Preliminary guide to the identification of the early life history stages of Priacanthid fishes of the Western Central Atlantic

The family Priacanthidae contains four genera and four species that occur in the western central North Atlantic (Starnes, 1988). Pristigenys alta is distributed in the Caribbean, Gulf of Mexico and along the east coast of North America. Although juveniles have been reported from as far north as southern New England waters, adults are not reported north of Cape Hatteras, NC. Priacanthus arenatus is distributed in tropical and tropically influenced areas of the western central North Atlantic in insular and continental shelf waters. Adult P. arenatus are distributed north to North Carolina and Bermuda, juveniles have been collected as far north as Nova Scotia. Cookeolus japonicus and Heteropriacanthus cruentatus are circumglobally distributed species and are both common in insular habitats. In the western central North Atlantic, C. japonicus ranges from New Jersey to Argentina; H. cruentatus from New Jersey and northern Gulf of Mexico to southern Brazil (Starnes, 1988). (PDF contains 6 pages)

Species composition, distribution, and relative abundance of fishes in the coastal habitat off the southeastern United States

Ichthyofauna of the coastal «10 m depth) habitat of the South Atlantic Bight were investigated between Cape Fear, North Carolina, and the St. John's River, Florida. Trawl collections from four nonconsecutive seasons in the period July 1980 to December 1982 indicated that the fish community is dominated by the family Sciaenidae, particularly juvenile forms. Spot (Leiostomus xanthurus) and Atlantic croaker (Micropogonias undulatus) were the two most abundant species and dominated catches during all seasons. Atlantic menhaden (Brevoortin tyrannus) was also very abundant, but only seasonally (winter and spring) dominant in the catches. Elasmobranch fIShes, especially rajiforms and carcharinids, contributed to much of the biomass of fishes collected. Total fish abundance was greatest in winter and lowest in summer and was influenced by the seasonality of Atlantic menhaden and Atlantic croaker in the catches. Biomass was highest in spring and lowest in summer, and was influenced by biomass of spot. Fish density ranged from 321 individuals and 12.2 kg per hectare to 746 individuals and 25.2 kg per hectare. Most species ranged widely throughout the bight, and showed some evidence of seasonal migration. Species assemblages were dominated by ubiquitous year-round residents of the coastal waters of the bight. Diversity (H') was highest in summer, and appeared influenced by the evenness of distribution of individuals among species. (PDF file contains 56 pages.)

Length-weight relationship and the diets of Clarias lazera (Cuvier and Valenciennes), family Clariidae (Osteichthyes: Siluriformes) in Zaria, Nigeria

The length-weight relationship and the diets of Clarias lazera were investigated between July 1981 and June 1982. About 450 specimens were examined. The standard lengths of the fish ranged from 8.5 cm to 42.2 cm. Significant differences were found between the standard lengths of the males and females with the latter slightly shorter. Somatic weights varied between 10 g to 502 g. Length-weight regression analysis gave a "b" value of 3.02 for both males and females combined; thus indicating an isometric growth. Analysis of the food in the stomachs showed that the fish is an omnivore although, it fed more on insects and fish than other food items

Triploidy induction in Heterobranchus longifilis (Family: Clariidae) by cold shock

Triploid was induced in African Catfish (Heterobranchus longifilis) by cold shocking activated eggs at 5 degree C for forty minutes starting 3-4 minutes after fertilization. Triploidy was confirmed from mitotic chromosomes prepared from embryo which showed 100% triploidy in the cold shocking treatment and 100% diploidy in the control treatment

Effects of some environmental factors on the fecundity of Tilapia species (Family Cichlidae) in Kigera Reservoir, New Bussa

The effects of some environmental factors on the fecundity of Tilapia species (Family Cichilidae) was carried out at the Kigera dam. Four Tilapia species caught were Tilapia zilli, Hemichromis fasciatus, Sarotherodon galilaeus and Oreochromis niloticus while the environmental factors considered were water temperature, Dissolved Oxygen, pH value, level of rainfall and rate of sunshine and range of time. 43 fish comprising of 25 male with (58.1%) and 18 females having (41.9%) were studied with 74.42% been sexually matured. Both high levels of rainfall and dissolved oxygen favoured fecundity. The spawning peak occurred in (July), environmental factors monitored indicated that dissolved oxygen ranges from 3.7 to 4.45mg/lit rainfall ranges from (34.90mm to 237.80mm) sunshine ranges from (5hrs-8hrs) and pH ranges from (7.35-7.45). The spawning of these species in their natural or hatchery condition is therefore best achieved during the peak of raining season

Structure of the limbs and its significance for the ecology and systematics of the family Chydoridae. [Translation of: Voprosy Gidrobiologii, p385, 1965]

For an explanation of the dynamics of numbers of chydorids, appearing a massive group in the littoral of fresh water bodies, the structure of the limbs of 29 species was studied.

Key to the larvae of the genera of the sub-family Orthocladiinae from Larvae and Pupae of midges of the sub-family Orthocladiinae of the fauna of the USSR. [Translation from: Larvae and pupae of midges of the subfamily Orthocladiinae of the fauna of the USSR (Diptera, Chironomidae = Tendipedidae) (ed. Pankratova V.Ya.), 51-55. Leningrad, Nauka, 1970. ]

A key to the larvae of the genera of the sub-family Orthocladiinae from Larvae and Pupae of midges of the sub-family Orthocladiinae. Parts of the key refer to the rest of the publication which is not included in this partial translation.

Family: Cladophora Kutzing 1843. identification key. [ Translation from: Flora Slodkowodna Polski 10, 227-263, 1972.]

A description of the algal genus Cladophora from Vol 10 of the ”Freshwater Flora of Poland”. Illustrations are included.

The family of chironomids or midges - Chironomidae. Keys to larvae and pupae [Translation from: Guide to the freshwater invertebrates of the European area of the USSR (Plankton and benthos) (ed. L. A. Kutikova and Ya. I. Starobogatov), p.371-431. Leningrad, Gidrometeoizdat, 1977]

The translation of this section of the larger publication ”Opredelitel' presnovodnykh bespozvonochnykh evropeiskoi chasti SSSR. (Plankton i bentos)” provides identification keys to the larvae and pupae of chironomids that occur in the Soviet Union. The morphology of the larvae of Chironomidae is described in the introductory part.

Biologie et dynamique d'un Sciaenidae ouest-africain Pseudotolithus senegalensis (V.)

In relation to the hydroclimate prevailing off Congo (B) and Côte d'Ivoire, synchronic variations are described in abundance and distribution of Pseudotolithus senegalensis V., economically the most important species in the West African trawl fishery. Although this fish prefers the warm surface layer, it is relatively indifferent to hydrological conditions, since it may also occur in the thermocline down to the higher levels of 'Central South Atlantic Water'. The oxygen concentration appears to have an important effect upon their distribution, especially the low concentrations occurring with the upwelling. The main biological functions, such as spawning and recruitment times, condition factor, diet and ring appearance on otoliths, also follow cycles, which are parallel with the hydroclimate one. Therefore, the ring-shaped structures revealed by burning previously ground otoliths could be easily interpreted. Thus, an accurate method for ageing tropical fish is now available. From the age determinations for the Congolese stock, it appears that growth is fast and total mortality rate high. An influence of fishing effort, which increased 3 times during the exploited phase of sampled specimens, appears both in growth and in total mortality. From there an estimate for the fishing mortality could be given. The estimates of dynamic parameters for the Congolese stock are then used in the Beverton-Holt model. A valuable increase of the yield could be expected, if mesh size is widened and effort restricted.

Population structure of pink salmon (Oncorhynchus gorbuscha) in British Columbia and Washington, determined with microsatellites

Population structure of pink salmon (Oncorhynchus gorbuscha) from British Columbia and Washington was examined with a survey of microsatellite variation to describe the distribution of genetic variation. Variation at 16 microsatellite loci was surveyed for approximately 46,500 pink salmon sampled from 146 locations in the odd-year broodline and from 116 locations in the even-year broodline. An index of genetic differentiation, FST, over all populations and loci in the odd-year broodline was 0.005, with individual locus values ranging from 0.002 to 0.025. Population differentiation was less in the even-year broodline, with a FST value of 0.002 over all loci, and with individual locus values ranging from 0.001 to 0.005. Greater genetic diversity was observed in the odd-year broodline. Differentiation in pink salmon allele frequencies between broodlines was approximately 5.5 times greater than regional differentiation within broodlines. A regional structuring of populations was the general pattern observed, and a greater regional structure in the odd-year broodline than in the even-year broodline. The geographic distribution of microsatellite variation in populations of pink salmon likely ref lects a distribution of broodlines from separate refuges after the last glaciation period.

Effect of environmental conditions on the distribution of Pacific mackerel (Scomber japonicus) larvae in the California Current system

We modeled the probability of capturing Pacif ic mackerel (Scomber japonicus) larvae as a function of environmental variables for the Southern California Bight (SCB) most years from 1951 through 2008 and Mexican waters offshore of Baja California from 1951 through 1984. The model exhibited acceptable fit, as indicated by the area under a receiver-operating-characteristic curve of 0.80 but was inconsistent with the zero catches that occurred frequently in the 2000s. Two types of spawners overlapped spatially within the survey area: those that exhibited peak spawning during April in the SCB at about 15.5°C and a smaller group that exhibited peak spawning in August near Punta Eugenia, Mexico, at 20°C or greater. The SCB generally had greater zooplankton than Mexican waters but less appropriate (lower) geostrophic f lows. Mexican waters generally exhibited greater predicted habitat quality than the SCB in cold years. Predicted quality of the habitat in the SCB was greater from the 1980s to 2008 than in the earlier years of the survey primarily because temperatures and geostrophic flows were more appropriate for larvae. However, stock size the previous year had a larger effect on predictions than any environmental variable, indicating that larval Pacific mackerel did not fully occupy the suitable habitat during most years.

Use of SARIMA models to assess data-poor fisheries: a case study with a sciaenid fishery off Portugal

Research on assessment and monitoring methods has primarily focused on fisheries with long multivariate data sets. Less research exists on methods applicable to data-poor fisheries with univariate data sets with a small sample size. In this study, we examine the capabilities of seasonal autoregressive integrated moving average (SARIMA) models to fit, forecast, and monitor the landings of such data-poor fisheries. We use a European fishery on meagre (Sciaenidae: Argyrosomus regius), where only a short time series of landings was available to model (n=60 months), as our case-study. We show that despite the limited sample size, a SARIMA model could be found that adequately fitted and forecasted the time series of meagre landings (12-month forecasts; mean error: 3.5 tons (t); annual absolute percentage error: 15.4%). We derive model-based prediction intervals and show how they can be used to detect problematic situations in the fishery. Our results indicate that over the course of one year the meagre landings remained within the prediction limits of the model and therefore indicated no need for urgent management intervention. We discuss the information that SARIMA model structure conveys on the meagre lifecycle and fishery, the methodological requirements of SARIMA forecasting of data-poor fisheries landings, and the capabilities SARIMA models present within current efforts to monitor the world’s data-poorest resources.