| Themes | DiscardLess Case studies Description |
| Name of the indicator | Where the species are mostly discarded inside the case studies for the second gear (in the list of Gears sorted by the discards values of each gear for the last available year of data) |
| Definition | Discards estimated by species and statistical rectangle for the case study in 2013. |
| Objectives | View how discards by species are spatially distributed inside the case study and for one major gear |
| View | |
| Calculation description |
We used the landings weigth given by statistical rectangle and the discards ratio at the regulated area level (for each species/vessel length/gear/country/year strata)
We sum the total values of discards by gears and we filter the data for the 2nd more important gear in terms of total discards.
Using discards ratio and landings we estimate a total discards for each rectangle / species for the specific year using calculation described in the presentation part of the website.
|
| Reading guide | For each rectangle you get the Discards weigth for each of the 5 first major species. Other, merge discards weight of other species. |
| Data sources |
Data used to produce figures comes from the STECF dissemination tool . Details on data can be found in the Fisheries Dependent Information working group report and from the Mediterranean and Black sea report |
| Comments | Please note that time series might be incomplete for some countries/indicators. |
| Query |
with part1 as
(
select distinct country,annexe,reg_area,reg_gear,reg_gear_cod,species,year_d,rectangle,english_name,sum(A.landings) as landings,sum(discards)/(sum(discards)+sum(B.landings)) as tx_discards ,sum(discards) as discards
from landing_rect_sd A inner join discard_landings_sd B
using(country,annexe,reg_area,reg_gear,reg_gear_cod,species,year_d,vessel_length,specon) inner join cs_rectangles using(rectangle) left join asfis on (species=a_code)
where id_case=6 and annexe like 'MED' and country like 'GRC' and year_d=2014
and discards>0 group by country,annexe,reg_area,reg_gear_cod,reg_gear,species,year_d,rectangle,english_name order by year_d,sum(A.landings)
)
,part2 as
(
select country,annexe,reg_gear,reg_gear_cod,species,year_d,rectangle,english_name,landings,reg_area,case when tx_discards=1 then 0.99 else tx_discards end as tx_discards,discards from part1
)
,selection_engin as
(
select reg_gear,sum(discards) as VAL from part2 group by reg_gear order by VAL desc limit 1 offset 1
)
,part4 as
(
select distinct rectangle as LIEU,english_name as GROUPE,sum(((1/(1-tx_discards))*landings)-landings) as VAL,reg_gear from part2 inner join selection_engin using(reg_gear)
group by LIEU,GROUPE,reg_gear
)
,total as
(select GROUPE,sum(VAL) as tot from part4 group by GROUPE order by tot DESC limit 6)
,regroupement as
(select distinct LIEU,case when total.GROUPE is null then 'Other' else GROUPE end as GROUPE,VAL as VAL,reg_gear
from part4 left join total using(GROUPE))
select distinct LIEU,GROUPE,sum(VAL)/nb_year as VAL,reg_gear from regroupement,
(select count(distinct year_d) as nb_year from part1) tmp group by LIEU,GROUPE,nb_year,reg_gear
order by LIEU,GROUPE
|
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