Sharkdefense

Key takeaways

Sharkdefense belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Sharkdefense to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Sharkdefense from memory before moving on to harder problems.

Reference excerpt

SharkDefense is a research organization and think tank focused on shark bycatch reduction. Its core research involves chemical and electrochemical shark repellent technologies. SharkDefense's repellent experiments have been featured extensively in the US and European media. SharkDefense is the discover of the permanent-magnetic and electrochemical repellent effects on sharks. These findings represent the first research efforts focused exclusively at selectively repelling sharks from commercial fishing gear without affecting the target catch. The repellent effect of electropositive metals on sharks was confirmed by the National Marine Fisheries Service, notably, Stoner and Kaimmer, and studies completed by Brill et al. (2008) and Wang et al. (2008) also support the repellent effects. The preliminary research results on permanent magnetic shark repellents were reviewed, judged, and awarded the first place 2006 WWF SmartGear award. In 2008, the Department of Primary Industries and Fisheries (DPI&F) and James Cook University (JCU), Australia confirmed that permanent (ferrite) magnets technology repel grey reef sharks, hammerheads, sharp-nosed sharks, blacktip sharks, the vulnerable sawfish and the critically endangered spear tooth shark. In 2014, SharkDefense partnered with SharkTec LLC to commercialize an aerosol semiochemical shark repellent product. Both companies are working to broaden the commercial use of SharkDefense's technologies.

History SharkDefense was formed in September 2001 by Eric Stroud and Jean Stroud. Its research program began at the Oak Ridge Shark Laboratory with a search for trace chemical messengers present in decayed shark tissue. In 1943, Burden et al. from the Woods Hole Oceanographic Institution (WHOI) had reported that decayed shark tissue was successful at halting feeding in captive dusky smooth-hound sharks (Mustelis canis). In the efforts to develop and test a chemical shark repellent package led by Dr. Harold Coolidge of the Harvard Museum, the WHOI team selected ammonium acetate as the active in the decomposing shark tissue, however, instrumental analysis by the Oak Ridge Shark Lab in 2002 failed to find ammonium acetate. It was hypothesized by SharkDefense that ammonium acetate was an approximation of the ammonium cation (based on the ammonia-like smell of the shark tissue or a urea-urease reaction), and the acetate conjugate base (based on the acetic acid which WHOI had already found to have repellent properties). After 2002, many new compounds were found and catalogued by SharkDefense, who maintains a repellent compound database.

Milestones 1. Apr. 15, 2003 – First successful field test of a semiochemical shark repellent, Triangle Rocks, South Bimini, Bahamas 2. May 2004 – A gustatory shark repellent (“5ISO”) is isolated and successfully tested 3. Nov. 2004 – Accidental discovery of the repellent effects of a rare-earth magnet is made at the Oak Ridge Shark Lab 4. Jul 12, 2005 – Testing at Achotines, Panama on captive yellowfin tuna (T. albacares) confirms that both semiochemical mixtures and the gustation compound are selective shark repellents and do not repel a commercially-valuable fish species. 5. Sep. 15, 2005 - A 0.1ppm solution of a synthetic shark repellent compound terminates tonic immobility in juvenile lemon sharks (N. brevirostris). 6. Nov. 16, 2005 – Chemical repellents are successfully incorporated into a time-release gel matrix, providing more than 4 hours of protection time. 7. May 1, 2006 – Accidental discovery is made using an electropositive metal as an experimental control at South Bimini, Bahamas. 8. May 11, 2006 – SharkDefense is the grand prize winner of the 2006 WWF Smart Gear [1] competition for its proposal on permanent magnet shark repellents. 9. Aug. 31, 2007 - Fish attractant qualities of the gustation compound are confirmed. 10. Jun. 2007 – SMART Hook technology developed.

Current members 2001 – Present. Mr. Eric M. Stroud (Seton Hall University, Ph.D. candidate) was the co-founder of SharkDefense and led the initial research to identify chemical repellent actives. He is the managing partner and is researching chemical signals and necromones as part of his PhD. 2006 – Present. Dr. Patrick H. Rice (University of Miami, RSMAS), partner, joined the SharkDefense team in 2005 while researching the repellent effects of permanent magnets. He is the director of marine sciences at Florida Keys Community College and is senior marine biologist with SharkDefense. 2006 – 2012. Mr. Craig P. O’Connell (Coastal Carolina University, Ph.D. student), partner, joined the SharkDefense team as marine biologist in 2006 while working on a contract shark repellent-sunscreen project at South Bimini, Bahamas. He is researching magnetoreception as a shark bycatch mechanism for his Ph.D. 2010 - 2011. Mr. Conrad Eskelinen (DiveBum Studios), partner, joined the SharkDefense team as creative director in 2010. 2003 – Present. Dr. Samuel H. Gruber (University of Miami, RSMAS, professor emeritus), consultant, has assisted and supervised many SharkDefense repellent trials at the Bimini Biological Field Station. 2003–Present. Mr. Grant T. Johnson (South Bimini, Bahamas), consultant, providing field and testing support. 2004 – Present. Ms. Katie Grudecki (South Bimini, Bahamas), consultant, providing field and testing support. 2004 – 2010. Mr. Sean Williams (Bimini Biological Field Station), consultant, providing field testing support.

References

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Worked examples

Example 1 — a first encounter with Sharkdefense

Start with the simplest possible case. Write down what Sharkdefense claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Sharkdefense before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Sharkdefense ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Sharkdefense

In research: Sharkdefense appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Sharkdefense in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Sharkdefense is common in secondary-school and first-year university syllabi. It links to neighbouring topics Shark conservation, so understanding it makes those chapters shorter.
In everyday life: Look for Sharkdefense outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

How to study Sharkdefense in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Sharkdefense means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Sharkdefense out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Sharkdefense in simple terms?

SharkDefense is a research organization and think tank focused on shark bycatch reduction. Its core research involves chemical and electrochemical shark repellent technologies.

Why does Sharkdefense matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Sharkdefense?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Sharkdefense.