This study examined the reproductive characteristics of invasive lionfish in Bermuda. Researchers collected female lionfish from 2013-2016 and measured their total length, body mass, and gonadosomatic index (GSI). They found that lionfish in Bermuda have similar body sizes to those in Little Cayman. Bermuda lionfish appear to spawn seasonally from June to September when water temperatures are warmest, unlike in Little Cayman where they spawn year-round. Lionfish were only found actively spawning in depths from 45-65 meters during this time period. The study provides new information about seasonal spawning patterns and depth distribution of lionfish in Bermuda.

1. Conclusion
Reproductive Characteristics of Invasive Lionfish in Bermuda
Jennifer Salas, Corey Eddy, and Diego Bernal
Department of Biology, University of Massachusetts, Dartmouth, MA
Contact Information: Twitter: @salas_jenn24, Email:jennifer.salas93@gmail.com
Methods
Results
• Lionfish (Pterois miles and P. volitans) are native to the
Indo-Pacific oceans and have been recently reported in
the Western Atlantic (WA) Ocean from Brazil to North
Carolina.
• This study focuses on lionfish in Bermuda. Bermuda was
one of the first places outside of the United States to be
invaded by lionfish but it has the smallest lionfish
population.
• Lionfish in the WA have a broad diet, occupy anywhere
from 20m to 80m, 10oC to 30oC and appear to have no
natural predators. (Kimball 2004)
• In the WA, lionfish appear to spawn all year, have large
quantities of eggs at one time, however their frequencies
of spawning are unknown. GSI = 1E-06(TL2.4703)
R² = 0.16758
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
25 75 125 175 225 275 325 375 425
GSI(%)
TL (mm)
GSI vs TL (mm)
• Seasonal spawning appears to happen through out
the year when the water is warmer then potentially
more lionfish are actively spawning.
• In the winter months they tend to be resting in the
developing stage.
Figure 4: GSI and the TL of the fish. The circles in red and blue have
already spawned. Sample size= 62 fish.
Figure 3: TL and body mass comparison. Black line represents the regression line of
Bermuda, purple line is Little Cayman (Gardner 2015). Sample size= 62 fish.
Figure 6: June through September data of spawning ability and depth fish
were caught at. Numbers on top of column represent sample size.
0
5
10
15
20
25
30
35
0m-45m 45m-60m
#ofFishCaptured
Depth
June-September Depth vs Spawning ability
Immature Developing
Spawning Capable Actively Spawning
11
2
14
9
33
Discussion
• Body mass and total length of Bermuda lionfish
appear to be similar to Little Cayman. The fish that
are longer and have a higher body mass are fish that
have just spawned and are now resting.
• Higher GSIs were observed during the months lionfish
were spawning the most because the ovaries are
potentially bigger which makes the overall body
mass higher. There are no data from other studies
comparing GSI to the length of the fish. However,
Gardner observed higher GSIs when they were the
most reproductively active (Gardner 2015). Even
though the lionfish are not spawning year round,
when they do spawn their GSIs are higher like
Gardner 2015.
• Lionfish in Bermuda appear to be seasonal spawners,
unlike Little Cayman. However, there is a sign that
they are developing year ‘round. The most spawning
happens during June through September when the
water is the warmest.
• This graph shows that Lionfish are only actively
spawning in 45m to 65m. November through May
dates are not shown because we did not catch any
fish that were in water deeper then 25m. Also, there
are no data of other studies comparing depth and
maturity in ovaries. Lionfish have been observed in
deeper water but the research of why they are there
is unknown.
Figure 2: Development stage of the
eggs in the ovaries. These are
either immature (primary growth,
PG), developing (cortical alveoli,
CA, primary vitellogenic, VTG1 or
secondary vitellogenic, VTG2),
spawning capable (tertiary
vitellogenic, VTG3), actively
spawning (hydration, H, germinal
vesicle migration, GVM).
Acknowledgements
• Special thanks to Ken Oliveira, for letting us use his
equipment and Mass Histology for preparing most of our
slides.
• This research was supported by the National Science
Foundation research experiences for undergraduates.
Objective
Background
• This study quantifies the reproductive biology of lionfish in
Bermuda.
• This study also looks at if Bermuda is significantly different
from other WA regions, specifically looking at the
gonadosomatic indices (GSI), degree of egg
development throughout the year, and determined if
there are seasonal spawning events of lionfish.
• Female lionfish were collected off Bermuda from 2013 to
2016, TL, body mass were measured, and calculated by
the total ovary mass divided by the total fish mass and
multiplied by 100 which is determined by the GSI.
• The ovaries were weighed and cross sectioned at the
midpoint (Figure 1C).
• Ovary sections were dehydrated, embedded with wax,
cut into 5ųm and stained using as Hematoxylin and Eosin.
• Fixed and stained sections were viewed under a
microscope to 4x and the developmental stages were
identified. (Figure 2)
• Analysis of the developmental stage of the ovaries was
determined with correlation to the TL, ovary mass, body
mass, and depth of capture.
2
Figure 1: (A) Map of Bermuda (B) Representative mature female lionfish, TL= total length
(C) insert shows overall location of the ovaries. Insert grey area pictured shows a
mature ovary.
B C
Blue line: Where ovaries are sectioned.
Developing Actively
Spawning
Immature Spawning
Capable
Slide with cross
sectioned ovary. Darling, Emily S., et al. "Indo-Pacific lionfish are larger and more abundant on invaded reefs: a comparison of Kenyan and Bahamian lionfish populations." Biol Invasions, 17 May 2011.
Eddy, Corey, et al. Unpublished data.
Gardner, Patrick G., et al. "Reproductive Biology of Invasive Lionfish (Pterois spp.)." Frontiers in Marine Science, 30 Jan. 2015.
Kimball, Matthew E., et al. "Thermal tolerance and potential distribution of invasive lionfish (Pterois volitans/miles complex) on the east coast of the United States." MARINE ECOLOGY
PROGRESS SERIES, PDF ed., Nov. 2004.
Morris, James A., Jr., et al. "Oogenesis and spawn formation in the invasive lionfish, Pterois miles and Pterois volitans." Scientia Marina, Mar. 2011.
Paisano. "Lionfish." Caribe Sunset, www.caribesunset.com/news/LionFish.jpg. Accessed 8 Aug. 2016.
Figure 5: (A) Percent of fish caught compared to the spawning ability
and average temperature for each month. Numbers on top of column
represent sample size. (B) Seasonality graph in Little Cayman for
2011-2012 (Gardner 2015).
0
5
10
15
20
25
30
35
0
20
40
60
80
100
120
Temperatures(C)
PercentFishCaught
Month
Seasonality of Ovaries
Immature Developing
Spawning Capable Actively Spawning
Average Temperature
1 11
6
4
8 2
GSI = 3E-5(TL2.47 )
R² = 0.5812
GSI=3E-5(TL3.24)
=Immature
=Developing
=Mature ovaries
= Little Cayman
0
200
400
600
800
1000
1200
1400
1600
25 75 125 175 225 275 325 375 425
BodyMass(g)
TL (mm)
TL vs Body Mass
A B
A
0.5mm
0.2mm
0.5mm
0.3mm
References
TL
1
22
4 1 1
11
5
1
1
50
4
19
1
7
3
13
5.0 g