Lewis et at: Integrating DNA barcoding of fish eggs into ichthyoplankton programs 
163 
A B 
SST (°C) 
Figure 5 
Scatter plots and linear regression analysis results for the 5 identified species, collected from at least 15 
stations along the northeastern U. S. continental shelf during 2002-2012, for which a significant trend 
(P< 0.05 or 5%) was observed between egg diameter (measured in millimeters) and sea-surface temperature 
(SST) of the collection day (in degrees Celsius): (A) fourspot flounder (Hippoglossina oblonga), (B) Gulf 
Stream flounder ( Citharichthys arctifrons ), (C) butterfish {Peprilus triacanthus), (D) yellowtail flounder 
(LimancLa ferruginea), and (E) Atlantic cod (Gadus morhua). Each measured diameter is marked with an 
open circle, and a solid line illustrates the overall trend observed. The calculated P-value and the coefficient 
of determination (r 2 ) for each species are included in the top-right corner of each plot. 
Smith 4 ). Currently, many large organizations, such as 
the National Marine Fisheries Service, handle molecu- 
lar identification on a program-specific basis, each of 
which may use a different technique. The consequence 
of this fractured approach is a substantial redundancy 
in cost, effort, and equipment across programs. Addi- 
tionally, many smaller programs are unable to justify 
the start-up and reoccurring costs of a molecular labo- 
ratory and, therefore, continue to produce data with a 
substantial fraction of individual specimens not identi- 
4 Lewis, L., and B. Smith. 2013. Unpubl. data. Northeast 
Fish. Sci. Cent., Natl. Mar. Fish. Serv., NOAA, Narragansett, 
RI, and Woods Hole, MA. 
fied at the species level. The opportunity presented by 
DNA barcoding changes this fractured and inefficient 
approach to molecular identification into one unified 
method that can be shared across regions and types of 
sampling programs. 
Acknowledgments 
We thank the scientists and crew of the research ves- 
sels, too many to name individually, who contributed 
to the collection of ichthyoplankton samples over sev- 
eral decades, and in particular J. Prezioso, who ensured 
that additional ethanol-preserved samples were collect- 
