A simple molecular protocol for the identification of hybrid Western Atlantic seahorses, Hippocampus erectus × H. reidi, and potential consequences of hybrids for conservation

Abstract

Seahorses hold an iconic status and are popular exhibits in zoos and public aquaria, where they are often on display in multi-species systems. Two of the more popularly kept species are the lined seahorse, Hippocampus erectus , and the longsnout seahorse, H. reidi . These two species are from different evolutionary subclades, but can produce viable hybrid F 1 offspring, therefore species segregation should be maintained for seahorse conservation breeding programmes. Hybrid H . erectus ♂ × H . reidi ♀ F 1 offspring exhibit higher median meristic counts for various traits, although large ranges in counts make it difficult to identify hybrids by meristics alone. A molecular protocol was developed to identify both the parent species and the reciprocal hybrids using polymerase chain reaction restriction-fragment length polymorphism (PCR-RFLP). The PCR-RFLP protocol employed the use of the BsrBI and Ms1I restriction enzymes at the Tmo-4c4 and S7 loci, respectively. The developed protocol was effective at discerning hybrids (F 1 ) from the parent species and identifying some post-F 1 H . erectus × H . reidi hybrids, but not the direction of the cross. Although captive-bred hybrids may be considered to pose a threat to wild populations if released, there are many benefits to producing captive hybrid seahorses, including improved aquaculture techniques that can curb the wild collection of seahorses.