Debating marine biology and the marine environment issues

[Ghandi]

Ok folks, the site is miserably quiet so I have a challenge for you all!

Each week I will pick a topic or us to debate (suggestions will be accepted), the topics will relate to marine biology and the marine environment. I will for the most part assume the role of devils advocate in these debates which will give everyone the opportunity to flex their mental muscles and I invite those who require a greater challenge to argue against their own personal views. As well as good mental exercise and practice in debating this will hopefully give people a wider and better understanding of the issues marine scientists deal with!

RULES:

1, No personal insults. Its a debate not a fight.

2, Stay on topic- opening tangents will detract from the thread.

3, Try to substantiate arguments where possible and cite source material when you can.

4, ENJOY.

[Ghandi]

TOPIC 1: COMMERCIAL FISHING IS ESSENTIAL FOR MAINTAINING A HEALTHY MARINE ENVIRONMENT

Ladies and gentlemen you have 24h to form your arguments and start posting if by then no one has found an argument to support my statement i will argue in its favour.

GOOD LUCK!

[Iceelover]

The environments were fine before commercial fishing came about and still are fine where commercial fishing is not present. The word "essential" does not belong in that sentence.

[David]

Hrumph, I concur entirely with Iceelover. Commercial fishing may be essential to humans, especially at our current numbers, but the ocean is clearly suffering in multiple ways from the shear volume of biomass we have and continue to remove from it every year.

Dr. Jackson says it best (February 17, 2009):


The only argument I can think of to support your idea is that commercial fishing could be used keep populations of species like jellyfish and other "harmful" species in check. Of course, those species are now in need of "management" because of our mismanagement/overfishing of species that used to keep them in check (like sea turtles, tunas, etc.). I'd prefer to see us work to increase those species back to a somewhat "normal" level but where's the profit in that? Interesting topic indeed. Hmmmm.

[Oarfish]

What state are we referring to as being a healthy state? The state at which humans are healthiest? The state at which jellyfish are healthiest? Or perhaps tuna? Sharks? Maybe we're referring to a state in which the fewest organisms in an area are in a critical state for survival? But if that's the case, wouldn't a biome with no animals be healthiest, since plants could grow in peace?

Perhaps we should determine what we mean by healthy.

[David]

Good point, I took that to mean sustainable with few threatened or endangered species. Marine plants aren't in trouble as far as I know... in fact, they are thriving with excess nutrients, etc. except for kelps which are having trouble with warming waters....

[Oarfish]

Then we could say that areas where fishes have been depleted are healthy, as they contain no threatened or endangered species. We could also say that a city park, home to squirrels and songbirds, is still a healthy biome after it has been bulldozed and renovated into a parking lot, since neither the squirrels nor the songbirds (even though they have been forced to leave the area and possibly killed in the process) are endangered as a species.

If we interpret "endangered" as having a looming threat which could kill an organism, then a jungle could be considered unhealthy, since leopards and pythons endanger the smaller creatures. I don't think this is unhealthy, provided the organisms being killed are in no danger of being depleted from the area.

However, if the prey becomes overhunted, and and the biome is no longer healthy.

If we require that a biome have multiple species, then Antarctica and the civilized world are ruled out as unhealthy. However, the climate and predators met while traveling serve as population control there, and there seems to be a steady population, so obviously the penguins aren't overly dominant.

Having said this, a human-only biome should be considered healthy as well, provided there is no danger of humans overpopulating the area or being depleted in the area. But what about a factory with toxic material? OSHA would have a fit! Now we must modify our definition to include a state of sickness as well.

Having ranted for awhile, I'm defining a healthy biome as one where no species is in danger of becoming overpopulated or depleted or contracting an abnormality that is detrimental to its existence.

Whew! I'm curious to see if anyone else can go further...

[David]

In my opinion, a lack of life does not indicate a healthy ecosystem. "An ecosystem is a natural unit consisting of all plants, animals and micro-organisms (biotic factors) in an area functioning together with all of the physical (abiotic) factors of the environment. An ecosystem is a unit of interdependent organisms which share the same habitat. Ecosystems usually form a number of food webs which show the interdependence of the organisms within the ecosystem." - Wikipedia: Ecosystem

Without plants, animals, etc. there is no ecosystem in my understanding (otherwise known as a parking lot lol). We know pretty well how much and what kinds of life lived where in the ocean before humans (see http://www.shiftingbaselines.org/slides ... ne_hi.html - there are records from various sources that have been preserved and studied). Those initial numbers should be the goal to shoot for rather than simply looking at what's left or cleaning the slate entirely. Of life that does exist now in the ocean, using the standard definitions of threatened and endangered should apply to them to help determine if the ocean is healthy (while also looking at various physical factors that would or could effect ocean life - pollution and global warming, for instance...).

You mention that a healthy biome is one where no species is in "danger of becoming overpopulated" - but who decides that? Healthy ecosystems should balance themselves given limited interference from humans.

"Contracting an abnormality that is detrimental to its existence" is called mutation I believe and is also natural usually. I suspect you mean those caused by us (which I believe is very hard to determine usually).

Will be interesting to see what Ghandi's view is....

Then we could say that areas where fishes have been depleted are healthy, as they contain no threatened or endangered species. We could also say that a city park, home to squirrels and songbirds, is still a healthy biome after it has been bulldozed and renovated into a parking lot, since neither the squirrels nor the songbirds (even though they have been forced to leave the area and possibly killed in the process) are endangered as a species.

If we interpret "endangered" as having a looming threat which could kill an organism, then a jungle could be considered unhealthy, since leopards and pythons endanger the smaller creatures. I don't think this is unhealthy, provided the organisms being killed are in no danger of being depleted from the area.

However, if the prey becomes overhunted, and and the biome is no longer healthy.

If we require that a biome have multiple species, then Antarctica and the civilized world are ruled out as unhealthy. However, the climate and predators met while traveling serve as population control there, and there seems to be a steady population, so obviously the penguins aren't overly dominant.

Having said this, a human-only biome should be considered healthy as well, provided there is no danger of humans overpopulating the area or being depleted in the area. But what about a factory with toxic material? OSHA would have a fit! Now we must modify our definition to include a state of sickness as well.

Having ranted for awhile, I'm defining a healthy biome as one where no species is in danger of becoming overpopulated or depleted or contracting an abnormality that is detrimental to its existence.

Whew! I'm curious to see if anyone else can go further...

[Iceelover]

While I completely dislike the amount of reading involved in the last two posts, and disagree that a animals (such as squirrels) cease to exist in an area that has been made into a parking lot (parking lots have tons of animals living there) ...

The debate was on the statement that COMMERCIAL FISHING IS ESSENTIAL FOR MAINTAINING A HEALTHY MARINE ENVIRONMENT

I took that to mean that if given a healthy marine environment, in order to keep it at a healthy level, commercial fishing would have to be placed into effect.

This is given a healthy environment. Im not sure if you guys were arguing about a healthy environment or a healthy ecosystem.
One marine environment could be toxic to those that live in another environment. Within one environment, the ecosystems change over the course of years. Species come and go, adapt and re-adapt, eat and are eaten. Yet just because there is a different or changing ecosystem does not mean that the environment is unhealthy (by the way, I took unhealthy to mean that no ecosystem could survive). The new ecosystem could thrive just as well as the old one in the same environment.

I think the coolest thing about ecosystems is that they can adapt to new things. When commercial fishing enters the environment, it acts as a predator. If the ecosystem can adapt, and isnt wiped out by it, then It could still be considered healthy. (This differs from when another animal enters the environment and wipes out the ecosystem because in order for it to wipe out the entire ecosystem it would have to wipe itself out. Where as commercial fishing is an action and does not live, it is not part of the ecosystem, it just tries to be cool like that)

Commercial fishing can cause the ecosystem to adapt and become a new one, if the new one survives, it can still be considered healthy. If no new one emerges, it is an unhealthy environment and nothing can survive there. Either way, that word essential just bothers the crap out of me

[David]

LOL, too funny. Sorry to make you read so much, I thought we were discussing, not arguing. Would love to see a parking lot full of animals btw.

OK, the topic is: COMMERCIAL FISHING IS ESSENTIAL FOR MAINTAINING A HEALTHY MARINE ENVIRONMENT

So, like you point out, we can assume the marine environment is originally healthy given the above. The question is whether or not commercial fishing is "essential" for maintaining a healthy marine environment. I say simply no. Because it's clearly been shown to have been healthier than it is now and commercial fishing has clearly been shown to significantly decrease biomass, upset food webs, and wreak havoc on numerous populations of marine species. I'd need a few days to find references but most of that is widely known.

Better?