Covering up the by-catch problem

Nature ◽  
2017 ◽  
Vol 550 (7676) ◽  
pp. 304-304
Keyword(s):  
By Catch

Survival of by-catch from a beam trawl

1995 ◽  
Vol 126 ◽  
pp. 31-38 ◽  
Author(s):  
MJ Kaiser ◽  
BE Spencer
Keyword(s):  
Beam Trawl ◽  
By Catch

The Cost of Fishing on Juveniles of Finfish and Shellfish: Assessment of Economic Impacts of Trawl Juvenile by-Catch along the Coast of North Andhra Pradesh, India

2021 ◽  
Vol 37 (1) ◽  
pp. 409-426
Author(s):  
Pralaya Ranjan Behera ◽  
Shubhadeep Ghosh ◽  
K. Sree Ramulu ◽  
Muktha Menon ◽  
M. A. Jishnudev ◽  
...  
Keyword(s):  
Andhra Pradesh ◽  
Economic Impacts ◽  
By Catch ◽  
The Cost

scholarly journals Effect of Cutting Ratio and Catch on Drag Characteristics and Fluttering Motions of Midwater Trawl Codend

2021 ◽  
Vol 9 (3) ◽  
pp. 256
Author(s):  
Wei Liu ◽  
Hao Tang ◽  
Xinxing You ◽  
Shuchuang Dong ◽  
Liuxiong Xu ◽  
...  
Keyword(s):  
Drag Force ◽  
Mesh Size ◽  
Current Speed ◽  
Midwater Trawl ◽  
Minimum Drag ◽  
Fish Catch ◽  
Spatial Geometry ◽  
By Catch ◽  
Trawl Fisheries ◽  
Crucial Part

The codend of a trawl net is the rearmost and crucial part of the net for selective fish catch and juvenile escape. To ensure efficient and sustainable midwater trawl fisheries, it is essential to better understand the drag characteristics and fluttering motions of a midwater trawl codend. These are generally affected by catch, cutting ratio, mesh size, and twine diameter. In this study, six nylon codend models with different cutting ratios (no cutting, 6:1, 5:1, 4:1, 7:2, and 3:1) were designed and tested in a professional flume tank under two conditions (empty codends and codends with catch) and five current speeds to obtain the drag force, spatial geometry, and movement trend. As the cutting ratio of empty codends decreased, the drag force decreased, and the drag coefficient increased. The unfolding degree of codend netting and the height of empty codends were found to be directly proportional to the current speed and inversely proportional to the cutting ratio. The positional amplitude of codend with cutting ratio 4:1 was the smallest for catch. The drag force of codends with catch increased as the current speed increased, and first decreased and then increased as the cutting ratio decreased. To ensure the best stability and minimum drag force of the codend, it is recommended to use the 4:1 cutting ratio codend.

scholarly journals In Utero Exposure to Δ9-Tetrahydrocannabinol Leads to Postnatal Catch-Up Growth and Dysmetabolism in the Adult Rat Liver

2021 ◽  
Vol 22 (14) ◽  
pp. 7502
Author(s):  
Shelby L. Oke ◽  
Kendrick Lee ◽  
Rosemary Papp ◽  
Steven R. Laviolette ◽  
Daniel B. Hardy
Keyword(s):  
Mitochondrial Dysfunction ◽  
Animal Studies ◽  
Weight Ratio ◽  
Wistar Rat ◽  
Hepatic Function ◽  
Fetal Life ◽  
Adult Rat ◽  
Catch Up ◽  
By Catch

The rates of gestational cannabis use have increased despite limited evidence for its safety in fetal life. Recent animal studies demonstrate that prenatal exposure to Δ9-tetrahydrocannabinol (Δ9-THC, the psychoactive component of cannabis) promotes intrauterine growth restriction (IUGR), culminating in postnatal metabolic deficits. Given IUGR is associated with impaired hepatic function, we hypothesized that Δ9-THC offspring would exhibit hepatic dyslipidemia. Pregnant Wistar rat dams received daily injections of vehicular control or 3 mg/kg Δ9-THC i.p. from embryonic day (E) 6.5 through E22. Exposure to Δ9-THC decreased the liver to body weight ratio at birth, followed by catch-up growth by three weeks of age. At six months, Δ9-THC-exposed male offspring exhibited increased visceral adiposity and higher hepatic triglycerides. This was instigated by augmented expression of enzymes involved in triglyceride synthesis (ACCα, SCD, FABP1, and DGAT2) at three weeks. Furthermore, the expression of hepatic DGAT1/DGAT2 was sustained at six months, concomitant with mitochondrial dysfunction (i.e., elevated p66shc) and oxidative stress. Interestingly, decreases in miR-203a-3p and miR-29a/b/c, both implicated in dyslipidemia, were also observed in these Δ9-THC-exposed offspring. Collectively, these findings indicate that prenatal Δ9-THC exposure results in long-term dyslipidemia associated with enhanced hepatic lipogenesis. This is attributed by mitochondrial dysfunction and epigenetic mechanisms.

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 Actual conditions of discards of by-catch from small-scale trawl fishery in Ariake Sea

2003 ◽  
Vol 69 (3) ◽  
pp. 330-336 ◽  
Author(s):  
YOSHIO HIRAI ◽  
HIDEYUKI NISHINOKUBI
Keyword(s):  
Small Scale ◽  
Ariake Sea ◽  
Trawl Fishery ◽  
By Catch

Schooling behaviour of jack mackerel, Trachurus declivis (Jenyns), observed in the Tasmanian purse seine fishery

1993 ◽  
Vol 44 (4) ◽  
pp. 577 ◽  
Author(s):  
H Williams ◽  
G Pullen
Keyword(s):  
School Size ◽  
East Coast ◽  
Diurnal Changes ◽  
Jack Mackerel ◽  
Schooling Behaviour ◽  
Summer Schools ◽  
By Catch ◽  
Catch Rates ◽  
Lunar Effects ◽  
Purse Seine Fishery

The seasonal, lunar and diurnal changes in schooling of jack mackerel were examined using log-book information collected from an industrial fishery off the east coast of Tasmania between 1985 and 1989. School size increased significantly from spring to autumn. The ratio between surface and subsurface schools encountered by the fishery also changed seasonally. Surface schools predominate during summer, whereas subsurface schools become more frequent during autumn. The fishery was predominantly a day fishery and no lunar effects on catch rates or fishing intensity were detected. Catches mainly comprised jack mackerel, although redbait (Emmelichthys nitidus Richardson) and blue mackerel (Scomber australasicus Cuvier) were a significant by-catch. In summer, schools were almost exclusively composed of jack mackerel, but in other seasons mixed schools were found. Data presented, together with evidence from other sources, suggest that the availability of schools to the fishery may be closely related to the availability of feed.

scholarly journals Habitat use patterns of franciscana dolphins (Pontoporia blainvillei) off southern Brazil in relation to water depth

2009 ◽  
Vol 89 (5) ◽  
pp. 943-949 ◽  
Author(s):  
Daniel Danilewicz ◽  
Eduardo R. Secchi ◽  
Paulo H. Ott ◽  
Ignacio B. Moreno ◽  
Manuela Bassoi ◽  
...  
Keyword(s):  
Habitat Use ◽  
Rio Grande ◽  
Limiting Factors ◽  
Small Scale ◽  
Southern Brazil ◽  
Rio Grande Do Sul ◽  
Use Patterns ◽  
Management Procedures ◽  
By Catch ◽  
Pontoporia Blainvillei

The patterns of habitat use by the franciscana dolphins (Pontoporia blainvillei) along its distribution are poorly known. This study investigates the patterns of habitat use with respect to depth for 181 individuals of different age, size, gender and reproductive condition off Rio Grande do Sul, southern Brazil. The results reveal that franciscanas are very homogeneously distributed according to depth. Individuals from all lengths utilize nearly the entire range of depths of the surveyed area. Larger or older animals do not use deeper waters than younger animals, indicating that body size and age are not limiting factors for franciscanas that occupy deeper or offshore waters. Gestation seems to not cause a change in the distribution of females. Although the sex-ratio of the overall data did not vary from 1:1 in different depth intervals, a small-scale comparison between the northern and southern coast demonstrated the existence of some kind of sexual segregation. Franciscana by-catch in Rio Grande do Sul is not sustainable and it is agreed that management procedures are needed. Nevertheless, the available data on species distribution do not allow the designing of a protected area in order to minimize the by-catches of a particular sex/reproductive class.

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