Dual wield even on the sea-Pursuing high fishing gear performance and excellent environmental consideration“UMI”&“NAGISA”Foundation

We are currently developing fishing gear (pipes) used for oyster farming using "polylactic acid" as a raw material. It is difficult to completely stop the pipes as theyflow out into the sea due to accidental events such as storms or collisions of ships
with oyster rafts. In response to this situation, we are developing so-called "dualwield" pipes that have high performance as fishing gear and environmentally frien
dly properties. Specifically, we are working on the development of pipes (fishing gear) that are digested in the stomach even if they are eaten by seabirds and whales, and are decomposed by bacteria after a certain number of years in the sea.

Conditions for "new oyster pipe"① The existing production line can be used
② The price is the same as the current product③ Be strong④ Do not spread after outflow⑤ Non-toxic or low toxicity⑥ Being able to digest quickly in the body
⑦ Biodegradation is gradualWe have selected "polylactic acid," a pl
ant-derived material, as a material thathas the potential to meet the above seven conditions.
At the time of manufacture, oyster pip
es made of polylactic acid met the above
conditions ①, ④, ⑤ and ⑥.
For this reason, we verified ③ and ⑦of the above conditions in the verification test at the oyster farm.
As a result of the verification, it wasfound that the condition ③ is not sticky
and easily cracked. Regarding condition⑦, it was found that the biodegradation
speed was too fast (weight decreased by
30% in 1.5 years in seawater).
For this reason, regarding ③, we asked Nichimo Co., Ltd. to improve it and provided us with a new oyster pipe madeby adding a plasticizer to polylactic acid.
The results of the on-site verification w
ere good, and we were able to meet thecondition ③ without any problems. On t
he other hand, in order to satisfy the condition of ⑦, further ingenuity is requir
ed in the future.

The possibilities of "polylactic acid" are further expanded
・This material can be used not only foroyster pipes, but also for other types of fishing gear.
・Nichimo Co., Ltd., which cooperates with us, made prototypes of conger eel cylinders, octopus traps, squid needles,etc. using this material and conducteda fishing test. The results were good,
and the performance and catch perfor
mance were similar to those of existin
g petroleum-derived plastic fishing gear.
"To conclude"
・The price of polylactic acid is high, andreducing manufacturing costs is an issue for the future.
・Regarding condition ⑦ (gradual biodegradation), we will further cooperate wit
h the manufacturer to realize it.
・We would like to express our deep grat
itude to the Fisheries Agency, Govern
ment of Japan for financially supporti
ng this demonstration test, Nichimo Co., Ltd., and the aquaculture company
in Hiroshima for providing the protot
ype of the oyster pipe and the place for the demonstration test.
(Writing) Fukuda Kengo (Doctor of Fis
heries Science), Manager, Business Sec
tion 2, “UMI”&“NAGISA”Foundati
on info@umitonagisa.or.jp

Drifting oyster pipe

Polylactic acid oyster pipe test

Polylactic acid + additives

Polylactic acidpolyethylene(Material currently used)
Prototype sample (dyes added for distinction)