TY - JOUR
T1 - Dinámica poblacional incierta y variables de estado en alfonsino (Beryx splendens)
AU - Wiff, Rodrigo
AU - Quiroz, Juan Carlos
AU - Gatica, Claudio
AU - Contreras, Francisco
AU - Paramo, Jorge
AU - Barrientos, Mauricio A.
PY - 2012/3
Y1 - 2012/3
N2 - Alfonsino (Beryx splendens) is a species associated with seamounts, with an important fishery in Juan Fernandez archipelago, Chile (33°40′S, 79°00′W). Since 2004, this resource has been managed by catch quotas estimated from stock assessment models. The alfonsino model involves high levels of uncertainty for several reasons including a lack of knowledge of aspects of the population dynamics and poorly informative time-series that feed the proposed evaluation models. This work evaluated three hypotheses regarding population dynamics and their influence on the main state variables (biomass, recruitment) of the model using age-structured and dynamic biomass models. The hypotheses corresponded to de-recruitment of older individuals, non-linearity between standardized catch per unit effort, and population abundance as well as variations of the relative importance of length structures. According to the results, the depletion of the spawning biomass between 1998 and 2008 varied between 9 and 56%, depending on the combination of hypotheses used in the model. This indicates that state variables in alfonsino are not robust to the available information; rather, they depend strongly on the hypothesis of population dynamics. The discussion is focused on interpreting the causes of the changes in the state variables in light of a conceptual model for population dynamics in alfonsino and which pieces of information would be necessary to reduce the associated uncertainty.
AB - Alfonsino (Beryx splendens) is a species associated with seamounts, with an important fishery in Juan Fernandez archipelago, Chile (33°40′S, 79°00′W). Since 2004, this resource has been managed by catch quotas estimated from stock assessment models. The alfonsino model involves high levels of uncertainty for several reasons including a lack of knowledge of aspects of the population dynamics and poorly informative time-series that feed the proposed evaluation models. This work evaluated three hypotheses regarding population dynamics and their influence on the main state variables (biomass, recruitment) of the model using age-structured and dynamic biomass models. The hypotheses corresponded to de-recruitment of older individuals, non-linearity between standardized catch per unit effort, and population abundance as well as variations of the relative importance of length structures. According to the results, the depletion of the spawning biomass between 1998 and 2008 varied between 9 and 56%, depending on the combination of hypotheses used in the model. This indicates that state variables in alfonsino are not robust to the available information; rather, they depend strongly on the hypothesis of population dynamics. The discussion is focused on interpreting the causes of the changes in the state variables in light of a conceptual model for population dynamics in alfonsino and which pieces of information would be necessary to reduce the associated uncertainty.
KW - Beryx splendens
KW - Chile
KW - Population dynamics
KW - Seamounts
KW - Southeastern pacific
KW - Stock assessment
KW - Uncertainty
UR - http://www.scopus.com/inward/record.url?scp=84861469179&partnerID=8YFLogxK
U2 - 10.3856/vol40-issue1-fulltext-19
DO - 10.3856/vol40-issue1-fulltext-19
M3 - Article
AN - SCOPUS:84861469179
VL - 40
SP - 201
EP - 212
JO - Latin American Journal of Aquatic Research
JF - Latin American Journal of Aquatic Research
SN - 0718-560X
IS - 1
ER -