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My thesis examined the implications of life history and ecology for population-level responses of the European long-snouted seahorse ( Hippocampus guttulatus Cuvier 1829) to habitat alteration, exploitation and a recommended minimum size limit for seahorse management. The research employed a mark-recapture study, underwater visual censuses (UVCs) and catch data from an unrelated experimental sampling program in the Ria Formosa Lagoon (southern Portugal). These small-bodied fish are characterized by rapid growth rate, early age at maturity, high natural mortality, short generation time, short life span and multiple spawnings per year, traits that are usually associated with resilience to exploitation. However specialized parental care, complex social interactions, small adult home ranges and benthic habit confer risk to H. guttulatus. Population-level responses to experimental reductions in non-selective fishing effort differed in magnitude and direction between H. guttulatus and its smaller congener, Hippocampus hippocampus: the abundance of H. guttulatus increased significantly while its congener decreased in abundance. Hippocampus guttulatus preferred more complex, vegetated habitats, while H. hippocampus preferred more open, sparsely vegetated habitats. Thus it seems probable that H. guttulatus fared better in the more complex habitats that developed when seining stopped, whereas H. hippocampus fared better in the less complex habitat arising from repeated seining. I used an age-structured stochastic simulation to evaluate the biological implications of a recommended generic strategy (10 cm minimum size limit) for managing the exploitation and international trade of seahorses, using H. guttulatus as a model. The smallest size limit that was robust (using the magnitude of population decline and probability of quasi-extinction as criteria) to a range of fishing rates, maximum population growth rates (rmax) and models of density-dependence

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Thesis (PhD)--Stellenbosch University, 2003. / ENGLISH ABSTRACT: The aims of this study were to investigate genetic issues pertaining to the conservation of the Knysna seahorse, Hippocampus capensis, and to determine the phylogenetic placement of this endangered estuarine species among marine seahorses. This was accomplished by focusing on three aspects of the taxonomy: the interspecific level; the inter-population level; and the intra-population level. To determine which species are closely related to H. capensis, and how the evolutionary history of this lineage relates to that of other seahorses, sequence data derived from four gene fragments (the nuclear RPI and Aldolase and the mitochondrial 16S rRNA and cytochrome b genes) were used to determine the phylogenetic relationships among 30 species belonging to the genus Hippocampus. There were marked differences in the rate of evolution among these gene fragments, with Aldolase evolving the slowest and the mtDNA cytochrome b gene the fastest. Among individual partitions, the RPI gene recovered the highest number of nodes supported by >70% bootstrap values from parsimony analysis, and >95% posterior probabilities from Bayesian inference. The combined analysis based on 2317 nucleotides resulted in the most robust phylogeny. A distinct phylogenetic split was identified between the pygmy seahorse, H. bargibanti, and a clade including all other species. Three species from the western Pacific Ocean included in this study, namely H. bargibanti, H. breviceps, and H. abdominalis, occupy basal positions in the phylogeny. This and the high species richness in the region suggest that the genus probably originated in this region. There is also fairly strong molecular support for the remaining species being subdivided into three main evolutionary lineages: two West Pacific clades and a clade of species present in both the Indo-Pacific and the Atlantic Ocean, which includes H. capensis. The phylogeny obtained herein suggests that seahorses belonging to the latter clade colonised the Atlantic Ocean at least twice, once before the closure of the Tethyan Seaway, and once afterwards. Phylogenies reconstructed using mitochondrial DNA gene fragments (l6S rRNA, cytochrome band 382 bp of the rapidly evolving control region) indicate that H. capensis is closely related to an Indian Ocean lineage of H. kuda and a Red Sea lineage of H. fuscus. Other lineages closely associated with these taxa include H. kuda from the West Pacific, the East Atlantic species H. algiricus, the West Atlantic species H reidi, the East Pacific species H ingens, and the Hawaiian species H fisheri. No control region alleles were shared among H capensis and any of the marine seahorses, suggesting that the Knysna seahorse is phylogenetically distinct. The evolutionary history of H capensis, and the extent of gene flow between its three known populations, were investigated using control region sequences from 138 specimens. Most samples were obtained by taking fin clips; this method was studied on captive seahorses and no negative effects were found. Similarly high levels of genetic diversity were found in two of the wild populations (Knysna and Keurbooms Estuaries), whereas diversity in the third population (Swartvlei Estuary) was lower. Although most haplotypes are shared among at least two populations, based on the haplotype frequency distributions the three assemblages constitute distinct management units. The extant population structure of H capensis suggests that the Knysna seahorse originated in the large Knysna Estuary. The presence of seahorses in the two smaller estuaries is either the result of a vicariance event at the beginning of the present interglacial period, or colonisation of the estuaries via the sea, or a combination of the two. Population genetic parameters of the Knysna population and those of two populations of closely related marine seahorses (H kuda from the Philippines and H fuscus from the Red Sea) were similar, suggesting that the Knysna population is not genetically impoverished, despite its comparatively small area of occupancy. / DEUTSCHE ZUSAMMENFASSUNG: Die hier prasentierte wissenschaftliche Studie beschaftigte sich mit genetischen Themen relevant flïr den Artenschutz des Knysna Seepferds, Hippocampus capensis, und den phylogenetischen Beziehungen dieser ausschliesslich in Estuaren (Flussmtindungen) vorkommenden gefahrdeten Art mit den im Meer lebenden Seepferden. Die folgenden taxonomischen Einheiten wurden verglichen: Arten, Populationen und Sub-Populationen. Urn festzustellen, welche Arten nah mit H. capensis verwand sind, und wie die Evolution dieser Gruppe sich von der anderer Seepferdgruppen unterscheidet, wurden genetische Sequenzen von vier Genen (den nuklearen RPI und Aldolase und den mitochondrischen 16S rRNA und Cytochrom b Genen) von 30 Seepferdarten verwendet und phylogenetische Beziehungen rekonstruiert. Betrachtliche Unterschiede wurden festgestellt hinsichtlich der Geschwindigkeit in der Mutationen stattgefunden haben: Aldolase mutierte am langsamsten und Cytochrom b am schnellsten. Eine auf RPI Sequenzen basierende Phylogenie hatte die hëchste Anzahl von Gabelungspunkten, die sowohl von parsimonischen Analysen, als auch von bayesischer Inferenz untersttitzt wurden. Die robusteste Phylogenie wurde jedoch gefunden, wenn Sequenzen von allen vier Genen kombiniert wurden (im ganzen 2317 Nukleotide). Eine betrëchtliche genetische Distanz wurde zwischen dem Pygmaen-Seepferd, H. bargibanti, und einer Gruppe, die aus allen anderen Arten bestand, gefunden. Drei Arten vom westlichen Pazifik, namlich H. bargibanti, H. breviceps und H. abdominalis, hatten basale Positionen in der Phylogenie. Das, und der Artenreichtum dieser Region, sind Anzeichen daflïr, dass Seepferde mëglicherweise ursprtinglich aus dem westlichen Pazifik stammen. Es wurde weiterhin gefunden, dass alle tibrigen Seepferdarten in drei Hauptgruppen unterteilt werden kannen: die Verbreitungsgebiete zweier dieser Gruppen beschranken sich hauptsachlich auf den westlichen Pazifik, aber die dritte Gruppe kommt sowohl im Indo-Pazifik, also auch im Atlantik vor (H. capensis ist mit dieser letzteren Gruppe assoziiert). Es gibt gute Anzeichen dafllr, dass die Seepferde der letztgenannten Gruppe den Atlantik mindestens zweimal kolonisiert haben, einmal vor der Schliessung der tethyschen Seeverbindung, und einmal danach. Phylogenien, die ausschliesslich mit mitochondrischen Genen rekonstruiert wurden (16S rRNA, Cytochrom b und 382 Nukleotide der schnell-mutierenden Kontollregion), zeigen, dass H capensis sehr nah verwandt mit H kuda aus dem Indischen Ozean und H fuscus aus dem Roten Meer ist. Andere nah verwandte Arten sind H kuda from westlichen Pazifik, H algiricus vom ëstlichen Atlantik, H reidi vom westlichen Atlantik, Hingens vom ëstlichen Pazifik, sowie die in Hawaii vorkommende Art H fisheri. Keine der Kontrollregionallele, die in H capensis gefunden wurden, kamen in anderen Arten vor. Dies zeigt, dass das Knysna Seepferd eine eigenstandige Art ist, und Paarungen mit anderen Arten nicht vorkommen. Die Evolutionsgeschichte von H capensis, und das Ausmass von genetischem Austausch zwischen den drei Populationen dieser Art, wurden untersucht, indem Kontrollregionsequenzen von 138 Individuen analysiert wurden. Die meisten Proben stammten von Flossenschnitten; diese Methode wurde zuvor an in Gefangenschaft lebenden Seepferden ausprobiert, und es wurden keine negativen Folgeerscheinungen beobachtet. Genetische Diversitat war ungefahr gleich hoch in zwei der Populationen (Knysna und Keurbooms Estuare), aber eine deutlich niedrigere Diversitat wurde in der dritten Population gefunden (Swartvlei Estuar). Obwohl die meisten Allele in mindestens zwei Populationen gefunden wurden, sind die drei Populationen unterschiedliche genetische Einheiten, eine Schlussfolgerung, die hauptsachlich auf Unterschiede in der relativen Haufigkeit der Allele beruht. Die Populationsstruktur von H capensis deutet darauf hin, dass diese Art ihren Ursprung im Knysna Estuar hat. Die Prasenz von Seepferden in den beiden anderen Estuaren ist entweder das Resuitat von Vikarianz (eine Spaltung der urspri.inglichen Population) zu Beginn der jetzigen Interglazialzeit, oder Kolonisierung der Estuare durchs Meer, oder eine Kombination beider Szenarios. Populationsgenetische Parameter der Knysna Population und die zweier Populationen von nah verwandten Arten (H kuda aus den Philippinen und H fuscus aus dem Roten Meer) zeigten keine grossen Unterschiede. Dies deutet darauf hin, dass das Knysna Seepferd trotz seines vergleichbar kleinen Verbreitungsgebietes nicht unter geringer genetischer Diversitat leidet. / AFRIKAANSE OPSOMMING Die doelwitte van hierdie studie was om die Knysna seeperdjie, Hippocampus capensis, te ondersoek relatief tot die spesie se bewaring asook om die filogenetiese posisie van hierdie bedreigte estuariene spesie binne mariene seeperdjies te bepaal. Drie aspekte van die taksonomie word ondersoek: interspesie verwantskappe, interbevolking verwantskappe en intra-bevolking verwantskappe. Om te bepaal watter spesies na verwant is aan H capensis, asook om die evolusionêre geskiedenis van hierdie groep met die van ander groepe te vergelyk, word nukleotieddata van vier ONS fragmente (die nukleêre RPI intron en Aldolase, en die mitochondriale 16S rRNA en sitokroom b fragmente) van 30 spesies van die genus Hippocampus gebruik. Aansienlike verskille in die tempo van evolusionêre verandering tussen hierdie ONS fragmente word gevind: Aldolase was die stadigste en die mitochondriale sitokroom b die vinnigste. Die RPI intron het die meeste knoesteringe gehad wat ondersteun word deur hoë stewelvasgordnommers (>70%) van parsimoniese analises en hoë agterwaarskynlikheide (>95%) van Bayesiese gevolgtrekkinge. Die kombineerde analise wat 2317 nukleotiede ingesluit het, het die beste filogenie geproduseer. 'n Besliste filogenetise verdeling was gevind tussen die pigmee seeperdjie, H bargibanti, en 'n groep wat al die ander spesies ingesluit het. Drie spesies van die westelike Stille Oseaan wat in hierdie studie ingesluit is, H bargibanti, H breviceps en H abdominalis, neem primitiewe posisies in die filogenie in. Dit, en die hoë spesiesrykdom in daardie gebied dui aan dat dit moontlik is dat die genus in die westelike Stille Oseaan ontstaan het. Daar is ook taamlike goeie molekulêre ondersteuning dat al die ander spesies in drie evolusionêre hoofgroepe verdeel kan word: twee groepe wat hoofsaaklik in die westelike Stille Oseaan voorkom, en 'n groep van spesies wat in die Stille Oseaan, die Indiese Oseaan en in die Atlantiese Oseaan voorkom, wat H capensis insluit. Die filogenie wat hier gevind is dui aan dat seeperdjies van hierdie laas genoemde groep die Atlantiese Oseaan minste twee keer gekoloniseer het, een keer voor die sluiting van die Tetiese Seepad, en een keer daarna. Filogenies wat met mitochondriale ONS fragmente gerekonstrueer is (16S rRNA, sitokroom b en 382 nukleotide van die vinnig evolveerende kontrolestreek) dui aan dat H capensis na verwant is aan 'n groep van H kuda wat in die Indiese Oseaan voorkom en H fuscus van die Rooi See. Ander groepe wat na verwant is aan hierdie takson is H kuda van die westelike Stille Oseaan, H algiricus van die Oos Atlantiese Oseaan, H reidi van die Wes Atlantiese Oseaan, en die Hawaiise spesie H fisheri. Geen kontrolestreek allele was gedeel tussen H capensis en enige mariene seeperdj ie spesies; dit dui aan dat die Knysna seeperdjie filogeneties verskillend is. Die evolusionêre geskiedenis van H capensis, en die omvang van die genetiese interaksies tussen sy drie bekende bevolkings, word ondersoek met kontrolestreek nukleotieddata van 138 monsters. Die meeste van hierdie monsters was verkry deur vinknipsels; hierdie metode was getoets op seeperdjies in gevangenskap en geen negatiewe gevolge was gevind nie. Genetiese diversiteit was omtrent dieselfde in twee van die natuurlike bevolkings (Knysna en Keurbooms Estuariums), maar diversiteit in die derde bevolking (Swartvlei Estuarium) was laër. Alhoewel die meeste allele gedeel was tussen ten minste twee bevolkings, dui die verspreiding van allelfrekwensies aan dat die drie bevolkings aparte bestuurseenhede is. Die ekstante bevolkingsstruktuur van H capensis dui aan dat die Knysna seeperdjie in die groot Knysna Estuarium ontstaan het. Die teenwordigheid van seeperdjies in die twee kleiner estuariums is óf die resultaat van 'n vikariansie voorval aan die begin van hierdie interglasiale tydperk, óf kolonisasie van die estuariums deur die see, óf 'n kombinasie van albei. Bevolkingsgenetiese parameters van die Knysna bevolking en van twee bevolkings van na verwante seeperdjie spesies (H kuda van die Filippyne en H fuscus van die Rooi See) was soortgelyk, wat aandui dat die Knysna bevolking nie geneties verarm is nie, alhoewel dit 'n betreklik kleiner streek bewoon.

Thesis (Ph.D.). / Written for the Dept. of Biology. Title from title page of PDF (viewed 2008/07/24). Includes bibliographical references.

This thesis investigates the potential role of historical isolation of ocean basins in promoting diversification among marine organisms in Southeast Asia. It also questions the possible effects of Pleistocene exposure of the Sunda Shelf on present day marine distributions and genetic diversity. Four species of exploited seahorses (genus Hippocampus), with differing ecological parameters, are used to test historical hypotheses. The results (based on cytochrome b DNA sequencing) suggest that significant phylogeographic structure does exist among seahorse populations in Southeast Asia, but that the patterns are only partially concordant across species. Distinct phylogeographic breaks are seen in H. barbouri, H. kuda, and H. trimaculatus, whereas greater spatial overlap of haplotypes in H. spinosissimus indicates more extensive gene flow. The phylogeographic history of the two shallow water species (H. barbouri and H. kuda) appears to have been primarily shaped by fragmentation and/or long-distance colonisation events. Both species show patterns consistent with hypotheses of divergence mediated by ocean basins separations. The deeper water species (H. spinosissimus and H. trimaculatus) show more evidence of range expansion and isolation by distance. Hippocampus trimaculatus shows a deep east-west phylogeographic division at right angles to that predicted by the separation of the Indian versus Pacific Ocean basins and instead parallels the terrestrial division known as Wallace's Line. Different species have also responded differently to the reflooding of the Sunda Shelf at the end of the last Ice Age: the two deeper water species have colonised it extensively suggesting limited barriers to movement, whereas the shallow water species have not. It is possible that the populations of H. kuda now inhabiting the shelf may stem from populations that found refuge in brackish water lakes when the shelf was exposed to the air. All four species are heav

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Orientador: Wagner Cotroni Valenti / Coorientador: Ricardo Jorge Guerra Calado / Banca: Alessandra da Silva Augusto / Banca: Cintia Miyaji / Banca: Helcio Luis de Almeida Marques / Banca: Márcia Santos Nunes Galvão / Resumo: Este trabalho teve por objetivo estudar o mercado, a produção e a comercialização de cavalos-marinhos com foco no atendimento da demanda mundial de forma mais sustentável e na conservação desses animais. Assim, a tese foi dividida em cinco artigos: (1) apresenta um panorama da pesquisa mundial no século XXI sobre cavalos-marinhos. Observou-se que os campos de pesquisa fundamentais para subsidiar decisões governamentais e que abordam as questões que afetam a produção, o comércio e a manutenção das populações naturais de cavalos-marinhos não vem sendo cobertos adequadamente. Cinco áreas foram identificadas como prioritárias para o avanço do conhecimento científico, atendendo à demanda e a conservação dos cavalos-marinhos. (2) Discute a comercialização e o mercado; mostra que o mercado é pouco conhecido e que as regulamentações internacionais para comércio de cavalos-marinhos estão sendo ineficientes na conservação. (3) Apresenta as principais oportunidades e limitações de se cultivar cavalos-marinhos em estuários em Manguezal como alternativa para produção de baixo custo. Observou-se que essa prática é bastante promissora, podendo aproveitar a disponibilidade local de reprodutores, água, espaço, alimento natural, mão de obra e gerar renda adicional para comunidades locais de forma mais sustentável. Alterações ambientais bruscas, predadores, obstrução das redes e escapes são as principais limitações. (4) Visa otimizar o transporte de animais vivos. Observou-se que Hippocampus re... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The aim of this work was to study the trade, the production and the commercialization of seahorses focusing on meeting world demand in a more sustainable way and on the conservation of these animals. Thus, this thesis was divided in five articles: (1) shows an overview of the seahorse research in the 21st century. It was observed that the key research fields necessary to support government decisions on addressing issues affecting the production, trade and maintenance of wild seahorses populations, have not been properly studied. Five knowledge gaps were identified as priorities for improving scientific knowledge, considering both world demand and seahorse conservation. (2) Discusses commercialization and trade; Shows that there is little information on trade and that international regulations of seahorse trade have been ineffective to promote their conservation. (3) Shows the main opportunities and constraints to produce seahorses in mangrove estuary as an alternative for low-cost aquaculture. It was observed that this system has great potential; it can rely on the availability of local broodstock, water, space, natural food, labour, and provide additional income for local communities in a more sustainable way. Sudden environmental changes, predators, net obstruction, and escapees are the main constraints of this system. (4) Aims to optimize transport of live seahorses. It was reported that Hippocampus reidi could be transported in plastic bags containing 300 mL of water, sal... (Complete abstract click electronic access below) / Doutor

Syngnathidae (seahorse, pipefish, pipehorses & seadragons) are highly visual feeders with different species feeding on specific types of prey, a behaviour that has been related to snout length. Worldwide, many species have become threatened by habitat destruction, collection for the aquarium trade and exploitation for traditional medicine, as well as recreational and commercial bycatch. Attempts to establish aquaculture programs have been of limited success. Little is known about their visual capabilities in detail. The visual systems of fishes are known to have evolved specific adaptations that can be related to the colour of water in which they live and specific visual tasks such as predator detection and acquisition of food. This study examined the ocular and retinal morphology, photoreceptor structure and spectral sensitivity of adult individuals of a local pipefish (S. argus), local seahorse (Hippocampus subelongatus) which both inhabit green water seagrass beds, and a tropical species of seahorse (Hippocampus barbouri) from blue water coral reefs. Some juveniles were also investigated. Accordingly, we developed an understanding of the features that are common to all syngnathids and those that have evolved for specific environments. Cryosections of the eyes were taken to determine morphological distinctions of this group. Lens characteristics measured using a spectrophotometer determined 50% cut-off wavelengths below 408nm for all 3 species, hence no transmission of UV light to the retina. Histological examination determined a cone dominated fovea in the ventro-temporal retina and very large rods concentrated in the peripheral retina and adjacent to the optic nerve. Microspectrophotometry measured the absorption characteristics of the visual pigments within the photoreceptors showing the presence and maximum sensitivity (λmax) of rods, SWS single cones, and a broad, complex array of LWS double/twin cones. The results are discussed in relation to the light environment inhabited by each species and their feeding requirements. The implications for the design of suitable light environments for aquarium and aquaculture programs for the Syngnathidae are also discussed. Rearing success of this family of fish, for both the aquarium trade and re-stocking programs, would be advised to take lighting regimes and specifics of the animals’ vision into account