Abstract:With the increasing intensity of human fishing activities and the growing prominence of environmental
pollution issues, the nearshore marine fishery resources in the northern South China Sea have experienced severe
decline. Priacanthus macracanthus has always been one of the main targets of trawl fishing vessels, and it is
facing prominent issues of early maturity and small body size. However, there is a lack of research on the resource
quantity of P. macracanthus. In order to achieve sustainable utilization and management of its resources, it is
necessary to evaluate the maximum sustainable yield (MSY) and catchable resource quantity of P. macracanthus.
The surplus production model is one of the commonly used methods for estimating the biological reference points
of fish stocks. It has the advantages of requiring less data and being easy to operate. However, in the process of
resource assessment, the selection of models and data sources is an important factor that affects the estimation
results of fishery population management parameters, such as optimal fishing effort, MSY, and total allowable
catch (TAC). In order to make the assessment results closer to the real fishery resources, it is necessary to provide
continuous and effective survey data and scientifically reasonable models. Therefore, this study takes the resource
assessment of P. macracanthus in the northern South China Sea as an example. The stratified sampling survey data
of catch production on fishing ports in the northern South China Sea from 2008 to 2020 were used to analyze the
catch per unit effort (CPUE) of each operation gear in different power ranges. Based on six surplus production
models, the MSY of P. macracanthus were estimated. The TAC were estimated according to decision-making
principles and graphical methods. The fishery stock status of P. macracanthus was determined based on the Kobe
diagram. The results showed that the annual trawl catch of P. macracanthus accounted for the highest proportion,
with an average of 79.36%. In the past 10 years, its catch showed a fluctuating downward trend. The Schaefer
model, Fox model, and D-Fox model had good applicability to the CPUE data of P. macracanthus (mean absolute
percentage error MAPE<100%), with estimated MSY ranging (2.5–3.2)×104 t, with an average of 2.9×104 t. The
TAC range was (2.4–3.0)×104 t, with an average of 2.7×104 t. The Kobe diagram showed that the P. macracanthus
stock in the northern South China Sea was in the safety state, and there had been no overfishing in recent years. In
this study, it is discussed that not all the catch data corresponding to the main engine power of fishing vessels can
be analyzed using the surplus production model. Secondly, the catch data corresponding to the same main engine
power range are not applicable to the analysis of all surplus production models. Finally, we believe that when
assessing the MSY of a single fishery resource, it is not only necessary to consider the diversity of assessment
models, but also the use of data from different sources. This study suggests that the different results obtained by
fitting the data from different main engine power ranges of fishing vessels can provide a reference interval for the
values of MSY and TAC. It can also provide a broader perspective on the overall analysis of the assessment results.
Taking the mean value is a beneficial attempt to explore reasonable values for MSY and TAC.
