System for Sampling Large Trawl Catches of Research Vessels

1976 ◽  
Vol 33 (4) ◽  
pp. 833-839 ◽  
Author(s):  
S. E. Hughes

Procedures and sampling gear designed 1) to sample large research trawl catches prior to sorting by species and 2) to reduce catch handling time and permit an increase in the number of hauls per cruise, are discussed and illustrated. The rationale behind the method relies on the hypothesis that species and size stratification in the codend of the trawl are bilaterally symmetrical The codend is positioned above a deck bin prior to releasing the catch so that a sampling net can be lifted from the deck bin to remove about one half of the total catch. The sampled portion is processed on a fish sorting table, and the unused portion brailed overboard by a net which lines the entire deck bin. Tests conducted in Puget Sound indicated that the species composition and length distribution in the sample adequately represented the total catch; errors greater than 25% were usually restricted to species composing less than 5% of the catch, and for dominant species errors were less than 10%.

2009 ◽  
Vol 123 (1) ◽  
pp. 48 ◽  
Author(s):  
A. M. Herrell ◽  
D. A. Methven

A total of 7130 fish from 13 taxa were collected during summer and autumn, 2002-2005 using box traps at two sites in the Tabusintac River Estuary, New Brunswick, Canada. The objective was to determine seasonal change in species composition and catches, and to access change in annual returns of Atlantic Salmon, an important recreational fishery during autumn on the Tabusintac, Miramichi and neighboring rivers. Taxa richness and composition varied annually and from trap to trap. Richness ranged from 8-10 taxa annually and catches were usually highest in the trap closest to the ocean despite its slightly smaller size. Taxa contributing greater than one percent of the total catch during the four years of sampling included six diadromous taxa: Blueback Herring and Alewife (41.65%), Striped Bass (21.54%), Atlantic Salmon (3.98%), Tomcod (2.95%), Brook Trout (1.05%), American Eel (5.27%); one freshwater species, White Sucker (11.96%); one marine species, Winter Flounder and one resident estuarine species, Smooth Flounder which together account for 11.19% of the total catch. The remaining five species (American Smelt, Northern Pipefish, White Perch, Cunner, Sea Lamprey) contributed 0.39% of the total catch. The fish fauna 14-15 km up the Tabusintac River was not species rich, due in large part to the limited sampling time each year and due to fishing with just one sampling gear, a stationary box trap. Additional species would have been collected if smaller mesh sampling gear were used. Comparisons were made with other studies and the phenology of the dominant species on the Tabusintac and Miramichi River Estuaries during the ice free season is established. Most catches appear to be related to pre- or post-spawning movements of anadromous fishes.


2018 ◽  
Vol 23 (11) ◽  
pp. 2087 ◽  
Author(s):  
Peng-Yu Jin ◽  
Lu Tian ◽  
Lei Chen ◽  
Xiao-Yue Hong

Understanding pest species composition and their geographic distribution of important spider mites is fundamental and indispensable to establish an integrated pest management program. From a long-term survey during 2008–2017 in mainland China, we found that Tetranychus truncatus was the most frequently sampled Tetranychus spider mite (48.5%), followed by T. pueraricola (21.2%), T. kanzawai (12.5%), T. urticae (red) (5.7%) and T. urticae (green) (4.5%). Among them, T. truncatus was the major mite pest in the north of China. T. kanzawai was the dominant species in the Middle and Lower Reaches of the Yangtze River Region and T. pueraricola was the most important species in the southwest region. Other common and serious pests include Amphitetranychus viennensis (6.8%) and Panonychus citri (3.8%). This pattern was largely different from that in 2002–2004, when T. urticae (green and red) was believed to be the most serious mite pest. The factors involved in the change of species composition are not clear and need more exploration. We suggested that the increasing corn planting range may be partly responsible for the conversion of dominant species from other spider mites to T. truncatus. Further research on the mechanisms underlying the change of dominant species will help develop integrated management strategies.


2016 ◽  
Vol 16 (3) ◽  
Author(s):  
Felipe Augusto Trindade Gondim-Silva ◽  
Alessandra Rodrigues Santos Andrade ◽  
Rafael Oliveira Abreu ◽  
Jamile Santos Nascimento ◽  
Geovane Paixão Corrêa ◽  
...  

Abstract The Conde municipality is located in the northern coast of the state of Bahia (NC), northeastern Brazil, and is part of the Atlantic Tropical domain. The anuran fauna of the northern portion of the NC is still poorly known if compared to the southern portion. The Restinga is one of the predominant environments of the coastal plains of the NC and it is characterized essentially by presenting sandy soil covered by herbaceous and shrubby vegetation. The objective of this study was to determine the anuran species composition and diversity for the Restinga of the Conde municipality. Sampling was carried out at night by active search over four periods of five consecutive days each, two over the 'main rainy season' and two in a 'lesser rainy season', using 14 sample units (SUs) and five extra sample plots (EPs). We calculated dominance and species diversity using the Berger-Parker and Shannon-Wiener H' indices, respectively. We used accumulation curves and the Jackknife 1 estimator to estimate anuran species richness, considering only the data obtained from the SUs. We recorded 713 anuran specimens distributed within 33 species, 13 genera and five families (Bufonidae, Craugastoridae, Hylidae, Leptodactylidae and Microhylidae). The Hylidae and Leptodactylidae families had the highest species richness. Considering only the SUs (Jackknife 1 estimator in brackets), we recorded 28 species in the study area (33.9 ± 2.3), 13 in Shrubby Vegetation Zones - SVZ (20.8 ± 2.9) and 25 in Freshwater Wetland Zones - FWZ (28.9 ± 1.9). The abundance and species diversity of the FWZ (n = 638 specimens; H'= 2.4) were higher than those recorded for the SVZ (n = 52 specimens; H' = 1.9). The SVZ and FWZ showed distinct dominant species, wherein Pristimantis paulodutrai was the dominant species in SVZ and Scinax fuscomarginatus in FWZ. The Restinga of the Conde municipality stands out as the one with the highest anuran species richness already recorded considering only SVZ and FWZ. Moreover, its anuran species composition represented 55% of the anuran species known for the NC and included taxa common to three different morphoclimatic domains (Tropical Atlantic, Cerrado and Caatinga).


2017 ◽  
Vol 8 (2) ◽  
pp. 123-129
Author(s):  
Cecep Kusmana ◽  
Anggun Rahayu Melyanti

BKPH Tampomas is part of the FMU area of Sumedang entirely classified into protected forest area. However, part of treated as CBFM with the aim of involfing the community in forest concervation activities the aim of this research is to describe and compare the structure and composition of the plant species between the subjected to CBFM and non CBFM Tampomas. The reaserch location was based on forest status of the protected area as having the same stand age and tree spacing. Data collection conducted throught the analysis of vegetation and soil sampling at each observation location species richness of BKPH Tampomas protection forest was relatively low either non CBFM of protected forest, CBFM protection forest of coffe and CBFM protection forest of cardamon. At the level of seedling stage there are 9 species and Calliandra haematocephala, the dominant. Species at the pole stage are found 3 species with Pinus merkusii species as the dominant species, at the tree stage are 2 species that dominated by Pinus merkusii. The covercrop found were 30 species and dominated by Lepturus repens. The low soil fertility and sandy soil texture composition also account for the low plant species in the BKPH Tampomas protection forest areas.Key words : CBFM cardamon, CDFM coffee, species composition, structure vegetation, Tampomas Mountain


2016 ◽  
Vol 7 (2) ◽  
Author(s):  
Agus Alim Hakim ◽  
M Mukhlis Kamal ◽  
Nurlisa A Butet ◽  
Ridwan Affandi

Freshwater eel (Anguilla spp.) is a catadromus fish that migrates from freshwater into seawater for spawning and return to freshwater during larvae stage to grow. The objective of this study was to determine species composition of tropical freshwater eels based on morphology collected from several rivers flowing in to the Palabuhan Ratu Bay. Young, adult, and glass eels were caught in August 2014 until Desember 2014. Glass eels were only caught in Cimandiri River. Freshwater eels were classified by ano-dorsal length (AD) divided by total length (TL), cluster analysis, and discriminant analysis based on morphometric data. The results showed different AD/TL of young and adult, i.e., 1.93±0.51 for A. bicolor bicolor, and 16.99±0.65 for A. marmorata, and three different AD/TL of glass eels i.e.,1.72±1.05 for A. bicolor bicolor6.60±1.79 for A. nebulosa nebulosa, and 15.07±1.04 for A. marmorata. Cluster analysis showed three groups of population  characters of young and adult eels i.e.  A. bicolor bicolor (2 groups) and A. marmorata (1 group). Discriminant analysis showed three groups of glass eels population i.e., A. bicolor bicolor, A. nebulosa nebulosa, and A. marmorata. Morphological identification showed that young and adult eels in Cibareno  and Citepus rivers had two species i.e., A. bicolor bicolor and A. marmorata. Glass eels from Cimandiri river had three species i.e., A. bicolorbicolor, A. nebulosanebulosa, and A. marmorata. A. bicolor bicolor was found in each rivers and as a dominant species in Palabuhan Ratu Bay.Keywords: A. bicolor bicolor, A. marmorata, A. nebulosa nebulosa, species composition


Author(s):  
Sergei L. Esyunin ◽  
◽  
Nadezhda L. Ukhova ◽  
Anna M. Domolazova ◽  
◽  
...  

The assemblages of herpetobion spiders from four habitats: two seven-year-old burns, spruce-birch and fir-spruce forests, were examined in the Visimskiy Reserve (Sverdlovsk Region) during May-September 2017 using pitfall-traps. The structure of the spiders population of burns significantly differs from that of forests in species composition, total occurrence rate (ind./100 trap-days), seasonal dynamics and composi-tion of the dominant species. Differences in the structure of the population are most pronounced in the summer. In summer spider assemblages of burns, the most abundant are Agyneta allosubtilis, Alopecosa pulverulenta, P. fulvipes, P. lugubris, P. riparia and Piratula hygrophila, in forests - Allomengea scopigera and Haplodrassus soerenseni.


Author(s):  
Е. Пещанская ◽  
В. Кожевников

Необходимость восстановления луговой степи центрального Ставрополья возникла ещё в середине прошлого столетия. Причиной тому послужило усиление воздействия антропогенных факторов на окружающую среду: распашка целины, промышленное и гражданское строительство, чрезмерный выпас скота, а также воздействие различного вида эрозий. В целях сохранения уникального природного комплекса степей с большим набором ценных и редких видов, а также в качестве опыта по восстановлению кормовых угодий в Ставропольском ботаническом саду в 1963 году были начаты исследования по интродукции дёрна. В период с 1963 по 1984 год на площади около 2 га были воссозданы фрагменты луговой степи. Изучение состояния искусственных ценозов, получение сравнительных данных в отношении видового состава, хозяйственно-ботанических групп, урожайности ценозов важнейшие компоненты исследования. В качестве эталонов обследовались территории естественных целинных степей (эталоны) (г. Бучинка, г. Стрижамент, урочище Новомарьевская поляна) с доминантами, сходными с доминантами изучаемых участков, восстановленных дёрном ( Бучинка , Стрижамент , Новомарьевская поляна ). Количество видов на эталонных участках составляет 6592, на восстановленных участках 83103. Видовой состав максимально представлен разнотравьем: от 44 до 72 видов. Во всех выборках проб преобладают злаки (31,9446,17) и разнотравье (29,4041,64), значительный удельный вес приходится на сухие остатки (старику) 7,6128,64. Масса бобовых колеблется в пределах от 0,85 до 11,01, осок от 0,1 до 13,83. Урожайность травостоя восстановленных ценозов сохраняется высокой 3,243,97 т/га. Показатели урожайности травостоя восстановленных формаций превышают показатели эталонов с разницей от 0,61 до 1,65 т/га. Restoration of grasslands became important in the Central Stavropol region in the middle of the last century. The reason was an increased anthropogenic effect: plowing, industrial and civil engineering, cattle grazing and erosion. Experiments on turf introduction got started at the Stavropol Botanical Garden in 1963 to preserve and restore the unique natural steppe area with a large number of valuable and rare species. Fragments of steppe were grown on 2 ha area from 1963 to 1984. The investigation focused on ecosystem conditions, species composition, botanical groups and yield. Natural steppes performed as controls (Buchinka, Strizhament, Novomaryevskaya Polyana) having similar dominant species as the trial areas. Control areas contained 6592 species, the restored ones 83103. There were 4472 different grass species grown. Proportions of gramineous averaged to 31.9446.17, grass mixtures 29.4041.64, grassland litter 7.6128.64. Contents of legumes varied within 0.8511.01, sedge 0.113.83. Grass productivity of the restored area was high 3.243.97 t ha-1. It exceeded the one of the natural areas by 0.611.65 t ha-1.


Author(s):  
Vu Ngoc Ut ◽  
Au Van Hoa ◽  
Huynh Phuoc Vinh

Fish biodiversity on Hau (Bassac) river was investigated to assess the status of species composition and fishing by fishing gears during a year. Sampling was implemented monthly at the upper part (An Giang province), middle part (Can Tho City) and lower part (Soc Trang province) of Hau River using trawl net as main sampling gear. Additionally, fish composition was also recorded from four other most popular fishing gears including cast net, gill net, fixed net and hook operated in the study sites. Fish species composition was determined by fishing gears and their abundance (CPUE) was calculated only from the main sampling gear (trawl net). The results showed that a total of 176 fish species belonging to 16 orders and 49 families was recorded. Perciformes was the most abundant group with 51 species followed by Cypriniformes with 46 species. The number of fish species was decreasing from upper part to lower part. Trawl net was considered the most destructive gear as up to 145 fish species caught by this device, followed by gill net with 98 species, fixed net 75, cast net 57, and hooks 16 species. CPUE was very low ranging from  0.53 kg.ha−1 h−1 to 26.30 kg.ha−1 h−1. Higher CPUE was recorded at lower part in compared to upper part and middle part, and at dry season in compared to rainy season. Regulation on fishing gears, fishing ground and season should be taken into consideration to protect and conserve the resources.


2010 ◽  
Vol 84 (1) ◽  
pp. 131 ◽  
Author(s):  
Jonathan C. P. Reum ◽  
Mary E. Hunsicker ◽  
Caroline E. Paulsen

1968 ◽  
Vol 44 (6) ◽  
pp. 31-35 ◽  
Author(s):  
Carl H. Winget

Second-growth, tolerant hardwood stands developed rapidly and, almost entirely from shade-tolerant advance growth, regardless of cutting intensity. Non-commercial woody species were seldom important competitors. Sugar maple, associated with beech on upland and balsam fir on lowland sites, was the dominant species. Yellow birch, basswood and hemlock, important contributors to wood volumes harvested, were minor components of second-growth stands. Valuable minor species such as red oak, white ash, and black cherry had practically disappeared. The application of known techniques for regenerating disturbance-dependent species is urgently required.


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