Fishing plantations are enclosures or specific areas where the captured and produced fish can be prepared for distribution to outlets. There are also fish farms.
It's about a regulation whose measures are not limited to an increased size of the spacial and temporal closure. With respect to tuna, the number of plantations for the vessels each year is limited or reduced, avoid repercussions or effects from the index of fleet fishing capture.

ESP: Plantaciones pesqueras son recintos o zonas encerradas donde los pescados capturados y producidos pueden ser preparados para la distribución y la alimentación para los lugares donde se venden.
Es sobre la regulación cuyas medidas no se limitan a una ampliación de la veda espacio-temporal. Se trata de la captura de atún, acotando (reduciendo y limitando) el número de plantaciones que los buques pueden realizar al año, evitando las repercusiones o los efectos en los índices de la captura de la flota.

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Note added at 1 day 17 hrs (2021-08-04 02:58:13 GMT)
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https://www.google.com/search?rlz=1C1AOHY_enGB959GB959&sourc...

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Note added at 2 days 1 hr (2021-08-04 10:31:42 GMT)
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There's a reference to a fishing river plantation in Georgia, U.S.
https://www.littlerivergeorgia.com/fishing/
Here's a reference to a fishing plantation and hunting lodge in the United States.
https://myrtlewoodplantation.com/index.php/hunting-fishing/


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Note added at 2 days 1 hr (2021-08-04 10:46:40 GMT)
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"Fishery is the enterprise of harvesting fish and other aquatic life. Commercial fisheries include wild fisheries and fish farms, both in fresh water and oceans. 500 million people worldwide depend on fisheries. Recreational fishing is also popular in various places." Economic, social and environmental factors have called for regulations and restrictions on fishing. These prevent conflicts while laws are in place, where as before, people were more free to fish in many places.
https://en.wikipedia.org/wiki/Fishery
'El pesquero es la empresa de la cosecha de pescados y otra vida acuática. El pesquero comercial incluye el pesquero silvestre y las fincas pesqueras, ambos en el agua fresca y los océanos. 500 milliones de la gente mundial dependen de los pesqueros. La pesca recreativa también es popular en varios lugares acuáticos." Unos factores económicos, sociales y ambientales han llevado a unas restricciones y normas sobre la pesca. Las normas reguladas impiden conflictos mientras que las leyes están puestas. Al contrario, en el pasado, se podía ir a la pesca libremente entre varios lugares acuáticos.

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Note added at 2 days 1 hr (2021-08-04 10:51:00 GMT)
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Here's a reference to a fishing lake in West Sussex.
It's a six-lake fishery set in scenic ancient woodland in the Sussex countryside.
http://www.fisheries.co.uk/furnacelakes/


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Note added at 2 days 1 hr (2021-08-04 10:53:06 GMT)
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My first explanation was from an excerpt from a Spanish text on fishing plantation size limitations.