Whether fish, used for human recreation and consumption sees the fish suffer, is an emotional and divisive issue in the community.

I know being a vegetarian myself. Then there are political parties like the Shooters and Fishers Party in Australia and animal rights groups, like Animal Liberation.

Some also take a view there is no suffering for fish. Their claims as they put are based upon science, university research, facts and evidence.

Also with pain and suffering in mind, what about plants? Are plants subject to suffering?

It's certainly an "emotional issue" for weirdos. Divisive? No. Weirdos have already cut themselves off from the majority, who don't give a toss about such nonsense, so it's not divisive either.

Ask a shark, they eat quite a lot of them
Some vegans are a bit out there

Plants, according to Jack C Schultz, "are just very slow animals".

This is not a misunderstanding of basic biology. Schultz is a professor in the Division of Plant Sciences at the University of Missouri in Columbia, and has spent four decades investigating the interactions between plants and insects.

Instead, he's making a point about common perceptions about plants, which he feels are often dismissed. Plants fight for territory, seek out food, evade predators and trap prey. They are as alive as any animal, and – like animals – they exhibit behaviour.

To see this, you just need to make a fast movie of a growing plant – then it will behave like an animal. This is the position of Olivier Hamant, a plant scientist at the University of Lyon, France. A time-lapse camera reveals the world of plant behaviour.

These plants are moving with purpose, understanding awareness of what is going on around them. To respond correctly, plants need sophisticated sensing devices tuned to varying conditions.

http://www.bbc.com/earth/story/20170109-plants-can-see-hear-and-smell-and-respond

//Do fish feel pain?//

According to eminent biologist Stephen Jay Gould, there's no such thing as a fish:

http://www.youtube.com/watch?v=uhwcEvMJz1Y

I'm going to assume you're referring to Osteichthyes. Yes, they feel pain. There is some contention over whether or not crustaceans (lobster, crab) feel pain.

//Are plants subject to suffering?//

No, they don't have a brain or nervous system, so they can't feel pain.

<<It's certainly an "emotional issue" for weirdos. Divisive? No. Weirdos have already cut themselves off from the majority, who don't give a toss about such nonsense, so it's not divisive either.>>

My point was to leave this as an open ended question and see how people would react.

So, take the following into consideration:

"More fish kill events are expected in New South Wales’s inland rivers in coming days as temperatures rise in the state’s west followed by a forecast cool period, the agriculture minister, David Littleproud, has warned."

The federal government announced a $5m recovery package for the Murray-Darling after up to 1m fish died at Menindee, including 70-year-old Murray cod, with the money for cleanups and fish restocking.

https://www.theguardian.com/australia-news/2019/jan/14/minister-warns-of-more-fish-deaths-this-week-as-temperatures-rise-in-nsws-west

Do fish have feelings? Maybe...

"The question of whether animals other than humans can think and feel has been debated for centuries. Most of us would agree that humans have a level of consciousness, loosely defined as an ability to experience thoughts and emotions. But which other creatures have consciousness remains an open and controversial question.

We can also ask whether there are different degrees of consciousness and whether the experiences of other organisms are similar to our own. Many may think that dolphins and deer have the ability to feel emotions, but what about a fish, a bug or a plant? Which brings us to another key question for scientists: how do we figure out if animals or plants feel? My colleagues and I recently carried out research that looks at one way of answering this question, and found that fish appear more likely to experience emotions that we previously thought."

https://theconversation.com/do-fish-have-feelings-maybe-54291

Something to think about, with the amount of fish dying at present?

Nathan J- I found these two articles from relatively good sources (Psych Today sometimes has questionable material imho)

http://www.psychologytoday.com/us/blog/the-green-mind/201412/are-plants-entering-the-realm-the-sentient
http://www.scientificamerican.com/article/do-plants-think-daniel-chamovitz/

I understand 75% of our genes are similar to a pumpkin- if this is true we share some "attributes"- brain?? Stephen Wolfram discusses the concept of Universal Sampling. There is the concept of Panpsychism. Roger Penrose talks of Quantum Consciousness. Plant consciousness is an interesting but controversial area- I share Toni Lavis' caution.

Consciousness is one of the frontiers of science- but consciousness is different than thinking.

There are probably many ways to implement a neural network that are not anthropocentric.

I'll plead the Socrates defense- "I don't know".

Thanks for the interesting topic Nathan J.

We know the brain is built in layers reflecting different stages of life- worms, reptiles, mammals, primates, humans. Reptiles come from "Lung Fish" from memory. Reptiles seem to have flight/ fight; fear/ aggression- I suspect fish would have a similar brain functionality to reptiles- even worms seem to indicate an experience of pain.

How this relates to morality is uncertain- mankind are omnivores- their physiology seems to be finely tuned to their diet- vegetarians extraordinary claims need extraordinary evidence- though perhaps paleo diets or similar contained less meat than contemporary diet- but our lives are different than Paleolithic people.

"Herding" creatures (whether land or water) seem to have different brains than "hunting" creatures.