Slow growth of the overexploited milk shark Rhizoprionodon acutus affects its sustainability in West Africa
Age and growth of Rhizoprionodon acutus were estimated from vertebrae age bands. From December
2009 to November 2010, 423 R. acutus between 37 and 112 cm total length (LT) were sampled
along the Senegalese coast.Marginal increment ratio was used to check annual band deposition. Three
growth models were adjusted to the length at age and compared using Akaike’s information criterion.
The Gompertz growth model with estimated size at birth appeared to be the best and resulted in
growth parameters of L? =139?55 (LT) and K =0?17 year?1 for females and L? =126?52 (LT) and
K =0?18 year?1 for males. The largest female and male examined were 8 and 9 years old, but the
majority was between 1 and 3 years old. Ages at maturity estimated were 5?8 and 4?8 years for females
and males, respectively. These results suggest that R. acutus is a slow-growing species, which render
the species particularly vulnerable to heavy fishery exploitation. The growth parameters estimated in
this study are crucial for stock assessments and for demographic analyses to evaluate the sustainability
of commercial harvests
Auteur(s) : [Ba Abdoulaye 1, Diouf Khady 2, Guillaume Francois 3, Jacques Panfili 4
Pages : 912–929
Année de publication : 2015
Revue : Journal of Fish Biology
N° de volume : 87
Type : Article
Mise en ligne par : BA Abdoulaye