81 
National Marine 
Fisheries Service 
NOAA 
Fishery Bulletin 
established In 1881 -cf. 
Spencer F. Baird 
First U S Commissioner 
of Fisheries and founder 
of Fishery Bulletin 
Identifying populations of the blue jack 
mackerel (Trachurus picturatus) in the Northeast 
Atlantic by using geometric morphometries and 
otolith shape analysis 
Email address for contact author: joana.pr.vasconcelos@madeira.gov.pt 
Abstract— The population structure 
of the blue jack mackerel (Trachurus 
picturatus, Osteichthyes, Carangi- 
dae), in the northeast Atlantic is 
still unknown. To identify any dis¬ 
tinct population units, three areas 
were selected: waters off Madeira, 
Peniche (mainland Portugal), and 
the Canary Islands. Knowledge of 
population structure is an aspect of 
the population dynamics of a spe¬ 
cies that is essential to effectively 
assess the existence of stocks and 
manage fisheries. In this study, geo¬ 
metric morphometries and otolith 
shape analysis were successfully 
applied for population identifica¬ 
tion. Multivariate analysis of vari¬ 
ance (MANOVA) revealed no body 
shape differences between males 
and females in each area studied, 
and therefore the sexes were com¬ 
bined for the analysis. The results 
of the discriminant analysis showed 
that a low misclassification occurred 
among areas; 78.0% of individuals 
were correctly classified. MANOVA 
performed on the otolith normalized 
elliptic Fourier descriptors revealed 
significant areal differences, but no 
difference between sexes. An overall 
classification success of 73.3% in the 
canonical discriminant analysis was 
achieved. These results indicate the 
usefulness of both otolith and body 
shape analysis for differentiation of 
blue jack mackerel stocks from the 
northeast Atlantic and indicate the 
existence of at least three distin¬ 
guishable populations of this species. 
Manuscript submitted 28 March 2017. 
Manuscript accepted 20 November 2017. 
Fish. Bull. 116:81-92 (2018). 
Online publication date: 13 December 2017. 
doi: 10.7755/FB.116.1.9 
The views and opinions expressed or 
implied in this article are those of the 
author (or authors) and do not necessarily 
reflect the position of the National 
Marine Fisheries Service, NOAA. 
Joana Vasconcelos (contact author) 1 ' 2 ' 3 
Ana R. Vieira 4 
Vera Sequeira 4 
Jose A, Gonzalez 5 
Manfred Kaufmann 3 ' 6 
Leonel Serrano Gordo 4 7 
1 Direqao de Serviqos de Investigate 
Direqao Regional de Pescas da Regiao 
Autonoma da Madeira 
Estrada da Pontinha 
9004-562 Funchal, Madeira, Portugal 
2 Centro de Ciencias do Mar e do 
Ambiente (MARE) 
Quinta do Lorde Marina 
Sitio da Piedade 
9200-044 Caniqal, Madeira, Portugal 
3 Universidade da Madeira 
Faculdade de Ciencias da Vida 
Campus Universitario da Penteada 
Caminho da Penteada 
9020-105 Funchal, Madeira, Portugal 
4 MARE 
Faculdade de Ciencias 
Universidade de Lisboa 
Rua Ernesto Vasconcelos 
Campo Grande, 1749-016 Lisboa, Portugal 
In fisheries management, under¬ 
standing population structure is key 
because a stock is the basic unit in 
population dynamic models that are 
used both to determine the status of 
a stock and to implement manage¬ 
ment actions appropriate for ensur¬ 
ing the sustainability of a population 
(Secor, 2014). Begg and Waldman 
(1999) suggested a holistic approach 
to understanding populations of fish 
by using both genetic and phenotypic 
analyses to define stock boundaries, 
because this integrative approach 
5 Ecologfa Marina Aplicada y Pesquerfas 
Instituto de Estudios Ambientales y Recursos 
Naturales (i-UNAT) 
Universidad de Las Palmas de Gran Canaria 
Campus Universitario de Tafira 
3501 7 Las Palmas de Gran Canaria, Spain 
6 Centro Interdisciplinar de Investigaqao 
Marinha e Ambiental da Madeira 
Ediffcio Madeira Tecnopolo (Piso 0) 
Caminho da Penteada 
9020-105 Funchal, Madeira, Portugal 
7 Departamento de Biologia Animal 
Faculdade de Ciencias 
Universidade de Lisboa 
Rua Ernesto Vasconcelos 
Ediffcio C2, 2°Piso 
Campo Grande, 1 749-016 Lisboa, Portugal 
maximizes the likelihood of correctly 
defining a fish stock and enables a 
higher degree of confidence than that 
generated by a single procedure. 
The capacity of populations in dif¬ 
ferent environmental conditions to 
adapt and develop as separate bio¬ 
logical entities is counterbalanced by 
the shifting of individual fish among 
populations (Turan, 2004). However, 
each individual fish is characterized 
by a number of distinctive features 
that are influenced by environmen¬ 
tal and genetic factors (Cadrin and 
