Historical presence of the roundscale spearfish, Tertrapturus georgii off Ocean City , MD.

• Main Author: Murray, Meredith
• Format: Other/Unknown Material
• Language: unknown
• Published: Scholarly Repository 2013
• Subjects: Roundscale spearfish; Tetrapturus georgii; Environmental Sciences; North Atlantic
• Online Access: https://scholarlyrepository.miami.edu/rsmas_intern_reports/205; https://scholarlyrepository.miami.edu/cgi/viewcontent.cgi?article=1192&context=rsmas_intern_reports

Prior to 1993 there were no documented reports of roundsca1e spearfish, Tetrapturus georgii, in the western North Atlantic Ocean. Recent genetic and morphometric evidence indicates the species makes up 22% of present-day catches; however, whether these proportions have changed over time is unknown. In this study, morphometric measurements were taken of fish purported to be white marlin, Kajikia albida, which were captured from the 1930’s through the 1980’s. Measurements were taken from the tip of the lower jaw to the end of the branchiostegal membrane (LJBR) and to the opercle (LJOP) for each fish. A published discriminant function was then used to determine the probability of the individual being a roundscale spearfish based on the LJBR:LJOP ratio. Using this function it was determined that four of the 46 fish examined (9.5%), had a greater than 75% probability of being roundscale spearfish. These new data do not support the notion that roundscale spearfish presence has increased in recent years.