scholarly journals Multiple-Phase Biometric Relationships and Sexual Maturity in the Atlantic Bluefin Tuna, Thunnus thynnus (Osteichthyes: Scombridae)

Animals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 390
Author(s):  
Giambattista Bello ◽  
Nicoletta Santamaria ◽  
Aldo Corriero
Keyword(s):  
Sexual Maturity ◽  
Fork Length ◽  
Bluefin Tuna ◽  
Change Points ◽  
Growth Equation ◽  
Regression Equations ◽  
Body Proportion ◽  
Atlantic Bluefin Tuna ◽  
Multiple Phase ◽  
Section Surface

Most fish undergo distinct growth phases during ontogenesis. An extremely important passage from the juvenile to adult phase occurs at the onset of sexual maturity, which shows in body proportion and/or growth rate changes. These can be detected as change-points in biometric relationships. In this paper, the Atlantic bluefin tuna was analyzed to verify whether its somatic proportions show any sign of discontinuity during growth, i.e., whether any change-points may be detected in its somatic proportions. This fish has never been examined in this respect, and single-phase models, which are indeed easier to both compute and apply, are used in stock analyses. The following somatic relationships were analyzed in Atlantic bluefin tuna captured in the Mediterranean Sea between 1998 and 2010: “fork length–weight” regression, the von Bertalanffy growth equation, and “first dorsal spine cross section surface–fork length” regression. All of the examined relationships were found to be best modelled by multiple-phase regression equations, and all of them showed a change-point within the range of 101–110 cm fork length, which corresponds to 3–4 years of age. The present results, based on reproductive state-independent analyses, corroborate the disputed hypothesis that Atlantic bluefin tuna from the eastern stock in fact reproduce for the first time at this age.

scholarly journals Sexual maturity in western Atlantic bluefin tuna

2014 ◽  
Vol 4 (1) ◽  
Author(s):  
Gilad Heinisch ◽  
Hanna Rosenfeld ◽  
Jessica M. Knapp ◽  
Hillel Gordin ◽  
Molly E. Lutcavage
Keyword(s):  
Sexual Maturity ◽  
Bluefin Tuna ◽  
Western Atlantic ◽  
Atlantic Bluefin Tuna

scholarly journals Temporal distribution of size and weight of fattened Bluefin tuna (Thunnus thynnus l.) from Tunisian farms: (2005-2010)

2013 ◽  
Vol 15 (1) ◽  
pp. 115 ◽  
Author(s):  
A. HATTOUR ◽  
W. KOCHED
Keyword(s):  
Fork Length ◽  
Weighted Average ◽  
Temporal Distribution ◽  
Bluefin Tuna ◽  
Thunnus Thynnus ◽  
Length Frequency ◽  
Average Value ◽  
Atlantic Bluefin Tuna ◽  
Straight Line ◽  
The Mean

The present study analysis size and weight-frequency composition of Atlantic bluefin tuna (Thunnus thynnus thynnus) fattened in Tunisian farms for the period 2005-2010 and compare these morphometric parameters with those from wild bluefin tuna landed on 2001 at Sfax port (Tunisia). A total of 6,757 wild and fattened bluefin tuna were measured as straight-line fork length and 49,962 were weighted. Average value of K for wild BFT was 1.59 and respectively 2.43, 2.32, 2.15, 1.61, 1.79 and 1.90 for Fattened BFT after 5-6 months from 2005 to 2010. Length frequency of fattened bluefin showed clearly a substantial increase in juvenile rate. The percentage which was 21.4% in 2005 reached 31.3% in 2009. For weight distribution, 73.3% of the fish caught in 2001 are below the annual mean (75.7 kg), while means 71 to 72% of fattened fish were under annual mean weight. Year 2009 is exceptional because only 57% of fattened fish were under the mean weight. This demonstrates that the fish caught are becoming increasingly small. Mean weight for fattening period (77 to 124 kg) are obviously higher than those of the wild fish (75,7kg).This study showed an increment in the amount of specimen under first sexual maturity which will not have the chance to spawn.

scholarly journals Surfacing and vertical behaviour of Atlantic bluefin tuna (Thunnus thynnus) in the Mediterranean Sea: implications for aerial surveys

2020 ◽  
Vol 77 (5) ◽  
pp. 1979-1991
Author(s):  
Robert Klaus Bauer ◽  
Fabien Forget ◽  
Jean-Marc Fromentin ◽  
Manuela Capello
Keyword(s):  
Mediterranean Sea ◽  
Fork Length ◽  
Bluefin Tuna ◽  
Aerial Survey ◽  
Thunnus Thynnus ◽  
Survey Period ◽  
Atlantic Bluefin Tuna ◽  
Aerial Surveys ◽  
Gulf Of Lion ◽  
Nw Mediterranean

Abstract Atlantic bluefin tuna (Thunnus thynnus) (ABFT) frequently engage in surface basking and foraging behaviour that makes them detectable from afar. This behaviour is utilized for the development of fisheries-independent abundance indices based on aerial surveys, although changes in the surface-feeding dynamics of ABFT are not yet accounted for. We investigated the daytime surfacing behaviour of ABFT at different temporal and vertical resolutions based on 24 individuals (117–158 cm fork length), tagged with pop-up archival tags in the Gulf of Lion, NW-Mediterranean Sea between 2015 and 2016. The results suggest that ABFT remain usually <2 min continuously within the visible surface (0–1 m) during daytime. ABFT presence in the 0–1 and 0–20 m layers varied over time and between individuals but showed a seasonal decline towards autumn with the breakdown of thermal stratification. Furthermore, the rate of surfacing events was highly correlated with the time spent in the 0–20 m layer. Geolocation estimates confirm a strong site fidelity of ABFT during the aerial survey period (August–October) in the Gulf of Lion. Our results support the choice of the survey region and period, but related indices should account for the seasonality of ABFT surface behaviour [i.e. the time spent in the 0–20 m layer.

scholarly journals Select biological characteristics of the mossul bleak Alburnus mossulensis Heckel, 1843(Actinopterygii: Cyprinidae) in the Ataturk Dam Lake, Turkey

2018 ◽  
Vol 65 (4) ◽  
Author(s):  
Arif Parmaksız ◽  
Ahmet Oymak ◽  
Necmettin Dogan ◽  
Erhan Unlu
Keyword(s):  
Sexual Maturity ◽  
Condition Factor ◽  
Age Groups ◽  
Fork Length ◽  
Biological Characteristics ◽  
Regression Equations ◽  
Reproductive Characteristics ◽  
Absolute Fecundity ◽  
Weight Relationship ◽  
Atatürk Dam Lake

Maturity, growth and reproductive characteristics of the mossul bleak Alburnus mossulensis, from Ataturk Dam Lake (Euphrates) were assessed. Maturity composition of the analysed samples varied between age groups I and VII. The ratio of females to males was 1.047:1. Fork length of the samples varied between 40-198 mm and weights were in the range of 0.45-68 g. The regression equations derived for the length-weight relationship was Log W = -5.5531+3.2958 Log FL (r2=0.9593) for females and Log W=-5.3695+3.2112 Log FL (r2=0.9487) for males. Mean condition factor was determined as 1.069 for females and 1.062 for males. Absolute fecundity was established to be between 288 and 3380. The age of sexual maturity was 3 years in females and 2 years in males.

scholarly journals Automatic Bluefin Tuna Sizing with a Combined Acoustic and Optical Sensor

Sensors ◽  
2020 ◽  
Vol 20 (18) ◽  
pp. 5294
Author(s):  
Pau Muñoz-Benavent ◽  
Vicente Puig-Pons ◽  
Gabriela Andreu-García ◽  
Víctor Espinosa ◽  
Vicente Atienza-Vanacloig ◽  
...  
Keyword(s):  
Computing Time ◽  
Fork Length ◽  
Bluefin Tuna ◽  
Stereoscopic Vision ◽  
Optical Data ◽  
Real Time Processing ◽  
Acoustic Data ◽  
Atlantic Bluefin Tuna ◽  
Video Frames ◽  
Processing Techniques

A proposal is described for an underwater sensor combining an acoustic device with an optical one to automatically size juvenile bluefin tuna from a ventral perspective. Acoustic and optical information is acquired when the tuna are swimming freely and the fish cross our combined sensor’s field of view. Image processing techniques are used to identify and classify fish traces in acoustic data (echogram), while the video frames are processed by fitting a deformable model of the fishes’ ventral silhouette. Finally, the fish are sized combining the processed acoustic and optical data, once the correspondence between the two kinds of data is verified. The proposed system is able to automatically give accurate measurements of the tuna’s Snout-Fork Length (SFL) and width. In comparison with our previously validated automatic sizing procedure with stereoscopic vision, this proposal improves the samples per hour of computing time by 7.2 times in a tank with 77 juveniles of Atlantic bluefin tuna (Thunnus thynnus), without compromising the accuracy of the measurements. This work validates the procedure for combining acoustic and optical data for fish sizing and is the first step towards an embedded sensor, whose electronics and processing capabilities should be optimized to be autonomous in terms of the power supply and to enable real-time processing.

scholarly journals Tracking Atlantic bluefin tuna from foraging grounds off the west coast of Ireland

2020 ◽  
Vol 77 (6) ◽  
pp. 2066-2077
Author(s):  
Thomas W Horton ◽  
Barbara A Block ◽  
Alan Drumm ◽  
Lucy A Hawkes ◽  
Macdara O’Cuaig ◽  
...  
Keyword(s):  
North Atlantic ◽  
West Coast ◽  
Time Series Data ◽  
Fork Length ◽  
Bluefin Tuna ◽  
Series Data ◽  
Future Research ◽  
The West ◽  
Northeast Atlantic ◽  
Atlantic Bluefin Tuna

Abstract Pop-up archival tags (n = 16) were deployed on Atlantic bluefin tuna (ABT) off the west coast of Ireland in October and November 2016 (199–246 cm curved fork length), yielding 2799 d of location data and 990 and 989 d of depth and temperature time-series data, respectively. Most daily locations (96%, n = 2651) occurred east of 45°W, the current stock management boundary for ABT. Key habitats occupied were the Bay of Biscay and the Central North Atlantic, with two migratory patterns evident: an east-west group and an eastern resident group. Five out of six tags that remained attached until July 2017 returned to the northeast Atlantic after having migrated as far as the Canary Islands, the Mediterranean Sea (MEDI) and the Central North Atlantic. Tracked bluefin tuna exhibited a diel depth-use pattern occupying shallower depths at night and deeper depths during the day. Four bluefin tuna visited known spawning grounds in the central and western MEDI, and one may have spawned, based on the recovered data showing oscillatory dives transecting the thermocline on 15 nights. These findings demonstrate the complexity of the aggregation of ABT off Ireland and, more broadly in the northeast Atlantic, highlighting the need for dedicated future research to conserve this important aggregation.

scholarly journals Otolith shape variation provides a marker of stock origin for north Atlantic bluefin tuna (Thunnus thynnus)

2016 ◽  
Vol 67 (7) ◽  
pp. 1023 ◽  
Author(s):  
Deirdre Brophy ◽  
Paula Haynes ◽  
Haritz Arrizabalaga ◽  
Igaratza Fraile ◽  
Jean Marc Fromentin ◽  
...  
Keyword(s):  
North Atlantic ◽  
Stock Assessment ◽  
Fork Length ◽  
Bluefin Tuna ◽  
Shape Variation ◽  
Thunnus Thynnus ◽  
Mixing Rate ◽  
Otolith Shape ◽  
Atlantic Bluefin Tuna ◽  
Significant Difference

Two stocks of bluefin tuna (Thunnus thynnus) inhabit the north Atlantic; the western and eastern stocks spawn in the Gulf of Mexico and the Mediterranean Sea respectively. Trans-Atlantic movements occur outside spawning time whereas natal homing maintains stock structure. Commercial fisheries may exploit a mixed assemblage of both stocks. The incorporation of mixing rates into stock assessment is precluded by uncertainties surrounding stock discrimination. Otolith shape descriptors were used to characterise western and eastern stocks of Atlantic bluefin tuna in the present study and to estimate stock composition in catches of unknown origin. Otolith shape varied with length and between locations and years. Within a restricted size range (200–297-cm fork length (FL)) the two stocks were distinguished with an accuracy of 83%. Bayesian stock mixture analysis indicated that samples from the east Atlantic and Mediterranean were predominantly of eastern origin. The proportion assigned to the eastern stock showed slight spatial variation; however, overlapping 95% credible intervals indicated no significant difference (200–297cm FL: central Atlantic, 73–100%; Straits of Gibraltar, 73–100%; Morocco, 50–99%; Portugal 64–100%). Otolith shape could be used in combination with other population markers to improve the accuracy of mixing rate estimates for Atlantic bluefin tuna.

Review of Sexual Maturity in Atlantic Bluefin Tuna, Thunnus thynnus (Linnaeus, 1758)

2019 ◽  
Vol 28 (2) ◽  
pp. 182-192 ◽  
Author(s):  
Aldo Corriero ◽  
Gilad Heinisch ◽  
Hanna Rosenfeld ◽  
Ivan Katavić ◽  
Letizia Passantino ◽  
...  
Keyword(s):  
Sexual Maturity ◽  
Bluefin Tuna ◽  
Thunnus Thynnus ◽  
Atlantic Bluefin Tuna

Tracking the fidelity of Atlantic bluefin tuna released in Canadian waters to the Gulf of Mexico spawning grounds

2015 ◽  
Vol 72 (11) ◽  
pp. 1700-1717 ◽  
Author(s):  
Steven G. Wilson ◽  
Ian D. Jonsen ◽  
Robert J. Schallert ◽  
James E. Ganong ◽  
Michael R. Castleton ◽  
...  
Keyword(s):  
Gulf Of Mexico ◽  
Fork Length ◽  
Bluefin Tuna ◽  
Deepwater Horizon ◽  
Series Data ◽  
Spawning Grounds ◽  
Atlantic Bluefin Tuna ◽  
Drilling Rig ◽  
Archival Tags ◽  
The Mean

The objective of this study was to advance the use of pop-up satellite archival tags to track the migrations of Atlantic bluefin tuna (Thunnus thynnus) to their spawning grounds. Deployment of tags occurred in the Gulf of St. Lawrence, Canada, during fall months from 2007 to 2013. Pop-up satellite archival tags (n = 135) were attached to 125 Atlantic bluefin tuna (curved fork length (CFL) = 268 ± 20 cm (mean ± SD)) with the objective of keeping tags on until visitation to a spawning area or longer. A dataset of 18 800 days was acquired, which included 5800 days of time-series data from 19 recovered satellite tags. Many Atlantic bluefin tuna visited the Gulf of Mexico spawning grounds (74%), the mean size of which was 275 ± 14 cm (CFL ± SD, n = 49), with a measured CFL of 243 to 302 cm. These fish had a mean entry date into the Gulf of Mexico of 14 January ± 42 days (SD). The mean residency period for fish that had tracks with entrance and exit from the Gulf of Mexico was 123 ± 49 days (SD) (n = 22). Atlantic bluefin tuna that moved into the Gulf of Mexico during the spawning season remained west of the 45°W meridian for the duration of the track. Electronic tagging datasets from two fish were obtained before, during, and after the Deepwater Horizon oil spill. Both fish utilized habitat in the vicinity of the Macondo Well on 20 April 2010 when the Deepwater Horizon oil drilling rig accident occurred. Spawning hotspots are identified in the Gulf of Mexico using kernel density analyses and compared with the newly established closed areas.

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