Stock Identification of HaddockMelanogrammus aeglefinuson Georges Bank Based on Otolith Shape Analysis

Abstract
Otolith shape analysis was examined to determine its utility for stock identification of haddock Melanogrammus aeglefinus on Georges Bank. Otolith samples were collected from the Northeast Peak (eastern Georges Bank) and the Great South Channel (western Georges Bank) spawning components to examine stock continuity across Georges Bank. Otolith shape was described using 20 Fourier harmonics, four morphometric characteristics (area, length, width, and perimeter), and two shape indices (circularity and rectangularity). Potential confounding sources of variation (fish length, otolith position, age-group, and year-class) were examined and accounted for in the analyses before interpretation of spatial/stock differences. Significant age-specific differences in otolith shape between eastern and western Georges Bank haddock indicated stock separation across the Bank. Classification success for each spawning component ranged from 63 to 80% across age-groups and appeared to depend on growth rate differences....