Stock Assessment of the Commercial Small Pelagic Fishes in the Beibu Gulf, the South China Sea, 2006-2020.

Long-term variations in population structure, growth, mortality, exploitation rate, and recruitment pattern of two major commercial small pelagic fishes (CSPFs) ( and ) are reported based on bottom trawl survey data collected during 2006-2020 in the Beibu Gulf, South China Sea. All individuals collected during each sampling quarter over a period of 15 years were subjected to laboratory-based analysis. In this study, the stock of and inhabiting the Beibu Gulf was assessed using length-based methods (bootstrapped electronic length frequency analysis (ELEFAN)) to complete stock assessment in different fishery management periods (the division of fisheries management periods was based on China's input and output in the South China Sea offshore fisheries over 15 years, specifically divided into period I (2006-2010), period II (2011-2015), and period III (2016-2020)).

Opportunity for marine fisheries reform in China.

China's 13th Five-Year Plan, launched in March 2016, provides a sound policy platform for the protection of marine ecosystems and the restoration of capture fisheries within China's exclusive economic zone. What distinguishes China among many other countries striving for marine fisheries reform is its size-accounting for almost one-fifth of global catch volume-and the unique cultural context of its economic and resource management. In this paper, we trace the history of Chinese government priorities, policies, and outcomes related to marine fisheries since the 1978 Economic Reform, and examine how the current leadership's agenda for "ecological civilization" could successfully transform marine resource management in the coming years.

[Risk assessment of coastal ecosystem in Beibu Gulf, Guangxi of South China].

Based on the marine ecological investigation in the coastal area of Beibu Gulf, Guangxi in September 2009, a GIS-based evaluation was conducted on the present status of ecological environment quality, including seawater quality, nutrient level, biomass, primary productivity, biodiversity, and ecological buffer capacity, in the area in autumn, and the integrated ecological risk index (ERI) was adopted to assess the risk of the coastal ecosystem in the Gulf. In September 2009, the study area had a better ecological environment quality. Most of the risk indicators were at medium or lower level, and the total area was overall at low ecological risk level.

[Variations of fish species diversity, faunal assemblage, and abundances in Daya Bay in 1980-2007].

Based on the 2004-2005 otter trawl survey data and the 1980-2007 relevant historical records, this paper analyzed the variations of fish species composition, faunal assemblage, diversity indices, dominant species, and abundance in Daya Bay. In the 2004-2005 trawl survey, a total of 107 fish species were recorded, belonging to 50 families and 13 orders, among which, meso-demersal fish were predominant, with 48 species recorded, and followed by pelagic and demersal fishes, with 37 and 21 species, respectively. The fishes in the Bay belonged to tropical and subtropical fauna, with the dominance of warm water fishes (97 species) and warm-temperate water fishes (10 species).

[Evaluation of sustainable utilization of fishery resources in Guangdong Province].

Sustainable utilization of fishery resources is the key for the sustainable development of fisheries, and its evaluation is a critical topic in the management of fisheries. Based on the theories of sustainable utilization, an index system suitable for the evaluation of the sustainable utilization of fishery resources in Guangdong Province was established, and a hierarchy and comprehensive grey evaluation model was adopted to evaluate this sustainable utilization in 1978-2007. In the study period, the utilization level of fishery resources in this province had an overall decrease, being the lowest in 1998, only 37.

[Effects of fishing on the marine ecosystem of Beibu Gulf].

By using Ecopath with Ecosim 5.1 software, the Ecosim model of Beibu Gulf marine ecosystem in 1959-1960 was constructed, which included about 20 functional groups such as fishery, marine mammals, sea-birds, sharks, pelagic fishes, demersal fishes, and benthic crustaceans, etc. Through the comparison with the investigation data in 1997-1999, the effects of fishing on the structure and function of Beibu Gulf marine ecosystem were analyzed.

[Mass-balance ecopath model of Belbu Gulf ecosystem].

Based on the investigation of fishery resources and eco-environment in the Beibu Gulf of northern South China Sea from October 1997 to May 1999, and with EwE software, a mass-balance ecopath model of Beibu Gulf ecosystem was constructed, which consisted of 16 functional groups (boxes) including marine mammals and seabirds, each representing the organisms with similar roles in the food web, and covered the main trophic flow in Beibu Gulf ecosystem. The food web in Beibu Gulf ecosystem was dominated by detrital path, and benthic invertebrate played a significant role in transferring energy from detritus to higher trophic levels. Phytoplankton was the primary producer, and the fractional trophic levels ranged from 1.

[Fisheries biology of Nemipterus bathybius and its optimum catchable size in northern South China Sea].

Based on the investigation data in 1997-1999 and 1964-1965, this paper studied the population structure, stock density distribution and its seasonal variation, growth and mortality, as well as the feeding behaviour of Nemipterus bathybius (Snyber) in northern South China Sea. The results indicated that the body length of the samples was 4.2-21.

[Estimation of growth and mortality parameters of Argyrosomus argentatus in northern South China Sea].

In this paper, Argyrosomus argentatus in northern South China Sea was grouped into the colony in continental shelf of northern South China Sea and that in Beibu Gulf. Based on the trawl survey data during 1960s and 1990s, and by using ELLEFAN technique, the growth and mortality parameters of Argyrosomus argenrtatus in northern South China Sea were estimated. The estimated parameters for Von Bertalanffy growth equation were Linfinity = 382 mm, K = 0.