Climate-induced habitat suitability intensifies fishing-induced
life-history variation of a migratory long-lived fish
Abstract
Intense fishing pressure and climate change are major threats to coastal
fisheries. Larimichthys crocea (large yellow croaker) is a
long-lived fish, which performs seasonal migrations from its spawning
and nursery grounds along the coast of the East China Sea (ECS) to
overwintering grounds offshore. This study used length-based analysis
and habitat suitability index (HSI) model to evaluate current
life-history parameters and overwintering habitat suitability of
L. crocea, respectively. We compared both life-history parameters
and overwintering HSI between recent (2019) and historical (between 1971
to 1982) to analyze the fishing pressure and climate change effects on
the overall population and overwintering phase of L. crocea. In
the context of overfishing, the length-based analysis indicated serious
overfishing of L. crocea, characterized by reduced catch yield,
size truncation, constrained distribution, and advanced maturation in
the ECS, namely recruitment bottleneck. In the context of climate
change, the overwintering HSI modeling results indicated that climate
change has led to decreased sea surface temperature during L.
crocea overwintering phase over the last half-century, which in turn
led to area decrease and an offshore-oriented shifting of optimal
overwintering habitat. The fishing-caused size truncation may constrain
the migratory ability and distribution of L. crocea, subsequently
led to the mismatch of the optimal overwintering habitat against climate
change background, namely habitat bottleneck. Hence, while heavily
fishing was the major cause of L. crocea fishery collapse,
climate-induced overwintering habitat suitability may have intensified
the fishery collapse of L. crocea population. It is important for
management to take both overfishing and climate change issues into
consideration when developing stock enhancement activities and policy
regulations, particularly for migratory long-lived fish that share a
similar life history to L. crocea. Combined with China’s current
restocking and stock enhancement initiatives, we propose recommendations
for future restocking of L. crocea in China.