Understanding Changes in Transitional Areas of the Pacific 24-26, 2018, in La Paz Biological responses of small yellow croaker (Larimichthys polyactis) to multiple stressors: a case study in the Yellow Sea, China Xiujuan Shan 1,2, Tao Yang 1, Guozheng Zhang 1, Xianshi Jin 1,2 1 Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao; 2 Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao; E-mail: shanxj@ysfri.ac.cn
. Multiple stressors in China coastal waters Climate change: climatic oscillation warming Overexploitation: overfishing reclamation... Eutrophication: land-sourced pollution and commercial activities 1960 1980 2000
Changes of CPUE in the Yellow Sea 200 160 October May CPUE (kg haul-1h-1) 80 40 0 1958-1959 1985-1986 1998-2000 2005 2009-2010 2014-2015 The CPUE data was collected by Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Science, based on scientific surveys. Only in 1950s the surveys used fishing vessels, and in other years, the surveys were based on research vessels.
Changes of species composition in the Yellow Sea
4.5 Changes of trophic levels in the Yellow Sea Trophic levle of fishery 4.0 species 3.5 4.07 4.05 3.68 3.84 3.48 3.46 October May 3.78 3.84 3.73 3.47 3.0 The trophic levels from 1985-2000 cited from Zhang & Tang (2004). The other data was as above mentioned.
In China seas, MTC increases at the fastest rate in the Yellow Sea (0.08 oc per decade); Cheung et al, 2012
Primary production Second production Top production Good environmental conditions Time Bad environmental conditions BOTTOM- UP TOP- DOWN WASP- WAIST Control mechanism of marine organisms in coastal waters
-- It is difficult to use any traditional theory (bottom-up control or top-down control or wasp-waist control) to directly or clearly explain the long-term variations of the different levels. -- Different control mechanisms may apply in different periods due to varying conditions. Although each control mechanism has its opportunity to control the ecosystem over a given period, it cannot become the exclusive control mechanism in the long-term. -- Therefore, an acceptable explanation is that the apparently dynamic characteristics of the different levels of productivity may be a consequence of multi-factorial controls. The multicontrol mechanism may contribute to ecosystem complexity and uncertainty in terms of different levels of productivity in a coastal ecosystem.
Small yellow croaker
Growth rate of fish larvae 1 ω=k L 公式 (1) Gallucci, V. F., Quinn, T. J. Reparameterizing, fitting, and testing a simple growth model [J]. Trans. Am. Fish. Soc., 1979, 108(1): 14-25. Li et al, 2011
Variations in average body length and body weight Three phases: (1) 1960s-1980s: sharp decrease; (2) early-1990s: slight increase; (3) late 1990s: decrease again, even less than that in 1980s. A 平均体长 Mean body length/ cm C 22 20 18 16 14 12 10 平均体长 Mean body length/ cm 24 22 20 18 16 14 12 10 雌性 Female 雄性 Male 1960 1982 1983 1993 2003 2004 年 Year 雌性 Female 雄性 Male 1960 1986 1994 1998 2001 2005 2007 2010 平均体重 Mean weight/ g B D 平均体重 Mean weight/ g 220 170 70 20 250 200 150 100 50 0 雌性 Female 雄性 Male 1960 1982 1983 1993 2003 2004 年 Year 雌性 Female 雄性 Male 1960 1986 1994 1998 2001 2005 2007 2010 年 Year 年 Year Li et al, 2011 Variations in average body length (A, C) and average body weight (B, D) A B: Northern Yellow Sea-Bohai Sea stock; C D: Southern Yellow Sea Stock
Frequency (%) 40 35 30 25 20 15 10 5 0 1960 1985 1998 2008 Body length (cm) Body length distribution of the small yellow croaker spawning stock in the Yellow Sea from 1960 to 2008 Shan et al, 2016
Age structure of small yellow croaker in the Yellow Sea Year Age structure (%) 1 2 3 4 5 6 7 8 9 Bey ond 10 Average age (yr) 1960 0.9 16.4 33.6 23.2 6.2 2.6 3.8 3.8 2.0 7.5 4.49 1985 28.8 55.5 8.7 3.3 2.6 0.9 0.2 1.99 1998 97.6 2.36 0.04 1.02 2008 93.4 5.7 0.9 1.08 Shan et al, 2016
L 50 / mm 165 150 135 105 90 L50 L 50 : 152.8-105.3 mm A 50 :1.5-0.9 a a BH-NYS A50 1.8 1.6 1.4 1.2 1.0 0.8 A 50 (yr) Body length and age at median sexual maturity of small yellow croaker decreased; L 50 / mm 200 180 160 140 100 L 50 : 184.4-110.1 mm A 50 :2.4-1 a b SYS 80 1960 1970 1980 1990 2000 2010 年 Year 3.0 2.5 2.0 1.5 1.0 A 50 (yr) Body length and age at median sexual maturity (L 50 and A 50 ) were estimated by ASR transformative logistic model and inverse von Bertalanffy growth function Li et al, 2011
Shan et al, 2016 Biological parameters of small yellow croaker in the Yellow Sea from 1960 to 2008 Year Biological parameters 1960 1985 1998 2008 Growth coefficient k 0.26 0.4 0.48 0.56 Zero-length age t 0-0.58-0.37-0.3-0.25 Asymptotic length L /cm 34.21 30.17 25.54 27.00 Age at inflexion of body weight growth t r 3.78 2.44 1.99 1.61 Total mortality coefficient Z 0.51 1.80 2.84 2.40 Natural mortality coefficient M 0.24 0.33 0.39 0.77 Fishing mortality coefficient F 0.27 1.47 2.45 1.63 Goodness of fit R n 0.30 0.26 0.27
Correlations between the decadal changes in the biological parameters of small yellow croaker and influencing factors Biological parameters Sea surface temperature (SST) Feeding grade Fishing vessel power/ MW Growth coefficient k 0.6491 0.6923 0.7273 Zero-length age t 0 0.6249 0.7352 0.7596 Asymptotic length/cm L 0.7549 0.6536 0.7361 Age at inflection of body weight growth t r 0.6073 0.7427 0.7689 Total mortality coefficient Z 0.6404 0.6346 0.7273 Fishing mortality coefficient F 0.6403 0.7092 0.6756 Natural mortality coefficient M 0.5606 0.6645 0.6716 Mean value 0.6396±0.0193 0.6903±0.0135 0.7238±0.0356 Shan et al, 2016
Shan et al, 2011 2009-2010 Euphausia pacifica IRI=8601.4 Feeding habit 2000-2001 Leptochela gracilis IRI=249.9 1985-1986 anchovy IRI=1577.3 Euphausia pacifica IRI=6807.8 Crangon affinis IRI=344.1 Calanus sinicus IRI=127.5 Metapenaeopsis dalei IRI=220.9 Crangon affinis IRI=157.5 Leptochela gracilis IRI=102.4 Collichthys lucidus IRI=20.5 Crangon affinis IRI=77.7 H =1.2 anchovy IRI=35.7 Chinese prawns IRI=10.3 Thryssa kammalensis IRI=44.1 H =2.5 H =2.1
Distribution N N 38 38 36 36 34 Spring 34 unit kg/h 32 30 118 Corresponding months, small yellow croaker in YS migrated northward. 0-0.5 0.5-5 5-10 10-20 20-60 60-200 32 2001.4 122 124 126 E 30 118 N N 38 38 36 36 34 34 32 32 2010.5 122 122 124 126 E 30 118 E 2007.8 122 124 126 E N 38 36 36 34 34 32 32 30 118 126 Summer 2000.8 30 118 N 38 124 2000.10 122 124 126 E 30 118 N N 38 38 36 36 34 34 32 32 Autumn 2009.10 122 124 126 E Winter 2010.1 2000.12 30 118 122 124 126 E 30 118 122 124 126 E Shan, et al, 2011
Changes of catch and ENSO 1.2 0.8 0.4 S ONI 0.0-0.4-0.8-1.2 50 产量 Yield/ 千吨 thousand tons 40 30 20 10 EN1987,H1988 EN1992-93/95, H1993-96 EN1998, H1998-00 The yield increased in those years and in 1-2 years after an El Niños event. 0 1960 1970 1980 1990 2000 2010 年 Year ONI and small yellow croaker production from Jiangsu Province Li, et al, 2012
Small yellow croaker Original (static) distribution Distribution after 50 years (Climate projection from NOAA/GFDL CM) 2.1) Relative abundance Low High Cheung et al, 2008
Summary The average length of fish in 2008 was reduced by ~85% than those occurring in 1985; ~93% of the total catch was dominated by one-year-old individuals; Growth parameters also varied significantly over the years, i.e. k (growth coefficient) and t 0 (zero-length age) gradually increased from 0.26 and -0.58 yr in 1960 to 0.56 and -0.25 yr in 2008; L (body length) sharply decreased from 34.21 cm in 1960 to 24.06 cm in 2008, and t r decreased from 3.78 yr in 1960 to 1.61 yr in 2008. There was a great increase both in natural mortality coefficient and fishing mortality coefficient; Changes in the biological characteristics of small yellow croaker were induced by different stressors ranked as: fishing vessel power> feeding grade> sea surface temperature.
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