- Видео 16
- Просмотров 15 441
Oceans Explained
Великобритания
Добавлен 7 мар 2022
Struggling with a difficult concept? Can't quite understand a definition? Oceans Explained is here to answer all of the marine biological and oceanographic concepts, theories and questions that aren't explained anywhere else!
Length measurements of snow crab (Chionoecetes opilio) merus leg segment
Detailed explanation of how to identify the merus segment of the 1st walking leg of snow crab (Chionoecetes opilio) and how to take an accurate length measurement.
Samples were collected using standard snow crab pots during the 2024 snow crab survey conducted by the Norwegian Institute of Marine Research in the Barents Sea, to inform the snow crab stock assessment.
Music Sources
Onceagain, bensound.com
JuliusH, Calm waves, pixabay.com
Samples were collected using standard snow crab pots during the 2024 snow crab survey conducted by the Norwegian Institute of Marine Research in the Barents Sea, to inform the snow crab stock assessment.
Music Sources
Onceagain, bensound.com
JuliusH, Calm waves, pixabay.com
Просмотров: 138
Видео
Surplus Production Models (SPM) - What they are and how to calculate - Fisheries Stock Assessment
Просмотров 6427 месяцев назад
This video provides a detailed explanation of what surplus production models (SDMs) are, when they are used and the data requirements, including how to reach estimates of biological parameters including r (growth rate), k (carrying capacity) and initial biomass. The equations of the model are broken down step by step and 'translated' into simple to understand R code. Model outputs are explained...
Model Selection - Fisheries Stock Assessment and Management
Просмотров 81611 месяцев назад
Which type of model to use when? This video summarises the main groups of stock assessment models, including surplus production, length and cohort/age based models and virtual population analysis (VPA) and the types of data required for each. Detailed explanation of surplus production models: ruclips.net/video/DE4Q82QgSBs/видео.html Music Sources Creative minds, bensound.com Juliush, pixabay.com
Length measurements of snow crab (Chionoecetes opilio)
Просмотров 604Год назад
Detailed explanation of how to take measurements of carapace width and the length and height of the right claw of snow crab (Chionoecetes opilio). Samples were collected using a bottom trawl during the 2023 winter survey conducted by the Norwegian Institute of Marine Research in the Barents Sea. Music Sources Creativeminds, bensound.com Juliush, pixabay.com
How to determine the developmental stage of snow crab (Chionoecetes opilio) eggs
Просмотров 630Год назад
Detailed description of each of the three main observable stages of egg development in snow crab (Chionoecetes opilio). Samples were collected using a bottom trawl during the 2023 winter survey conducted by the Norwegian Institute of Marine Research in the Barents Sea. Music Sources Creative minds, bensound.com Juliush, pixabay.com
Determining the sex and stage of maturity of snow crab (Chionoecetes opilio)
Просмотров 432Год назад
Detailed description of how to distinguish between male and female snow crab (Chionoecetes opilio) as well as between juvenile and sexually mature individuals. Samples were collected using a bottom trawl during the 2023 winter survey conducted by the Norwegian Institute of Marine Research in the Barents Sea. Music Sources Onceagain, bensound.com Juliush, pixabay.com
Calculating catch per unit effort for different gears - Fisheries Stock Assessment and Management
Просмотров 2,5 тыс.Год назад
Explanation of what catch per unit effort (CPUE) is and how to calculate it. Also includes an overview of the typical ways of accounting for effort in different types of fisheries, including longline, gill net, purse seine, trawling and pot and trap fisheries. The importance of calculating CPUE instead of relying on landings data alone is highlighted through the use of the big eye tuna (Thunnus...
ICCAT Swordfish stock assessment - sample preparation for age and growth analysis
Просмотров 432 года назад
Step by step explanation of how swordfish (Xiphias gladius) samples collected by observers from onboard Portuguese commercial longline vessels are prepared for further analysis. Includes the processing of liver and gonads for histology and egg quality analysis and the preparation of samples for DNA analysis. Samples were collected as part of an ICCAT project and processed at IPMA, Olhão. The su...
ICCAT Swordfish stock assessment - removal of anal fin spines and preparation for ageing
Просмотров 482 года назад
Step by step explanation of how anal fin spines from swordfish (Xiphias gladius) samples collected by observers from onboard Portuguese commercial longline vessels are prepared for further analysis. Includes the heating of the fins and correct way to remove the flesh without damaging the spines. Samples were collected as part of an ICCAT project and processed at IPMA, Olhão. The subsequent data...
Stable Isotope Sample Preparation
Просмотров 4492 года назад
Step by step breakdown of how to weigh samples for stable isotope analyses and how to select the desired weights. The size of the receptacle for each sample is discussed as well as how to secure the powdered samples and correctly prepare these for analysis. @IMBRSea Professional Practice 2022
Selectivity Curves - Fisheries Stock Assessment and Management
Просмотров 7212 года назад
Explanation of what selection curves are and how they relate to the terms 'selection' and 'selectivity' in the context of fisheries management. The example of different mesh sizes of both gillnets and the codend of trawls in the north-east Atlantic cod fishery (Gadus morhua) is used to show what typical selection curves can look like. Reasons for the use of selection curves are discussed, inclu...
Defining Selectivity - Fisheries Stock Assessment and Management
Просмотров 5522 года назад
Explanation of the terms 'selection' and 'selectivity' in relation to fisheries management. The three main processes that determine selection in fisheries and the factors that drive these are broken down and discussed. Specifically, the importance of temporal and spatial overlap of the fished population with the gear and the accessibility and vulnerability of the target species to the gear. Mus...
Defining Gear Selectivity - Fisheries Stock Assessment and Management
Просмотров 6432 года назад
Explanation of what gear selection or selectivity is in relation to fisheries science and why it is important. Includes description of size selection and species selection by gear and why this results in the recorded catch having a different size and species composition to the fished population. Music Sources Creative minds, bensound.com Juliush, pixabay.com
Calculating Hanging Ratio for gill nets - Definition and Explanation
Просмотров 5 тыс.2 года назад
Explanation of how to calculate hanging ratio (E) for gill nets and how differing levels of net flexibility, tension and mesh shape impacts and relates to size and species selectivity, catching efficiency and bycatch. Examples given include the cod fishery in northern Norway, size selectivity of blue ling and the sole fishery around The Gambia. Image Sources: Gabis, G., Kelpsaite, L., Parkins, ...
Defining Fish Stocks - Fisheries Stock Assessment and Management
Просмотров 1,4 тыс.2 года назад
Explanation of what a fish stock is, how it is defined and why being able to distinguish fish stocks is important for sustainable fisheries management. Factors discussed include the geographical limits, gene pools and species identified.
Knife Edge Selection Curve - Fisheries Stock Assessment and Management
Просмотров 4802 года назад
Knife Edge Selection Curve - Fisheries Stock Assessment and Management
Great content as always. Thank you for your great work!
Thank you, so good to hear!
I really like your videos and great channel :), any idea when the next one is coming out?
Your videos regarding fisheries are amazing and full of knowledge, keep growing
Thank you! I'm glad they are helpful :)
make a video whow to ring a net ,if possible .
Thanks for the request - happy to tailor it to specific deployment methods/target species
Wow, thank you this is such a good explanation!
Thanks, glad I could help!
hi, i'm from Indonesia. thanx for the explanation
Glad I could help!
Next video explaining how to determine none biary crabs please 🙏 🦀🌈🦀
Fantastic! Very informative!!
Cantankerous crabs can't cancan. Coincidentally cephalopods can, Careening comically, captivating curves clinging closely. Callous crustations cringe conceding crossly, claws click clacking cryptically, cephalopods can cause captivating carbuncles, carousing carnival celebrities consensually. Crippling crab centenary celebrations continually. Crustations cautiously collaborate, could conceivably consider controlling culprits callously, considering constraint candidly convenient contextually. Clever Chionoecetes conclaves caught cephalopod cancan crew completely, calling convicted criminals, "Colossal C**ts". Charming!
It's all crab
Its all crab.
It's all crab, isn't it...
i dont know how i got here but 🦀
0:50 is not right picture. E=0,7 for central image E 0,3(or0,5) for image on the left And image on the right the net hanging on E= 0,9 ))
Hi! Thanks for your comment - hanging ratio is calculated by the length of the headrope divided by the stretched length of the mesh, using the same units for both. In this example, I have kept the length of the headrope as '1 meter' for all three examples. Therefore for the first image, dividing 1 meter by 1.4 meters gives a hanging ratio of 0.7 (unitless). This is repeated for all three examples, so 1/2 is 0.5 and 1/3 is 0.3...
@@oceans_explained коэффициент вы определяете правильно. Но ваши изображения не соответствуют значению коэффициента, При E=0,7 (0,71) форма ячейки стремится к квадрату, всё по теореме Пифагора. Этому соответствует изображение в центре. При E=0 сеть не имеет длины. При E=1 сеть не имеет высоты.
@@vladnet4748Mozhno s vami svezatsja po emailu?
Captavating, award winning content to make your ancestors proud!
Keep up the good work. These videos are wonderful!!
Thanks! Any suggestions for future topics are welcome!
🐟🐠🐋🐬🦈🐙
11/10 Would show my Gran!!
This channel just gets better and better. Bravo!
Oscar worthy content right here!!!
Such a masterpiece
Nice job Gennie!