A microsatellite marker tool for parentage analysis in Senegal sole (Solea senegalensis): Genotyping errors, null alleles and conformance to theoretical assumptions

A set of 50 potential microsatellite loci previously described in several flatfish species was evaluated for designing a suitable tool for parentage assessment in Senegal sole (Solea senegalensis). Low cross-amplification within Pleuronectiformes, even between congeneric species, was achieved. This suggests a low conservation of microsatellite flanking regions in this order regarding other fish orders of similar evolutionary age. Twelve loci showed appropriate amplification and polymorphism to acquire enough statistical power for parentage analysis. All forty-one individuals from one broodstock and 320 offspring were analyzed using this set of markers. The high potential of microsatellites for parentage exclusion (Excl1 = 0.9999; Excl2 = 1) permitted us to trace back all offspring to single pairs of parents. The families obtained were used to analyze the performances of the loci applied and to identify possible sources of error for parentage analysis in Senegal sole. The 2.5% of single mismatches in the families studied were attributed mostly to genotyping errors and to a lesser extent to null alleles. The average mutation rate estimated over 7680 gametes was in the range reported within fish (3.9 × 10^− 4) and did not compromise parentage analysis. All loci conformed to theoretical assumptions (Mendelian segregation, independent segregation), excluding the F13-II8/4/7 and Sol 9A loci, which showed strong genotypic association in the families analyzed. A set of 4 microsatellites (Sol CA13, F13-II8/4/7, Smax-02 and Sse GATA38) was finally selected for parentage evaluation in S. senegalensis combining both enough exclusion potential (> 0.970) and the lowest economic cost.     

Evaluation of a naturalised rock ramp fish passage for cool‐ and warm‐water fish in a tributary of Saginaw Bay,Lake Huron

Dams across the Great Lakes basin are nearing or beyond their original design life, posing both challenges and opportunities to natural resource managers. Ageing dams can be repaired to preserve function and maintain safety, removed to promote full connectivity or retrofitted with a fish passage structure to increase connectivity without reservoir loss. The success of rock ramp structures is not well documented, especially for cool‐ and warm‐water fishes in the Great Lakes basin. The success of a recently built (2009) rock ramp for increasing upstream fish passage on the Shiawassee River in Michigan, USA, was evaluated. While there was evidence of limited fish passage during the study period (2011–2016), catches of spring migratory fishes, fish eggs and larvae were significantly higher below the rock ramp than above, indicating the dam with rock ramp fish pass continues to limit upstream migration. Overall connectivity appears improved relative to a reference, dammed river, but falls short of full connectivity.