auditory trauma (deafness) and barotrauma AS THE

MAJOR cause of sea turtles mortality!

1. Why do sea turtles strand on a beach?

(Question sent in by third-grade student from Nashville.)

2. Why do sea turtle collide with boats and get killed?

(Question sent in by 8-year-old student from Texas.)

3. Why do sea turtles drown in fisherman's nets?

(Question from Mrs. Gray's second-grade class in Chicago.)

4. Sea turtles have no vocal cords so why do they have ears?

(Question sent in from sea turtle experts at Sea World in Orlando.)

by Captain David Williams

Deafwhale Society, Inc

PO Box 319, Dumaguete City

6200 Oriental Negros

Philippines

Copyright Notice: The content of these pages is copyright © Captain David Williams 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, and 2008. Reproduction of part or all of the contents in any form is prohibited other than as follows: You may print or download to a local hard disk selected extracts from these pages for your personal use only. You may also copy information contained on these pages to individual third parties for their personal information only, but only if: You acknowledge Captain David Williams and this web site as the source of the material. In addition to the acknowledgement, you must also include a reference to the Deafwhale Society's web site address http://www.deafwhale.com and you also inform the third party that these conditions apply to him or her, and that he or she must also comply with them. The above permissions do not permit incorporation of the information on this web site or any part of it in any other work or publication, whether in hard copy or electronic or film or other form. In particular, no part of the Deafwhale Society's web pages may be distributed or copied for any commercial purpose. No part of the Deafwhale Society's web site may be reproduced on or transmitted to or stored in any other web site, or in any other form of electronic retrieval system. Users wishing to make copies, other than as permitted above, should apply for individual permission. Requests should be sent in the first instance to Captain David Williams. Any attempt to plagiarize any of this copyrighted information will result in a lawsuit. Reference this webpage as the source when quoting this article.

At a deep water location, just south of the continental slope in the Gulf of Mexico, seismic exploration noises could be detected audibly virtually all the time during a 12-hour recording period (Shooter). In fact, if the compass courses of all the seismic boats that have completed airgun surveys over the last 20 years were drawn by a gossamer-thin black line across a chart of the Gulf of Mexico, the Gulf would disappear and be replaced by solid black mass. Many other areas of the world's oceans would take on a similar look.

At the present time, there are ~525 airgun-equipped seismic survey vessels operating world-wide, all pounding away at the ocean floor around the clock --- boom, boom, boom, boom, every 10 seconds, 24 hours per day, seven days per week!

Thirty years ago, seismic exploration at sea for oil was conducted with dynamite; damage was easy to spot because dead fish and sea turtles floated to the surface leaving a trail behind the boat. Pressure from the fishing community forced the development of the airgun. The first devices were small, and not nearly as effective at sending a pressure pulse strong enough to penetrate 2-3 miles of solid seafloor. But, it didn't take long for technology to change the picture.

Modern airguns can hold up to 2,000 cubic inches of highly compressed air. They are strung out behind the vessel in arrays of up to one hundred guns which are fired at the same time to increase the amount of energy placed in the water. The result is a GOD-awesome boom every ten seconds which raps the hull of the ship as though someone hit it with a giant hammer. This boom has an average pressure pulse of 1,800 pounds per square inch.

Why don't the public hear the truth? The answer is simple: The oil industry has paid millions on millions of dollar to the world's top scientists and government employees to get them to write complex reports on how these airguns are harmless to animals.

The material these money-hungry scientific crooks churn out is so twisted with mumbo-jumbo nonsense as to be completely meaningless to the average scientist. Not only are these biased reports loaded with misleading material, but they refer to the published lies of other crooked scientists to prove their point. The first scientist lies and the rest all fall inline repeating the original lie and adding their own twisted version to it. It's all a massive cover-up to keep the public in the dark. It works because the public tends to believe that scientists don't lie. Nothing could be further from the truth. The money the oil industry and the navy is willing to spend to fool the public is ample reward to attract hundreds of greedy scientists who will write anything the oil industry wants.

For example, a study was done by Brazilian scientists not long ago entitled, "Occurrence of sea turtles during seismic surveys in Northeastern Brazil."  These scientists types concluded the following:

The authors went on to say, "The authors thank Grant Geophysical from Brazil Ltd. to make available the results of sightings of sea turtles." In other words, the oil industry employees counted the sea turtles and the scientists collected a small grant to write nonsense. But you don't need a misleading group of scientists to tell you what to believe and not to believe. Common sense will tell you that a rapid pressure pulse of 1,800 psi (one meter from the airgun) would surely blow out a sea turtle's ear. This level is one hundred million times more powerful then the energy needed to deafen man.

Airgun arrays do produce a slower increase in pressure over time then explosives. The crooked oil industry scientists insist that these booms do not harm critters in the sea because this slower rise time to peak pressure gives the middle ear muscles time to respond and damp the signal. But sea turtles don't have middle ear muscles to protect their ear. Simply put: Sea turtle ears are more like pressure sensing devices than ears. Load noise is not what deafens a sea turtle -- it's the excessive pressure change that blows out their ear!

The use of explosives in the marine environment leaves little to question. Yet, to fool the public, crooked scientists paid by the oil industry to investigate the environmental damage of underwater explosives discuss issues like detonating velocities which range from 20,000 to 27,000 feet per second, and brisance which is the measure of shattering power. They also discuss such things as impulse, energy flux, and ideal damage parameters. All of this mumbo-jumbo scientific junk is again meaningless. The conversation should switch to the simple questions; and, there are only two. How big was the explosion, and how far away were the victims?

Why Do Sea Turtles Have Ears?

On 24 October 1989, a short report was shown on channel 7 in Miami, Florida. Reporter Janet Rose aired a story about a well known sea turtle in the Florida Keys. The story featured a big burly 250 pound diver who was lobster hunting along a reef when a 500 pound sea turtle, called Crazy Charlie by the locals, attempted to copulate with him. The diver was scare out of his wits when the turtle pinned him down and started humping away. This was the third time Charlie had tried to have sex with a diver. The news reporter said cataracts had weakened the old turtle's vision and suggested he had trouble telling the difference between scuba divers and female turtles. But Crazy Charlie wasn't attracted to the diver by his looks -- he was drawn in by the sound of his bubbles. Divers and females sea turtles both blow bubbles underwater that crack and pop and can be heard for a long distance. The bubbles serve as a sexual signal and a means whereby mating sea turtles find each other.

Even though sea turtles do not have vocal cords, there is no reason to assume they are mute. Land species produce grunts, roars, and moans, which appears most frequent in males engaged in courting or copulation. Since the evolution of turtles was from the sea to the land, one would expect that the grunts, roars, and moans of land turtles are associated with a similar method of communications in their water-dwelling ancestors. But no vocal box in turtles forces one to explain how a sea turtle might grunt and roar underwater. The answer is simply and common sense. The sea turtle's grunts and moans turn into big bubbles underwater. As the bubbles expand, they reach a point where the water pressure exceeds the internal air pressure and the bubble collapses with a load bang---the perfect underwater signal.

It is not uncommon for divers making bubbles to spot sea turtles. Close observation will show that the sea turtles swim to within sight of the scuba divers and then turn and swim away indicating that they were drawn in by the popping bubbles. This type of signal is unique in the marine environment, and would enable turtles to easily find mates in low visibility.

Another postulated use of hearing concerns the most endangered sea turtle of all; the Kemp's Ridley. This species exhibits strange behavior when they come ashore to lay eggs which is done only on a small remote section of beach at Rancho Nuevo, Mexico. They come ashore only in broad daylight, and only when the waves are pounding violently. It could be possible that they are homing-in on the acoustical signature of this beach which is created by the pounding waves in combination with some unique feature of the bottom terrain in this area.

Kemp's Ridley began to disappear in the early 50's which was hypothesized by scientists to be due to uncontrolled harvesting by local residents. But, this also corresponds with the massive use of explosives and seismic airguns for oil exploration in the Gulf of Mexico. This species has been protected from beach harvesting for years but has not shown any come-back whatsoever. Auditory trauma might just be the "straw" that added to their demise after they were weakened by over-harvesting.

But why are you hearing this from a lowly sea captain? Because crooked money-hungry scientists don't talk about deafness and barotrauma in sea turtles because 90% of their blood money comes from the oil industry and the US Navy who don't want the subject discussed. These greedy scientists know if they talk about the auditory trauma in marine critters, then they will not get any more sea turtle blood money -- its that simple!

One might assume that EVERYONE who has ever studied sea turtles throughout history has missed an extremely important aspect of sea turtle survival because not one single word of scientific material has ever been written dealing with the survival of sea turtles if their hearing faculties were impaired. Fact is, the word "deafness" has never appeared in any scientific material or book about sea turtles. Nor is there any research about why sea turtles have ears in the first place. Oh... and there's absolutely nothing is the scientific literature about barotrauma is sea turtles either!

Scientists say the leading causes of turtle mortality in the Gulf of Mexico is entrapment in fishing nets. On Florida's East Coast, boat collisions are the most documented cause of death. So... these jerks feed the public bullshit blaming it all on the fishermen and the boaters when the real culprits are the ones who a paying the scientist the blood money.

In my opinion, the greater percent of net entrapped turtles have suffered prior auditory damage created by the use of explosives and seismic air cannons (airgun arrays) in the marine environment. They are unable to determine sound direction and swim to the bottom in the direct path of the shrimp fishermen's nets. Those struck by boats simply never hear noise of an approaching vessel.

The Potential for Deafness in Sea Turtles

In order to determine the potential for deafness it is necessary to examine the method of reception. This should indicate the areas of the ear more likely to suffer barotrauma, and the types of pressure waves that would be most damaging. The ear drum (tympanic membrane) of the sea turtle is covered by the skin of the face. This area is relatively soft and yielding and can be felt with the finger. The outer layer of the ear drum lies at the side of the head, well behind the eye, and above the level of the corner of the mouth. The middle layer of this membrane is particularly thick and contains a large amount of fatty tissue. The inner layer is formed by a plate of cartilage, which is the main part of the extracolumella. The ear drum is attached by a heavy posterior ligament and a thin anterior ligament.

The extracolumella is attached to the columella. This pencil shaped rod attaches directly to the cochlea. This middle ear arrangement is odd compared to mammals due to the lack of a mechanical transformer to match impedance of aerial sounds.

The tympanic cavity, the cavernous sinus, and the Eustachian tube of the sea turtle ear all contain enclosed air pockets and would be extremely sensitive to any pressure pulse, especially from seismic airgun arrays used to explore for oil and from distant explosions.

The outer ear of turtles is connected directly to the inner ear by an almost straight rod. Obviously, sea turtles would not hear to well in air. They may actually "fell" the vibrations via the soil when on land, rather than via an air conduction channel through the middle ear system.

A mechanical transformer in a well developed middle ear has an important secondary function. It serves to protect the delicate inner ear. The muscles of such a system tighten automatically by a pre-programmed reflex response whenever vibration exceed certain limits; thereby, restricting movement in order to afford a great degree of protection. This total lack of a protection system in sea turtles is a major weakness of the ear underwater for this species. It would appear that intrusion from high intensity sound could easily destroy their hearing.

It is also easy to understand why their ears have not evolved this protection. The coastal water habitat of turtles was a silent world, and void of excessive pressure changes before the recent invasion by man.

Water also tends to transmit pressure without significant loss. Peak over-pressure from underwater explosive events is much higher at the same distance from their epicenters than the corresponding over-pressure in air. For example, a 1 megaton explosion underwater will cause a 500 psi over-pressure at 6.2 miles from the epicenter, but less than 1 psi for the same distance in air. (Tsipis 1983)

Sound travels as a series of pressure variations. Traveling in air, the variations of pressure are low and the light weight air molecule is moved a great distance. Just the opposite is true in water. The acoustical pressure is sixty times higher, but the water molecule moves only a short distance (1/60th the distance of the air molecule). Sound underwater carries a short punch; but, it is sixty times more powerful!

High intensity sound energy (a series of rapid pressure changes) underwater would react more violently with areas of anatomy which offers the greatest mismatch to sound in water (impedance). Flesh and bones, composed mostly of water, would offer less mismatch, and suffer the least damage. Sound energy (a series of rapid pressure changes) would be more destructive in the air pockets of the lungs, the tympanic cavity, the cavernous sinus, and the Eustachian tube of the sea turtle ear. Exposure to excessive pressure underwater would rupture the alveoli in the lungs and mutilate the entire hearing apparatus.

Moving down the scale of intensity, destructive pressure would cause minor damage in the lungs, and destroy the ear. On a lesser degree only the ear would suffer barotrauma, and the turtle would be deafened, yet appear outwardly healthy.

This would not kill them, nor would a deaf turtle die within a few days. How long a deafened turtle could survive is a mystery. It is conceivable that he could survive for years or until he became entrapped in a shrimper's net or struck by a boat.

References:

Barger, J.E., Hamblen, H.R. (1980) The Air Gun explosive Underwater Transducer. J. Acoust. Soc. Am. 68(4)

Coles, R.A. (1968) Hazardous Exposure to impulsive Noise. J.A.S.A. Vol 43 No. 2

Davis, H.& S.R. Silverman (1978) Hearing and Deafness. Holt, Rinehart and Winston ISBN 0-03-089980-X

Fairbridge, R.W. (1974) Ed. Encyclopedia of Oceanography. Van Nostrand Reinhold Co.

Gregory, J. B., C. E. Smith (1984) Environmental Effects Of Wellhead Removal by Explosives. Minerals Management Service OCS report MMS 84-0001

Ichiye, T., H. Kuo & Carnes, M.R. (1973) Assessment of Currents and Hydrography of the Eastern Gulf of Mexico. Texas A&M University contribution # 601

Ingmanson, D.E. & W. J. Wallace (1973) Oceanology: An Introduction. Wadsworth Publishing Co.

Kinsler, L.E. & Frey, A.R., (1962) Fundamentals of Acoustics, second ed. John Wiley & Sons, Inc. New York

Klima, E.F, et al (1987) Potential impact on sea turtles, dolphins, and fishes of explosives used in offshore platform removals. J.Acoust.Soc. Suppl. 1, vol.82, Fall 1987 p-S97

Klima, E.F. (1988) Person Communication Director, National Marine Fisheries Service, Galveston Texas

Molinari, R.L. et al (1977). Current Direction Data Measured by NOAA Laboratory in the Caribbean Sea & Gulf of Mexico from 10/75 t0 6/76 by satellite-tracked buoys (map).

Molinari, R.L. (1980) Current Variability and it's Relation to Sea-Surface Topography in the Caribbean Sea and Gulf of Mexico. Marine Geodesy Vol.3 pp409-436

Moore, C.J.B. (1977) Introduction to Psychology of Hearing. University Park Press ISBN 0-8391-0996-2

Richardson, Ed G., K. L. Graham (1987) Programmatic environmental assessment - Structure removal activities. Minerals Management Service MMS 87-0002 (OCS EIS/EA)

Saunders, J.C., S.P.Dear & Schneider, M.E. (1985) The Anatomical Consequences of Acoustic Injury: A Review and Tutorial. J. A. S. A. Vol.78 No.3 pp833-860

Shooter, J.H., T.E.DeMary & R.A.Koch, (1982) Ambient noise in the western Gulf of Mexico. Applied Res. Labs., University of Texas, ARL-TR-82-15

Spiess, F.N., J Northrop & Werner, E.W. (1968) Location and enumeration of underwater explosions in the North Pacific. J.A.S.A. Vol. 43 No.3 pp640-641

Tsipis, Kosta (1983?) Arsenal. (publisher unknown)

United States Coast Pilot (1987) 1-2-3-4-5 NOAA

Urick, J.R. (1979) Sound Propagation in the Sea. Defense Advanced Research Projects Agency (Secretary of Defense)

Urick, J.R. (1984) Ambient Noise in the Sea. Naval Sea Systems Command, Dept. of Navy

Urick, J.R. & R.T.Moore (1958) Low Frequency Sound Transmission in Very Shallow Water. Navy Mine Defense Lab. Tech. Paper 117

Walton, T.L. (1973) Littoral Drift Computations along The Coast of Florida by Means of on Ship Wave Observations. Coastal and Oceanographic Engineering Laboratory, Univ. of Florida-Gainsville Tech. report #15

Wever, E.G. (1978) The Reptile Ear---Its Structure and Function. Princeton University Press

Zwislocki, J. J. (1988) Personal communications. Founder, Inst. for Sensory Res. Syracuse University N. Y.