The evolution and physiology of male pregnancy in syngnathid fishes

Whittington, Camilla M.; Friesen, Christopher R.

doi:10.1111/brv.12607

Cited by 50 publications

(50 citation statements)

References 204 publications

(360 reference statements)

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“…Like other syngnathids, seadragons have specialized morphological traits such as a tube-like toothless mouth, the absence of pelvic fins and scales, a bony armor covering the body, and "male pregnancy." Males of all syngnathids incubate the fertilized eggs on a specialized incubation area, and in the modern lineages, even in enclosed brood pouches, making them prime examples for sex-role reversal (1)(2)(3). On the basis of the position of the brood pouch, syngnathids have been divided into tail-brooders (subfamily Syngnathinae represented by seahorses, some pipefishes and seadragons) and trunk-brooders (subfamily Nerophinae represented by Manado pipefish) (4,5).…”

Section: Introductionmentioning

confidence: 99%

Seadragon genome analysis provides insights into its phenotype and sex determination locus

Liu

Zhang

et al. 2021

Sci. Adv.

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The iconic phenotype of seadragons includes leaf-like appendages, a toothless tubular mouth, and male pregnancy involving incubation of fertilized eggs on an open “brood patch.” We de novo–sequenced male and female genomes of the common seadragon (Phyllopteryx taeniolatus) and its closely related species, the alligator pipefish (Syngnathoides biaculeatus). Transcription profiles from an evolutionary novelty, the leaf-like appendages, show that a set of genes typically involved in fin development have been co-opted as well as an enrichment of transcripts for potential tissue repair and immune defense genes. The zebrafish mutants for scpp5, which is lost in all syngnathids, were found to lack or have deformed pharyngeal teeth, supporting the hypothesis that the loss of scpp5 has contributed to the loss of teeth in syngnathids. A putative sex–determining locus encoding a male-specific amhr2y gene shared by common seadragon and alligator pipefish was identified.

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Section: Introductionmentioning

confidence: 99%

Seadragon genome analysis provides insights into its phenotype and sex determination locus

Liu

Zhang

et al. 2021

Sci. Adv.

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“…Due to the uncommon nature of reproduction, syngnathids offer a unique opportunity to examine pathways of repercussion of breeder's dietary resources on breeding performance and the resulting newborn quality. Reproduction in seahorses has received increasing attention in recent years, mostly on the effect of environment (e.g., photoperiod regime and temperature) (Lin et al, 2006(Lin et al, , 2008bPlanas et al, 2010Planas et al, , 2013 zootechnical conditions (e.g., sex ratio, aquaria design, and seahorse size) (Woods, 2000;Dzyuba et al, 2006;Faleiro et al, 2008Faleiro et al, , 2016Planas et al, 2008) and biological / physiological features (Boisseau, 1967;Carcupino et al, 2002;Poortenaar et al, 2004;Stölting and Wilson, 2007;Scobell and MacKenzie, 2011;Zhang et al, 2019;Wittington and Friesen, 2020). Only a few studies have focused on the effects of feeding and dietary sources on breeding success and newborn features in seahorses under ex-situ conditions (Lin et al, 2007;Faleiro and Narciso, 2010;Binh and Serrano, 2012;Otero-Ferrer et al, 2012Palma et al, 2012Palma et al, , 2017Saavedra et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

A Multidisciplinary Experimental Study on the Effects of Breeders Diet on Newborn Seahorses (Hippocampus guttulatus)

et al. 2020

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The global trade in seahorses is increasing and new rearing techniques are currently available for a few species. One of the main bottlenecks in seahorse production is reproductive success, which is dependent upon the administration of high quality diets to breeders. However, little is known about the most adequate diets, on how they should be administered and on how they might affect newborn performance. In this study, three homogeneous groups of adult seahorses Hippocampus guttulatus were maintained in captivity. Each group was fed on one of the following diets since the onset of the breeding period: unenriched adult Artemia (diet A), unenriched adult Artemia and mysidaceans (diet AM) and mysidaceans (diet M). As a positive control, a wild pregnant male was used. The mixed diet AM provided the highest overall breeding success and reasonable fatty acid profiles, and better resembled newborn from a wild male. The use of mysidaceans solely (Diet M) provided the worse results in spite of the high DHA content. Significant differences were observed in newborn characteristics and fatty acid profiles among dietary groups and along the breeding season, especially in total n-3 HUFA and DHA. Monospecific diets including Artemia or mysidaceans very likely suffered nutritional deficiencies, which were reflected in morphological alterations of the muscle tissue (diet A) or abnormal early mortalities in newborn (diet M). Three progressive stages were identified along the whole breeding period: initial mixed capitalincome period (100-120 days since the onset of the breeding period), followed by an inflection period (short transitional stage-income sources), and finally a long period characterized by the use of income sources and the progressive exhaustion of body reserves. Special attention should be deserved to the progressive changes in fatty acid profiles along the breeding season, resulting in a decrease in newborn performance. Considering the time required for a diet to be reflected in newborn, we recommend Hippocampus guttulatus breeders to be fed on a high quality diet for at least 3 months prior the breeding period.

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“…and copepods), keeping of breeders, and maintenance of a nursery facility for juveniles as they grow into an appropriate size [43,44,51,181,183]. There is no larval breeding stage because fertilized eggs are incubated inside the male's pouch [43,[184][185][186][187]. Seahorse species in captivity usually become sexually active at ages of around 3 to 6 months.…”

Section: Methods Of Seahorse Aquaculturementioning

confidence: 99%

Diversity of Seahorse Species (Hippocampus spp.) in the International Aquarium Trade

Koning

Hoeksema

2021

Diversity

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Seahorses (Hippocampus spp.) are threatened as a result of habitat degradation and overfishing. They have commercial value as traditional medicine, curio objects, and pets in the aquarium industry. There are 48 valid species, 27 of which are represented in the international aquarium trade. Most species in the aquarium industry are relatively large and were described early in the history of seahorse taxonomy. In 2002, seahorses became the first marine fishes for which the international trade became regulated by CITES (Convention for the International Trade in Endangered Species of Wild Fauna and Flora), with implementation in 2004. Since then, aquaculture has been developed to improve the sustainability of the seahorse trade. This review provides analyses of the roles of wild-caught and cultured individuals in the international aquarium trade of various Hippocampus species for the period 1997–2018. For all species, trade numbers declined after 2011. The proportion of cultured seahorses in the aquarium trade increased rapidly after their listing in CITES, although the industry is still struggling to produce large numbers of young in a cost-effective way, and its economic viability is technically challenging in terms of diet and disease. Whether seahorse aquaculture can benefit wild populations will largely depend on its capacity to provide an alternative livelihood for subsistence fishers in the source countries. For most species, CITES trade records of live animals in the aquarium industry started a few years earlier than those of dead bodies in the traditional medicine trade, despite the latter being 15 times higher in number. The use of DNA analysis in the species identification of seahorses has predominantly been applied to animals in the traditional medicine market, but not to the aquarium trade. Genetic tools have already been used in the description of new species and will also help to discover new species and in various other kinds of applications.

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The evolution and physiology of male pregnancy in syngnathid fishes

Cited by 50 publications

References 204 publications

Seadragon genome analysis provides insights into its phenotype and sex determination locus

Seadragon genome analysis provides insights into its phenotype and sex determination locus

A Multidisciplinary Experimental Study on the Effects of Breeders Diet on Newborn Seahorses (Hippocampus guttulatus)

Diversity of Seahorse Species (Hippocampus spp.) in the International Aquarium Trade

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