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A high-resolution molecular method for identification of smalltooth sawfish prey

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Date Issued:
2019-06-05
Summary:
The foundation of food web analysis is a solid understanding of predator-prey associations. Traditional dietary studies of fishes have been by stomach content analysis. However, these methods are not applicable to Critically Endangered species such as the smalltooth sawfish (Pristis pectinata). Previous research using the combination of stable isotope signatures from fin clips and 18S rRNA gene sequencing of fecal samples identified the smalltooth sawfish as piscivorous at high taxonomic levels. Here, we present a high taxonomic resolution molecular technique for identification of prey using opportunistically acquired fecal samples. To assess potential biases, primer sets of two mitochondrial genes, 12S and 16S rRNA, were used alongside 18S rRNA, which targets a wider spectrum of taxa. In total, 19 fish species, from 7 orders and 11 families, native to the Gulf of Mexico were successfully identified, including one ray, the southern stingray (Dasyatis americana). Silver perch (Bairdiella chrysoura), bay anchovy (Anchoa mitchilli), tidewater mojarra (Eucinostomus harengulus), spotted seatrout (Cynoscion nebulosus), ladyfish (Elops saurus), and spot (Leiostomus xanthurus) were most prevalent in our analysis. The sawfish prey identified comprised diverse taxa, indicating that this species is a generalist piscivore. These findings and the molecular approach used will aid recovery planning for the smalltooth sawfish and has the potential to reveal previously unknown predator-prey associations from a wide range of taxa, being specifically desirable for use with rare and hard to sample species.
Title: A high-resolution molecular method for identification of smalltooth sawfish prey.
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Name(s): Hancock, Taylor Lee, author
Type of Resource: text
Genre: Thesis
Issuance: single unit
Date Issued: 2019-06-05
Physical Form: PDF
Extent: 44 pgs.
Language(s): English
Summary: The foundation of food web analysis is a solid understanding of predator-prey associations. Traditional dietary studies of fishes have been by stomach content analysis. However, these methods are not applicable to Critically Endangered species such as the smalltooth sawfish (Pristis pectinata). Previous research using the combination of stable isotope signatures from fin clips and 18S rRNA gene sequencing of fecal samples identified the smalltooth sawfish as piscivorous at high taxonomic levels. Here, we present a high taxonomic resolution molecular technique for identification of prey using opportunistically acquired fecal samples. To assess potential biases, primer sets of two mitochondrial genes, 12S and 16S rRNA, were used alongside 18S rRNA, which targets a wider spectrum of taxa. In total, 19 fish species, from 7 orders and 11 families, native to the Gulf of Mexico were successfully identified, including one ray, the southern stingray (Dasyatis americana). Silver perch (Bairdiella chrysoura), bay anchovy (Anchoa mitchilli), tidewater mojarra (Eucinostomus harengulus), spotted seatrout (Cynoscion nebulosus), ladyfish (Elops saurus), and spot (Leiostomus xanthurus) were most prevalent in our analysis. The sawfish prey identified comprised diverse taxa, indicating that this species is a generalist piscivore. These findings and the molecular approach used will aid recovery planning for the smalltooth sawfish and has the potential to reveal previously unknown predator-prey associations from a wide range of taxa, being specifically desirable for use with rare and hard to sample species.
Identifier: fgcu_ETD_0296 (IID)
Note(s): Degree Awarded: Master of Science
Department of Marine & Ecological Sciences
Subject(s): feeding ecology
high-throughput sequencing
trophic ecology
Diet.
Molecular ecology.
Sawfishes
Persistent Link to This Record: http://purl.flvc.org/fgcu/fd/fgcu_ETD_0296
Use and Reproduction: Creator(s) holds copyright.
Use and Reproduction: http://rightsstatements.org/vocab/InC/1.0/
Host Institution: FGCU