Evaluation of Hook and Bait Type on the Catch Rates in the Western North Atlantic Ocean Pelagic Longline Fishery

2012 ◽  
Vol 88 (3) ◽  
pp. 529-545 ◽  
Author(s):  
Daniel G Foster ◽  
Sheryan P Epperly ◽  
Arvind K Shah ◽  
John W Watson
Keyword(s):  
Atlantic Ocean ◽  
North Atlantic ◽  
North Atlantic Ocean ◽  
Longline Fishery ◽  
Pelagic Longline Fishery ◽  
Catch Rates ◽  
Pelagic Longline

scholarly journals Analysis of marine mammal bycatch in the Uruguayan pelagic longline fishery operating in the Southwestern Atlantic Ocean

2015 ◽  
Vol 72 (5) ◽  
pp. 1637-1652 ◽  
Author(s):  
Cecilia Passadore ◽  
Andrés Domingo ◽  
Eduardo R. Secchi
Keyword(s):  
Atlantic Ocean ◽  
Marine Mammals ◽  
Population Decline ◽  
Additive Models ◽  
Longline Fishery ◽  
Southwestern Atlantic ◽  
Southwestern Atlantic Ocean ◽  
Pelagic Longline Fishery ◽  
The Impact ◽  
Pelagic Longline

Abstract Bycatch is one of the main causes of human-caused mortality and population decline of many marine mammals. Monitoring bycatch is the first step to understand the impact of the fisheries on the species affected. Understanding how the interaction between marine mammals and fishing operations varies in space and time, and how it is influenced by environmental variables, is essential for designing mitigation strategies to reduce bycatch mortality. In this paper, we use data gathered by scientific observers and a fishing skipper to analyse marine mammals bycatch by the Uruguayan pelagic longline fishery operating in the Southwestern Atlantic Ocean from 1996 to 2007. The total bycatch per unit effort (Bcpue) was 0.0150 marine mammals/1000 hooks and the highest values (∼0.2) were recorded between 37°–38°S and 49°–51°W. Total cetacean Bcpue during the study period was low (0.0051 cetacean/1000 hooks) and occurred between 32°–37°S and 46°–54°W. Generalized additive models showed that cetaceans' bycatch was mainly affected by the depth, sea surface temperature, and season. Although cetaceans were captured year-round, the highest values were registered in spring months, most bycatch events occurred over the continental slope (median = 619 m) and in waters with a median temperature of 19.7°C. The bycatch of pinnipeds was influenced by depth, location, and season. Pinniped bycatch occurred mainly in winter, in waters ranging from 80 to 5000 m of depth (median = 2366 m) between 34°–37°S (median = 35.9°S) and 54°–49°W (median = 51.8°W). The spatial analysis showed that most bycatch events occurred within the Brazil–Malvinas Confluence zone, an area of high productivity where the pelagic longline fleet concentrates its fishing effort and where marine mammals probably concentrate to feed.

A comparison of circle hook and J hook performance in a western equatorial Atlantic Ocean pelagic longline fishery

2011 ◽  
Vol 107 (1-3) ◽  
pp. 39-45 ◽  
Author(s):  
J.C. Pacheco ◽  
D.W. Kerstetter ◽  
F.H. Hazin ◽  
Humberto Hazin ◽  
R.S.S.L. Segundo ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
Longline Fishery ◽  
Equatorial Atlantic ◽  
Equatorial Atlantic Ocean ◽  
Pelagic Longline Fishery ◽  
Pelagic Longline

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).

scholarly journals Horizontal and vertical movements of immature dusky sharks Carcharhinus obscurus in relation to commercial longline fisheries in the western North Atlantic Ocean

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Andrea M. Kroetz ◽  
Simon J. B. Gulak ◽  
John K. Carlson
Keyword(s):  
North Carolina ◽  
Atlantic Ocean ◽  
North Atlantic ◽  
North Atlantic Ocean ◽  
Fishing Effort ◽  
Depth Range ◽  
Incidental Capture ◽  
Carcharhinus Obscurus ◽  
Longline Fisheries ◽  
Pelagic Longline

Abstract Background Many species of sharks, including the dusky shark Carcharhinus obscurus, are often incidentally captured in commercial pelagic and bottom longline fisheries. Incidental capture can lead to at-vessel or post-release mortality and can be detrimental to populations of threatened, endangered, or prohibited species. The estimated at-vessel mortality for dusky sharks can be high in longline fisheries and, to minimize mortality, time–area closures have been designated in the western North Atlantic Ocean to mitigate interactions with longline fisheries, yet incidental capture of dusky sharks is still common. We compared the vertical and horizontal movements of dusky sharks to the overall fishing effort and depth fished of commercial pelagic and bottom longline fisheries to determine when and where overlap is present that could lead to incidental capture. Results Twenty-one (n = 21) dusky sharks were tagged with pop-up archival transmitting satellite tags and all were immature animals (123–200 cm FL) apart from two individuals (230 and 300 cm FL). Sharks were tagged off the coasts of North Carolina (71%) and Florida (29%). Twenty tags (95%) reported and provided tracks between 1 and 107 days (median 15 days) and 10 tags (50%) remained on sharks for > 4 days. Most individuals remained within the bottom longline closed area off the coast of North Carolina during their time at liberty. Dusky sharks primarily occupied the 20–40 m depth range 26% of the time, and overlapped with bottom and pelagic longline gears 41% and 59% of the time, respectively. Overlap was highest in the winter and spring for both commercial fisheries. Conclusions The use of archival satellite telemetry in this study has provided valuable preliminary information on vertical and horizontal movements of immature dusky sharks in western North Atlantic Ocean. Dusky sharks may be more vulnerable to incidental capture in the pelagic longline fishery due to the high fishing effort, larger areas of horizontal overlap, and greater percentage of vertical overlap. This information will inform mitigation measures of commercial longline fisheries, which can work toward population rebuilding of the species.

scholarly journals An overview of the hooking mortality of elasmobranchs caught in a swordfish pelagic longline fishery in the Atlantic Ocean

2012 ◽  
Vol 25 (4) ◽  
pp. 311-319 ◽  
Author(s):  
Rui Coelho ◽  
Joana Fernandez-Carvalho ◽  
Pedro G. Lino ◽  
Miguel N. Santos
Keyword(s):  
Atlantic Ocean ◽  
Longline Fishery ◽  
Pelagic Longline Fishery ◽  
Pelagic Longline

scholarly journals Depredation by killer whale (Orcinus orca) and false killer whale (Pseudorca crassidens) on the catch of the Uruguayan pelagic longline fishery in Southwestern Atlantic Ocean

2015 ◽  
Vol 72 (5) ◽  
pp. 1653-1666 ◽  
Author(s):  
Cecilia Passadore ◽  
Andrés Domingo ◽  
Eduardo R. Secchi
Keyword(s):  
Atlantic Ocean ◽  
Killer Whale ◽  
Orcinus Orca ◽  
Longline Fishery ◽  
Southwestern Atlantic ◽  
Killer Whales ◽  
Southwestern Atlantic Ocean ◽  
Pelagic Longline Fishery ◽  
Pseudorca Crassidens ◽  
Pelagic Longline

Abstract This study analyses depredation by killer whales (Orcinus orca) and false killer whales (Pseudorca crassidens) on catches of the Uruguayan pelagic longline fishery in the Southwestern Atlantic Ocean between 1998 and 2007. Data were collected by scientific observers from the National Observer Program of the Tuna Fleet operating in the area between 19°–40.5°S and 20°–54°W. Depredation occurred in 67 of the 1029 sets and was restricted to the area from 25°–40.5°S to 27°–53°W, though larger proportions of depredation (DP: percentage of total fish caught damaged by cetaceans) were observed in the Brazil–Malvinas (Falkland) Confluence area (34°–37°S and 51°–53°W) where most of the fishing effort was concentrated. Depredation occurred year-round though intra-annual variability in its intensity was recorded. The overall DP was 0.37% and was slightly higher in autumn. The spatial analysis showed that DP within grids of 1 × 1° was homogeneous and generally &lt;2.5%. Ten out of 57 fish species caught by the fishery were depredated by cetaceans. Swordfish (Xiphias gladius) showed the highest DP per species (1.17%). Using the frequency of resources selectivity index of Ivlev, it was determined that swordfish was selected as a preferred prey in 43.9% of the sets with depredation. Generalized linear models indicated that distance to coast, year, and vessel were significant variables in explaining the number of fish depredated per fishing event. The presence of killer whales in the fishing ground seems not to affect the catch per unit effort by the longline fishery. The losses caused by depredation of cetaceans on the catch are low with probably minor economic effects to the Uruguayan longline fishing industry.

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