scholarly journals The Maximum Length Record of the Blackspot Seabream (Pagellus bogaraveo Brünnich, 1768) for the Entire Aegean Sea and Turkish Territorial Waters

2020 ◽  
Vol 8 (10) ◽  
pp. 2125-2130
Author(s):  
Şenol Paruğ ◽  
Özgür Cengiz
Keyword(s):  
Stock Assessment ◽  
Biological Activities ◽  
Aegean Sea ◽  
Maximum Length ◽  
Northern Spain ◽  
Domestic Markets ◽  
Total Length ◽  
North East ◽  
The North ◽  
Pagellus Bogaraveo

The maximum length, weight, and age information of organisms in an ecosystem, moreover, the first records of migrated exotic species are essential in terms of the basis for the studies on population dynamics, stock assessment, and biological activities. Therefore, the recording of such data may be necessary for scientific databases and new related studies. The Blackspot seabream (Red seabream - Pagellus bogaraveo), which belongs to the Sparidae family, is an important seafood which is marketed fresh and frozen around the Mediterranean and the Aegean seas. Nowadays, this species has high prices depending on market demands in domestic markets as a result of overfishing and is also cultured in northern Spain. It is classified as “Near Threatened Species” in the red list due to its decreasing population trend by the IUCN. A single specimen of the Blackspot seabream with 30.7 cm in total length and 390.00 g in total weight, which was angled in the Saros Bay with a handline by a fisherman on February 08, 2019, was obtained from a fishmonger in Çanakkale. Even though there are bigger individuals in the North-east Atlantic probably depending on polar and/or deep-sea gigantism, the mentioned measurement is the proven maximum total length of this species for the Aegean Sea up to the time.

Further results from a tagging study of pelagic sharks in the north-east Atlantic

1990 ◽  
Vol 70 (4) ◽  
pp. 707-720 ◽  
Author(s):  
J. D. Stevens
Keyword(s):  
Northern Spain ◽  
East Atlantic ◽  
North West ◽  
North East ◽  
The North ◽  
Isurus Oxyrinchus ◽  
South West ◽  
Predicted Values ◽  
Galeorhinus Galeus ◽  
South West England

A further 69 recaptures are reported from a tagging study of pelagic sharks initiated in 1970 in the north-east Atlantic. Galeorhinus galeus tagged in England were recaptured in the eastern Atlantic from southern Spain to north-west of Iceland. Among the 42 G. galeus recaptured the longest time at liberty was about 12 years and the greatest distance travelled was 2461 km. Among the 21 Prionace glauca recaptured the l ongest time at liberty was 10.7 years, and seven sharks moved distances between 4362 and 7176 km. One shark tagged in south-west England was recaptured in the South Atlantic off South America. An Isurus oxyrinchus was at liberty for 4–6 years and a Lamna nasus for up to about 13 years. Lamna nasus were recaptured from northern Norway to northern Spain. The growth rates of the tagged sharks were close to the predicted values for G. galeus, were slower for P. glauca and faster for L. nasus.

scholarly journals Using spatial indicators to investigate fish spawning strategies from ichthyoplankton surveys: A case study on co-occurring pelagic species in the NE Aegean Sea

2019 ◽  
Author(s):  
STAVROULA TSOUKALI ◽  
MARIANNA GIANNOULAKI ◽  
APOSTOLOS SIAPATIS ◽  
EUDOXIA SCHISMENOU ◽  
STYLIANOS SOMARAKIS
Keyword(s):  
Sea Water ◽  
Aegean Sea ◽  
Chub Mackerel ◽  
Spawning Period ◽  
North East ◽  
The North ◽  
Animal Populations ◽  
Fish Spawning ◽  
Spatial Indicators

Multispecies ichthyoplankton associations are believed to be adaptive and their objective definition can be useful in designating species with similar or contrasting spawning strategies. In this case study, a suite of indicators, recently developed to characterize the spatial patterns of animal populations, are applied on egg abundance data of summer-spawning European anchovy (Engraulis encrasicolus), round sardinella (Sardinella aurita) and chub mackerel (Scomber colias), in an effort to identify common or contrasting spawning patterns in the North-East Aegean Sea (NEA) and their relation to the major oceanographic features of the area. A considerable increase in abundance and area of presence was observed between the early (May) and advanced (July) phase of the 2010 spawning period. The definition of major spatial patches revealed a persistent multispecies spawning location associated with the outflow of Black Sea water (BSW). A second major patch was defined for anchovy and chub mackerel in July, clearly associated with the Samothraki gyre (SG). In contrast, round sardinella spawned in coastal waters outside the SG. Surprisingly, in May 2010, the spawning intensity of anchovy was very low in the SG which was attributed to unfavorable conditions caused by the bloom of mucilage-producing phytoplankton cells. The levels of aggregation and occupation of space seemed to be adequately described by the indices of Positive, Equivalent and Spreading Area. Conclusively, many of the spatial indicators applied in this study have the potential to become important tools for studying egg distributions and the changing priorities of adult fish in selecting spawning sites.

Effects of variable mean target strength on estimates of abundance: the case of Atlantic mackerel (Scomber scombrus)

2016 ◽  
Vol 74 (3) ◽  
pp. 822-831 ◽  
Author(s):  
Ben Scoulding ◽  
Sven Gastauer ◽  
David N. MacLennan ◽  
Sascha M. M. Fässler ◽  
Phillip Copland ◽  
...  
Keyword(s):  
Stock Assessment ◽  
Target Strength ◽  
Fish School ◽  
Acoustic Data ◽  
Atlantic Mackerel ◽  
Scomber Scombrus ◽  
North East ◽  
The North ◽  
Frequency Split ◽  
Abundance And Distribution

Atlantic mackerel Scomber scombrus is a small pelagic, migratory fish which supports commercial fisheries. These fish school and are detectable using echosounders, yet fishery-independent estimates of their abundance in the North East Atlantic do not consider acoustic data. Accurate estimates of mean target strength (TS) are presently limiting echo-integration surveys from providing useful estimates of Atlantic mackerel abundance and distribution. This study provides TS estimates for in situ mackerel from multi-frequency split-beam echosounder measurements. TS equals −52.79 dB at 18 kHz, −59.60 dB at 38 kHz, −55.63 dB at 120 kHz, and −53.58 dB at 200 kHz, for a mean mackerel total length = 33.3 cm. These values differ from those currently assumed for this species in analyses of acoustic survey data. We investigate the sensitivity of acoustically estimated mackerel biomass around the Shetland Islands, Scotland, in 2014, to various estimates of TS. Confidence limits were obtained using geostatistics accounting for coverage and spatial autocorrelation. Stock biomasses, estimated from 38 and 200 kHz data, differed by 10.5%, and stock distributions were similar to each other and to the estimates from an independent stock assessment. Because mackerel backscatter at 38 kHz is dominated by echoes from the flesh and may have similarities to echoes from fish with swimbladders, and backscatter at 200 kHz is dominated by relatively stable echoes from the backbone, we recommend using 200 kHz data for estimates of Atlantic mackerel biomass.

Fishery Management in the Northeast Atlantic: the Role of the International Council for the Exploration of the Sea

1973 ◽  
Vol 30 (12) ◽  
pp. 2031-2037 ◽  
Author(s):  
A. J. Lee
Keyword(s):  
Fishery Management ◽  
Marine Pollution ◽  
Stock Assessment ◽  
Biological Data ◽  
Minimum Size ◽  
International Council ◽  
Liaison Committee ◽  
North East ◽  
The North ◽  
Working Groups

Rational management by the North-East Atlantic Fisheries Commission (NEAFC) is aided by scientific advice given to it by the International Council for the Exploration of the Sea (ICES). Such advice is provided through a Liaison Committee consisting of the Chairmen of eight Area- and Sub-Committees and five co-opted members. The members of the Liaison Committee act on their own and not on behalf of governments or other bodies. Advice comes to a large extent through working groups, which pass their views to the Liaison Committee. This decides what advice to pass to the commission. The responsibility of the Liaison Committee is to see that the advice is scientifically sound and based on adequate information.There are 23 working groups covering the main fisheries of the region. They usually meet early in the year and the Liaison committee considers their reports in February, to prepare its own report for circulation one month before the commission meeting in May. This tight timetable is becoming more difficult to meet as NEAFC calls for advice on more stocks. It is complicated by the fact that other meetings (notably that of the International Commission for the Northwest Atlantic Fisheries) are held at about the same time, and that many scientists are involved in both; there are not enough to do all the work.The great strength of ICES is that it is a scientific forum as well as being a scientific advisory body to NEAFC. A major concern in recent years has been the dependence of recruitment on parent stock. Nearly all the demersal fisheries of the area have come under mesh and minimum size regulations; attention is now focused on the pelagic fisheries and on methods of management involving control of the total amount of fishing and the assignment of catch quotas. This will call for improved methods of stock assessment. More reliable estimates of future recruitment are also essential.ICES has been ahead of public opinion in respect to concern for the environment, and an Advisory Committee on Marine Pollution has been established which is analogous to the Liaison Committee, and provides advice to the council.International agreement in fisheries is slowed by three factors. Conflicts of interests among nations are lessened in the ICES–NEAFC framework because of the way in which the Liaison Committee is constituted. Fisheries biologists are conservative when it comes to providing advice on which decisions are made, with a tendency to wait for more data or to reach agreement on the lowest level when opinions differ. It would be better in some cases to offer a range of alternatives. Scientists also have an obligation to inform the commission of their views on all developments and not wait until their advice is sought. Finally, while theory lags behind events, there is an increasing tendency for ICES scientists to give commissioners early warning of the effects of various developments.Prior disclosure to NEAFC of national plans that would affect fishing would be helpful in making earlier advice possible. There is also need for various countries to strengthen their capability to carry out research in stock assessment and to provide statistics and associated biological data quickly. Agreements on these aspects were reached at the Special NEAFC Meeting at the level of ministers, and at the Stockholm Conference. It is hoped that these can be implemented soon.

scholarly journals A New Maximum Size Record of the Shi Drum (Umbrina cirrosa Linnaeus, 1758) for Aegean Sea

2020 ◽  
Author(s):  
Ö. Cengiz ◽  
Ş. Ş. Paruğ
Keyword(s):  
Aegean Sea ◽  
Maximum Size ◽  
September 11 ◽  
Maximum Length ◽  
Total Weight ◽  
Single Specimen ◽  
Total Length ◽  
New Findings ◽  
The World ◽  
Northern Aegean Sea

Abstract The present study has been conducted to find out new findings on maximum length and weight values of Umbrina cirrosa in the Bay of Saros (Northern Aegean Sea, Turkey). On September, 11, 2016, a single specimen of Umbrina cirrosa with 68.8 cm total length and 2600.00 g total weight was caught by handline at a depth of 20 m. The provable size is the second largest length ever reported in the all seas of the world

Ectoparasites of the blackspot seabream Pagellus bogaraveo (Teleostei: Sparidae) from Portuguese waters of the north-east Atlantic

2012 ◽  
Vol 93 (2) ◽  
pp. 503-510 ◽  
Author(s):  
Margarida Hermida ◽  
Cristina Cruz ◽  
Aurélia Saraiva
Keyword(s):  
East Atlantic ◽  
Marine Aquaculture ◽  
North East ◽  
The North ◽  
Sampling Locations ◽  
High Prevalence ◽  
Commercially Important ◽  
Potential Impact ◽  
Pagellus Bogaraveo ◽  
First Time

The ectoparasite community of the blackspot seabream, Pagellus bogaraveo, was studied in different locations in Portuguese waters of the north-east Atlantic Ocean. This is the first study to focus on the ectoparasites of this commercially important sparid fish. Nine ectoparasite species were detected. Gnathia sp., Aega deshaysiana, A. antillensis, Rocinela danmoniensis and Argulus sp. are reported for the first time on this host. Significant differences were detected among the sampling locations, with monogeneans being more prevalent in mainland waters, and crustaceans being more prevalent in the Atlantic islands of Madeira and Azores. Fish from Madeira showed significantly higher infection levels of all ectoparasites, especially crustaceans, and particularly high prevalence of Hatschekia pagellibogneravei. The potential impact of the species detected on captive fish is also discussed, since the blackspot seabream is a promising new species for marine aquaculture.

scholarly journals Biology of the thornback ray (Raja clavata Linnaeus, 1758) in the North Aegean Sea

2021 ◽  
Vol 50 (2) ◽  
pp. 115-127
Author(s):  
Koray Cabbar ◽  
Cahide Çiğdem Yiğin
Keyword(s):  
Aegean Sea ◽  
Total Weight ◽  
Total Length ◽  
The North ◽  
Disc Width ◽  
Thornback Ray ◽  
Raja Clavata ◽  
North Aegean ◽  
Males And Females ◽  
North Aegean Sea

Abstract The study deals with aspects of the population dynamics in the thornback ray (Raja clavata L., 1758), one of the most abundant cartilaginous fish caught in the North Aegean Sea. Females accounted for 73.08% and males 26.92% of all individuals. Total length of females and males ranged between 50.2 and 89.9 cm (disc width: 33.4–62.0 cm), and between 43.1 cm and 82.7 cm (disc width: 30.7–64.2 cm), respectively. Relationships between total length (TL) and total weight (TW), and between disc width (DW) and total weight (TW) were described by the equations: TW = 0.0041 TL3.10 and TW = 0.0178 DW3.03, respectively. Age data derived from vertebrae readings were used to estimate growth parameters using the von Bertalanffy function: L∞ = 101.71 cm, K = 0.18 y−1, t0 = −0.07 y for males and L∞ = 106.54 cm, K = 0.16 y−1, t0 = −0.28 y for females. The maximum age was 8 years for males and females. Total length at first maturity of males and females was 70.9 cm and 81.2 cm, respectively. Based on the gonadosomatic index and gonadal macroscopic observations, it was determined that the spawning period lasted throughout the year. Stomach content analysis showed that crustaceans (53.03% IRI) and teleosts (14.70% IRI) were the most preferred prey.

Estimating uncertainty of data limited stock assessments

2016 ◽  
Vol 74 (1) ◽  
pp. 69-77 ◽  
Author(s):  
Alexandros Kokkalis ◽  
Anne Maria Eikeset ◽  
Uffe H. Thygesen ◽  
Petur Steingrund ◽  
Ken H. Andersen
Keyword(s):  
Stock Assessment ◽  
Assessment Method ◽  
Fish Stocks ◽  
Stock Status ◽  
North East ◽  
The North ◽  
Stock Biomass ◽  
Uncertainty Estimates ◽  
Stock Assessments ◽  
Spawning Stock

Many methods exist to assess the fishing status of data-limited stocks; however, little is known about the accuracy or the uncertainty of such assessments. Here we evaluate a new size-based data-limited stock assessment method by applying it to well-assessed, data-rich fish stocks treated as data-limited. Particular emphasis is put on providing uncertainty estimates of the data-limited assessment. We assess four cod stocks in the North-East Atlantic and compare our estimates of stock status (F/Fmsy) with the official assessments. The estimated stock status of all four cod stocks followed the established stock assessments remarkably well and the official assessments fell well within the uncertainty bounds. The estimation of spawning stock biomass followed the same trends as the official assessment, but not the same levels. We conclude that the data-limited assessment method can be used for stock assessment and that the uncertainty estimates are reliable. Further work is needed to quantify the spawning biomass of the stock.

scholarly journals Applying a two-stage Bayesian dynamic model to a short lived species, the anchovy in the Aegean Sea (Eastern Mediterranean). Comparison with an Integrated Catch at Age stock assessment model.

2014 ◽  
Vol 15 (2) ◽  
pp. 350 ◽  
Author(s):  
M. GIANNOULAKI ◽  
L. IBAIBARRIAGA ◽  
K. ANTONAKAKIS ◽  
A. URIARTE ◽  
A. MACHIAS ◽  
...  
Keyword(s):  
Egg Production ◽  
Missing Values ◽  
Stock Assessment ◽  
Eastern Mediterranean ◽  
Aegean Sea ◽  
Production Method ◽  
Assessment Model ◽  
Two Stage ◽  
Commercial Catch ◽  
The North

Two different stock assessment models were applied to the North Aegean Sea anchovy stock (Eastern Mediterranean Sea): an Integrated Catch at age Analysis and a Bayesian two-stage biomass based model. Commercial catch data over the period 2000-2008 as well as acoustics and Daily Egg Production Method estimates over the period 2003-2008 were used. Both models results were consistent, indicating that anchovy stock is exploited sustainably in relation to an exploitation rate reference point. Further, the stock biomass appears stable or increasing. However, the limitations in age-composition data, potential problems related to misinterpretation of age readings along with the existence of missing values in the survey data seem to favour the two-stage biomass method, which is based on a simplified age structure.  

Changes in Western mackerel (Scomber scombrus) spawning stock composition during the spawning season

1986 ◽  
Vol 66 (2) ◽  
pp. 367-383 ◽  
Author(s):  
Wendy A. Dawson
Keyword(s):  
North Sea ◽  
Stock Assessment ◽  
East Atlantic ◽  
The West ◽  
Scomber Scombrus ◽  
North East ◽  
The North ◽  
Spawning Stock ◽  
The North Sea ◽  
Central North Sea

INTRODUCTIONTwo groups of mackerel (Scomber scombrus L.) are recognised by the International Council for the Exploration of the Sea (I.C.E.S.) for stock assessment purposes in the north-east Atlantic. The North Sea ‘stock’, which overwinters along the edge of the Norwegian Trench and spawns off the south coast of Norway, in the Skagerrak, Kattegat and the central North Sea (Hamre, 1980), and the Western ‘stock’, which overwinters and spawns along the edge of the continental shelf from the west of Ireland to the Bay of Biscay (Lockwood, Nichols & Dawson, 1981).

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