scholarly journals Lengths at maturity and conversion factors for skates (Rajidae) around the British Isles, with an analysis of data in the literature

2012 ◽  
Vol 69 (10) ◽  
pp. 1812-1822 ◽  
Author(s):  
Sophy R. McCully ◽  
Finlay Scott ◽  
Jim R. Ellis
Keyword(s):  
Temporal Changes ◽  
Biological Data ◽  
Marine Science ◽  
British Isles ◽  
Conversion Factors ◽  
Total Length ◽  
Disc Width ◽  
Spatial Differences ◽  
First Maturity ◽  
The Relationship

Abstract McCully, S. R., Scott, F., and Ellis, J. R. 2012. Lengths at maturity and conversion factors for skates (Rajidae) around the British Isles, with an analysis of data in the literature. –ICES Journal of Marine Science, 69: 1812–1822. Biological data on skates (Rajidae) from around the British Isles were collected between 1992 and 2010. The relationship between total length and weight for nine species (Amblyraja radiata, Dipturus batis-complex, Leucoraja fullonica, L. naevus, Raja brachyura, R. clavata, R. microocellata, R. montagui, and R. undulata) are provided for each sex and ICES ecoregion (when significantly different). Conversion factors for disc width to total length are provided. The lengths at first maturity and of the largest immature skates are reported for each sex, and the lengths at 50% maturity are estimated. Spatial differences in the length at maturity of R. clavata (females only) and L. naevus (both sexes) were observed. The lengths at maturity are discussed in relation to the results of earlier studies, and methodological differences are considered to have influenced reputed decreases in the length at maturity. A more standardized approach to collecting and reporting maturity information is required if potential spatial differences and temporal changes are to be investigated.

scholarly journals Reproductive Biology of Coral Catshark Atelomycterus marmoratus (Anonymous [Bennett], 1830) in Seribu Islands, Indonesia

2019 ◽  
Vol 20 (8) ◽  
Author(s):  
Selvia Oktaviyani ◽  
WANWAN KURNIAWAN ◽  
FAHMI
Keyword(s):  
Reproductive Biology ◽  
Gonadosomatic Index ◽  
Maturity Stage ◽  
Total Length ◽  
Mean Size ◽  
The Mean ◽  
First Maturity ◽  
The Relationship ◽  
Monthly Variations ◽  
Size At First Maturity

This study provides information on the reproductive biology of the coral catshark caught in the waters around Seribu Islands, Indonesia. A total of 257 coral catsharks were collected from February 2017 to January 2018. The total length of coral catshark ranged from 170 to 585 mm for females and 255-575 mm for males, respectively. The total weight of females ranged from 85 to 640 g and males from 100 to 620 g The sex ratio between females and males was 0.45 and it was not significantly different from the expected 1:1 ratio. The growth pattern of coral catsharks in Seribu Island was negatively allometric and the population was dominated by mature sharks. The mean size at first maturity was estimated to be 557 mm for females and 514 mm for males, based on to the relationship between the proportion between maturity stage and total length. The ovulation season was estimated occur from October to March, whereas September to April was mating season based on monthly variations of gonadosomatic index (GSI) values and the occurrence of egg cases in uterus.

scholarly journals Aspects of the reproductive biology of skates (Chondrichthyes: Rajiformes: Rajoidei) from southern Africa

2007 ◽  
Vol 65 (1) ◽  
pp. 81-102 ◽  
Author(s):  
David A. Ebert ◽  
Leonard J. V. Compagno ◽  
Paul D. Cowley
Keyword(s):  
Reproductive Biology ◽  
Southern Africa ◽  
Sexual Maturity ◽  
Size At Maturity ◽  
Total Length ◽  
Large Size ◽  
Disc Width ◽  
New Information ◽  
Males And Females ◽  
First Maturity

AbstractEbert, D. A., Compagno, L. J. V., and Cowley, P. D. 2008. Aspects of the reproductive biology of skates (Chondrichthyes: Rajiformes: Rajoidei) from southern Africa. – ICES Journal of Marine Science, 65: 81–102. New information is presented on the reproductive biology of 22 southern African skate species. Sex ratios for most species were relatively even. Sexual dimorphic differences in disc shape were evident in all species, but the total length (LT) to disc width (D) relationship was significantly different in only three species, and the LT to weight (W) relationship significant in just five species. Sexual dimorphism relative to maximum total length (LTmax) was absent in all but the two largest species. Males and females of the same species grow to a similar LTmax except those whose LTmax is >1.5 m LT. Size at first and 50% (LT50) sexual maturity was approximately the same for both sexes in all but the two largest species. First maturity occurred at >60% of LTmax for all species for which sufficient data were available, and most (n = 18) matured at >75% LTmax. The large size at maturity relative to LTmax suggests that growth slows or is partially suspended following sexual maturity. The egg cases of 15 species are described, and a key to their identification is presented. Egg cases in utero were observed throughout the year suggesting that most species reproduce year-round.

scholarly journals Population structure and reproductive biology of Haemulopsis corvinaeformis (Perciformes, Haemulidae) in the south coast of Pernambuco, northeastern Brazil

2018 ◽  
Vol 108 (0) ◽  
Author(s):  
Leandro N. Eduardo ◽  
Alex S. Lira ◽  
Thierry Frédou ◽  
Flavia Lucena Frédou
Keyword(s):  
Population Structure ◽  
Reproductive Biology ◽  
Management Practices ◽  
Northeastern Brazil ◽  
Important Species ◽  
Shrimp Fishery ◽  
Total Length ◽  
Males And Females ◽  
First Maturity ◽  
The Relationship

ABSTRACT: Roughneck Grunt (Haemulopsis corvinaeformis Steindachner, 1868) is the second most important species caught as bycatch of the shrimp fishery in Pernambuco, Northeastern Brazil. However, the population dynamic of this species is poorly known in the region. The aim of this study was to describe aspects of the population structure and reproductive biology of the H. corvinaeformis, providing important information for the development of sustainable management practices. Specimens were collected monthly from August 2011 to July 2012 and quarterly from October 2012 to June 2014. A total of 1,140 individuals was collected; 340 males (29.8%), 391 females (34.3%), and 409 were immature and could not be sexed (35.9%). Total length ranged from 7 to 25 cm. In general, total length of females [12.85 ± 2.49 cm (mean± SD)] and males [12.72 ± 2.46 cm (mean ± SD)] were similar (p > 0.05). The proportion of males and females was similar along the year, except in March. The relationship between total length and total weight was statistically significant (p< 0.05), showing an isometric growth. The (GSI) coupled with the distribution of maturational stages suggests that females reproduce all year around, with a peak during October-November. The length at first maturity (L50) was estimated at 11.88 cm for females and 11 cm for males.

scholarly journals Age and growth of two bream species in the Tudakul reservoir of Uzbekistan

2021 ◽  
Vol 244 ◽  
pp. 02041
Author(s):  
B. Kamilov ◽  
M. Yuldashov ◽  
R. Khakimova ◽  
M. Ibodova
Keyword(s):  
Total Body Length ◽  
Age And Growth ◽  
Average Height ◽  
Average Growth ◽  
Total Length ◽  
Males And Females ◽  
Total Body ◽  
First Maturity ◽  
The Relationship ◽  
White Bream

The study was carried out in 2014-2018 at the Tudakul reservoir, Uzbekistan. Samples included 278 European bream (Abramis brama), and 83 Amur white bream (Parabramis pekinensis). The age, total length and weight of the fish varied from 1 to 5 years, from 14 to 50 cm, from 30 to 1,405 g for the European bream and from 1 to 6 years, from 24 to 53.5 cm and 105 – 2,138 g for the white Amur bream and European bream, respectively. The relationship between total length (TL) and weight (W) is described by the equation W = 0.005 * TL3.2555 (r = 0.98) for European bream and W = 0.005 * TL3.201 (r = 0.96) for white Amur bream. Recovered average growth rate of European bream: TL1 - 13.5 cm; TL2 - 28.1 cm, TL3 - 37.95 cm, TL4 - 42.6 cm, TL5 - 48.6 cm.The average height of the Amur white bream: TL1 - 12.6 cm, TL2 - 23.3 cm, TL3 - 31.5 cm, TL4 - 37.9 cm, TL5 - 41.7 cm, TL6 - 44.2 cm. Lee’s phenomenon did not appear. All yearling fish were juvenile. In 2-year-old fish of both sexes of both species, the gonads were at stage II. Males and females of both species reached their first maturity at 3-4 years of age, when the total body length of the European bream was 30–32 cm, and the Amur white bream was 34–35 cm.

scholarly journals Reproductive biology of striped snakehead, Channa striata (Bloch, 1793) in Lake Rawa Pening, Central Java

2019 ◽  
Vol 19 (3) ◽  
pp. 475
Author(s):  
Djumanto Djumanto ◽  
Atik Murjiyanti ◽  
Nuravida Azlina ◽  
Aisyah Nurulitaerka ◽  
Anissa Dwiramdhani
Keyword(s):  
Condition Factor ◽  
Fish Length ◽  
Oocyte Diameter ◽  
Total Length ◽  
Central Java ◽  
Gonadal Maturity ◽  
Fish Samples ◽  
Channa Striata ◽  
First Maturity ◽  
The Relationship

The striped snakehead (Channa striata Bloch, 1793) is the top predator fish found in Lake Rawa Pening and other freshwaters. Its population was declining due to very high fishing pressures, habitat quality decreases, and other fac-tors. The aim of this study was to examine the condition factor and fecundity of snakehead in Lake Rawa Pening. Fish sampling was carried out monthly from October 2017 to August 2018, using fish fence made from bamboo blinds operated by local fishermen. Total length, individual body weight, stage of gonadal maturity (MS), gonadal weight, and oocytes diameter of fish samples were measured. Fish condition factor, gonado somatic index (GSI), oocyte diameter, fecundity, and the size of first maturity of fish were determined. There were 409 individuals snakehead fish collected consisting of 138 females and 271 males. Fish length ranged from 234-646 mm (males) and 242-648 mm (females). The average of the condition factor (K) of male ranged from 0.778 to 0.923, while in female ranged from 0.826 to 0.929. The relationship between the length-weight of male and female was isometric. The percentage of female snakehead that reached MS I; II; III; IV was 15.6; 27.0; 37.4; 20.0%, respectively. The GSI ranged from 1.52 to 3.54. Oocyte diameter ranged from 0.5 to 1.7 mm with an average of 1.2 mm. Fecundity ranged from 2,843-23,230 eggs with an average of 9,167 eggs. The female snakehead was predicted to reach the first sexual maturity at a total length of 315 mm.

scholarly journals Do spatial differences in the personal car market reflect a centre-periphery structure? The case of Poland

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Bartłomiej Kołsut ◽  
Tadeusz Stryjakiewicz
Keyword(s):  
Spatial Accessibility ◽  
Car Ownership ◽  
Central Character ◽  
Correlation And Regression Analysis ◽  
Spatial Inequalities ◽  
Car Market ◽  
Spatial Differences ◽  
Level Of Economic Development ◽  
The Relationship ◽  
Distribution Of Income

Abstract Aim of the study A centre-periphery structure reflects spatial inequalities in the level of economic development of countries and regions. Most often, it provides a simplified picture of spatial distribution of income or spatial accessibility. In this study the authors try to identify the relationship between the level of centrality/peripherality of an area and selected features of the personal car market, using the case of Poland. Method In order to identify the relationship between the level of centrality/peripherality of an area and selected features of the peresonal car market, the correlation and regression analysis has been used. As a dependent variable the index of centrality/peripherality consisting of population and enterprise income has been calculated for all Polish communes (gminas). The features of the car market (independent variables) are: 1) car ownership (number of cars per 1000 inhabitants), 2) sales of new cars, 3) the import of second-hand cars, and 4) the average age of personal cars. Result The research confirmed a positive correlation between the index of centrality/peripherality (and hence the central character of the commune) and the sales of new automobiles, and a negative correlation with the average age of cars. There is no correlation between the level of centrality/peripherality of an area and the indicators of car ownership and the import of second-hand vehicles.

scholarly journals Diagnosing the transition layer at extratropical latitudes using MLS O<sub>3</sub> and MOPITT CO analyses

2013 ◽  
Vol 13 (14) ◽  
pp. 7225-7240 ◽  
Author(s):  
J. Barré ◽  
L. El Amraoui ◽  
P. Ricaud ◽  
W. A. Lahoz ◽  
J.-L. Attié ◽  
...  
Keyword(s):  
Data Assimilation ◽  
Transition Region ◽  
Transition Layer ◽  
Transport Model ◽  
Global Scale ◽  
British Isles ◽  
Chemistry Transport Model ◽  
Free Model ◽  
The Relationship

Abstract. The behavior of the extratropical transition layer (ExTL) is investigated using a chemistry transport model (CTM) and analyses derived from assimilation of MLS (Microwave Limb Sounder) O3 and MOPITT (Measurements Of Pollution In The Troposphere) CO data. We firstly focus on a stratosphere–troposphere exchange (STE) case study that occurred on 15 August 2007 over the British Isles (50° N, 10° W). We evaluate the effect of data assimilation on the O3–CO correlations. It is shown that data assimilation disrupts the relationship in the transition region. When MLS O3 is assimilated, CO and O3 values are not consistent between each other, leading to unphysical correlations at the STE location. When MLS O3 and MOPITT CO assimilated fields are taken into account in the diagnostics the relationship happens to be more physical. We then use O3–CO correlations to quantify the effect of data assimilation on the height and depth of the ExTL. When the free-model run O3 and CO fields are used in the diagnostics, the ExTL distribution is found 1.1 km above the thermal tropopause and is 2.6 km wide (2σ). MOPITT CO analyses only slightly sharpen (by −0.02 km) and lower (by −0.2 km) the ExTL distribution. MLS O3 analyses provide an expansion (by +0.9 km) of the ExTL distribution, suggesting a more intense O3 mixing. However, the MLS O3 analyses ExTL distribution shows a maximum close to the thermal tropopause and a mean location closer to the thermal tropopause (+0.45 km). When MLS O3 and MOPITT CO analyses are used together, the ExTL shows a mean location that is the closest to the thermal tropopause (+0.16 km). We also extend the study at the global scale on 15 August 2007 and for the month of August 2007. MOPITT CO analyses still show a narrower chemical transition between stratosphere and troposphere than the free-model run. MLS O3 analyses move the ExTL toward the troposphere and broaden it. When MLS O3 analyses and MOPITT CO analyses are used together, the ExTL matches the thermal tropopause poleward of 50°.

scholarly journals ANÁLISIS HIDROGRÁFICO E ICTIOLÓGICO DE LAS CAPTURAS REALIZADAS CON UNA RED DE TRAMPA FIJA EN LA LAGUNA DE GANDOCA, LIMÓN, COSTA RICA

2010 ◽  
Vol 2 ◽  
pp. 9
Author(s):  
Rosario Benavides Morera ◽  
Carlos L. Brenes
Keyword(s):  
Costa Rica ◽  
Fresh Water ◽  
Annual Cycle ◽  
Tidal Wave ◽  
Maximum Temperature ◽  
Water Runoff ◽  
Direct Influence ◽  
Salinity Field ◽  
First Maturity ◽  
The Relationship

Se realizó un estudio ictiológico de las capturas obtenidas con una red de trampa fija y un registro de las  propiedades hidrológicas en la Laguna de Gandoca, Limón, entre abril del 2006 y julio del 2007. Se identificaron 13 especies pertenecientes a 10 familias. El 98% de las capturas estuvo conformado por cuatro especies de valor comercial: Centropomus pectinatus (77%), Eucinostomus gula (9%), Caranx latus (7%) y Stellifer colonensis (5%). C. pectinatus (róbalo) estuvo presente en todas las capturas. Para C. pectinatus, se determinó que la relación longitud total - peso se ajustó potencialmente a través de la ecuación Pt= 0.004Lt3.1848. La talla de primera madurez de los róbalos se determinó en 30 cm de longitud total. En el ciclo anual de las propiedades termohalinas superficiales, la temperatura máxima se registró en el mes de setiembre (32°C) y la mínima durante diciembre (25.5°C). La laguna exhibe sus mayores salinidades en octubre (21), mientras que las salinidades menores ocurrió en julio y diciembre (1). Entre setiembre y noviembre, la influencia de la onda mareal se extendió de hasta media laguna con salinidades de 20, mientras que en la parte más interna no excedió a 5. Los valores más altos de contenido de oxígeno se observaron entre setiembre y noviembre, cuando el aporte de agua dulce proveniente de las escorrentías es mínimo. Finalmente, las características espacio-temporales del campo salino tienen una influencia directa en la composición y distribución de la ictiofauna que habita en la laguna.An ichthyological study of the fishing catch in a fixed trap net along with hydrographic sampling of the hydrological properties in Gandoca Lagoon, Limón, was carried out between April 2006 and July 2007. Thirteen species belonging to 10 families were identified. Ninty-eight percent of the captures belong to four species of commercial value: Centropomus pectinatus (77%), Eucinostomus gula (9%), Caranx latus (7%) and Stellifer colonensis (5%). C. pectinatus was present in all captures. For C. pectinatus (snook), the relationship between total length and weight was adjusted potentially through the equation Pt= 0.004Lt3.1848. The size of first maturity of snooks was 30 cm. The annual cycle of surface termohaline properties shows the maximum temperature in September (32°C) and the minimum during December (25.5°C). The Lagoon exhibits maximum salinities in October (21) and minimum in July and December (1). Between September and November the influence of the tidal wave extends to the middle of the lagoon with salinities of 20, while in the inner part it does not exceed 5. The highest values in oxygen content were observed between September and November, when the contribution of fresh water runoff is minimal. The space-time characteristics of the salinity field have a direct influence on the composition and distribution of the icthyofauna that inhabits the Lagoon.

scholarly journals Length and Weight Relationships for 31 Species of Fishes Caught by Trawl Off the Arabian Sea Coast of Oman

2008 ◽  
Vol 13 ◽  
pp. 43
Author(s):  
Brett A. Human ◽  
Haithem Al-Busaidi
Keyword(s):  
Fish Species ◽  
Arabian Sea ◽  
Stock Assessment ◽  
Fork Length ◽  
Biological Parameters ◽  
Conversion Factors ◽  
Weight Measurement ◽  
Total Length ◽  
Commercial Species ◽  
Sea Coast

Length and weight measurement for 31f ish species encountered in the Arabian Sea , o f f t h e Oma n Coast, were collected by demersal trawling during March 2007 and March 2008. A total of 3,261 specimens were measured for total length, or fork length, where appropriate, and green weight. Several commonly caught commercial species undergo onboard processing (dressing) prior to packaging, and dressed weight to green weight regressions and conversion factors were calculated for 12 of these species. The relationships obtained in this study were compared with those of other  studies for the same fish species. These data are fundamental to understanding the biological parameters of fishes, and can be applied to fisheries stock assessment and management models. 

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