Reproduction and food habits of the lined seahorse, Hippocampus erectus (Teleostei: Syngnathidae) of Chesapeake Bay, Virginia

Abstract

The reproductive and feeding biology of the lined seahorse, Hippocampus erectus, was studied in Chesapeake Bay. Seahorses are monogamous, and males incubate the eggs received from females in a closed brood pouch (= marsupium). Females do not play any parental care after mating. Total sex ratio and the operational sex ratio was strongly skewed toward females. Males and females had similar number of eggs/embryos and hydrated oocytes, respectively. The number of eggs/embryos found in the male brood pouch varied from 97 to 1,552 (fish from 80 to 126 mm TL), whereas the number of hydrated oocytes in female varied from 90 to 1,313 (fish from 60 to 123 mm TL). Both, the number of eggs/embryos and hydrated oocytes were better linearly correlated to total weight than to total length. The small snout and mouth size limits the feeding of the lined seahorse to small prey size. Amphypods were the predominant food items found in the guts, especially Ampithoe longimana, Gammarus mucronatus, and Caprella penantis. The lined seahorse is not abundant in Chesapeake Bay, but keeps a breeding population which is probably brought inside the bay by currents on drifting vegetation. Chances to find a partner may be difficult because of its low abundance, due to turbid waters, and its sedentary behavior.Key words: parental care, fecundity, fertility, amphipods, estuary. RESUMOReprodução e hábito alimentar do cavalo-marinho Hippocampus erectus (Teleostei: Syngnathidae) de Chesapeake Bay, Virgínia A biologia reprodutiva e alimentar do cavalo-marinho Hippocampus erectus foi estudada no estuário de Chesapeake Bay, Virgínia. Cavalos-marinhos são monógamos, sendo que o macho incuba os ovos recebidos da fêmea em uma bolsa incubadora fechada (= marsúpio). As fêmeas não desempenham qualquer cuidado com a prole após a fecundação. A razão sexual total e operacional foi fortemente direcionada para as fêmeas. sapeake Bay, mas mantém uma população reprodutiva. As chances para encontrar um parceiro são pequenas, devido à baixa abundância, às águas túrbidas e ao comportamento sedentário da espécie.Palavras-chave: cuidado paternal, fecundidade, fertilidade, anfípodas, estuário.

Assessing diet composition of seahorses in the wild using a non destructive method: Hippocampus reidi (Teleostei: Syngnathidae) as a study-case

“…The occasional consumption of insects (ants) observed in this study is unique, and is possibly related to the massive presence of mangrove trees along the margins of the estuary. While Harpacticoida was the principal item consumed by Hippocampus zosterae (Tipton & Bell, 1988), H. subelongatus (Kendrick & Hyndes, 2005) and H. reidi (this study), the other studied seahorse species mostly consumed Cyclopoida copepods, amphipods and caridean shrimps (see Kanou & Kohno, 2001;Kendrick & Hyndes, 2005;Teixeira & Musick, 2001;Burchmore et al, 1984;Woods, 2002). These results highlight the importance of crustaceans as a prey category to seahorses.…”

“…Reproductive state: IM = immature, OF = ovipositor region flat, OB = ovipositor region bulging, B = brooding, NB = non-brooding. while mid size and larger specimens fed almost exclusively on amphipods (Teixeira & Musick, 2001). Additionally, Tipton & Bell (1988) found an increase in the consumption of amphipods by larger specimens of H. zosterae, despite the dominance of harpacticoid copepods in all size classes, and Kanou & Kohno (2001) reported that juveniles H. mohnikei exhibited a division of prey items between size classes, with the smaller seahorses feeding mainly on cyclopoid copepods smaller than those consumed by larger specimens.…”

Effects of light intensity, stocking density, feeding frequency and salinity on the growth of sub-adult seahorses Hippocampus erectus Perry, 1810

“…However, the low survivorship of juvenile seahorses and low reproductive efficiency of the broodstock seahorses have restricted seahorse culture for many years (Herald and Rakowicz, 1951;Scarratt, 1995;Wilson and Vincent, 1998;Wong and Benzie, 2003;Lin et al, 2006). Therefore, recent research works have mainly focused on the growth and survivorship of juveniles (Scarratt, 1995;Woods, 2000Woods, , 2003aSheng et al, 2006;Lin et al, 2008), and on broodstock reproduction (Selman et al, 1991;Vincent, 1995;Teixeira and Musick, 2001;Perante et al, 2002;Lin et al, 2006Lin et al, , 2007Faleiro et al, 2008). The effects of illumination, feed ration, stocking density and gender segregation on growth and survival have been examined in Hippocampus abdominalis (Woods, 2000(Woods, , 2003a(Woods, , 2005.…”

Reproductive output of male seahorses,Hippocampus abdominalis,from Wellington Harbour, New Zealand: Implications for conservation

“…Strawn (1958) also found that in Hippocampus zosterae from Florida there was an increasing relationship between length of seahorses and the number of eggs contained in the brood pouches of male seahorses, and Texeira & Musick (2001) observed the same trend in Hippocampus erectus from Chesapeake Bay. This correlation is logical given that pouch volume, and hence eggcarrying capacity, increases as males increase in overall size.…”

“…zosterae. Texeira & Musick (2001) found non-fertilised eggs frequently in wild H. erectus (i.e., occurring in 50% of males examined and ranging in percentage of total pouch contents from 1.7% to 33%). In captive H. fuscus, Vincent (1990) found that males failed to incubate on average between 9 and 48% of their broods, with lower failure rates in mating pairs that had been together longer.…”