为了考查水温、盐度和溶氧对红鳍东方鲀(Takifugu rubripes)幼鱼游泳能力的影响,测定了其在不同水温[15.2、20.2、25.6(对照)和30.4℃]、盐度[0、10、20、32(对照)和40]和溶氧[2.14、4.10、5.81和7.36 mg/L(对照)]条件下的临界游速和最大游速.结果表明,水温和溶氧含量均显著影响实验鱼的临界游速和最大游速(P<0.01).随水温和溶氧含量升高,实验鱼的临界游速和最大游速均逐渐增加.水温(T,℃)与临界游速(Ucrit,cm/s)和最大游速(Umax,cm/s)均呈二次函数关系,关系式分别为Ucrit=?0.095T 2+5.450T?47.79,R2=0.995(P<0.01)和Umax=?0.018T 2+2.204 T?12.27,R2=0.981(P<0.01).溶氧含量(DO,mg/L)与临界游速和最大游速也均呈二次函数关系,关系式分别为Ucrit=0.230DO2+1.561DO+5.84,R2=0.995(P<0.01)和Umax=?0.806 DO2+11.10DO?3.919,R2=0.985(P<0.01).不同盐度下实验鱼的临界游速和最大游速与对照组均无显著差异(P>0.05).结论认为,低温和缺氧会降低红鳍东方鲀放流苗种的游泳能力,进而降低其放流后的捕食成功率,提高被捕食概率.%We investigated the effects of water temperature, salinity, and dissolved oxygen (DO) content on the swimming ability of juvenile tiger pufferTakifugu rubripes. The critical swimming speed (Ucrit, cm/s) and maxi-mum swimming speed (Umax, cm/s) of the juvenileswas determined under different temperatures (15.2℃, 20.2℃, 25.6℃ and 30.4℃), salinities (0, 10, 20, 32 and 40), and DO content (2.14 mg/L, 4.10 mg/L, 5.81 mg/L and 7.36 mg/L). TheUcrit andUmax both increased as water temperature (T,℃) was increased from 15.2 to 30.4℃:Ucrit increased from 13.12 to 29.07 cm/s;Umax increased from 17.51 to 37.38 cm/s. The relationship betweenT andUcrit orUmax could be interpreted with quadratic models, as:Ucrit =?0.095T 2+5.450T?47.79,R2=0.995 (P<0.01); and Umax =?0.018T 2+2.204T? 12.27,R2=0.981 (P<0.01). TheUcrit andUmax also increased as DO was increased from 2.14 to 7.36 mg/L:Ucrit increased from 10.40 to 29.54 cm/s;Umax increased from 16.43 to 33.65 cm/s. The rela-tionship between DO andUcrit orUmax could be interpreted with quadratic models, as:Ucrit=0.230DO2+ 1.561DO+5.84,R2=0.995 (P<0.01); andUmax=?0.806DO2+11.10DO?3.919,R2=0.985 (P<0.01). The salinity challenges had no significant effects uponUcrit andUmax of the juvenile tiger puffer(P>0.05). Temperature is known to strongly influence the contractile properties of muscles. According to "compression of the recruitment order theory", recruiting all of a fish's aerobic fibers at a lower speed results in reduced sustainable performance. The effects of temperature on the physical properties of water may also affect fish swimming ability. The viscosity of water decreases as temperature increases, and this may increase the swimming efficiency of fish in warmer wa-ters. The swimming ability of juvenile tiger puffer might be limited by the cardiorespiratory system in response to hypoxia as a result of impaired functioning of the oxygen transport and exchange system. Furthermore, as another response to hypoxia, increases in respiratory frequency to improve the absorbance of oxygen must evoke an additional energy cost to the animal. The absence of any significant changes in theUcrit andUmax of the juvenile tiger puffer following the various salinity challenges could be a direct result of this species' exceptional ability for maintaining plasma homeostasis and water balance in the tissues. In natural environments, lower temperatures and hypoxia would reduce the swimming ability of juvenile tiger pufferand thereby weaken their predation and/or predator-avoidance capacity. These findings increase our understanding of the biology and ecology of the tiger puffer, and may be useful for enhancing stocks of this near-threatened species.
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