Submarine Dive Video

The Diversity and Distribution of Cephalopods in the Charlie-Gibbs Fracture Zone Richards JC1*, Vecchione M1,2

1Department of Invertebrate Zoology, National Museum of Natural History, Smithsonian Institution2National Marine Fisheries Service, National Museum of Natural History, Washington DC, 20560, USA

References1. Cook A.B, Sutton T.T, Galbraith J.K, Vecchione M, 2012, ”Deep-pelagic (0–3000m) fish

assemblage structure over the Mid-Atlantic Ridge in the area of the Charlie-Gibbs Fracture

Zone”, Deep Sea Research Part II, 98: 279-291

2. GeoMapApp: http://www.geomapapp.org

3. Ryan et al., 2009

4. Clarke, KR (1993). Non-parametric multivariate analyses of changes in community structure.

Australian Journal of Ecology 18: 117-143

5. Vecchione M, Young R.E, and Piatkowski U, 2010, “Cephalopods of the northern MidAtlantic

Ridge”, Marine Biology Research, 6: 1, 25 – 52

6. v7: Clarke, KR, Gorley, RN, 2015. PRIMER v7: User Manual/Tutorial. PRIMER-E, Plymouth,

296pp.

AcknowledgementsWe thank April Cook for providing the discrete-depth zones and their volume calculations. We thank Abby Reft

for assisting with specimens. We thank NOAA for providing ship time and support for the 2009 Bigelow Cruise

and the 2004 SARS Cruise. We Thank Elizabeth Cottrell for mapping with GeoMapApp. A special thanks to the

Smithsonian Institution. All data are associated with the MARECO program of the Census of Marine Life. Funding

was provided by NSF.

IntroductionThe majority of the oceans still remain unexplored. For this reason, the MARECO project of the

Census of Marine Life explored biodiversity along the Charlie-Gibbs Fracture Zone (CGFZ):

the region of the Mid-Atlantic Ridge running from Iceland to the Azores.

Cephalopods play an integral part in marine environments, where they take on both predator

and prey roles. Cephalopods are also important within the fishing industry. The distribution

and diversity of cephalopods was quantified in order to learn more about the ecosystems

surrounding the CGFZ.

Muusoctopus johnsonianus Gonatus steenstrupi Mastigoteuthis agassizii

Sampling Sites

0 m

700 m

200 m

1900 m

2900 m

Ocean FloorBottom

Mid Water

North

America

Africa

Charlie Gibbs Fracture Zone

Eleven sites along the CGFZ were

sampled. Each site consisted of two

major trawling zones: Mid water and

bottom. The mid water zone is further

broken up into four discrete depth

ranges: 0 – 200 meters, 200 – 700

meters, 700 - 1900 meters, and 1900

– 2900 meters.1 Roughly 20 species of

cephalopod were collected across all

sites.

9 11 13

12

15

18

17

16

2019 21

Atlantic Ocean

MethodsSite DiversitySubmarine Dive Video

Squid Abundances Site Similarity

50 hours of video across 11 dives were viewed.

Sightings of the most common species, Gonatus

steenstrupi, were recorded alongside the time of

day and depth. Dive data is separate from trawl

data.

The total number of species recorded at each

site via trawling was mapped using

GeoMapApp. Each site was divided between

mid water and bottom trawling zones.

The total number of Gonatus steenstrupi caught

at all sites via discrete depth trawling was

standardized by the total water filtered at each

depth. Trawls were divided temporally (e.g. Day

and Night). Only mid water depth ranges were

used for these calculations.

The species composition (number of individuals of

each species) at each site was compared to other

sites with Bray-Curtis Similarity.6 These similarity

values were used to produce tree diagrams.5 Each

site was categorized as north or south and divided

between mid water and bottom.

0

1000

2000

12:00 AM 6:00 AM 12:00 PM 12:00 AM 6:00 PM

Gonatus steenstrupi ROV sightings

Dep

th (m

ete

rs)

Squid

Sighting

Conclusion:

Gonatus steenstrupi are most common closer to the ocean surface; the majority live

above depths of 1000 meters.

Graph depicting 11 separate dives and their distinct paths; red points signify the sighting of a

Gonatus steenstrupi. Blue represents day and purple represents night.

NightDay

Site Diversity

Squid Abundances Site Similarity

04 1284

Night Day

2900

700

1900

200

0

Abundance (Squids/104 m3 water)

Gonatus steenstrupi Diel Abundances

Dep

th (m

ete

rs)

Conclusion:

Gonatus steenstrupi display the highest abundances during the day and at

shallower depths.

Juvenile G. Steenstrupi

collected during trawls

Day vs. Night (i.e. Diel) graph depicting G. steenstrupi abundances at various depths.

Charlie Gibbs Fracture Zone

Mid Water Site Diversity

Charlie Gibbs Fracture Zone

Bottom Site Diversity

Number of

Species

present:

1

3

5

8

Maps depicting the number of species present at each site. Each site is divided into

two zones: mid water and bottom. Blue signifies a northern site and red signifies a

southern site.

Mean North

Diversity: 2.4

Mean South

Diversity: 4.75

Mean South

Diversity: 3.25

Mean North

Diversity: 3.5

Squid Species

Showcase:

Conclusion:

Mid waters in southern sites have the highest diversity and mid

waters in northern sites have the lowest diversity.

0

20

80

100

60

40

20 21 1715 16 919 1213 1118

Sim

ila

rity

(%

)

Mid Water Site Similarity

Sim

ila

rity

(%

)

0

20

80

100

60

40

19 11 13 15 20 9 21 17

North

South

Legend:

Bottom Site Similarity

Octopod

Species

Showcase:

Tree depicting similarity (%) amongst the mid water trawl zones of sites.

Tree depicting similarity (%) amongst the bottom trawl zones of sites.

0%

40%

22%

32%

46%

56%

71%

14%11%

30%

43%

62%

80%

63%

79%89%

96%

Conclusion:

Mid water sites are more similar than bottom sites.

Photograph courtesy of David Shale, MARECO Photograph courtesy of David Shale, MARECO Photograph courtesy of David Shale, MARECO

North

South

Legend: