The Lionfish TutorialsDissection

Lionfish in the Atlantic

Goals of Dissection

• Determine status and assess changes in:

– Physiology– Biology– Ecology

More specifically…

• Condition• Population dynamics• Growth and Age• Reproduction• Feeding ecology• Genetics

Lionfish Dissection

Data collected:

- Total & standard length- Weight- Sex & gonad tissue sample (reproductive status)- Gill tissue/fin clips (DNA analysis)- Tissue sample (stable isotope analysis)- Otoliths (growth)- Gape height & width- Stomach contents

http://216.218.184.99/lionfish/lionfish_dev/sites/default/files/documents/Lionfish%20Dissection.pdf

Euthanasia and Animal Welfare

• Standards for humane treatment of animals used in scientific study

• Euthanization of collected animals– Eugenol– Ice Slurry– Pithing

Handling precautionsand procedures

• Venomous spines• Precautions• Treatment• Disposal of specimens

Measurement and Sampling

• External• Internal• Units• Minimizing error• Data sheets

Dissection Methodology

• External– Length– Weight– Gape– Tissue

Internal Sampling

• Opening the gut cavity• Gender ID and reproductive staging• Fat• Stomach• Otoliths

Gonad Staging

Male - Gonads elongated with ratio of length:width greater than 2

• M1 – Immature – Testes appear as clear, threadlike structures 1-3 mm in diameter and 5-10 mm in length. Immature female ovaries are largely indistinguishable from immature male testes.

• M2 – Mature – Testes appear cream-colored with well-defined edges. Testes are typically not larger than 10 mm in diameter and 20 mm in length in the largest of specimens.

 

Gonad Staging

 Female - Gonads oval, cream-pink in color, ratio of length:width less than 2.

• F1 – Early Developing - Ovaries are cream colored and round with no edges. Width may vary from 5 - 15 mm. Eggs are not visible macroscopically. Ovaries are more firm than during the Developing stage.

• F2 – Developing – Ovaries are cream colored with some pinkish portions. Eggs are visible as small white spheres. Ovaries may vary from a width of 15 mm to more than 30 mm. No gelatinous mucus is visible around periphery.

Gonad Staging

 Female - Gonads oval, cream-pink in color, ratio of length:width less than 2.

• F3 – Mature/Spawning Capable- Ovaries are large with clear gelatinous mucus containing visible eggs. Ovary size may vary from a width of 15 mm to more than 30 mm.

• F4 – Actively Spawning – Ovaries are hydrated. A large number of clear eggs are encompassed in gelatinous mucus visible along periphery of the ovary.

Lionfish Fat

Nassau grouperYellow tail snapper

Banded coral shrimp

Lionfish consume prey over half their size

Reef squirrelfishSpanish hogfish

Redband parrotfish

• Over 70 different prey species found in lionfish stomachs• Commercially and recreationally important species (grazers and cleaners) –

keeping the reef healthy and fish clean

64 prey fish plus a shrimp!

Stomach Contents

Lionfish Stomach Contents

For each prey:

- Identification- Total length- Digestion level

- Scale of 1 to 5: 1= ID to species level, 5= unidentifiable)

- Volume

Otolith removal

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AcknowledgementsDr Stephanie GreenDr James MorrisLad AkinsDr Dayne BuddoCape Eleuthera InstituteREEF