dirk steinke - vertebrates plenary
DESCRIPTION
Marine fish eggs and larvae from the east coast of South AfricaTRANSCRIPT
Marine fish eggs and larvae from theEast coast of South Africa
Dirk Steinke, Allan Connell, Tyler Zemlak, Paul Hebert
History
Allan Connell
1985 - a major effluent pipeline was about to begin discharging industrial effluent over a shallow continental shelf area in Richards Bay
1985 - surface plankton samples were collected, over several years, to assess the diversity of fish species spawning in the area, and the intensity and seasonality of spawning.
1986 – a second study in Park Rynie was started in order to collect alive specimens.
1987 – cataloguing of eggs and hatched larvae started
2004 – DNA Barcoding was added to the procedure(including sampling of adults for reference library)
History
Work flow
• By collecting both offshore (5km) and inshore (0.5km) a reasonable assessment of location of spawning was obtained for all the common eggs in the study area.
• A simple “key” based on the physical features of pelagic fish eggs, was used to separate eggs into basic groups.
• eggs were hatched and both eggs and larvae were photographed.
• once larvae had fully pigmented eyes, theywere anaesthetised with MS222, prior to fixing in 98% alcohol for DNA Barcoding.
• other larvae were reared to the point where fin counts and juvenile features aided in identification.
Work flow
• DNA extraction was done using standard protocols at the CCDB.
• A reduced elution volume was used.
• PCR used Fish Cocktail (Ivanova 2007).
• Sequences were queried against BOLD using its Identification Engine (only 100% were considered).
• reared larvae of the same batch were fixed in formalin and serve as‘para-vouchers’
Today
• some 2100 larvae have been barcoded since 2005
• the local adult reference library (assembled in parallel) contains some 900 species
• some 1500 species of marine fishes from South Africa are barcoded
• 9000 fish species have been barcoded world-wide
0 500 1000 1500 20000
5
10
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40
Are we done?
Phy
loge
netic
Div
ersi
ty (
PD
)
# barcodes
• PD calculated using Conserve based on NJ trees generated in MEGA 4.0
• Sample size progressively increased by 10 random sequences
Results
• 1638 specimens (78%) could be identified using BOLD
• they represent 280 known species
• 10 of those are new records for South Africa
• the remaining 22% could not be matched to any barcode sequence on BOLD or GenBank.
0
10
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100
% Offshore
% Inshore
Monodactylus falciformis Cubiceps pauciradiatusPomadasys olivaceus
Some observations
Mean monthly eggs per sample, averaged over 24 years
Trends
Trends
• large rainfall causing mud to be washed out from rivers• the high nutrient load of such a deluge caused massive increase in egg
numbers• three most prolific pelagic egg spawners: Sardinops sagax, Etrumeus
teres, and Scomber japonicus
www.fisheggsandlarvae.com
Acknowledgements:
Erin CorstorphineTyler ZemlakPhilip Heemstra
Biodiversity Institute of Ontario
Thank you!