Earthquake effects on trout fishing…?
A strong earthquake rattled central New Zealand on Tuesday afternoon. The quake measured 6.2 in magnitude, according to geological monitoring service GeoNet. Its epicentre was 25km south-west of the town of Taumarunui, on the central North Island, and it struck at a depth of 207km.
More than 9000 people reported feeling the quake within 10 minutes of it striking at 3.14pm. All except me – I was enjoying a granny nap.
In New Zealand, there are dozens of minor earthquakes every day with 418 earthquakes registered by Geonet in the past week.
Many of the quakes were too small to be felt by anyone, but were still picked up Geonet.
Based on TRM inmates very unscientific results, the Tongariro River fishing was unusually erratic.
After a week of generally steady results with some delighted fishos after landing their limit of six (Hi Paddy – image on right) the pattern on Tuesday was harder and erratic. The fish knew something was amiss.
i.e. One of our more reliable fishos, Bruce Hutchins from New Plymouth, reported landing four and losing one before the quake struck but he commented, for him it was hard work. Then on the next day after the quake he landed five in the morning session, which indicated how quickly the trout recovered from any “quake stress”.
Bruce (image on right) also commented that any decent shake quickly becomes visually obvious from pumice flaking off the high cliffs which immediately colours up the rest of the river. This would also affect the trout behaviour and the fishing. For the fish, the flies would be much more difficult to identify aa they just stop feeding to wait until it clears.
Bruce was wading in the tail of Cicada Pool a couple of years ago when a huge flake peeled off the cliff and crashed into the pool. He just avoided being swamped by the mini tsunami.
The images below illustrate the high unstable pumice cliffs up the Tongariro River that erode and crumble under the slightest hiccup.
The following was TRM’s report after a similar earthquake fright on May 29th 2017:
About the Lateral Line
Trout have inner ears, which allow them to hear sounds as we do. They also have lateral lines, special sense organs used to “feel” sounds. Lateral lines allow trout to hear sounds that are too low for humans to hear. Every trout has two lateral lines, one on each side of its body. A lateral line is made of a series of U-shaped tubes. Every time the water outside the U vibrates because of a sound, a tiny hair at the base of the U wiggles, which sends a nerve signal to the brain. The trout’s brain translates the wiggle into information about where the vibration came from. Trout use lateral lines to find food, escape predators and keep away from obstacles.
Sometimes I suspect SWMBO has a lateral line too.
One scientific explanation is:
Recent animal sensory literature has been analyzed to evaluate the plausibility of reports of unusual animal behavior prior to earthquakes. Some species of fish possess remarkable sensitivity to pressure waves with frequencies below 50 Hz, which would enable them to sense earthquakes at least 1 to 3 Richter Magnitudes smaller than those detectable by human beings. Fish also have organs which can detect slight movements of water, although the available experimental data do not allow us to determine quantitatively whether they are sensing accelerations of water or variations in water displacement. Thus observations of unusual behavior of fish before earthquakes may be explained if the fish are responding to small foreshocks.
Most scientific explanations arrive after the event… I told you so… I knew all along… Yeah right.
The lateral line is a system of sense organs found in aquatic vertebrates, used to detect movement, vibration, and pressure gradients in the surrounding water. The sensory ability is achieved via modified epithelial cells, known as hair cells, which respond to displacement caused by motion and transduce these signals into electrical impulses via excitatory synapses. Lateral lines serve an important role in schooling behavior, predation, and orientation. For example, fish can use their lateral line system to follow the vortices produced by fleeing prey. Lateral lines are usually visible as faint lines of pores running lengthwise down each side, from the vicinity of the gill covers to the base of the tail. In some species, the receptive organs of the lateral line have been modified to function as electroreceptors, which are organs used to detect electrical impulses, and as such, these systems remain closely linked. Most amphibian larvae and some fully aquatic adult amphibians possess mechanosensitive systems comparable to the lateral line.
The lateral line system allows the detection of movement, vibration, and pressure gradients in the water surrounding an animal, providing spatial awareness and the ability to navigate in the environment.
Therefore it is far more sensitive to any variances or vibrations and pressure gradients, etc. So now you know…