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| 基于耳石微结构探究内外因子对黄海鳀早期生长的影响 |
| Exploring the effects of internal and external factors on the early growth of anchovy (Engraulis japonicus) in the Yellow Sea based on otolith microstructure |
| 投稿时间：2024-09-21 修订日期：2024-10-19 |
| DOI： |
| 中文关键词: 鳀 耳石微结构 黄海 内外因子 |
| 英文关键词: anchovy otolith microstructure Yellow Sea internal and external factors |
| 基金项目:国家自然科学基金项目 |
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| 摘要点击次数: 114 |
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| 中文摘要: |
| 鳀(Engraulis japonicus)是黄海最重要的小型中上层鱼类,其补充的成功很大程度上取决于早期生长。本研究基于多年样品的耳石微结构分析,追溯其孵化日期,采用混合效应、梯度森林、广义加性模型和滑动窗口等方法,探究了内外因子对鳀早期生长的影响。结果表明,母系效应与鳀早期生长之间呈现正相关关系。海表温度、混合层深度、海表盐度是影响黄海鳀早期生长的关键环境因子。尤其海表温度对鳀早期生长产生滞后效应,<15日龄(滞后一天),15-40日龄(滞后两天),预测鳀早期生长会随着海表温度的升高而增长。本研究揭示了内外因子对鳀早期生长的影响,对黄海鳀资源的可持续利用具有重要意义。 |
| 英文摘要: |
| Marine small pelagic fish are abundant and widely distributed, serving as important commercial fishing objects. Anchovy (Engraulis japonicus) as a typical representative of small pelagic fish, accounts for more than 30% of the global fisheries yield and is the primary food source for mackerel and other economic fish species, which play a crucial role in transferring the energy from the primary producers to high trophic level predators within the food chain. And anchovy, as one of the most commercially valuable pelagic species in the Northwest Pacific Ocean, is the main commercial fish species in the Bohai, Yellow, and East China Seas. Historically, it has been one of the largest single-species biomasses in the Yellow Sea, thus becoming a key component of the Yellow Sea marine ecosystem. Due to overfishing and the effects of climate change, catches have shown inter-annual fluctuations, leading to a decrease in anchovy resources, the number of predators (the small yellow croaker, the mackerel etc.) is decreasing, the trophic level is declining, and the material and energy flow of the food web are damaged. To maintain ecological balance, attention is paid to the recruitment of the stock resources. Numerous studies have linked recruitment to growth, particularly highlighting the early life stage as a “window” of high vulnerability and mortality rates that determine the success of subsequent recruitment of fish stocks. According to the “Growth-Mortality” hypothesis, the survival of larvae and the subsequent recruitment process are influenced by the growth rate during the early life stages. Small changes in early growth stages may significantly impact on mortality and recruitment by extending the developmental stage. The Yellow Sea, being a marginal sea of the Northwest Pacific Ocean, is influenced by the Yellow Sea warm currents, the Yellow Sea coastal currents and the Yellow Sea cold water masses, pooling nutrients and supporting a diverse phytoplankton community. This makes it a high-production area for various economically important fishes, such as anchovy and mackerel, and also an important spawning and nursery ground for anchovy. The strong tidal currents in the Yellow Sea significantly influence vertical circulation, resulting in fronts. Studies have shown that the early growth of anchovy and frontal upwelling system has a direct or indirect connection, the study of anchovy""s early growth pattern in the Yellow Sea has an important biological significance as well as theoretical and technical support. Anchovy internal mechanism also plays an important role in growth. In recent years, the eggs of anchovy in the Yellow Sea have shown a trend of decreasing size and a significant increase in natural mortality, which is an adaptive response of female anchovy to long-term fishing pressure. Under enormous fishing pressure, the anchovy spawning stock has shown a tendency to decrease in age and length, affecting gonadal development. However, endogenous sources of mortality stem from inherited genetic, physiologic, or other non-external factors, such as the quality of eggs and sperm, and the relative density of sperm and eggs for fertilization restrictions. In particular, the maturation of the eggs may affect early growth. However, so far, much of the mechanism through which endogenous factors cause mortality of fish eggs remains unclear. To further explore the influence of the marine environment of the Yellow Sea and its complex intrinsic mechanisms on the early life history of anchovy, the study was based on the microstructural analysis of otolith from multi-year samples, tracing the hatching date. A mixed-effects was used to analyze the intrinsic factors affecting the early growth of anchovy. Gradient forest model and generalized additive models were used to explore the relationship between early growth and environmental factors. Finally, a sliding window approach was used to investigate the lagged effect of environmental factors on the early growth of anchovy and to predict the growth. In this study, the distance from the otolith core to the yolk-absorption mark (Absorption check, AC) was used to represent the growth period, serving as an indicator of the maternal effect on the growth of anchovy larvae. Sea surface temperature, mixed layer depth, northward sea water velocity, eastward sea water velocity, sea surface height, sea surface salinity, and concentration of chlorophyll a were considered as environmental factors affecting the early growth of anchovy. The results showed that there was a positive correlation between the maternal effect and the early growth of anchovy; Sea surface temperature, Mixed layer depth, and Sea surface salinity were identified as important environmental factors affecting the early growth of the three spawning stocks of anchovy, with varying degrees of importance. Changes in environmental factors have been shown to have a lag effect on otolith growth rate of about one week. In this study, sea surface temperature, as the only environmental factor that produces a lag effect, has different time windows for producing a lag effect on anchovy larvae of different ages, less than 15 Age (Lag=1 day), and 15 -40 Age (Lag=2 days). When sea surface temperature was the sole influence on early anchovy growth, early anchovy growth was predicted to increase with sea surface temperature, with wider daily increments of otolith for 15 to 40 Age than 15 Age in the same temperature interval. However, in real conditions, as shown by the generalized additive model analysis, the relationship between sea surface temperature and growth tends to become complicated due to the synergistic influence of various factors. Therefore, future studies should elucidate the growth mechanism of anchovy from the perspective of energy balance. This study applies several models to the study of early growth of anchovy, providing a scientific basis for understanding early growth and offering scientific and technological support for the conservation and scientific management of anchovy resources in the Yellow Sea from the point of view of internal and external factors affecting the key life history stages. |
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