Data from: Evolution and diversity of two cisco forms in an outlet of glacial Lake Algonquin

The diversity of Laurentian Great Lakes ciscoes (Coregonus artedi, sensu
lato) arose via repeated local adaptive divergence including deepwater
ciscoes that are now extirpated or threatened. The nigripinnis form, or
Blackfin Cisco, is extirpated from the Great Lakes and remains only in
Lake Nipigon. Putative nigripinnis populations were recently discovered in
sympatry with artedi in a historical drainage system of glacial Lake
Algonquin, the precursor of Lakes Michigan and Huron. Given the apparent
convergence on Great Lakes form, we labelled this form blackfin. Here, we
test the hypothesis that nigripinnis may have colonized this area from the
Great Lakes as a distinct lineage. It would then represent a relict
occurrence of the historical diversity of Great Lakes ciscoes.
Alternatively, blackfin could have evolved in situ in several lakes. We
captured more than 600 individuals in the benthic or pelagic habitat in 14
lakes in or near Algonquin Provincial Park (Ontario, Canada). Fish were
compared based on habitat, morphology and genetic variation at 6676 SNPs.
Contrary to our expectations, both cisco and blackfin belonged to an
Atlantic lineage that colonized the area from the east, not from the Great
Lakes. Sympatric cisco and blackfin were closely related while fish from
different lakes were genetically differentiated, strongly suggesting the
repeated in situ origin of each form. Across lakes, there was a continuum
of ecological, morphological and genetic differentiation that could be
associated with alternative resources and lake characteristics. This study
uncovers a new component of cisco diversity in inland lakes of Canada that
evolved independently from ciscoes of the Laurentian Great lakes. The
diversity of cisco revealed in this study and across their Canadian range
presents a challenge for designating conservation units at the
intraspecific level within the framework of the Committee on the Status of
Endangered Wildlife in Canada (COSEWIC).

圣劳伦斯五大湖广义湖白鲑（Coregonus artedi, sensu lato）的多样性起源于反复的本地适应性分化，其中包含现已局部灭绝或受威胁的深水湖白鲑类群。黑鳍湖白鲑（Blackfin Cisco）的nigripinnis型已从五大湖区域性灭绝，仅残存于尼皮贡湖。近期，在冰期阿尔冈金湖——密歇根湖与休伦湖的古水系——的历史流域中，发现了与artedi同域分布的推定nigripinnis种群，研究团队将此类群命名为黑鳍型。本研究旨在验证两项假说：其一，nigripinnis型可能作为独立演化支系从五大湖扩散至此，若该假说成立，则其代表了五大湖湖白鲑历史多样性的孑遗种群；其二，黑鳍型可能在多个湖泊中独立演化形成。
研究团队在加拿大安大略省阿尔冈昆省立公园及其周边的14个湖泊的底栖或远洋生境中，捕获了600余尾个体。基于生境、形态特征以及6676个单核苷酸多态性（Single Nucleotide Polymorphisms, SNPs）位点的遗传变异，对样本开展了比较分析。
与预期相悖的是，湖白鲑与黑鳍型均隶属于大西洋演化支系，其扩散来源为东部区域而非五大湖。同域分布的湖白鲑与黑鳍型亲缘关系紧密，而不同湖泊的种群间存在显著遗传分化，这强烈支持各类群均为原位独立起源。
跨湖泊分析显示，生态、形态与遗传分化呈现连续梯度，该梯度可能与不同的资源利用模式及湖泊自身特征相关。本研究揭示了加拿大内陆湖泊中一类全新的湖白鲑多样性组分，其演化路径独立于圣劳伦斯五大湖的湖白鲑类群。
本研究及加拿大全域范围内已报道的湖白鲑多样性，对加拿大濒危野生动物状况委员会（Committee on the Status of Endangered Wildlife in Canada, COSEWIC）框架下种内保护单元的划定工作提出了挑战。