Lab 1 Paper: eDNA Shark Diversity Flashcards

1
Q

Name and describe two advantages of monitoring elasmobranchs with eDNA compared to traditional
monitoring techniques?

A

Traditional monitoring techniques are resource intensive, selective and dependent on taxonomic expertise as well as being invasive and traumatic

Outperform traditional methods for diverse taxa
More cost-effective and non-invasive

Easy to standardize and no taxonomic expertise

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2
Q

Describe two disadvantages of using eDNA to determine elasmobranch abundance and richness

A

DNA in ocean water degrades beyond detectability within a few days, only detecting recent sharks in the area

Taxonomic resolution is dependent on the chosen markers

Taxonomic ambiguity due to limited sequence variability

Difficulty distinguishing closely related species

Estimating abundance is not cut and dry

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3
Q

Why are sharks vulnerable to overexploitation?

A

They are perceived to be in competition with fishers and dangerous in nature (untrue)

They have slow growth rates and low fecundities, particularly vulnerable to overfishing

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4
Q

According to the paper, why are the Bahamas, New Caledonia and Chesterfield more diverse (i.e.
higher richness) than the other sampling locations?

A

The Bahamas has a shark sanctuary status and heavy protection so it has the least fishing pressure.

New Caledonia and Chesterfield were found to be so diverse because they are still very pristine ecosystems further away from the capital. Less pressure

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5
Q

Briefly describe the issues with the genera Carcharhinus, Rhizopronodon and Negaproprion
identification with the eDNA sampling technique?

A

100% sequence identity matches with more than one species

Carcharhinus is taxonomically problematic and polyphyletic

Rhizopronodon and Negaproprion are less speciose

Very closely related species within these genera are often identified from one sample.

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