scholarly journals An analysis of historical landing data of some pelagic species caught by purse seines in the Aegean Sea

2021 ◽  
Vol 38 (4) ◽  
pp. 417-426
Author(s):  
Zafer Tosunoğlu ◽  
Tevfik Ceyhan
Keyword(s):  
Sustainable Use ◽  
Aegean Sea ◽  
Pelagic Fish ◽  
Historical Period ◽  
Scomber Japonicus ◽  
Sardina Pilchardus ◽  
Fishing Activity ◽  
Pelagic Species ◽  
Almost All ◽  
Boops Boops

The fishing activity with purse seines in the Aegean Sea accounts for almost half of the pelagic fish excluding anchovy (Engraulis encrasicolus Linnaeus, 1758) in Turkey. In this study, we aimed to analyse the catch amounts of some important pelagic species caught by Aegean purse seiners between 1973 and 2019. While mid-1990s are the most captured years for the European pilchard (Sardina pilchardus Walbaum, 1792) in Aegean Sea and also Turkish Seas, this amount has decreased at the level of 10000 mt in the mid-2000s and remained similar amounts up to now. Though European pilchard was the most caught species in the Aegean until 2011, this has changed in favour of anchovy in the last decade. Recently, almost all pelagic species such as mackerel (Scomber scombrus Linnaeus, 1758), chub mackerel (Scomber japonicus Houttuyn, 1782) and bogue (Boops boops Linnaeus, 1758) have been caught from the Aegean Sea in Turkey. In the study, the production of these species in the historical period was tried to be associated with the regulations implemented with circulars and notifications, and the problems preventing the sustainable use of these species that were caught by purse seiners were determined and solutions were proposed for the future.

scholarly journals Retention probability of purse seine grating sieve based on fish morphology

2021 ◽  
Vol 38 (2) ◽  
pp. 173-180
Author(s):  
Zafer Tosunoğlu ◽  
Sinan Mavruk ◽  
Nazlı Kasapoğlu
Keyword(s):  
Simulated Data ◽  
Aegean Sea ◽  
Purse Seine ◽  
Maximum Height ◽  
Sardina Pilchardus ◽  
Maximum Width ◽  
Engraulis Encrasicolus ◽  
Sardinella Aurita ◽  
First Maturity ◽  
Boops Boops

The retention-releasing patterns of the double-grid grating sieve placed on the deck of the purse seiners were revealed for four case species (Sardina pilchardus, Sardinella aurita, Engraulis encrasicolus and Boops boops) using a simulated data predicted from total length (TL) – maximum height (Hmax) and TL – maximum width (Wmax) regressions. To calculate these relationships, samples were collected during commercial purse seine operations between 3 April 2017 and 21 March 2018 in Izmir Bay, Aegean Sea (Turkey). Optimal Bar Spacing (OBS) values corresponding to minimum landing sizes or the length at first maturity were calculated separately for each species. OBS values were found 10.97 mm for sardine (Sardina pilchardus), 11.29 mm for round sardine (Sardinella aurita), 7.78 mm for anchovy (Engraulis encrasicolus) and 17.89 mm for bogue (Boops boops). The bar spacing regulations may constitute a promising management measure to release undersized fish for the purse seine fishery in the Aegean Sea.

scholarly journals Feeding and ecomorphology of three clupeoids in the N Aegean Sea

2013 ◽  
Vol 15 (1) ◽  
pp. 9 ◽  
Author(s):  
P. K. KARACHLE ◽  
K. I. STERGIOU
Keyword(s):  
Trophic Level ◽  
Feeding Habits ◽  
Aegean Sea ◽  
Life Cycles ◽  
Mouth Area ◽  
Morphological Features ◽  
Sardina Pilchardus ◽  
Intestine Length ◽  
Sardinella Aurita ◽  
The Individual

The present study examines the feeding habits of anchovy (Engraulis encrasicolus), sardine (Sardina pilchardus) and round sardinella (Sardinella aurita). The results are combined with previously published information on feeding-related morphological features (i.e. mouth area, intestine length and tail area) in order to explore morphological affinities between species and the effect of ecomorphology on their co-existence. These species were mainly zooplanktivorous and no dietary differences were found with sex and season. Anchovy preyed mainly on Crustacea larvae, whereas sardine and round sardinella on Copepoda. In the majority of cases (>90%), the individual fractional trophic level of all species ranged between 3.0 and 3.5, classifying them as omnivores with preference to animals. The feeding-related morphological features differed between anchovy and the two other species, whereas only intestine length differed between sardine and round sardinella. The fact that round sardinella’s diet and morphology show a greater resemblance to those of sardine, further support the hypothesis that is a particulate feeder as sardine. Hence the three species tend to exploit the same food resources differently throughout the year. Thus, they make best use of the environment and its resources, in order to avoid competition and achieve optimum feeding conditions throughout their life cycles

scholarly journals Characterization of the fishes and of subsistence fishing in the Pantanal of Mato Grosso, Brazil

2000 ◽  
Vol 60 (3) ◽  
pp. 435-445 ◽  
Author(s):  
R. D. de OLIVEIRA ◽  
F. M. de B. NOGUEIRA
Keyword(s):  
Sustainable Use ◽  
Human Consumption ◽  
Fishing Activity ◽  
Mato Grosso ◽  
Fish Stocks ◽  
Central Brazil ◽  
Fish Meat ◽  
Poor Families ◽  
Subsistence Fishing

Fishing is one of the oldest human activities in the Pantanal of Mato Grosso in Central Brazil. In the of Bento Gomes River Basin (Pantanal of Poconé) the presence of fishermen is very common. The objective of this study is to describe the fishing activity in the basin in view of the elaboration of proposals for the sustainable use of this natural resource. Of the 256 fishermen that were registered most are fishing for their subsistence (92%) and the rest (8%) are occasional fishermen (locally called "de lufada" fishermen). "Traíra" (Hoplias gr. malabaricus) and "piranhas" (Serrasalmus marginatus, Serrasalmus spilopleura and Pygocentrus nattereri) were the species most frequently captured for human consumption. The fishing is more intensive during the ebb season and at the beginning of the drought season, when the waters begin to recede for the river channel, as the catch is facilitated by the concentration of fishes at the river margin. The fishermen and their families consume fish three to four times a week, twice a day. Fish meat is one of the only means of obtaining animal protein for dozens of poor families in the area. The number of fishermen, as well as the actual number of catches do not appear to compromise the natural fish stocks, although no specific capture criteria is obeyed by the fishing activity.

scholarly journals Assessment of the sardine (Sardina pilchardus Walbaum, 1792) fishery in the eastern Mediterranean basin (North Aegean Sea)

2011 ◽  
Vol 12 (2) ◽  
pp. 333 ◽  
Author(s):  
K. ANTONAKAKIS ◽  
M. GIANNOULAKI ◽  
A. MACHIAS ◽  
S. SOMARAKIS ◽  
S. SANCHEZ ◽  
...  
Keyword(s):  
Mediterranean Basin ◽  
Eastern Mediterranean ◽  
Population Analysis ◽  
Aegean Sea ◽  
Population Characteristics ◽  
Current Status ◽  
Sardina Pilchardus ◽  
North Aegean ◽  
North Aegean Sea ◽  
The Impact

The aim of this study was to describe the biometric characteristics of the European sardine (Sardina pilchardus) catches and assess the current status of sardine stock in North Aegean Sea based on population characteristics and abundance trends. The stock was dominated by age groups 1 and 2, not exceeding age group 4. The sardine stock in this area was assessed through an Integrated Catch-at-Age model which implements a separable Virtual Population Analysis on catch at age data with weighted tuning indices. Sardine landings data derived from the commercial purse seine fishery over the period 2000-2008 were combined with the age structure of the stock as resulted from fisheries independent acoustic surveys. Sensitivity analysis of the impact of natural mortality values on stock assessment results was applied. Additionally forecast of the sardine population parameters and catches under different exploitation scenarios was implemented in a medium term basis. Results indicated that the North Aegean Sea sardine stock is considered fully exploited with the fishery operating close but over the empirical exploitation level for sustainability. Finally, the status of the sardine stock in N. Aegean Sea is discussed in relation to the sardine stocks from the western and the central Mediterranean basin.

scholarly journals APLIKASI MODEL SURPLUS PRODUKSI NON-EKUILIBRIUM PADA PERIKANAN LAYANG ( Decapterus macrosoma) DI LAUT JAWA

2017 ◽  
Vol 23 (1) ◽  
pp. 57
Author(s):  
Suherman Banon Atmaja ◽  
Bambang Sadhotomo ◽  
Duto Nugroho
Keyword(s):  
Optimal Level ◽  
Pelagic Fish ◽  
Fish Stock ◽  
Optimum Level ◽  
Limited Capacity ◽  
Conservative Approach ◽  
Fishing Mortality ◽  
Fishing Activity ◽  
Input Control ◽  
Equilibrium Approach

Ikan layang (Decapterus macrosoma) dikelompokkan sebagai ikan pelagis yang menyukai habitat oseanik. Kajian ini membahas pendugaan biomassa dengan pendekatan model surplus produksi (MSY) pada spesies layang berdasarkan himpunan data runtut CPUE dan produksi perikanan pukat cincin yang berasal dari Pekalongan dan Juwana selama kurun waktu 1976-2009. Analisis menggunakan pendekatan non-ekuilibrium dengan bantuan perangkat aplikasi ASPIC 7. Hasil penelitian menunjukan sejak tahun 1991 sampai dengan 2005, status biomassa cenderung terus menurun dan tingkat eksploitasi telah melampaui ambang batas untuk menentukan pengelolaan dengan besaran keseimbangan Fmsy dan Bmsy =1. Sejak 2006, penurunan secara drastis baik jumlah armada pukat cincin maupun aktivitas penangkapannya telah memberikan peluang terhadap pemulihan stok menuju tingkat biomassa optimal. Keterbatasan kemampuan pengendalian terhadap dinamika perikanan berakibat pada peningkatan upaya penangkapan, perubahan kapasitas maupun taktik penangkapan. Pergeseran teknologi tersebut cenderung lebih rasional untuk peningkatan produktivitas dan abai terhadap tingkat mortalitas penangkapan yang sedang berjalan (Ft). Untuk itu, upaya pengendalian yang lebih konservatif tentang risiko terhadap pembiaran pola eksploitasi yang sedang berjalan sangat diperlukan. Evaluasi terhadap jumlah armada aktif merupakan landasan untuk mendapatkan status pemanfaatan yang sedang berjalan dan penutupan izin masuknya armada baru merupakan tindakan pengelolaan patut dilakukan untuk memperbesar peluang pemulihan stok pada tingkat optimal.The scads (Decapterus macrosoma) were grouped into pelagic fish associated with oceanic habitat. This study deal with the estimation of biomass and MSY of shortfin scads base on CPUE and production of purse seiners fishery in Pekalongan and Juwana during 1976-2009. Analysis was carried out using non-equilibrium approach through programs package of ASPIC 7. The results showed that since 1991 to 2005, the trend of biomass continued to decline and exploitation rates exceed management benchmarks i.e. Fmsy and Bmsy = 1. Since 2006, drastic decline in number of purse seine and their activity indicates that the probability of recovery biomass to optimum level were increased. However, due to limited capacity on managing the dynamics of fishing activity under the scheme of productivity and ignoring the increasing fishing mortality (Ft), the biomass tends to decline. Therefore, revisiting the fisheries system on input control should be more rational to maintain fishing mortality at equal to Fmsy. A conservative approach on restrictive licencing for new entrance would be necessary to increase the probability of rebuilding the pelagic fish stock at optimal level.

scholarly journals Effect of twine thickness on selectivity of gillnets for bogue, Boops boops,in Turkish waters

2011 ◽  
Vol 12 (2) ◽  
pp. 358 ◽  
Author(s):  
A. AYAZ ◽  
U. ALTINAGAC ◽  
U. OZEKINCI ◽  
O. OZEN ◽  
A. ALTIN ◽  
...  
Keyword(s):  
Mesh Size ◽  
Aegean Sea ◽  
The Mean ◽  
Northern Aegean Sea ◽  
Boops Boops

To investigate the effect of twine thickness on the selectivity of multifilament gillnet targeting bogue,Boops boops L., four different stations were sampled between March and November 2008 in the northern Aegean Sea. Gillnets with 22, 23, and 25 mm nominal mesh size (bar length) each having two different twine thicknesses (approximately 0.45 mm and 0.54 mm ∅) were applied for this purpose. The deviances from the SELECT method revealed that lognormal models provided the best fits for both of the twine thicknesses. Results from the two-way ANOVA analyses revealed that the mean total lengths increased with the mesh size (F = 87.36; df = 2; P < 0.0001) and decreased with the twine thickness (F = 46.12; df = 1; P < 0.0001). The 22 mm mesh size net (0.45 mm ∅) captured significantly larger fish than the 23 mm mesh size net (0.54 mm ∅) probably due to the higher elasticity and flexibility of the thinner twine. Thus, fisheries managers should take into consideration the twine thickness while advising mesh size regulations in gillnet fisheries.

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