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DNA barcoding reveals clear delineation between spawning sites for neritic versus oceanic fishes in the Gulf of Mexico

By: Makenzie Burrows, Jeremy S. Browning, Mya Breitbart, Steven A. Murawski, Ernst B. Peebles

We combined researchvessel cruises of opportunity with DNA barcoding to survey
planktonic, percomorph fish eggs at 40 stations distributed across and around the
Gulf of Mexico (GoM). The objectives were (a) to determine whether eggs of fishes
that are potential candidates for the daily egg production method (DEPM) can be
readily barcoded, (b) to identify taxa that are spawning in the GoM, (c) to determine
encounter rates for eggs of economically valuable taxa, and (d) to characterize indi-
vidual egg taxa as being primarily neritic, primarily oceanic, or primarily mixed (i.e.,
both neritic and oceanic). Of the 1,144 eggs that were individually barcoded, 709
(62%) were definitively identified to species (62 species from 42 families), with an
additional 20 taxa identified to genus or subfamily level. The eggs of 15 economi-
cally important species were identified, most of which had intermediate encounter
rates and moderately dispersed spatial distributions, as indicated by an index of
aggregation. SIMPROF analysis of stationwise cluster analysis identified eight signifi-
cant groups within the 35 stations that yielded percomorph eggs; a corresponding
specieswise analysis identified six groups of stations as having a neritic egg commu-
nity and two groups as having an oceanic community, with a community transition
located at the shelf break. Although the neritic and oceanic stations did not share
important species, it remains possible that coastal pelagic species have mixed ner-
iticoceanic distributions. Together, these results indicate DEPM fishegg surveys
based on DNA barcoding are feasible at the large marine ecosystem scale.
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