Change of relative fishing power index from technological development in the otter trawl fishery

2020 ◽  
Vol 56 (1) ◽  
pp. 26-36
Author(s):  
Hyun-Su JO ◽  
Young-Il SEO ◽  
Taeg-Yun OH ◽  
Young-Su AN ◽  
Byung-Yeob KIM ◽  
...  
2019 ◽  
Vol 55 (3) ◽  
pp. 198-205 ◽  
Author(s):  
Young-Il SEO ◽  
Taeg-Yun OH ◽  
Hyung-Kee CHA ◽  
Byung-Yeob KIM ◽  
Hyun-Su JO ◽  
...  

2019 ◽  
Vol 76 (6) ◽  
pp. 1554-1566
Author(s):  
Fabien Pointin ◽  
Fabienne Daurès ◽  
Marie-Joëlle Rochet

Abstract The EU Landing Obligation (LO) is designed to reduce bycatch (i.e. unwanted catch) through more selective fishing practices, such as avoidance behaviours which consist in allocating fishing effort to other species, fishing grounds or seasons. Incentives for fishers to change their behaviours depend on their economic performances as well as their ability to avoid bycatch. Changes in economic performances under the LO are evaluated based on cost and revenue equations. The nested grid method is then used to explore the spatial and temporal distribution of landings and discards, and to suggest alternative effort allocation to avoid bycatch. This article is focussed specifically on the French otter trawl fishery in the eastern English Channel and southern North Sea. Results suggest that under the LO the choke species problem will curtail fishing activities earlier in the year, leading to significant economic losses. In the absence of significant quota top-ups (at least 75%), a change in fishing practices consisting in reducing overall bycatch by 30% is insufficient to reduce losses. With a particular attention to choke species, more economically efficient avoidance strategies can be found thanks to the nested grid method.


2017 ◽  
Vol 74 (6) ◽  
pp. 1660-1671 ◽  
Author(s):  
Caroline Methling ◽  
Peter V. Skov ◽  
Niels Madsen

Abstract The reformed European Common Fisheries Policy introduced a discard ban, with a possibility of exempting species where a high discard survival can be demonstrated. This necessitates a validation of the methods used for estimating the discard mortality of candidate species. In this study, we assess whether reflex impairment can predict short-term mortality in commercially trawled European plaice upon landing and after air exposure of up to 90 min. Sub-lethal stress was assessed by a suite of physiological variables. Over a 10-day period, mortality was monitored for a total of 199 plaice following trawl and air exposure of varying duration, and for 50 control fish scored for reflex impairment on board the vessel. Mortality was only observed in fish exposed to air for >60 min, and averaged 11.1% (95% CI = 7.1–16.3%). Reflex impairment was found to be a significant (P < 0.001) predictor of mortality in a generalized linear model, excluding other initially included variables by using a stepwise method. Plasma cortisol, haematocrit, and plasma osmolality all indicated a profound and increasing level of stress with air exposure, accompanied by a near depletion of muscle phosphocreatine and nucleotides. Fishing site had an unexpected, but significant (p < 0.05) effect on stress levels, which was also reflected in reflex impairment and mortality. Based on these findings, a possible exemption from the discard ban should include considerations on the duration of air exposure.


2020 ◽  
Vol 224 ◽  
pp. 105431
Author(s):  
Elsa Cuende ◽  
Luis Arregi ◽  
Bent Herrmann ◽  
Manu Sistiaga ◽  
Iñigo Onandia
Keyword(s):  

2017 ◽  
Vol 29 (5) ◽  
pp. 1640-1647 ◽  
Author(s):  
Taeg-Yun OH ◽  
Young-Il SEO ◽  
Kang-Seok HWANG ◽  
Hyung-Kee CHA ◽  
Hyun-Su JO ◽  
...  

2016 ◽  
Vol 73 (4) ◽  
pp. 1104-1114 ◽  
Author(s):  
M. Kurtis Trzcinski ◽  
W. Don Bowen

Abstract Atlantic halibut (Hippoglossus hippoglossus) have a long history of exploitation in the Northwest Atlantic and have gone through several periods of high biomass followed by a population crash. An assessment model using data collected on the Scotian Shelf and southern Grand Banks shows that the population peaked in 1984, then decreased sharply to a low in 1993. Several management measures were taken during the decline, including reductions in total allowable catch and a minimum size limit. Concurrently, removals by the otter trawl fishery were drastically reduced following the collapse of the cod (Gadus morhua) fishery. In 2003, recruitment increased and continued to be high for 6 years. Fishing mortality rates were moderate in the late 1990s and 2000s and the population increased. By 2009, the Atlantic halibut population was highly productive with both high biomass and high levels of recruitment. The coincidence in the timing of population recovery and management actions indicates that effective management contributed to the recovery of Atlantic halibut.


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