Identification of Pleuragramma antarctica larvae in the Ross Sea via mitochondrial DNA

Research into the early life stages of Pleuragramma antarctica is essential to understanding how oceanographic variation will impact spatial distributions over time. The recent findings of nursery grounds in Terra Nova Bay have led to added inquiry into larval distribution and life history traits in the Ross Sea. A report submitted to the CCAMLR-EMM working group last year provided abundance, length and growth data for larvae found in the western and eastern Ross Sea during the austral summer of 2013, which were identified as P. antarctica based on morphological characteristics. We extracted genomic DNA from a sample of these larvae and, using fish universal primers, amplified part of the 16S rDNA and the D-Loop region. Despite evidence of DNA degradation, sequencing was nevertheless successful in a fraction of samples. Sequences were aligned with known GenBank sequences for P. antarctica and several of related notothenioids, which confirmed the species identity of larvae in the western Ross Sea as P. antarctica. Consistent with the previous report, D-Loop sequences also demonstrated that recently hatched larvae sampled from the eastern Ross Sea were from the same species, suggesting the possibility of another nursery ground for P. antarctica in the vicinity of the Bay of Whales. This is a novel use of mitochondrial DNA to test morphological identification when examining spatial distributions of P. antarctica that depart from expectation