Hunting

[PeanutBean]

I'm not sure that fishing could be counted as the largest effect, I don't know...maybe...it would depend on how we were measuring. But certainly the combined effects on the oceans are by far the farthest reaching. Warming of the oceans, the potential changes in the currents for oceans and land climate, fishing practices, ocean acidifcation.

I agree bottom drawling is just a disgrace. The Marine Conservation Society have put together a sustainable fish guide (https://www.fishonline.org/information/MCSPocket_Good_Fish_Guide.pdf). Not sure how relevant it will be to NZ but of course lots of fish are internationally sourced.

By the way did you catch my first post in response to your question? ETA page 3

 

[Dragonfly]

Dont like it at all

 

[PeanutBean]

You piqued my curiosity kiwi, so far it looks like, including bycatch which of course counts, there are more than 100 million metric tonnes of fish caught globally pa. From what I can find global meat production is about 229 million tonnes. Doesn't say if these are metric tonnes or not! US tons seen to be slightly less than metric, UK tons seem to be slightly more so I don't think it makes a huge difference.

What isn't measured in the fishing data is the damage to the immediate environment, to the predator prey relationship following extraction of so many wild fish, and the loss of biomass as a consequence of these. I think I'd need to delve deep into the literature to get estimates of this and they would be very specific to certain fishing grounds. I don't have access to papers at home so couldn't look this up anyway. Of course terrestrial farming has issues too, such as clearance of rainforest, but then once that's in place there aren't so many knock on effects to local food webs and ecosystems, not in quite the same way as with fishing as the terrestrial areas are rather more closed than a marine environment.

 

[kiwimama]

I'm not sure that fishing could be counted as the largest effect, I don't know...maybe...it would depend on how we were measuring. But certainly the combined effects on the oceans are by far the farthest reaching. Warming of the oceans, the potential changes in the currents for oceans and land climate, fishing practices, ocean acidifcation.

I agree bottom drawling is just a disgrace. The Marine Conservation Society have put together a sustainable fish guide (https://www.fishonline.org/information/MCSPocket_Good_Fish_Guide.pdf). Not sure how relevant it will be to NZ but of course lots of fish are internationally sourced.

By the way did you catch my first post in response to your question? ETA page 3

You piqued my curiosity kiwi, so far it looks like, including bycatch which of course counts, there are more than 100 million metric tonnes of fish caught globally pa. From what I can find global meat production is about 229 million tonnes. Doesn't say if these are metric tonnes or not! US tons seen to be slightly less than metric, UK tons seem to be slightly more so I don't think it makes a huge difference.

What isn't measured in the fishing data is the damage to the immediate environment, to the predator prey relationship following extraction of so many wild fish, and the loss of biomass as a consequence of these. I think I'd need to delve deep into the literature to get estimates of this and they would be very specific to certain fishing grounds. I don't have access to papers at home so couldn't look this up anyway. Of course terrestrial farming has issues too, such as clearance of rainforest, but then once that's in place there aren't so many knock on effects to local food webs and ecosystems, not in quite the same way as with fishing as the terrestrial areas are rather more closed than a marine environment.

I did, but by then it had been overtaken by about 3 pages about fox hunting and felt I couldn't reply after that long.

I don't think damage could only be measured by the amount of tonnes of product that results, as you have said. I just wonder what would happen if one species were wiped out and therefore the food chain altered. I wonder what would happen if all species in the ocean died? No seas = No life on Earth.

 

[PeanutBean]

Well we can kind of see what happens when a species is wiped out in small areas where the biodiversity is altered and reduced, say by servere local pollution. But the sea is amazing. Take the BP spill. It was horrible but in terms of natural oil seepage into the sea it really was a drop in the ocean. The sea can buffer some pretty big stuff. I think overfishing will lead to some stocks never recovering if it's not dealt with now. That will alter the dynamics of food webs those species are part of but overall I think biodiversity won't change that much. It's probably more likely to have a knock on effect on mammals including coastal ones but much as we love them mammals are a very small part of marine and coastal ecosystems.

I do think however that climate change and ocean acidification will cause astonishing levels of change in sealife. Taking out the molluscs and Crustacea that are low down the food chain will be catastrophic. But that discussion is outside the remit of this thread!

 

[cherryglitter]

I too have watched a programme about fishing.
We are over-fishing and the way some of the fish are treated is disgusting. It's terrible. Dead or semi-dying fish are thrown back into the ocean because it's not what a fisherman 'wanted' - there's no money there.
I know im going to completely off topic but it really does make me feel upset.

There needs to be more awareness of what is happening out there. We're going to wipe out sea and be left with nothing but crustaceans. It's disgusting in my opinion and it needs to be seriously reviewed!

We are fishing into extinction! It makes me so sad.

 

[cherryglitter]

Well we can kind of see what happens when a species is wiped out in small areas where the biodiversity is altered and reduced, say by servere local pollution. But the sea is amazing. Take the BP spill. It was horrible but in terms of natural oil seepage into the sea it really was a drop in the ocean. The sea can buffer some pretty big stuff. I think overfishing will lead to some stocks never recovering if it's not dealt with now. That will alter the dynamics of food webs those species are part of but overall I think biodiversity won't change that much. It's probably more likely to have a knock on effect on mammals including coastal ones but much as we love them mammals are a very small part of marine and coastal ecosystems.

I do think however that climate change and ocean acidification will cause astonishing levels of change in sealife. Taking out the molluscs and Crustacea that are low down the food chain will be catastrophic. But that discussion is outside the remit of this thread!

You've just said everything i've posted but in a much more intelligent way!!

 

[PeanutBean]

Lol cherryglitter, I'm a marine biologist! If you want to try take some action you could join the Marine Conservation Society (are you UK?). There is a good fish guide, I posted a link somewhere back in the thread, it shows a traffic light system for the sustainability of different species and their different sources.

Last November England got a new Marine Act, Scotland passed theirs earlier this year. It includes a requirement to establish marine conservation zones in UK coastal waters. You can find out more through MCS and also Natural England. MCS have a campaign called Your Seas Your Voice where you can nominate areas for conservation and/or vote of areas MCS have proposed.

The fishing situation in the UK is pretty disastrous. We only have governance of waters 12 miles from the coast. Beyond that the EU legislation comes into play - the Common Fisheries Policy. It's a farcical piece of legislation and fortunately the new Act asks for if to be reviewed.

The issue with bycatch is that in order to protect species only certain sizes can be landed (ie brought into market) and there are also quotas for species so if a vessel reaches their quota for mackerel they can't land anymore that year. But the sea does not contain species in convenient packages of type and size so it is impossible for fishers to not catch fish they can't land. Inevitably most caught fish will die even if thrown back. It's a ridiculous system.

The best way to deal with it is to bring in legislation for selective gear, of which there are a variety that through systems of differently sized grills at the mouth of the net, escape panels, and placement that plays on behavioural responses of fish, allow mostly only target fish into the net. In addition there should be immediate closures of nursery grounds abs vulnerable areas. Seasonal closures reflecting the life cycle of the species to maximise their chances of reproduction. And marine reserves which are totally undisturbed covering 30% of the sea which is the figure estimated to sufficiently allow recovery and maintain sustainability of stocks. Bans on vessels of a certain size would be useful too.

Sadly it's not going to happen because fishing has all these special historical, traditional values and culture which make it untouchable by science. Every piece of advice issued by fisheries scientists is watered down by politicians so far as to be ineffective. The politics in the EU fishing industry is beyond anything!