In research aimed at understanding the process of fish population decline when coral reefs sustain major damage, PhD student James Kerry and Professor David Bellwood have found that big fish show a marked preference for sheltering under large, flaRead more
However, at locations were there was excessive adverse impact (like pollution), the corals did not recover fully, even after eight years.
“You can imagine that when you are recovering from a sickness, it will take a lot longer if you don’t eat well or get enough rest,” said Jessica Carilli, a graduate student at Scripps Institution of Oceanography at UC San Diego.
“Similarly, a coral organism that must be constantly trying to clean itself from excess sediment particles will have a more difficult time recovering after a stressful condition like bleaching.”
Disease and overfishing also affected coral health. In places where there is overfishing, the population of bigger fishes like groupers are either significantly reduced or have vanished.
In the absence of these predatory fishes, other fish species thrive. One such species is the butterflyfish, which feed on coral and appear to be responsible for disease transmission amongst the corals.
In a study, scientists compared seven Marine Protected Areas [MPAs] where fishing had been banned for at least five years, and another seven neighbouring sites with similar diversity.
They discovered that the corals at the latter sites suffered more diseases; in some cases, the difference was twice as many. In addition, many butterflyfish were found at the sites where fishing was allowed, leading to a higher incidence of coral disease.
Dead zones are areas in the ocean where oxygen levels are so low that most fish cannot survive over the long term.
Blue marlins and many other billfish are high-energy fish that need large amounts of dissolved oxygen. By comparing the movement of the blue marlins and the location of low-oxygen areas, scientists have shown that blue marlins venture deeper when dissolved oxygen levels are higher, and remain in shallower surface waters when low dissolved oxygen areas encroach on their habitat from below.Read more
If you are participating in an organized “shark diving experience”, you may feel that the operator’s knowledge is sufficient and that you can sit back and watch the show. It’s important to remember that every shark interaction is different.Read more
Neurons consist of a somatic cell body containing the nucleus with DNA, and several cell organelles in the cytoplasma surrounding the nucleus (see Figure 1). The somatic part has many dendritic ends who receive signals from many other neurons. A long axon runs from the somatic part of the neuron, where the electric nerve signal travels with an astonishing speed of about 360km per hour. This electrical signal finalizes its axonal journey into many synaptic ends, where it manages to trigger synaptic secretions of chemicals (neurotransmitters: e.g.Read more
Palaeontologists have discovered exceptionally preserved fossil eyes of the top predator in the Cambrian ocean from the fearsome metre-long Anomalocaris that lived 500 million years agoRead more
Diving the North Sea is always an adventure. Even though the weather can be unpredictable, more and more divers have started to explore the wreck sites each year. But wreck diving can be dangerous, too. I have dived the wrecks of my North Sea for over a decade now, and I have seen the number of lines, hooks, sinkers and nets explode. On several occasions, my slow swimming exploration over a wreck was suddenly interrupted—something held me back. It could be a line, a line and hook, or a fine-mesh net that was almost invisible.Read more