Catch and effort of the bluefin tuna purse-seine fishery in Turkish waters

Karakulak, Firdes

doi:10.1016/s0165-7836(04)00071-2

Cited by 5 publications

(7 citation statements)

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“…BFTs were collected from various purse‐seiners (19–62 m in length, 24–694 GRT, and 300–2610 hp engine; see Karakulak, 2004) using purse‐seine nets of about 1500 m at depths of 200 m with a stretched mesh size of 48 mm (see Hoşsucu et al., 2001) from late winter to early summer of 2003 off Antalya Bay (Levantine Sea).…”

Section: Methodsmentioning

confidence: 99%

Lengthâweight and lengthâlength relationships of the bluefin tuna,Thunnus thynnusL., in the Turkish part of the eastern Mediterranean Sea

Perçin

Akyol

2009

Journal of Applied Ichthyology

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Summary This study describes length–weight (LWR) and length–length relationships (LLR) of bluefin tuna (BFT), Thunnus thynnus, in the eastern Mediterranean (Levantine Sea). Fulton’s condition factor (K) was also calculated for each standard length class for both sexes. A total of 363 specimens, 175 males and 188 females, were caught by purse‐seine from late winter to early summer 2003 off Antalya Bay, Turkey. Fork length values of 175 BFT males were between 114 and 250 cm with an average of 159.3 cm ± 2.14, and between 116 and 256 cm with an average of 163 cm ± 2.26 in 188 females. LWRs indicated positive allometric growth in both males and females. The coefficient b ranged from a minimum 3.32 for males to a maximum of 3.35 for females. Results indicated that the LLRs were highly correlated (r2 > 0.99, P < 0.001). K values ranged from 1.45 to 2.11 (mean: 1.56 ± 0.12) in males and from 1.43 to 2.14 (mean: 1.69 ± 0.06) in females.

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Section: Methodsmentioning

confidence: 99%

Lengthâweight and lengthâlength relationships of the bluefin tuna,Thunnus thynnusL., in the Turkish part of the eastern Mediterranean Sea

Perçin

Akyol

2009

Journal of Applied Ichthyology

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“…Here, exploitation also intensified during the 1950s through the development of a purse-seine fleet (Iyigungor, 1957). After the 1970s, poor catches forced BFT fishing fleets into the Sea of Marmara and the Aegean (Karakulak and Oray, 2009;Ulman et al, 2020) while the ancient Dalian fishery ended completely (Karakulak, 2004). BFT are now rare in the Black Sea and in the Sea of Marmara but show signs of recovery (Di .…”

Section: Industrialisation and Expansion Throughout The Atlantic (19t...mentioning

confidence: 99%

Exploitation history of Atlantic bluefin tuna in the eastern Atlantic and Mediterranean—insights from ancient bones

Andrews

Natale²,

Bernal‐Casasola

et al. 2022

ICES Journal of Marine Science

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Overexploitation has directly, negatively affected marine fish populations in the past half-century, modifying not only their abundance but their behaviour and life-history traits. The recovery and resilience of such populations is dependent upon their exploitation history, which often extends back millennia. Hence, data on when exploitation intensified and how populations were composed in historical periods, have the potential to reveal long-term population dynamics and provide context on the baselines currently used in fisheries management and conservation. Here, we setup a framework for investigations on the exploitation history of Atlantic bluefin tuna (Thunnus thynnus; BFT) in the eastern Atlantic and Mediterranean by collating records of their zooarchaeological remains and critically reviewing these alongside the literature. Then, we outline how novel multidisciplinary applications on BFT remains may be used to document long-term population dynamics. Our review of literature provides clear evidence of BFT overexploitation during the mid-20th century ce. Furthermore, a strong case could be made that the intensification of BFT exploitation extends back further to at least the 19th century ce, if not the 13th–16th century ce, in the eastern Atlantic and Mediterranean. However, a host of archaeological evidence would suggest that BFT exploitation may have been intensive since antiquity. Altogether, this indicates that by the currently used management baselines of the 1970s, population abundance and complexity was already likely to have declined from historical levels, and we identify how biomolecular and morphometric analyses of BFT remains have the potential to further investigate this.

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“…Maximum sinking depth, averaged sinking speed, current speed at 10 m, current speed at 70 m, current speed at 120 m, daylight condition, upper depth of thermocline, longitude, latitude, and captain's experience were classified into 3 groups, representing factors which may affect the success rate on unassociated sets. All factors were selected in the light of previous studies (Green, 1967;SPC, 1989;Inada et al, 1997;Karakulak, 2004;Tang et al, 2017), and fishing success on each predictor variable was evaluated based on observed data before fitting a statistical model.…”

Section: Data Measurement and Treatmentmentioning

confidence: 99%

“…In tuna purse seine fisheries, a captain's fishing experience is an important factor that influences the result of a set to great extent (Karakulak, 2004). Logically, the captain's fishing experience should be proportional to his age and years working at sea.…”

Section: Captain's Experiencementioning

confidence: 99%

Untitled

Dai¹,

Wang²,

Staples³

et al. 2020

Turk. J. Fish. Aquat. Sci.

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The fishing strategies of tuna purse seine fleets in the equatorial western Pacific Ocean have been characterized by a reversion to pursuing free-swimming schools of skipjack (Katsuwonus pelamis) and yellowfin tuna (Thunnus albacares) in recent years. This has prompted industry to evaluate how to improve their fishing success on unassociated sets. In this study, we determined which potential factors had a significant impact on the fishing result using data collected by observers in the equatorial western Pacific Ocean. The results showed that fishing success was significantly influenced by the average sinking speed of the gear, daylight conditions, and current speed in deep layer. Fast sinking speed will reduce the chance of escape for schools under the sinking net, improving the success ratio. Success rates were higher during the periods of low light intensity, such as dusk. The net sinking speeds were affected by current speed in deep layer, which often were associated with low success rates. The influential factors and their relative influence were listed, which will help fishermen to more effectively transfer their efforts from associated sets towards unassociated sets, contributing to the sustainable use and conservation of tuna stocks in the equatorial western Pacific Ocean.

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Catch and effort of the bluefin tuna purse-seine fishery in Turkish waters

Cited by 5 publications

References 0 publications

Lengthâweight and lengthâlength relationships of the bluefin tuna,Thunnus thynnusL., in the Turkish part of the eastern Mediterranean Sea

Lengthâweight and lengthâlength relationships of the bluefin tuna,Thunnus thynnusL., in the Turkish part of the eastern Mediterranean Sea

Exploitation history of Atlantic bluefin tuna in the eastern Atlantic and Mediterranean—insights from ancient bones

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Catch and effort of the bluefin tuna purse-seine fishery in Turkish waters

Cited by 5 publications

References 0 publications

Lengthâweight and lengthâlength relationships of the bluefin tuna,Thunnus thynnusL., in the Turkish part of the eastern Mediterranean Sea

Lengthâweight and lengthâlength relationships of the bluefin tuna,Thunnus thynnusL., in the Turkish part of the eastern Mediterranean Sea

Exploitation history of Atlantic bluefin tuna in the eastern Atlantic and Mediterranean—insights from ancient bones

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Lengthâweight and lengthâlength relationships of the bluefin tuna,Thunnus thynnusL., in the Turkish part of the eastern Mediterranean Sea

Lengthâweight and lengthâlength relationships of the bluefin tuna,Thunnus thynnusL., in the Turkish part of the eastern Mediterranean Sea