scholarly journals KERAGAAN TEKNIS JTEDs PADA ALAT TANGKAP ARAD DI PEKALONGAN

2017 ◽  
Vol 15 (2) ◽  
pp. 161
Author(s):  
Tri Wahyu Budiarti ◽  
Mahiswara Mahiswara
Keyword(s):  
East Coast ◽  
Small Fish ◽  
Total Catch ◽  
Size Selectivity ◽  
Fishing Vessel ◽  
Total Length ◽  
Trash Fish ◽  
The Future ◽  
By Catch

Peningkatan kebutuhan dasar hidup para nelayan di Pekalongan menyebabkan mereka mengembangkan alat tangkap serupa mini bottom seine (arad). Hal ini dapat mengganggu kelangsungan hidup sumber daya ikan di masa mendatang karena banyaknya hasil tangkapan sampingan ikan berukuran kecil yang belum layak tangkap. Menyikapi hal tersebut, telah dilakukan uji coba alat pereduksi ikan muda dan sampah dengan alat tangkap tangkap arad yang menggunakan perangkat JTEDs (Juvenile and Trash Excluder Devices) yang diopersikan dengan menggunakan kapal nelayan berdimensi 8,80 m panjang, 2,80 m lebar dan 1,10 m dalam di perairan utara Pekalongan pada akhir Juli 2006. Sebagai perlakuan digunakan JTEDs dengan lebar kisi-kisi 17,5 mm dengan bagian atasnya dibuat terbuka dan diberi cover net berbentuk kantong untuk menampung ikan yang lolos. Rata-rata hasil tangkapan ikan dalam condend adalah 5.774 kg dengan variasi total tangkapan per stasiun 2.630–10.250 kg. Rata-rata ikan yang masuk cover net adalah 10.241 kg dengan variasi total tangkapan per stasiun 5.640–14.340 kg. Hasil tangkapan dalam cover net menunjukkan bahwa ikan-ikan yang lolos tergolong ikan muda dan berukuran kecil. Selektivitas arad untuk ikan kuniran (Upenus sulphureus), petek (Leiognathus splenden dan L. decorus) masingmasing terjadi pada ukuran panjang 89,17 mm dan (67,43 dan 67,47 mm). The increase of basic live need of fishers in Pekalongan causes them to develop a gear like mini bottom seine (arad). This gear might disturb survival of fish resource in the future because of a large number of juvenile and trash fish caught. Therefore, the experiment on gear reducer for juvenile and by catch as well using JTEDs (Juvenile and Trash Excluder Devices) set in mini bottom seine operated by fisher’s fishing vessel with dimension size of 8.80 m in length, 2.80 m in body wide and 1.10 in depth, respectively was carried out on end of July 2006 in east coast water of Pekalongan. The treatment was JTEDs having 17.5 mm in grid equipped by cover net on the top side to hold small fish (juvenile) caught. The juvenile catch in the cod end averaged 5774 kg with variation from all stations of 5,640 – 14,340 kg. Total catch in cover net showed that un-seined fish was juvenile having small size. Selectivity of mini bottom seine (arad) for kuniran (Upenus sulphureus), petek (Leiognathus splenden and L. decorus) was observed for their total length of 89.17 mm, 67.43 and 67.47, respectively.

scholarly journals Mesh Size Selectivity of Tie-Down Gillnets for the Blackfin Flounder (Glyptocephalus stelleri) in Korea

2021 ◽  
Vol 11 (21) ◽  
pp. 9810
Author(s):  
Pyungkwan Kim ◽  
Hyungseok Kim ◽  
Seonghun Kim
Keyword(s):  
Master Curve ◽  
Mesh Size ◽  
Catch Rate ◽  
Small Fish ◽  
Size Selectivity ◽  
Curve Estimation ◽  
Total Length

Although gillnet fisheries are increasingly common in Korea, few studies have conducted sea trials using tie-down gillnets. Here, we analyzed the mesh size selectivity using tie-down gillnets with four different mesh sizes (84, 90, 105, and 120 mm) to catch blackfin flounders. A total of 10 sea trials were conducted at depths of 100–140 m in the waters of Yangyang County, Gangwon Province, Korea, and the catching efficiency and mesh size selectivity were comparatively analyzed. The net with a mesh size of 84 mm showed the highest number of catches (373), followed by the 90-mm (363) and 105-mm (307) meshes. The results of the master curve estimation showed that the larger the mesh size, the higher the total length representing the same retention probability. Therefore, the catch rate of small fish decreased with the increasing mesh size. For the 84-mm net, the 50% selection length for small fish (total length ≤ 170 mm) was estimated at 186.9 mm, which was approximately 17 mm larger than the length limit. The results show that when using tie-down gillnets, the size of the fish caught changed according to the changes in the mesh size.

Schooling behaviour of jack mackerel, Trachurus declivis (Jenyns), observed in the Tasmanian purse seine fishery

1993 ◽  
Vol 44 (4) ◽  
pp. 577 ◽  
Author(s):  
H Williams ◽  
G Pullen
Keyword(s):  
School Size ◽  
East Coast ◽  
Diurnal Changes ◽  
Jack Mackerel ◽  
Schooling Behaviour ◽  
Summer Schools ◽  
By Catch ◽  
Catch Rates ◽  
Lunar Effects ◽  
Purse Seine Fishery

The seasonal, lunar and diurnal changes in schooling of jack mackerel were examined using log-book information collected from an industrial fishery off the east coast of Tasmania between 1985 and 1989. School size increased significantly from spring to autumn. The ratio between surface and subsurface schools encountered by the fishery also changed seasonally. Surface schools predominate during summer, whereas subsurface schools become more frequent during autumn. The fishery was predominantly a day fishery and no lunar effects on catch rates or fishing intensity were detected. Catches mainly comprised jack mackerel, although redbait (Emmelichthys nitidus Richardson) and blue mackerel (Scomber australasicus Cuvier) were a significant by-catch. In summer, schools were almost exclusively composed of jack mackerel, but in other seasons mixed schools were found. Data presented, together with evidence from other sources, suggest that the availability of schools to the fishery may be closely related to the availability of feed.

scholarly journals Ecological Observations on Hybrid Populations of European Plethodontid Salamanders, Genus Speleomantes

Diversity ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 285
Author(s):  
Enrico Lunghi ◽  
Fabio Cianferoni ◽  
Stefano Merilli ◽  
Yahui Zhao ◽  
Raoul Manenti ◽  
...  
Keyword(s):  
Body Condition ◽  
Parental Species ◽  
Stomach Contents ◽  
Trophic Niche ◽  
Natural Hybrid ◽  
Ecological Information ◽  
Total Length ◽  
Plethodontid Salamanders ◽  
The Future ◽  
First Time

Speleomantes are the only plethodontid salamanders present in Europe. Multiple studies have been performed to investigate the trophic niche of the eight Speleomantes species, but none of these studies included hybrid populations. For the first time, we studied the trophic niche of five Speleomantes hybrid populations. Each population was surveyed twice in 2020, and stomach flushing was performed on each captured salamander; stomach flushing is a harmless technique that allows stomach contents to be inspected. We also assessed the potential divergence in size and body condition between natural and introduced hybrids, and their parental species. Previously collected data on Speleomantes were included to increase the robustness of these analyses. In only 33 out of 134 sampled hybrid Speleomantes we recognized 81 items belonging to 11 prey categories. The frequency of empty stomachs was higher in females and individuals from natural hybrid populations, whereas the largest number of prey was consumed by males. We compared the total length and body condition of 685 adult salamanders belonging to three types of hybrids and three parental (sub)species. Three group of salamanders (one hybrid and two parental species) showed significantly larger size, whereas no difference in body condition was observed. This study provided novel ecological information on Speleomantes hybrid populations. We also provided insights into the potential divergence between hybrids and parental species in terms of size and body condition. We discuss our findings, and formulate several hypotheses that should be tested in the future.

scholarly journals CRITICAL INPUTS INTO GISBORNE HILL COUNTRY

1984 ◽  
pp. 27-37
Author(s):  
M.J. Fitzharris ◽  
D.F. Wright
Keyword(s):  
East Coast ◽  
Farm Management ◽  
Animal Production ◽  
Management Study ◽  
Hill Country ◽  
Farm Production ◽  
The Future ◽  
Farm Profit ◽  
Stocking Rates ◽  
Practical Implications

The results of an analysis of four years data, 1975/76-1978/79, from a farm management study of Gisborne-East Coast hill country farms were presented at the 1980 Grasslands Conference. Analysis of three more years data, 1979/80-1981/82, essentially confirms the association of fencing and fertiliser with high levels of animal production. Recent escalating costs of fertiliser have cast doubts on its profitability. High stocking rates (usually beyond 12 su/ha) and high proportions of cattle (usually up to 50% of su) have emerged as other factors consistently associated with greater productivity and frequently with profitability. It is suggested that manipulation of these factors would be worthy of farmers consideration. The practical implications for the future of these findings are discussed. Keywords: Farm production, farm profit, Gisborne hill country

By-catch-associated demographics of two threatened seahorses from the south-east coast of India

2021 ◽  
Author(s):  
Kannan Shalu ◽  
Neelesh Dahanukar ◽  
Rajeev Raghavan ◽  
Kutty Ranjeet
Keyword(s):  
East Coast ◽  
The South ◽  
East Coast Of India ◽  
By Catch

To 1750

2017 ◽  
Author(s):  
William H. McNeill
Keyword(s):  
United States ◽  
Nineteenth Century ◽  
Civil War ◽  
American History ◽  
East Coast ◽  
The United States ◽  
The World ◽  
The Future ◽  
Columbian Exposition ◽  
The Republic

IN THE LATTER part of the nineteenth century, east coast city dwellers in the United States had difficulty repressing a sense of their own persistent cultural inferiority vis-à-vis London and Paris. At the same time a great many old-stock Americans were dismayed by the stream of immigrants coming to these shores whose diversity called the future cohesion of the Republic into question almost as seriously as the issue of slavery had done in the decades before the Civil War. In such a climate of opinion, the unabashed provinciality of Frederick Jackson Turner's (1861-1932) paper "The Significance of the Frontier in American History," delivered at a meeting of the newly founded American Historical Association in connection with the World Columbian Exposition in Chicago (1892), began within less than a decade to resound like a trumpet call, though whether it signalled advance or retreat remained profoundly ambiguous....

scholarly journals Preliminary observations of tag shedding, tag reporting, tag wounds, and tag biofouling for raggedtooth sharks (Carcharias taurus) tagged off the east coast of South Africa

2006 ◽  
Vol 63 (9) ◽  
pp. 1640-1648 ◽  
Author(s):  
M.L. Dicken ◽  
A.J. Booth ◽  
M.J. Smale
Keyword(s):  
South Africa ◽  
East Coast ◽  
Telephone Survey ◽  
Total Length ◽  
Significant Difference ◽  
Juvenile Sharks ◽  
Carcharias Taurus ◽  
Tag Shedding

Abstract A double-tagging experiment and integrated on-site questionnaire and telephone survey were used to investigate aspects of tag shedding, tag reporting, tag wounds, and tag biofouling for the raggedtooth shark (Carcharias taurus), tagged off the east coast of South Africa. Between 2002 and 2004, 84 juvenile (<1.8 m total length, TL), and 24 adult (>1.8 m TL) C. taurus were double-tagged. Of these, 11 juvenile and six adult double-tagged sharks were recaptured. Significantly, more tags were shed from adult than from juvenile sharks, and there was also a significant difference between the number of anterior and posterior tags shed. Rates of tag reporting were estimated from a survey of 477 randomly selected shore-anglers, and they varied both temporally and spatially from 27% to 100%. In all, 93 tag recaptures were reported in the survey, most (75.3%) with some biofouling. Tag-inflicted damage was reported in 35.5% of recaptured sharks, and the incidence of tag-inflicted damage was greater for disk (77.8%) than for dart tags (25.3%).

Allometry and population structure of Nicolea uspiana (Polychaeta: Terebellidae)

2010 ◽  
Vol 90 (5) ◽  
pp. 877-883 ◽  
Author(s):  
A.R.S. Garraffoni ◽  
L.Q. Yokoyama ◽  
A.C.Z. Amaral
Keyword(s):  
Population Structure ◽  
East Coast ◽  
Morphometric Parameters ◽  
Size Frequency Distribution ◽  
Relative Growth ◽  
Total Length ◽  
Length Width ◽  
Males And Females ◽  
The Individual ◽  
Individual Size

The relative growth and population structure of the terebellid Nicolea uspiana were investigated in the intertidal zone of a rocky shore on the south-east coast of Brazil, from May 2006 to May 2007. Eight hundred and forty-seven individuals of N. uspiana were analysed: 391 males, 163 females, and 293 immatures. Although significant differences in some morphometric parameters were found, there was no sexual dimorphism between males and females. There were differences in total length, width of segment 5, and length of the notopodial region between matures and immatures. The negative allometry of the total length in relation to five other parameters showed that this feature is a good measure for estimating the individual size, which was then used in the analysis of population structure. This population of N. uspiana showed a bimodal size–frequency distribution, with immature and mature individuals found during the entire year. This pattern indicates continuous reproduction, with each cohort growing for at least three to four months and being responsible for two consecutive settlement peaks.

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