What are the main effects of overfishing?

Overfishing is becoming a huge environmental issue, especially with the ongoing rapid growth of human population. Millions of people worldwide depend on fish to survive but due to very poor global management of fisheries overfishing is taking heavy toll in almost all of our oceans and seas with many fish species experiencing a significant decline in population.

According to the recent study by the Wildlife Conservation Society overfishing has caused modern fish species to have shorter life spans, faster growth rates, smaller average sizes, and fewer top predators. That was the main conclusion of a recent study in which researchers compared fish recently caught in coastal Kenya with the bones of fish contained in ancient Swahili.

Overfishing has therefore significantly reduced the number of large and long-living fish species that were more commonly caught in the Middle Ages. The only areas where fish population can still somewhat thrive and achieve longer lifespan are marine protected areas, though even in these areas fish communities can only partially achieve its "former glory days".

As said before the fishing pressure is growing all the time and the world still hasn't established the adequate global management to stop deterioration of remaining fisheries.

Particularly worrying is the fact that top predators are mostly affected with overfishing which is already causing severe changes in marine food chain.

One thing is sure - ignorance will not solve this serious issue. World needs to unite and come up with the solution that would ensure the adequate global management of remaining fisheries. Failing to do so could cost us dearly in years to come.

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Quick facts about white dwarfs

A white dwarf is the term in astronomy used to describe the last stage in the life cycle of a (massive) star like our Sun. This last stage in the life of star occurs when star sheds its outer atmosphere, leaving the glowing, gradually cooling, core as a white dwarf. For our Sun this process will begin about 5 billion years in the future.

In the last stage of their life, these massive stars have enormous density, for instance one teaspoon of white dwarf material is estimated to weigh more than a ton.

Many astronomers have specialized in studying white dwarfs mostly because they believe this research could eventually give us more exact info about the destiny and the end of our solar system as our Sun will also eventually end its life as white dwarf.

Most white dwarfs are mainly composed of the two simplest elements in universe, hydrogen and helium. However, white dwarfs can also contain elements such oxygen, nitrogen, silicon and even iron originating from the remains of planets. The scientists have even discovered a white dwarf star system where each star appears to have been stripped down to just its helium.

White dwarfs are among the oldest objects in known universe since they are the end point of life of the life cycles of most stars.

There are some scientists who believe that the best place to look for planets that can support life is around white dwarfs. What they believe is that these new planets could possibly form from a ring of debris left behind by the white dwarf.

The nearest white dwarf to Earth is so called Sirius B at a distance of about 8.5 light years.

When two white dwarfs merge, their combined mass can exceed beyond a tipping point, leading to a supernova-like explosion.

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How does human activity affect Earth's ecosystems?

Humans, or to be more precise human activity, is the main reason for severe ongoing changes in many of Earth's ecosystems. This is not only because of the ever-growing climate change impact but also because human population is constantly growing, expanding into new areas and changing native ecosystems, sometimes even to the point of no recognition.

Biodiversity loss is higher than ever before and the mass extinction of species certainly looks like a very real threat. And science is still not able to give us the exact answer to the question about the connection between species loss and the future look of earth's ecosystems.

Many species will in years to come likely go extinct while some other (particularly invasive species) will no doubt expand their range not only as a result of humans introducing these species to new environment(s) but also because some of these species will actually benefit from ongoing climate change and other environmental issues.

In order to fully understand the complexity of this issue scientists not only need to study the consequences of losing native species in an ecosystem but they also need to learn the consequences of adding new species.

Species loss and species gain occur in most cases parallel so scientists need to study both of these phenomenons in order to get the most accurate results. The main emphasis should be put on human activity, particularly answering the question how human activity influences production of Earth's ecosystems and are these ecosystems still able to perform their valuable tasks such as for instance storing carbon (forests, oceans).

Invasive species are spreading throughout the globe just like the humans are, constantly expanding their living area and shrinking the habitats of many plants and animals.

The knowledge about the ongoing changes in many Earth's ecosystems is still limited because many studies have been conducted in controlled environment which means that these studies have forgot the fact that species do not disappear from ecosystems by chance.

World certainly needs to enhance its knowledge about ecosystems and biodiversity as quickly as possible. Why? Because our future might depend on it.

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Astronomy is still a "could be" science

We like to think of ourselves as the species with advanced technologies but just think about our limited knowledge about the universe and our technological limitations are instantly exposed. Astronomy, despite delivering some useful theories is still very much a "could be" science, after all very few things are certainty for astronomers and most of the time you will hear how there "could be another life in the universe", how there "could be planets like ours", how there "could be species with far superior technology somewhere in the space", etc.

This "could be thing" is the direct result of our technological limitations and that's not something we should be ashamed of. After all, science is in the constant state of progress, and human knowledge as well as the technology keeps its natural process of upgrade.

This process cannot be accelerated just because of our desires, in this case the only "possible" way to speed things up would be if some technologically superior alien race would decide to share with us a few of their technological secrets, and this scenario certainly looks to be in the realm of imagination like coming up from some B-rated Sci-Fi movies.

Astronomy is well aware of its technological limitations and this is the reason why astronomers use "could be" so much. With such limited technology theories are all they really have so you can't blame astronomers for lacking the so much desired certainty.

Our Universe is limitless from our very own perspective and astronomers have incredible amount of questions that are still waiting for the right answers. The questions that have been answered so far weren't useless, on the contrary they have enabled the man to walk on the moon, the exploration of other planets in our solar systems as well as many other very useful things.

With time astronomy will be able to give more exact answers to questions that are currently belonging to could be category but given the magnitude of our Universe there will be always some questions in that category, regardless of our technological development.

After all, space is the mankind's final frontier...

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