Diurnal patterns in Gulf of Mexico epipelagic predator interactions with pelagic longline gear: implications for target species catch rates and bycatch mitigation

2017 ◽  
Vol 93 (2) ◽  
pp. 573-589 ◽  
Author(s):  
EricS Orbesen ◽  
Derke Snodgrass ◽  
GeoffreyS Shideler ◽  
CraigA Brown ◽  
JohnF Walter
Keyword(s):  
Gulf Of Mexico ◽  
Target Species ◽  
Diurnal Patterns ◽  
Predator Interactions ◽  
Catch Rates ◽  
Pelagic Longline

Fish and invertebrate by-catch in the crab pot fishery in the Isle of Man, Irish Sea

2017 ◽  
Vol 98 (8) ◽  
pp. 2099-2111
Author(s):  
Fikret Öndes ◽  
Michel J. Kaiser ◽  
Lee G. Murray
Keyword(s):  
Irish Sea ◽  
Target Species ◽  
Catch Per Unit Effort ◽  
Isle Of Man ◽  
Ecosystem Effects ◽  
By Catch ◽  
Catch Rates ◽  
Taxonomic Groups ◽  
Catch Composition ◽  
Autumn And Winter

Baited trap or pot fisheries are considered to have relatively few wider ecosystem effects on the marine environment, particularly when compared with towed mobile fishing gear. However, this assumption is rarely tested in the field. This study aimed to determine the composition of non-target species that occur in crustacean pots and to assess spatial and temporal differences in catches in the waters around the Isle of Man, Irish Sea. The data were collected using fishery independent surveys and a questionnaire study. Based on fishery independent surveys, a total of five taxonomic groups and 43 species occurred as by-catch. The dominant by-catch species was velvet crab Necora puber. The by-catch per unit effort (BPUE) for all of the non-target species was low particularly in comparison to towed bottom gear fisheries around the Isle of Man. BPUE of species composition varied considerably between different locations around the Isle of Man. The results of both the fishery independent and questionnaire data suggested that the by-catch rates varied with season with peak BPUE occurring in spring which then declined into autumn and winter. By-catch composition did not decrease significantly with an increasing target species catch. Overall, by-catch was low relative to target species catch which may be partially attributable to the use of escape panels in pot fisheries in the Isle of Man.

scholarly journals Reducing unwanted catches of trammel nets: experimental results of the “guarding net” in the caramote prawn, Penaeus kerathurus, small-scale fishery of the Ligurian Sea (western Mediterranean)

2018 ◽  
Vol 82 (S1) ◽  
pp. 131 ◽  
Author(s):  
Paolo Sartor ◽  
Daniel Li Veli ◽  
Francesco De Carlo ◽  
Alessandro Ligas ◽  
Andrea Massaro ◽  
...  
Keyword(s):  
Experimental Study ◽  
Economic Loss ◽  
Western Mediterranean ◽  
Small Scale ◽  
Target Species ◽  
Ligurian Sea ◽  
Sorting Time ◽  
Labour Costs ◽  
By Catch ◽  
Catch Rates

This study aimed to test the effectiveness of a “guarding net”, a device placed at the bottom of a trammel net, for reducing unwanted catches in the caramote prawn trammel net fishery of the Ligurian Sea. This specialized and profitable fishery is affected by unwanted catches that generate high discard rates and damage to the nets, with environmental impacts and costs for fishermen. The experimental study consisted in comparing the catches of a standard trammel net (STN) with those of two “experimental” trammel nets, e.g. STNs provided with a guarding net of 19 cm (TGN20) and 24 cm height (TGN25), respectively. The guarding net, a strip of gillnet placed at the bottom of the net, can be considered a by-catch reducer device (BRD). Some fishermen of the investigated fishery have been using this device for several years. The results of the 15 experimental fishing trials performed from June to July 2016 indicate that the guarding nets significantly reduce discards (e.g. crabs and other invertebrates); the biomass of the unwanted species caught was 75% lower than that produced by the STN. The catch rates of the target species obtained with TGN20 and TGN25 were also significantly lower than those of the STN, though of a lesser amount. Nonetheless, this economic loss can be compensated by the decrease in sorting time and material and labour costs that can be achieved using the guarding net.

scholarly journals Efficiency changes in bottom trawling for flatfish species as a result of the replacement of mechanical stimulation by electric stimulation

2020 ◽  
Author(s):  
Jan-Jaap Poos ◽  
Niels T Hintzen ◽  
Jacco C van Rijssel ◽  
Adriaan D Rijnsdorp
Keyword(s):  
European Union ◽  
Electric Stimulation ◽  
The European Union ◽  
Target Species ◽  
Bottom Trawling ◽  
Small Vessels ◽  
Main Target ◽  
The Difference ◽  
Catch Rates ◽  
Large Vessels

Abstract Although fishing with electricity is illegal in the European Union, a number of temporary licences allowed converting beam trawlers to pulse trawling. To analyse how the adaption of pulse trawling changed this fishery, we studied fishing speeds and landings per unit effort as proxies for catch efficiencies for the main target species. Compared to conventional tickler chain beam trawls, pulse trawls were towed at lower speeds (small vessels −10%, large vessels −23%). Large vessels that switched from conventional beam trawls to pulse trawls at the end of 2009 gradually increased catch efficiency for sole over the period of almost 1 year. While pulse trawling was found to have higher catch rates (kg/h) for sole (small vessels +74%, large vessels +17%), lower catch rates were observed for plaice (small vessels −31%, large vessels −32%). Vessels that switched later achieved immediate gains in catch efficiency for sole. The change in catch efficiency is likely due to the difference in cramp response between the species.

At-sea factors that affect yellowfin tuna grade in the Gulf of Mexico pelagic longline tuna fishery

2015 ◽  
Vol 164 ◽  
pp. 59-63 ◽  
Author(s):  
Daniel G. Foster ◽  
Glenn R. Parsons ◽  
Derke Snodgrass ◽  
Arvind Shah
Keyword(s):  
Gulf Of Mexico ◽  
Yellowfin Tuna ◽  
Pelagic Longline ◽  
Tuna Fishery

Size selectivity and catch rates of two small coastal shark species caught on circle and J hooks in the northern Gulf of Mexico

2013 ◽  
Vol 147 ◽  
pp. 145-149 ◽  
Author(s):  
Kristin M. Hannan ◽  
Alex Q. Fogg ◽  
William B. Driggers ◽  
Eric R. Hoffmayer ◽  
G. Walter Ingram ◽  
...  
Keyword(s):  
Gulf Of Mexico ◽  
Shark Species ◽  
Size Selectivity ◽  
Northern Gulf Of Mexico ◽  
Catch Rates

Calculation of untrawlable areas within the boundaries of a bottom trawl survey

2003 ◽  
Vol 60 (6) ◽  
pp. 657-669 ◽  
Author(s):  
Mark Zimmermann
Keyword(s):  
Relative Abundance ◽  
Species Group ◽  
Bottom Trawl ◽  
Trawl Survey ◽  
Gis Analysis ◽  
Target Species ◽  
Abundance Estimates ◽  
Original Target ◽  
Catch Rates ◽  
Trawl Surveys

A geographic information system (GIS) analysis of 5039 bottom trawl events from U.S. west coast bottom trawl surveys (1977–1998) estimated that the survey area was about 77% trawlable but five of the 30 strata were less than 50% trawlable. Untrawlable areas, by definition, cannot be surveyed with the bottom trawl; however, there has never been a means of identifying and excluding these areas from relative abundance estimates, which are calculated only from hauls completed in the trawlable portions of each stratum. Unknown amounts of untrawlable habitat are a problem for relative abundance estimation in many bottom trawl surveys. This manuscript describes one method of using the bottom trawling events of a survey, such as ripped-up hauls and abandoned stations, to calculate the amount of area that is untrawlable. A comparison of catch rates between undamaged tows and a limited number of damaged tows, which are normally discarded as faulty samples, showed that Sebastes catch rates were generally higher in damaged tows. Thus untrawlable areas may have substantial importance on relative abundance estimates of Sebastes, the original target species group for this survey.

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