Biology Faculty Articles

Title

Effects of Species Misidentification on Population Assessment of Overfished White Marlin Tetrapturus albidus and Roundscale Spearfish T. georgii

Document Type

Article

Publication Date

2009

Publication Title

Endangered Species Research

Keywords

Population assessments, Roundscale spearfish, Species identification, White marlin

ISSN

1863-5407

Volume

9

Issue/No.

2

First Page

81

Last Page

90

Abstract

The white marlin Tetrapturus albidus (Istiophoridae) is considered to be among the most overexploited species under international management jurisdiction in the Atlantic Ocean, resulting in diverse stakeholder concerns. Efforts have been made to add it to the US Endangered Species List. Its population status has become uncertain with the realization that: (1) longstanding misidentifications of white marlin have occurred with the recently recognized, morphologically similar and sympatric roundscale spearfish T. georgii; and (2) the 2 species have unknowingly been assessed and managed as a species group. We show that roundscale spearfish currently constitute a substantial proportion (~27%) of the overall ‘white marlin’ catch in the western North Atlantic, with high spatial variation within this region. Consequently, the accuracy of current biological knowledge on white marlin, some of which has formed the input for past population status modeling, is compromised by ‘contamination’ due to misidentification. Population assessment simulations in the western North Atlantic incorporating the proportion of roundscale spearfish (27%) were run; these indicated that historical changes in the ratio of the 2 species, as well as differences in the population growth rates between T. albidus and T. georgii, affect simulation results. Our findings suggest misidentifications between the species may have affected the accuracy of past T. albidus population assessments in the western North Atlantic, which therefore need re-visiting to permit improved management and recovery of this species. New collection of life history data for T. albidus and T. georgii is also recommended to corroborate the results of historical studies.

Comments

©2009 Inter-Research

NOAA Fisheries grant #: WC133F08SE2112

Research received extensive worldwide media coverage including in: L.A. Times, Miami Herald, Florida Sun-Sentinel, St. Louis Post-Dispatch, United Press International, Discovery, BBC Radio.

ResearcherID

G-4080-2013

DOI

10.3354/esr00234