Size Selectivity of Active Fishing Gear: Changes in Size, Age and Growth of Cirrhinus Mrigala from the Ganga River, India

2017 ◽  
Vol 08 (03) ◽  
Author(s):  
Amitabh Chandra Dwivedi ◽  
Priyanka Mayank ◽  
Ashish Tiwari
Keyword(s):  
Ganga River ◽  
Age And Growth ◽  
Fishing Gear ◽  
Size Selectivity ◽  
Cirrhinus Mrigala

Study on age and growth of Indian Major carp (Labeo rohita) from the Ganga River

2020 ◽  
Vol 9 (si) ◽  
pp. 276-279
Author(s):  
Amitabh Chandra Dwivedi ◽  
Priyanka Mayank ◽  
Vipin Kumar Misra ◽  
Shri Prakash ◽  
Asheesh Shivam Mishra
Keyword(s):  
Labeo Rohita ◽  
Ganga River ◽  
Age And Growth ◽  
Indian Major Carp

Age and Growth of Spotted Snakehead, Channa punctata from the Ganga River

2019 ◽  
Vol 59 (2) ◽  
pp. 197-204 ◽  
Author(s):  
M. A. Khan ◽  
S. Khan ◽  
Ankita ◽  
I. Ahmed ◽  
M. Nadeem
Keyword(s):  
Ganga River ◽  
Age And Growth ◽  
Channa Punctata

scholarly journals A general catch comparison method for multi-gear trials: application to a quad-rig trawling fishery for Nephrops

2017 ◽  
Vol 74 (5) ◽  
pp. 1458-1468 ◽  
Author(s):  
D. Browne ◽  
C. Minto ◽  
R. Cosgrove ◽  
B. Burke ◽  
D. McDonald ◽  
...  
Keyword(s):  
Comparison Method ◽  
Fishing Gear ◽  
Comparison Study ◽  
Size Selectivity ◽  
Modeling Framework ◽  
Modeling Methods ◽  
Mixed Effects Modeling ◽  
Management Measures ◽  
Main Driver ◽  
Catch Rates

Expeditious uptake of quad-rig trawling in the economically important Irish fishery for Nephrops norvegicus outpaced technical understanding of this newly introduced gear. The main driver for its introduction is increased catch rates of Nephrops. Higher Nephrops discard rates associated with quad-rig trawling are likely to be problematic under the landing obligation unless size selectivity can be improved. Catch comparison methods are suitable for assessing the performance of fishing gear modifications to reduce discards. Utilizing a quad-rig potentially increases the number of gears that can be included in a catch comparison study to four but current modeling methods are limited to two gears. Our study provides a new general multinomial mixed effects modeling framework that can be applied to two or more gears, elucidates how case-specific and choice-specific covariates may influence catch at length, and facilitates discussion on appropriate gear based management measures. Application of the method to catches from four different cod-end mesh sizes revealed significant effects of carapace length, catch weight and net position, on the numbers of Nephrops retained in each cod-end. Results suggest that management measures which specifically address different catch profiles associated with different numbers of trawling rigs are required to optimize Nephrops size selectivity.

scholarly journals Using vertical distribution to separate fish from crustaceans in a mixed species trawl fishery

2019 ◽  
Vol 76 (10) ◽  
pp. 1781-1794 ◽  
Author(s):  
Junita Diana Karlsen ◽  
Ludvig Ahm Krag ◽  
Bent Herrmann ◽  
Henrik Skaarup Lund
Keyword(s):  
Vertical Distribution ◽  
Separation Efficiency ◽  
Fishing Gear ◽  
Relative Height ◽  
Size Selectivity ◽  
Mixed Species ◽  
Nephrops Norvegicus ◽  
Trawl Fishery ◽  
Successful Separation ◽  
Commercial Species

A major challenge in mixed fisheries is achieving acceptable size selectivity for morphologically different species using the same fishing gear. Separator trawls can have different selective properties in the upper and lower compartments and provide successful separation of species. We used a horizontally divided codend with small square meshes (40 mm) and a simple frame to stimulate fish to swim into the upper compartment. The majority of the fish were separated successfully from Nephrops (Nephrops norvegicus), but their preference were uniform. Less than 10% of the Nephrops entered the upper compartment. Length-based analysis revealed three patterns of separation efficiency among nine commercial species: length-dependent separation and preference for the upper or lower compartments. The separation efficiency should be improved for small roundfish and flatfish. There was little diel effect on the separation efficiency. The preference of fish for a compartment, taking the relative height of that compartment into account, was established for this and similar previous studies to enable comparison of results. We recommend length-based analysis to account for the fished population when interpreting results.

Size Selectivity of Passive Fishing Gear: A Correction for Encounter Probability Applied to Gill Nets

1984 ◽  
Vol 41 (8) ◽  
pp. 1252-1255 ◽  
Author(s):  
Lars G. Rudstam ◽  
John J. Magnuson ◽  
William M. Tonn
Keyword(s):  
Swimming Speed ◽  
Sampling Period ◽  
Fishing Gear ◽  
Size Selectivity ◽  
Fish Size ◽  
Encounter Probability ◽  
Power Corrections ◽  
Gill Net ◽  
Coregonus Artedii ◽  
Coregonus Hoyi

The probability of catching a fish in a gill net may be separated into two components: (1) the probability of the fish encountering the net and (2) the probability of the fish being caught and retained in the net. We consider the probability of encounter to be directly proportional to the distance travelled by the fish during the sampling period. This distance will increase with fish size if different-sized fish swim for the same amount of time because swimming speed increases with fish size. Routine swimming speed measured in the laboratory for three size-classes of bloater (Coregonus hoyi) increased with length to the 0.8 power. Corrections for encounter probability were incorporated in gill net selectivity calculations for samples of cisco (Coregonus artedii), a species closely related to bloater. These corrections can significantly increase the proportional estimates of smaller relative to larger animals in the estimated population structure. The approach should also be applicable to other passive fishing gear, such as longlines and set nets.

scholarly journals On changing the size selectivity of fishing gear for Chionoecetes opilio in the Japan Sea.

1987 ◽  
Vol 53 (7) ◽  
pp. 1173-1179 ◽  
Author(s):  
Masatosi Sinoda ◽  
Tetsuro Ikuta ◽  
Atsushi Yamazaki
Keyword(s):  
Japan Sea ◽  
Fishing Gear ◽  
Size Selectivity ◽  
Chionoecetes Opilio ◽  
The Japan Sea

scholarly journals Catch and size selectivity of small-scale fishing gear for the smooth-hound shark Mustelus mustelus (Linnaeus, 1758) (Chondrichthyes: Triakidae) from the Aegean Turkish coast

2010 ◽  
Vol 11 (2) ◽  
pp. 213 ◽  
Author(s):  
T. CEYHAN ◽  
O. HEPKAFADAR ◽  
Z. TOSUNOGLU
Keyword(s):  
Mesh Size ◽  
Catch Rate ◽  
Small Scale ◽  
Fishing Gear ◽  
Size Selectivity ◽  
Small Scale Fisheries ◽  
By Catch ◽  
Catch Composition

Catch rate, CPUE, biomass ratios and size selectivity from traditional longline and trammel nets of Turkish coastal small-scale fisheries were investigated in order to describe the Smooth-hound shark (Mustelus mustelus) fishery. The SELECT method was used to estimate the selectivity parameters of a variety of models for the trammel nets inner panel of 150 and 170 mm mesh sizes. Catch composition and proportion of the species were significantly different in longline and trammel nets. While mean CPUE of longline was 119.2±14.3 kg/1000 hooks, these values for 150 and 170 mm trammel nets were 5.3±1.2 kg/1000 m of net and 12.7±3.9 kg/1000 m of net, respectively. Biomass ratios of the by catch to Smooth-hound catch were found to be 1:0.32 for 150 mm trammel net, 1:0.65 for longline and 1:0.73 for 170 mm trammel net. The estimated modal lengths and spreads were found to be 91.1 and 16.2 cm for 150 mm and 103.2 and 18.4 cm for 170 mm, respectively. The modal lengths of the species as well as the spread values increased with mesh size.

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