This paper was aimed at re-examining the validity of the results from Cahuin et al. (Estuar. Coast. Shelf Sci. 84, 2009) and identifying a model to describe the stock-recruitment relationship of the Peruvian anchoveta...This paper was aimed at re-examining the validity of the results from Cahuin et al. (Estuar. Coast. Shelf Sci. 84, 2009) and identifying a model to describe the stock-recruitment relationship of the Peruvian anchoveta (Eugraulis ringens). Regression analysis was used to determine if density-dependent effects were present. The analysis did not show the existence of any densitydependent effects. It is important to use environmental factors and take observational and process errors into account when attempting to identify density-dependent effects in fish populations. Sea surface temperature (SST) and Southern Oscillation Index (SOI) were used as independent variables to fit the recruitment dynamics of the anchoveta. Both SST and SOI were found to be significantly important parameters in structuring anchoveta dynamics according to Akaike Information Criterion (AIC) and R2 values. The results of this study do not correlate with the findings of Cahuin et al., (2009), where density-dependent effects and the presence of regimes were detected. In conclusion, the recruitment Rt is essentially determined in proportion to spawning stock biomass St, and then environmental factors in year t further change the recruitments. This mechanism is completely same with that for Japanese sardine proposed by Sakuramoto (The Open Fish. Sci. 5, 2012).展开更多
This study proposes a simulation model that well reproduces the spawning stock biomass of Pacific bluefin tuna. Environmental factors were chosen to estimate the recruitment per spawning stock biomass, and a simulatio...This study proposes a simulation model that well reproduces the spawning stock biomass of Pacific bluefin tuna. Environmental factors were chosen to estimate the recruitment per spawning stock biomass, and a simulation model that well reproduced the spawning stock biomass was developed. Then, effects of various fisheries regulations were evaluated using the simulation study. The results were as follows: 1) arctic oscillations, Pacific decadal oscillations and the recruitment number of the Pacific stock of Japanese sardine were chosen as the environmental factors that determined the recruitment per spawning stock biomass;2) spawning stock biomass could be well reproduced using a model that reproduced the recruitment per spawning stock biomass and the survival process of the population that included the effect of fishing;and 3) the effects of various fisheries regulation could be evaluated using the simulation model mentioned above. The effective regulation in the simulations conducted in this paper was a prohibition of fishing for 0- and 1-year-old fish in terms of recovering the spawning stock biomass. The reduction of fishing mortality coefficients for all age fish to 50% of actual values also showed a good performance. The recent reductions of the recruitment and spawning stock biomass were likely caused by heavy harvesting, especially of immature fish, since 2004.展开更多
根据1999-2008年东海区渔业资源底拖网大面定点调查获取的小黄鱼(Larimichthys polyactis)渔业生物学资料,利用AIC(Akaike Information Criterion)与BIC(Bayesian Information Criterion),对小黄鱼的Ricker、Beverton-Holt和Cushing繁...根据1999-2008年东海区渔业资源底拖网大面定点调查获取的小黄鱼(Larimichthys polyactis)渔业生物学资料,利用AIC(Akaike Information Criterion)与BIC(Bayesian Information Criterion),对小黄鱼的Ricker、Beverton-Holt和Cushing繁殖模型进行了拟合优度检验。针对选择的繁殖模型,经单因子相关分析和逐步回归分析,筛选对繁殖模型有重要影响的环境因子,经模型的拟合和检验,确定东海区小黄鱼的适用繁殖模型。结果表明:3种繁殖模型中,Ricker繁殖模型更适合模拟小黄鱼亲体与补充量关系,但吕泗渔场海域3-4月平均海水表温、7月海水表温和5月长江径流量、7-8月长江平均径流量以及当年夏季风速对模型中的补充量有着重要的影响;优化后的Ricker繁殖模型不仅可以提高东海区小黄鱼亲鱼量与补充量的拟合精度,而且可参考该模型修正当年度小黄鱼的资源管理目标,提高资源管理的科学性。展开更多
根据当前捕捞死亡系数,运用2种基于体长的B-H式单位补充量亲体量模型(Spawning biomass per recruit,SBR),评估了北部湾的带鱼资源状况。当前北部湾带鱼的SBR为42.07g,相当于初始亲体量的4.82%,表明现阶段北部湾的带鱼资源处于过度利用...根据当前捕捞死亡系数,运用2种基于体长的B-H式单位补充量亲体量模型(Spawning biomass per recruit,SBR),评估了北部湾的带鱼资源状况。当前北部湾带鱼的SBR为42.07g,相当于初始亲体量的4.82%,表明现阶段北部湾的带鱼资源处于过度利用状态,以捕捞低龄鱼为主。放大开捕体长和降低捕捞强度是恢复亲体资源量的有效手段。展开更多
文摘This paper was aimed at re-examining the validity of the results from Cahuin et al. (Estuar. Coast. Shelf Sci. 84, 2009) and identifying a model to describe the stock-recruitment relationship of the Peruvian anchoveta (Eugraulis ringens). Regression analysis was used to determine if density-dependent effects were present. The analysis did not show the existence of any densitydependent effects. It is important to use environmental factors and take observational and process errors into account when attempting to identify density-dependent effects in fish populations. Sea surface temperature (SST) and Southern Oscillation Index (SOI) were used as independent variables to fit the recruitment dynamics of the anchoveta. Both SST and SOI were found to be significantly important parameters in structuring anchoveta dynamics according to Akaike Information Criterion (AIC) and R2 values. The results of this study do not correlate with the findings of Cahuin et al., (2009), where density-dependent effects and the presence of regimes were detected. In conclusion, the recruitment Rt is essentially determined in proportion to spawning stock biomass St, and then environmental factors in year t further change the recruitments. This mechanism is completely same with that for Japanese sardine proposed by Sakuramoto (The Open Fish. Sci. 5, 2012).
文摘This study proposes a simulation model that well reproduces the spawning stock biomass of Pacific bluefin tuna. Environmental factors were chosen to estimate the recruitment per spawning stock biomass, and a simulation model that well reproduced the spawning stock biomass was developed. Then, effects of various fisheries regulations were evaluated using the simulation study. The results were as follows: 1) arctic oscillations, Pacific decadal oscillations and the recruitment number of the Pacific stock of Japanese sardine were chosen as the environmental factors that determined the recruitment per spawning stock biomass;2) spawning stock biomass could be well reproduced using a model that reproduced the recruitment per spawning stock biomass and the survival process of the population that included the effect of fishing;and 3) the effects of various fisheries regulation could be evaluated using the simulation model mentioned above. The effective regulation in the simulations conducted in this paper was a prohibition of fishing for 0- and 1-year-old fish in terms of recovering the spawning stock biomass. The reduction of fishing mortality coefficients for all age fish to 50% of actual values also showed a good performance. The recent reductions of the recruitment and spawning stock biomass were likely caused by heavy harvesting, especially of immature fish, since 2004.
文摘根据1999-2008年东海区渔业资源底拖网大面定点调查获取的小黄鱼(Larimichthys polyactis)渔业生物学资料,利用AIC(Akaike Information Criterion)与BIC(Bayesian Information Criterion),对小黄鱼的Ricker、Beverton-Holt和Cushing繁殖模型进行了拟合优度检验。针对选择的繁殖模型,经单因子相关分析和逐步回归分析,筛选对繁殖模型有重要影响的环境因子,经模型的拟合和检验,确定东海区小黄鱼的适用繁殖模型。结果表明:3种繁殖模型中,Ricker繁殖模型更适合模拟小黄鱼亲体与补充量关系,但吕泗渔场海域3-4月平均海水表温、7月海水表温和5月长江径流量、7-8月长江平均径流量以及当年夏季风速对模型中的补充量有着重要的影响;优化后的Ricker繁殖模型不仅可以提高东海区小黄鱼亲鱼量与补充量的拟合精度,而且可参考该模型修正当年度小黄鱼的资源管理目标,提高资源管理的科学性。
文摘根据当前捕捞死亡系数,运用2种基于体长的B-H式单位补充量亲体量模型(Spawning biomass per recruit,SBR),评估了北部湾的带鱼资源状况。当前北部湾带鱼的SBR为42.07g,相当于初始亲体量的4.82%,表明现阶段北部湾的带鱼资源处于过度利用状态,以捕捞低龄鱼为主。放大开捕体长和降低捕捞强度是恢复亲体资源量的有效手段。
