prespawners staging in Lake Tahoe in mid-September. An index of kokanee abundance in Lake Tahoe has historically been based on 1-day surveys every 1 November since 1960; however, estimated total spawner abundance was 19 times higher than the annual index of 158 spawners in 1991, 141 times higher than the index count of 100 spawners in 1992. The index count and mean fork lengths of spawners (278 ± 10 mm [2 SE] for males, and 248 ± 3 mm for females) in 1991 and 1992 were the lowest on record.     

Life history and ecology of Megarcys signata (Plecoptera: Perlodidae), Mill Creek, Wasatch Mountains, Utah

During an investigation of some of the stoneflies (Plecoptera) of Mill Creek, Wasatch Mountains, Utah, Megarcys signata, a large omnivorous stonefly, was found to have a univoltine life history and a slow seasonal life cycle. Temperature appears to affect the growth rate of Megarcys signata. Warmer stream temperatures accompany the acceleration of the growth rate, whereas cooler stream temperatures apparently retard the growth rate. Periods of maximum absolute growth rate correspond with maximum carnivorous feeding from August to September and March to April. Chironomidae, Ephemeroptera, and Plecoptera, in that order, were the most abundant prey in the foreguts. Young nymphs ingested considerable amounts of diatoms, filamentous algae, and detritus but not as much animal matter as did older nymphs. Megarcys signata was uniformly distributed throughout Mill Creek, except at the lowest station, where few nymphs were found. Emergence occurred in May and June, the peak occurring in June. The mean size of females and males decreased as emergence progressed. &nbsp;     

Responses of pink shrimp Farfantepenaeus brasiliensis (Latreille, 1817) (Penaeoidea) to physico-chemical parameters in a marine protected area: changes in abundance and distribution after 20 years

ABSTRACT

This study analysed the influence of temperature, salinity and sediment texture on the distribution of pink shrimp juveniles (Farfantepenaeus brasiliensis) over a 20-year period. The shrimps were sampled monthly in Fortaleza Bay, north coast of São Paulo, Brazil, in November 1988–October 1989 (period 1) and then 20 years later in November 2008–October 2009 (period 2). In period 1 we captured 80 juveniles whereas in period 2 we captured 226. The abundance and distribution of F. brasiliensis seemed to be modulated by temperature and sediment texture, along with the fishing activity. The management strategies established between the samplings might have been responsible for the higher abundance of juveniles seen during period 2. The strategies included the limitation of fishing effort, regulation of fishing equipment and the establishment of environmental protection areas and temporary fishing ban.     

Wildlife distribution and abundance on the Utah Oil Shale Tracts, 1975-1984

Distribution and abundance of 215 amphibians, reptiles, birds, and mammals were monitored for 10 years on Utah's Oil Shale Tracts using line transects, mist netting, and live trapping. Wildlife monitoring was conducted in four major vegetation types and during all seasons to establish a quantitative baseline for use in impact identification during oil shale mining. Habitat preferences were established for many species in cold desert vegetation of two types of desert shrub, and juniper and riparian woodlands. Seasonal, annual, and habitat distribution of each class demonstrated a variety of adaptive responses to environmental variables. The most important environmental variables, that is, those factors resulting in a predictable change in wildlife populations, were, in descending order: weather, food resource, shelter, and competition.     

Bats along the Republican River and its tributaries in southwestern Nebraska: distribution, abundance, and reproduction

Thirteen species of bats occur in Nebraska, but limited information is available on those inhabiting southwestern parts of the state. We investigated the distribution, abundance, and reproductive activity of bats in 5 counties in extreme southwestern Nebraska (Chase, Hays, Dundy, Hitchcock, and Red Willow). From April 2007 to April 2008, we deployed mist nets on 15 occasions at 8 localities over the Republican River and its tributaries. We captured 100 individuals representing 5 species, including the evening bat ( Nycticeius humeralis ), eastern red bat ( Lasiurus borealis ), hoary bat ( Lasiurus cinereus ), big brown bat ( Eptesicus fuscus ), and silver-haired bat ( Lasionycteris noctivagans ). All species raised young in this region of Nebraska, except L. noctivagans , which was documented only during migration. Lactating females of N. humeralis captured on 15 June and volant young captured on 23 June extend known dates of reproductive activity for this species in the state, and an adult female captured on 30 April represents the earliest seasonal record of this species from Nebraska. Our records of evening bats also extend the known distribution of this species farther west in Nebraska than previously reported. Changes in land use throughout the Great Plains during the last century have altered many habitats, such as gallery forests associated with rivers, and distributions of mammals, including bats, have shifted to reflect those ecological changes.     

Temperature and salinity relationships of the Nevadan relict dace

Pyramid Lake fish populations were sampled with nets on a monthly basis from November 1975 through December 1977. Fish species were taken in the following order of numerical relative abundance: tui chub ( Gila bicolor ), Tahoe sucker ( Catostomus tahoensis ), Lahontan cutthroat trout ( Salmo clarki henshawi ) including cutthroat-rainbow hybrids, cui-ui ( Chasmistes cujus ), and Sacramento perch ( Archoplites interruptus ). Relative abundance estimates are discussed with respect to seasonal availability, spatial distribution of the fish, sampling bias of the fishing methods, and biomass of the fish. Recent temporal trends in the population structure of the lake are presented.     

Interannual abundance of nonnative fathead minnows ( Pimephales promelas ) in Upper Klamath Lake, Oregon

Since its introduction about 20 yr ago, fathead minnow ( Pimephales promelas ) has become very abundant in Upper Klamath Lake, Oregon. In 1991 mean bench seine catch per unit effort (CPUE) was 214, compared to 25 for native blue chub ( Gila coerulea ), the next most abundant species. In 45 trap-net samples collected in 1992, fathead minnow constituted 59% of the fishes caught in Agency Lake subbasin, 27% in Upper Klamath Lake, and 17% in tributary inflow habitats. From 1991 to 1995 fathead minnow declined and the abundance of some native fishes increased. Introduction to Klamath Basin was coincident with U.S. Environmental Protection Agency of fathead minnow as bioassay subjects. Upper Klamath Lake fathead minnow have incomplete lateral lines and males have mandibular tubercles, diagnostic of the northeastern subspecies. Although the origin, as bait bucket transfer, forage fish, or laboratory release, cannot be determined with certainty, the possibility of laboratory release suggest modification of bioassay protocols to require destruction of test or excess subjects.     

Observations on the reproduction, sources of mortality, and diet of the Kendall Warm Spring dace

The life history of the endangered Kendall Warm Springs dace ( Rhinichthys osculus thermalis ) is largely unknown. Our study of its reproduction, sources of mortality, and diet indicated that Kendall Warm Springs dace seem to be reproductively active throughout the year, but the rate of reproduction appears to decrease during the winter. Males become sexually mature at 34 mm total length and females at 40 mm total length. We observed 2 sources of mortality: (1) emigration from the warm spring over a waterfall into the Green River and (2) predation on larvae by dragonfly ( Libellula saturata ) nymphs. Stomachs of Kendall Warm Springs dace contained small (≤ 1.5 mm total length) benthic invertebrates, primarily dipterans and mollusks.     

Life history of the Lahontan cutthroat trout, Salmo clarki henshawi, in Pyramid Lake, Nevada

Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 st1\:*{behavior:url(#ieooui) } /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} The Pyramid Lake Lahontan cutthroat trout ( Salmo clarki henshawi ) population was sampled on a monthly basis from November 1975 through December 1977. A subsample of 676 trout, stratified by fish size and lake habitat, provided biological data. The entire population is presently derived from hatchery production, stocked at lengths of approximately 75 to 300 mm. Peak annulus formation occurs in March and April, followed by the period of maximum growth. Scale patterns illustrate a variable growing season. Maximum growth in length is in the first three years of life; after that males begin to grow faster than females. Males attained a greater age in our sample; i.e., the oldest male was seven years old compared to six years for females. The Pyramid Lake Lahontan cutthroat trout exhibit nearly isometric growth. The legal sport fishery removed 380 mm); other decimating factors are poorly understood. No evidence of the following diseases or pathogens was found in the Pyramid Lake population, presuming a carrier incidence of 2 percent at the 95 percent confidence level: infectious pancreatic necrosis, infectious hematopoietic necrosis, viral hemorrhagic septicema, bacterial kidney disease, enteric redmouth, furunculosis, whirling disease, blood fluke; however, 7 of 235 (&asymp;3 percent) adults sampled at the Marble Bluff fishway were positive for furunculosis. Small trout feed primarily on zooplankton and benthic invertebrates; cutthroat trout >300 mm are piscivorous, feeding almost exclusively on tui chub ( Gila bicolor ). The spawning migration of Pyramid Lake cutthroat trout to the Marble Bluff egg taking facility in spring 1976 and 1977 peaked in April and May. Females mature at three or four years (352&ndash;484 mm), and males mature at two or three years (299&ndash;445 mm). Mean diameter of mature eggs is 4.51 mm; both ovum size and fecundity are a function of fish size. Fecundity ranges from 1241 to 7963 eggs, with a mean of 3815. Lahontan cutthroat trout comprise     

North American stoneflies (Plecoptera): systematics, distribution, and taxonomic references

A list of 537 Nearctic stonefly species is provided and distributions of all species are given by U.S. state and Canadian province. The list includes a bibliography of systematic and biogeographic papers published since the Zwick (1973) catalogue.