scholarly journals Shark pelagic longline fishery in the Gulf of Gabes: Inter-decadal inspection reveals management needs

2019 ◽  
Vol 20 (3) ◽  
pp. 532 ◽  
Author(s):  
BÉCHIR SAIDI ◽  
SAMIRA ENAJJAR ◽  
SAMI KARAA ◽  
KHALED ECHWIKHI ◽  
IMED JRIBI ◽  
...  
Keyword(s):  
Minor Component ◽  
Conservation Strategies ◽  
Longline Fishery ◽  
Life Stages ◽  
Sandbar Shark ◽  
Gulf Of Gabes ◽  
Additional Species ◽  
Gulf Of Gabès ◽  
Catch Rates ◽  
Pelagic Longline

This study explores the status of exploited shark populations in the Gulf of Gabes in relation to fishing pressure, based on data pertaining to shark longline fishery, collected during two periods. Catch data from 48 and 96 pelagic longline sets collected, respectively, during 2007/2008 and 2016/2017, were used to compare species composition and catch rates between periods. Four species were recorded during 2007/2008, while 11 additional species of pelagic and demersal elasmobranchs along with teleosts were fished during 2016/2017. Elasmobranch species dominated the catches with 94% and 99.3% in terms of specimens number, respectively, during 2016/2017 and 2007/2008. The sandbar shark, Carcharhinus plumbeus, was the predominant species in catch (>84% of all fishes) during both periods. Two other species of sharks, Carcharhinus brevipinna and Isurus oxyrinchus, were relatively common, while the other species were a minor component. Despite the increase in terms of diversity pertaining to species captured during 2016/2017, the nominal catch rates of elasmobranch and C. plumbeus decreased by 39.17% and 42.21%, respectively, suggesting populations’ declines. In addition, size distribution analyses revealed that this fishery may opportunistically operate on breeding and nursery areas, which affect main species over most of their life stages. The mortality and hooking location proportions were species-specific, with some species having significant percentages of live specimens at the time of haulback, providing an opportunity to release the sensitive life stages. Given the described state of shark exploitations in the Gulf of Gabes, urgent and efficient fishery regulation measures and conservation strategies, together with further investigations, are required to allow changing the unregulated shark longline fishery to a sustainable one.

Are circle hooks effective management measures in the pelagic longline fishery for sharks in the Gulf of Gabès?

2020 ◽  
Vol 30 (6) ◽  
pp. 1172-1181
Author(s):  
Bechir Saidi ◽  
Khaled Echwikhi ◽  
Samira Enajjar ◽  
Sami Karaa ◽  
Imed Jribi ◽  
...  
Keyword(s):  
Longline Fishery ◽  
Effective Management ◽  
Gulf Of Gabes ◽  
Gulf Of Gabès ◽  
Management Measures ◽  
Pelagic Longline Fishery ◽  
Pelagic Longline

Elasmobranchs longline fisheries in the Gulf of Gabès (southern Tunisia)

2013 ◽  
Vol 94 (1) ◽  
pp. 203-210 ◽  
Author(s):  
K. Echwikhi ◽  
B. Saidi ◽  
M.N. Bradai
Keyword(s):  
Mitigation Measures ◽  
Specific Information ◽  
Sandbar Shark ◽  
Carcharhinus Plumbeus ◽  
Gulf Of Gabes ◽  
Gulf Of Gabès ◽  
Elasmobranch Species ◽  
Size Limits ◽  
Species Specific ◽  
Longline Fisheries

In Tunisia, elasmobranch landings have decreased substantially in recent years. Generally, species-specific information is largely unavailable for artisanal fisheries, but it is essential to increase knowledge and to ensure proper management of these species. This study analysed elasmobranch catches with longline fishery in the Gulf of Gabès. In total, 21 and 20 pelagic and bottom longline fishing trips were conducted, respectively, from July to September in 2007 and 2008. A total of eight elasmobranch species were caught: four batoids and four sharks. Pelagic longline captures were hooked externally while a high number of individuals captured with bottom longline were hooked internally. Discards due essentially to low commercial value and size represented 7.6% of total number of elasmobranch specimens caught. Longline landings in the Gulf of Gabès were principally composed of sandbar shark, Carcharhinus plumbeus, representing, respectively, 94.14% and 21.17% in number of pelagic and bottom longline captures. The importance of rhinobatids and Mustelus capture with bottom longline reflect their abundance in this area compared to other Mediterranean zones. Juveniles, including neonates with umbilical scars, dominated carcharhnids specimens, while smoothhound and guitarfish captures were dominated by mature individuals. Mitigation measures based on gear modifications, size limits and delineated nursery areas in the Gulf of Gabès should be developed to protect these vulnerable species.

scholarly journals A Comparison of Alternative Circle Hook (Kahle Hook) and J Style Hook Performance in Experimental Pelagic Longline Fishery in Turkey

2015 ◽  
pp. 19-27 ◽  
Author(s):  
Aytaç Özgül ◽  
Ali Ulaş ◽  
Altan Lök ◽  
F. Ozan Düzbastılar ◽  
Cengiz Metin
Keyword(s):  
Longline Fishery ◽  
Fish Catch ◽  
Study Circle ◽  
The Difference ◽  
Pelagic Longline Fishery ◽  
By Catch ◽  
Catch Rates ◽  
Longline Fisheries ◽  
Marine Wildlife ◽  
Pelagic Longline

In recent years, circle hooks have been encouraged as an alternative to traditional J-hooks in pelagic longline fisheries to minimize by-catch mortality and injury to sea turtles and other marine wildlife. Prior to this study, circle hooks had not been used by domestic commercial pelagic longliners in Turkey. The main objective of the study was to evaluate the efficiency of kahle hook comparing with J-style hook baited with sardine (Sardina pilchardus) in pelagic longline fishery in the Aegean coast of Turkey (Kuşadası Bay).We used conventional J-style hooks (Mustad 2315DT-4/0) and kahle hooks (Eagle Claw142A-6/0) for each fishing operation and compared catch rates, catch compositions of target and non-target species. The relative performance of kahle and traditional J-style hooks was tested during 22 valid pelagic longline fishing operations between August 2010 and December 2012. A total of 2200 hooks were used equally amongkahle and J-style hooks consecutively. Captured fish were identified, total and fork lengths were measured,weighed, the time of haulback, and hook type as well as by-catch fish were recorded. A total of 78 fish were caught belonging to 13 species during the samplings. The overall CPUE was 4.73 fishes per 100 hooks for kahle hooks and 2.46 fishes for J-style hooks. For the CPUE of all fishes, the difference was statistically significant (Z = -1.977; P<0.05), in favour of the kahle hook being almost two times greater than the J-style hook. Likewise CPUE was 17007.69 g per 100 hooks for kahle style hooks and 4807.27 g for J-style hooks (Z = -1.997; P<0.05). While no difference was found between two hook models on by-catch species, kahle hooks were more efficient in comparison to J hooks on discard species. Swordfish (Xiphiasgladius) had the highest CPUE (2.82) among all species for kahle hooks followed by silver scabbard fish (Lepidopuscaudatus), 0.64. For J-style hooks, silver scabbard fish catch had the highest CPUE (0.64) followed by swordfish (0.55).

Interactions of loggerhead turtle with bottom longline fishery in the Gulf of Gabès, Tunisia

2011 ◽  
Vol 92 (4) ◽  
pp. 853-858 ◽  
Author(s):  
Khaled Echwikhi ◽  
Imed Jribi ◽  
Mohamed Nejmeddine Bradai ◽  
Abderrahmen Bouain
Keyword(s):  
Loggerhead Turtle ◽  
Mitigation Measures ◽  
Longline Fishery ◽  
Target Species ◽  
Gulf Of Gabes ◽  
Awareness Campaign ◽  
Gulf Of Gabès ◽  
Gear Modification ◽  
By Catch ◽  
In The Beginning

In the Gulf of Gabès (Tunisia), a fleet of bottom longliners operates in summer and in the beginning of autumn targeting groupers. This fleet interacts with loggerhead turtles. During twenty trips in which 48,020 hooks were deployed, a total of 16 loggerheads were captured, most of them were juveniles, and direct mortality was estimated to be 43.75%. During the fishing operation, the hauling of the gear started one to three hours after and sometimes occurred immediately after setting. Results obtained show that the soak time did not affect the capture of turtles and target species, whereas it influenced the mortality rate of turtles. Bottom longline should be studied more in depth throughout the Mediterranean Sea, as well as parameters related to the interaction with sea turtles. However, mitigation measures to reduce turtle by-catch are urgently needed. In this way, we propose: (i) reducing the fishing soak time; (ii) experimenting with gear modification such as the use of circle hooks; and (iii) conducting an awareness campaign aimed at fishermen to show them how to deal with turtle by-catch.

scholarly journals Tori lines mitigate seabird bycatch in a pelagic longline fishery

2021 ◽  
Author(s):  
Eric Gilman ◽  
Milani Chaloupka ◽  
Asuka Ishizaki ◽  
Mathew Carnes ◽  
Hollyann Naholowaa ◽  
...  
Keyword(s):  
Longline Fishery ◽  
Pelagic Longline Fishery ◽  
Pelagic Longline
Sign in / Sign up

Export Citation Format

Share Document