Marancik Katrin E.

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Marancik
First Name
Katrin E.
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  • Article
    Support for the Slope Sea as a major spawning ground for Atlantic bluefin tuna: evidence from larval abundance, growth rates, and particle-tracking simulations
    (Canadian Science Publishing, 2021-10-20) Hernández, Christina M. ; Richardson, David E. ; Rypina, Irina I. ; Chen, Ke ; Marancik, Katrin E. ; Shulzitsk, Kathryn ; Llopiz, Joel K.
    Atlantic bluefin tuna (Thunnus thynnus) are commercially and ecologically valuable, but management is complicated by their highly migratory lifestyle. Recent collections of bluefin tuna larvae in the Slope Sea off northeastern United States have opened questions about how this region contributes to population dynamics. We analyzed larvae collected in the Slope Sea and the Gulf of Mexico in 2016 to estimate larval abundance and growth rates and used a high-resolution regional ocean circulation model to estimate spawning locations and larval transport. We did not detect a regional difference in growth rates, but found that Slope Sea larvae were larger than Gulf of Mexico larvae prior to exogenous feeding. Slope Sea larvae generally backtracked to locations north of Cape Hatteras and would have been retained within the Slope Sea until the early juvenile stage. Overall, our results provide supporting evidence that the Slope Sea is a major spawning ground that is likely to be important for population dynamics. Further study of larvae and spawning adults in the region should be prioritized to support management decisions.
  • Article
    Identification of larval sea basses (Centropristis spp.) using ribosomal DNA-specific molecular assays
    (U.S. Dept. of Commerce, NOAA, 2008) Vandersea, Mark W. ; Litaker, R. Wayne ; Marancik, Katrin E. ; Hare, Jonathan A. ; Walsh, Harvey J. ; Lem, Siya ; West, Melissa A. ; Wyanski, David M. ; Laban, Elisabeth H. ; Tester, Patricia A.
    The identification of sea bass (Centropristis) larvae to species is difficult because of similar morphological characters, spawning times, and overlapping species ranges. Black sea bass (Centropristis striata) is an important fishery species and is currently considered to be overfished south of Cape Hatteras, North Carolina. We describe methods for identifying three species of sea bass larvae using polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) assays based on species-specific amplification of rDNA internal transcribed spacer reg ions. The assays were tested against DNA of ten other cooccurring reef fish species to ensure the assay’s specificity. Centropristis larvae were collected on three cruises during cross-shelf transects and were used to validate the assays. Seventysix Centropristis larvae were assayed and 69 (91%) were identified successfully. DNA was not amplified from 5% of the larvae and identification was inconclusive for 3% of the larvae. These assays can be used to identify sea bass eggs and larvae and will help to assess spawning locations, spawning times, and larval dispersal.
  • Article
    Juvenile fish assemblages collected on unconsolidated sediments of the southeast United States continental shelf
    (U.S. Department of Commerce, NOAA, 2006) Walsh, Harvey J. ; Marancik, Katrin E. ; Hare, Jonathan A.
    Patterns were investigated in juvenile fish use of unconsolidated sediments on the southeast United States continental shelf off Georgia. Juvenile fish and environmental data were sampled at ten stations along a 110-km cross-shelf transect, including four stations surrounding Gray’s Reef National Marine Sanctuary (Gray’s Reef NMFS). Cross-shelf stations were sampled approximately quarterly from spring 2000 to winter 2002. Additional stations were sampled on three transects inshore of Gray’s Reef NMS and four transects offshore of the Sanctuary during three cruises to investigate along-shelf patterns in the juvenile fish assemblages. Samples were collected in beam trawls, and 121 juvenile taxa, of which 33 were reef-associated species, were identif ied. Correspondence analysis on untransformed juvenile fish abundance indicated a cross-shelf gradient in assemblages, and the station groupings and assemblages varied seasonally. During the spring, fall, and winter, three cross-shelf regions were identified: inner-shelf, mid-shelf, and outer-shelf regions. In the summer, the shelf consisted of a single juvenile fish assemblage. Water depth was the primary environmental variable correlated with cross-shelf assemblages. However, salinity, density, and water column stratification also correlated with the distribution of assemblages during the spring, fall, and winter, and along with temperature likely inf luenced the distribution of juvenile fish. No along-shelf spatial patterns were found in the juvenile fish assemblages, but the along-shelf dimension sampled was small (~60 km). Our results revealed that a number of commercially and recreationally important species used unconsolidated sediments on the shelf off Georgia as juvenile habitat. We conclude that management efforts would be improved through a greater recognition of the importance of these habitats to fish production and the interconnectedness of multiple habitats in the southeast U.S. continental shelf ecosystem.