Mauk R J, Brown M L
Department of Wildlife and Fisheries Sciences, South Dakota State University, Brookings 57007-1696, USA.
Arch Environ Contam Toxicol. 2001 Feb;40(2):257-63. doi: 10.1007/s002440010170.
A decline in the walleye Stizostedion vitreum sport fishery in lower Lake Oahe, South Dakota, was documented in the early 1980s and has been attributed to poor natural reproduction and/or recruitment. Contaminants were suspected of causing low natural reproduction/recruitment in lower Lake Oahe as well as low hatchability of eggs produced from broodstock walleyes taken from lower Lake Oahe. Concentrations of dissolved selenium in the Cheyenne River, which enters lower Lake Oahe, have increased considerably over the last 15 years. To determine whether selenium concentrations contributed to the reproduction problems in the lower Lake Oahe walleye population, adult walleye were collected during spawning operations in April 1994, 1995, and 1996 to obtain tissue samples. Muscle, liver, reproductive tissue, and unfertilized eggs were analyzed with a modified fluorometric method for determining selenium concentrations in plants. These tissues were also analyzed for mercury content using cold-vapor atomic absorption. No statistical differences (p < 0.05) in selenium or mercury concentrations among sites could be determined that would explain differential walleye egg hatchability. Correlation analysis determined significant inverse associations existed between the gonadal somatic index of male walleye and gonadal tissue selenium concentrations (r = -0.41, p = 0.0012). Both walleye sexes exhibited significant inverse associations between the hepatic somatic index (HSI) and liver selenium concentrations (males r = -0.33, p = 0.0095; and females r = -0.38, p = 0.0034). Positive relationships existed for female walleye selenium concentrations in the liver and the ovaries (r = 0.37, p = 0.003) and the liver and muscle tissue (r = 0.28, p = 0.027). Mercury concentrations in walleye ovaries were positively correlated with HSI (r = 0.30, p = 0.0012), length (r = 0.36, p = 0.0046), relative weight (r = 0.36, p = 0.0054), and muscle concentrations (r = 0.49, p = 0.0001). Mercury concentrations in male walleye muscle were correlated with age (r = 0.57, p = 0.0001), length (r = 0.79, p = 0.0001), and mercury concentrations in the testes (r = 0.43, p = 0.0006).
20世纪80年代初，南达科他州奥阿希湖下游的大眼狮鲈游钓渔业出现衰退，这被认为是自然繁殖和/或补充不足所致。污染物被怀疑是导致奥阿希湖下游自然繁殖/补充不足以及从奥阿希湖下游采集的亲鱼所产鱼卵孵化率低的原因。流入奥阿希湖下游的夏延河中的溶解硒浓度在过去15年中大幅增加。为了确定硒浓度是否导致了奥阿希湖下游大眼狮鲈种群的繁殖问题，在1994年、1995年和1996年4月的产卵期收集成年大眼狮鲈以获取组织样本。使用改良的荧光法分析肌肉、肝脏、生殖组织和未受精卵，以测定植物中的硒浓度。这些组织还使用冷蒸气原子吸收法分析汞含量。无法确定各采样点之间硒或汞浓度存在统计学差异（p < 0.05），这可以解释大眼狮鲈鱼卵孵化率的差异。相关性分析确定雄性大眼狮鲈的性腺体指数与性腺组织硒浓度之间存在显著的负相关（r = -0.41，p = 0.0012）。大眼狮鲈的雌雄两性在肝脏体指数（HSI）与肝脏硒浓度之间均表现出显著的负相关（雄性r = -0.33，p = 0.0095；雌性r = -0.38，p = 0.0034）。雌性大眼狮鲈肝脏与卵巢中的硒浓度之间（r = 0.37，p = 0.003）以及肝脏与肌肉组织之间（r = 0.28，p = 0.027）存在正相关关系。大眼狮鲈卵巢中的汞浓度与HSI（r = 0.30，p = 0.0012）、体长（r = 0.36，p = 0.0046）、相对体重（r = 0.36，p = 0.0054）以及肌肉浓度（r = 0.49，p = 0.0001）呈正相关。雄性大眼狮鲈肌肉中的汞浓度与年龄（r = 0.57，p = 0.0001）、体长（r = 0.79，p = 0.0001）以及睾丸中的汞浓度（r = 0.43，p = 0.0006）相关。
