Kvistad Jake T, Galarowicz Tracy L, Clapp David F, Chadderton William L, Tucker Andrew J, Annis Gust, Herbert Matthew
Department of Biology, Biosciences 2100, Central Michigan University, Mount Pleasant, MI 48859 USA.
Cramer Fish Sciences, Watershed Sciences Laboratory, 1125 12th Avenue NW, Suite B-1, Issaquah, WA 98027 USA.
Biol Invasions. 2023 May 8:1-17. doi: 10.1007/s10530-023-03076-6.
The goal of most invasive species suppression programs is to achieve long-term sustained reductions in population abundance, yet removal programs can be stymied by density-dependent population responses. We tested a harvest removal strategy for invasive Rusty Crayfish () at two nearshore native fish spawning habitats in northern Lake Michigan. Changes in average Rusty Crayfish densities were evaluated with a before-after reference-impact study design. We removed 3182 Rusty Crayfish, primarily adults (> 20 mm carapace length), at two sites over two harvest seasons, expending 17,825 trap days in effort. Generalized linear modeling results suggested a statistically significant reduction in Rusty Crayfish densities was achieved at one reef, Little Traverse Bay (LTB Crib). Reduced densities were sustained over the egg maturation period for native fish and into the following year after removal ceased. By late summer/early fall, between consecutive suppression efforts in 2018 and 2019, we observed a threefold increase in pre-removal densities. Size-frequency histograms from diver quadrat surveys showed higher abundances of juvenile (< 20 mm carapace length) size classes the following spring and summer at LTB Crib compared to its paired reference site. Stock-recruit curves fit to count data, pooled across all sites, provided further evidence of density-dependence. With a proviso that we only conducted two seasons of consecutive suppression, this study highlights an important aspect of invasive species management and raises questions about the efficacy of adult-only crayfish removal strategies.
The online version contains supplementary material available at 10.1007/s10530-023-03076-6.
大多数入侵物种抑制计划的目标是实现种群数量的长期持续减少，但清除计划可能会受到密度依赖性种群反应的阻碍。我们在密歇根湖北部的两个近岸本地鱼类产卵栖息地测试了一种针对入侵性锈色螯虾（）的捕捞清除策略。通过前后对照影响研究设计评估了锈色螯虾平均密度的变化。在两个收获季节，我们在两个地点清除了3182只锈色螯虾，主要是成年个体（头胸甲长度>20毫米），共花费了17825个诱捕日。广义线性模型结果表明，在一个礁石区小特拉弗斯湾（LTB Crib），锈色螯虾密度实现了统计学上的显著降低。降低后的密度在本地鱼类的卵成熟期间持续存在，并在清除停止后的次年依然保持。到夏末/初秋，在2018年和2019年连续抑制措施之间，我们观察到清除前的密度增加了两倍。潜水员样方调查的大小频率直方图显示，与配对的对照地点相比，次年春季和夏季，LTB Crib处幼年（头胸甲长度<20毫米）大小类别的丰度更高。拟合所有地点计数数据的种群补充曲线提供了密度依赖性的进一步证据。鉴于我们只进行了两个连续抑制季节的研究，本研究突出了入侵物种管理的一个重要方面，并对仅清除成年螯虾的策略的有效性提出了疑问。
在线版本包含可在10.1007/s10530-023-03076-6获取的补充材料。
