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Present study describes the reproductive cycle, sex ratio, stages of the gonadal development and gonadal index (GI) of Conus coronatus collected from Buleji and Manora, Karachi. A total of 641 (329 from Manora and 312 from Buleji) C. coronatus of different sizes had randomly collected from April 2015 to March 2016. The females showed predominance in the population at both sites. Five different stages of the reproductive cycles of male and female C. coronatus: resting, developing, ripe, partially spawned, and spawned out were found. Spawning was observed throughout the year. At resting phase all the stages of spermatogenesis and oogenesis were absent. At developing stage oogonia, oocytes, spermatogonia, and spermatocytes were abundantly present in their respective follicles. At ripe stage, in males follicle countless spermatids and spermatozoa were observed however, in female the vitellogenic oocytes were been packed in follicles. At partially spawned stage, male follicles were partially empty while in female follicles unspawned mature ova were seen. At spawned out stage, both male and female follicles were empty. Gonadal development in males was at its highest peak (4.37) in summer (September 2015) at Manora and (4.00) in summer and winter (May 2015 and February 2016) at Buleji. However, in females, the highest value (5.00) of GI was observed only in summer (July and October 2015) at Manora and (4.36) in September (2015) at Buleji. [ABSTRACT FROM AUTHOR]

Helcionelloid molluscs are described from the Gislöv Formation (Cambrian Series 2, Stage 4; Vergalian–Rausvian regional stages) in Scania, southern Sweden. Seven species are distinguished,including ‛Pelagiella' sp., Helcionella antiqua, Davidonia puppis, Davidonia cf. rostrata, Latouchella cf. costata, Stenotheca norvegica, and an indeterminate helcionelloid. The c. 750 specimens were collected from a 30 cm interval with a diverse shelly fauna, encompassing the Ellipsostrenua spinosa Zone. The peak distribution of the molluscs is within the 2–3 mm size class, and there was limited sorting or transport prior to burial. Helcionella antiqua is characteristic of the helcionelloid assemblage, and together with Davidonia puppis, the only molluscs in the assemblage exceeding 10 mm in length. All species except 'Pelagiella' display full ontogenetic series providing verification of morphological transitions and direct ontogenetic ties between small helcionelloid juveniles or embryonic shells and their macro adults. Analysis of distributions indicates that the Gislöv assemblage is closely comparable to the Evjevik Member of the Mjøsa area, Norway, while sections in northern Sweden form a separate cluster. The distribution of the shelly assemblage in the E. spinosa Biozone is consistent with a temporal distribution of this fauna, rather than biofacies control. [ABSTRACT FROM AUTHOR]

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For the first time, the present study reports the life-history traits, comprising length-frequency distribution (LFD), sex ratio (SR), length-weight relationships (LWRs), condition factors (CFs), and relative growth ( W ), of Clupisoma garua in the coastal waters of Bangladesh. A total of 150 specimens ranging from 8.60 to 25.20 cm total length (TL) and 4.26 to 128.80 g body weight (BW) were collected using traditional fishing gear from August 2013 to July 2014. The overall sex ratio of males to females in the study did not differ significantly from the expected value of 1:1 (χ =0.96, P <0.05) but there were significant sex differences ( P <0.05) in the intercepts and slopes of graphs characterizing traits in C. garua. The calculated b values for the LWRs were 2.955, 2.893 and 2.927 for males, females and combined sexes, respectively, and there was negative allometric growth in all cases ( b <3). The condition factors ( K , K , K ) and relative growth ( W ) also did not differ significantly ( P <0.05) between the sexes. This study provides a useful tool for fishery specialists to evaluate the relative condition of fish and to initiate early management strategies and regulations for the sustainable management of the remaining stocks of this species in the entire coastal region of southern Bangladesh. [ABSTRACT FROM AUTHOR]

Specimens of the deep-sea sipunculan Phascolosoma turnerae were retrieved over a 5-year period from fibrous collectors placed for various time intervals at a depth of 520 m in the Tongue of the Ocean, Bahamas. Sipunculans removed from the collectors were counted, weighed, and maintained in the laboratory at 14°C, where they were monitored for gametogenic activity, spawning, development, and growth. In a 2-year study of seasonality, worms were most abundant in collectors retrieved in the spring and summer, and least abundant in the fall. Small animals (<0.01 g) were present in all seasons and represented ≥70% of the animals in winter collections. Large specimens (>0.16 g) were found from May through August, but in markedly lower frequencies than small animals. Over the entire study, spawning was observed in the laboratory from April through August. We inferred from analyses of size frequencies, growth, and spawning seasonality that settlement of the larvae occurs primarily from November through April and that oceanic larval life could be as short as 7 months and as long as 12-14 months. Cleavage of fertilized eggs, as observed from laboratory spawnings, was spiral and holoblastic, resulting in a trochophore that transformed into a typical planktotrophic pelagosphera larva at 21 d. A few larvae survived as long as 2 months in the laboratory. This is the first study of biological processes in living sipunculans from the deep sea, and one of the first studies of living deep-sea wood dwellers. [ABSTRACT FROM AUTHOR]

This study compared the size distributions of the filamentous green alga Ulothrix in Daphnia guts and ambient lake water from February to May 2004 in Meiliang Bay, Lake Taihu, China. The aim was to establish whether daphnids selected the filaments in a certain length range or ingested them indiscriminately regardless of size. We also investigated the effect of Daphnia body size on filament size selection. Both large-sized cladocerans, i.e. Daphnia spp., and the filamentous alga Ulothrix sp. were abundant in spring period (February–May 2004). We simultaneously investigated and compared the length distributions of Ulothrix in the lake and the guts of daphnids that varied in size. The maximum lengths of Ulothrix filaments ingested by each size class of daphnids varying in length from 0.75 to 2.90 mm ranged from 380 and 1030 µm; a range that is quite similar to the size ranges of filaments found in the lake. Also the size frequency of the filaments in Daphnia guts versus those in the lake did not differ significantly. The number of filaments in the guts of individual daphnids ranged from 0 to 668. Our results demonstrated that daphnids (>0.75 mm) did not feed selectivity on a certain length range of filaments but rather do so in proportion to their availability in the lake. Daphnids <0.75 mm did not feed on Ulothrix filaments. [ABSTRACT FROM AUTHOR]

The growth of North Atlantic albacore (Thunnus alalunga) was studied using three methods. Spines collected during a fishing season (n=761) were read and used to estimate growth parameters. Additional growth estimates were obtained by applying MULTIFAN to quarterly size frequency distributions of total international catch for the period 1990–1999 as well as using tag-recapture data (n=314). In the case of spines and tagging, models that allowed for individual variability in growth were evaluated. In the analysis with size frequency distributions, a model that allowed for seasonal growth and age-dependent standard deviation around the mean lengths-at-age was used. Growth estimates were consistent among the different methods, and a combined model based on ageing derived from spines and tagging data is proposed as the most comprehensive descriptor of growth of North Atlantic albacore. [Copyright &y& Elsevier]

The fractality of fault zones of thicknessTfor the 248-m-long core from a borehole penetrating the northern segment of the seismic Chelungpu Fault, Taiwan, was analyzed. The frequency curve ofTshows that the fractal dimension is normal whenTis smaller than a characteristic thicknessTc, and it becomes abnormally large whenTexceedsTc. The fractal dimensions of size and spatial distributions ofTincrease as the mean distribution density ofTincreases, which is inconsistent with the evolution laws for ordinary brittle faults. This discrepancy implies that the thickening rate ofTwhenTis more thanTc is not constant, but a decreasing function of fault displacement. The slow thickening rate is related to the elastohydrodynamic lubrication which was effective on the fault whenTexceedsTc. This slip instability mechanism can explain the large, fast and smooth slip on the northern segment of the Chelungpu Fault during the 1999 Chi-Chi earthquake. [ABSTRACT FROM AUTHOR]

Stock assessment is necessary to understand the status of fishery stocks. However, for the data-poor fishery, it is very challenging to assess the stock status. The length-based Bayesian biomass (LBB) technique is one of the most powerful methods to assess the data-poor fisheries resources that need simple length frequency (LF) data. Addressing the present gap, this study aimed to assess the stock status of three sardines (Sardinella fimbriata, Dussumieria acuta, and D. elopsoides) in the Bay of Bengal (BoB), Bangladesh using the LBB method. The estimated relative biomass for S. fimbriata was B/B0 < BMSY/B0, indicating the overfished biomass, while the assessed B/B0 > BMSY/B0 for D. acuta and D. elopsoides indicates healthy biomass. Additionally, for S. fimbriata, the length at first landing was smaller than the optimum length at first landing (Lc < Lc_opt), indicating an overfishing status, but a safe fishing status was assessed for D. acuta and D. elopsoides (Lc > Lc_opt). Therefore, increasing the mesh size of fishing gears may help to ensure the long-term viability of sardine populations in the BoB, Bangladesh. [ABSTRACT FROM AUTHOR]