Life history of wahoo, Acanthocybium solandri, in the Tropical Eastern Atlantic Ocean – the importance of applying a suite of methods for fisheries assessment in data-limited situations

Abstract

Unassessed  fisheries,  mostly  non-targeted  fisheries,  are  now particularly predominant in many commercial fisheries and are critical to food security in developing countries. These fisheries  typically  lack  reliable  data  essential  for  assessing  their  stocks,  leaving  them  susceptible  to  overfishing  and  declining  yield  over  time.  This  study  proposes  a  framework  for  determining  the  life  history  and  management  of  such  fisheries. Data on the length composition and reproduction of   wahoo   Acanthocybium   solandri,   a   common   bycatch   species    in    commercial    fisheries,    were    obtained    from    observers  aboard  Chinese  longline  vessels  in  the  Eastern  Atlantic  between  2010  and  2020  and  were  used  as  a  case  study.   A   comprehensive   methodological   approach   was   applied using data on this species to estimate its life history parameters,  to  evaluate  biological  reference  points,  and  to  provide  proxies  for  the  stock  status.  The  final  main  growth  parameters  obtained  were:  Linf  =  161.21  cm  FL  (157.34–194.68), K =  0.47/year  (0.14–0.65);  estimated  size  at  first  maturity was 89.6 cm FL. As assessed by the set of methods applied,  the  wahoo  stock  state  was  healthy  in  the  Tropical  Eastern  Atlantic  Ocean.  This  study  advises  against  using  a  single  approach  to  determining  life  history  parameters  in  data-limited fisheries, as this may affect reference points and thus management recommendations. This study provides a route whereby many easy-to-apply methods can be used to understand the status of multiple stocks in poorly managed fisheries, and thus provide management plans.