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Fri Oct 30 23:40:49 -0700 2020

DOI 10.3750/AIP2011.42.2.06

Turkish driftnet fishery for Albacore, thunnus alalunga, and incidental catches in the eastern Mediterranean


n = 13 +- 1.6 per 1000 m per day
90 +- 11 kg per 1000 m per day

individual nets 2000-7200 m
vessels
LOA 10.5-34m
GT 7-148
engine 25-1300 kW


cite: Krakaluk reported 18 vessels from 14-25m and 149-373 kw
      albacore 77% by number and 97% by mass

http://www.fao.org/fishery/fishtech/1011/en
reports driftnets are typ 20-30m height

Rope 23 tex / 21# multifilament nylon 170mm stretched mesh, 300-600 mesh deepness
= 23 g / 1000 m
http://www.louisianasportnets.com/netting.htm
reports #21 is 1.65 mm dia
210/21 denier

denier is "mass in grams per 9000 m" for some reason
210/21 means 21 filaments, totaling 210 grams per 9000 m = 23 tex = 23 g/km

assuming 80% elongation, that tells us 40-80m!!

Biomass and number ratios of the non-target species to the target albacore were
1 : 0.59 kg and 1 : 0.31 specimens, respectively (Table 2).

Table 2 reverses that:
Albacore : non-target
fish 1 : 0.31	1 : 0.59  <- table is correct

so we have catch -> effort, gear -> mass that's it
ugh. fishing days per year?? forgot to look.


let's assume a 50% hanging ratio so 1 km @ 170mm stretched = 11764 mesh width, 300-600 mesh deepness = 1200 km of twine per km
at 23 tex that is a shocking 27.6 TONS of nylon per km!!!???
148 GT vessel
but 7 km would exceed 148 GT

23 g/km = 27 kg of nylon. you idiot.


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Wed Nov 25 01:48:13 -0800 2020

This omits floats and leadlines, which probably add significant weight

floats are ~20g each

