北部湾鱼类碳、氮、磷生态化学计量特征

Ecological stoichiometry characteristics of carbon,nitrogen and phosphorus in fishes from Beibu Gulf,southern China

为探究北部湾鱼类生态化学计量特征,于2021年3月—4月采集分析了北部湾沿岸9个渔港的79种鱼类(382尾)碳(C)、氮(N)、磷(P)含量特征。结果表明北部湾鱼类C、N、P元素含量变化范围分别为33.87%—58.34%、6.31%—14.92%和0.77%—4.67%;C∶N、C∶P、N∶P的变化范围分别为3.43—9.72、19.15—173.06和5.04—33.68,其中P元素含量变化最大,导致C∶P和N∶P的变化。不同物种在科间的差异较大,科内的差异较小。不同体型和食性鱼类之间的C、N、P含量及比值具有显著差异(P<0.05)。鱼类的C∶P和N∶P与P含量呈显著负相关(R^(2)=0.966,P<0.01;R^(2)=0.877,P<0.01),P含量和Ca含量呈显著正相关(R^(2)=0.919,P<0.01),P含量的变化可能与鱼类骨骼和鳞片的形成有关。总之,北部湾鱼类未保持严格的生态化学计量平衡,鱼类生态化学计量特征存在显著的种间差异,主要因鱼类不同的体型和食性差异所致。

Fishes are essential for mediating biogeochemical cycles in coastal areas by storing carbon(C),nitrogen(N),and phosphorus(P)in their body tissues at theoretically homeostatic rates.To maintain homeostasis,the consumers need to be in balance with their resource supply or alter their stoichiometric traits in response to environmental changes.However,the potential variations in the C∶N∶P content ratios of marine fishes are poorly understood.To explore the ecological stoichiometry characteristics of carbon(C),nitrogen(N)and phosphorus(P)in fishes from the Beibu Gulf,a total of 79 species(382 individuals)were collected and analyzed from 9 fishing ports around the study area from March to April,2021.The results showed that the contents of C,N and P in fishes ranged from 33.87%—58.34%,6.31%—14.92%and 0.77%—4.67%,respectively,and the variations ranges of C∶N,C∶P and N∶P were 3.43—9.72,19.15—173.06 and 5.04—33.68,respectively.The P content varied the most,resulting in variations in C∶P and N∶P in fishes,signifying that P content is an essential interspecies trait and an important factor in the diversification of the elementals composition of fish.The taxonomic level of fish families is the best predictor of ecological stoichiometry due to the significant differences among different families and little differences within families.Besides,the significant differences were found in C,N,and P contents,C∶N,C∶P and N∶P among fishes with different body shapes and feeding habits(P<0.05).For instance,the ribbon-like form fish had the highest C content and the lowest P content,while the depressed form fish had the lowest C content and the highest P content;the omnivores had the lowest C content and the highest P content,which indicated that fish with higher C content had lower P content and vice versa.C∶P and N∶P of fish were significantly negatively correlated with P content(R^(2)=0.966,P<0.01;R^(2)=0.877,P<0.01).P content was significantly positively correlated with Ca content(R^(2)=0.919,P<0.01)and its change might be related to the formation of fish bones and scales.Our results indicated that the fishes from the Beibu Gulf did not maintain strict homeostasis,and significant interspecies differences in the ecological stoichiometry characteristics of fishes were found due to their different body shapes and feeding habits.The research results are of great significance to the sustainable development of marine biogeochemical cycles and fishery resources under anthropogenic and environmental changes.