The ontogeny of habitat associations in the tropical tiger tail seahorse Hippocampus comes Cantor, 1850

Abstract

This study examined how habitat associations changed with ontogeny in the tiger tail seahorse Hippocampus comes Cantor, 1850, over four reef zones in a coral reef ecosystem. Hippocampus comes showed ontogenetic differences in their use of habitat at the scale of reef zones (macrohabitat) and holdfasts (microhabitat). Across reef zones, juvenile size classes (25-105 mm standard length, L S ) were most abundant in wild macroalgal beds (Sargassum spp.) (55Á7%), while adults (>105 mm L S ) occupied both coral reefs (39Á7%) and macroalgal beds (42Á7%). Microhabitat use also varied with ontogeny. Juveniles generally used macroalgal holdfasts, while adults >135 mm L S used a greater diversity of specialized microhabitats that included branching sponges, branching corals and tall seagrass. Ontogenetic changes in habitat association, as well as size-related shifts in crypsis and aggregation, suggest that H. comes experiences fitness trade-offs that vary with size; juveniles may associate with habitat that reduces predation, while larger individuals may use distinct microhabitat in reef zones to optimize reproductive success. Results are discussed in the context of targeted exploitation, expanding artisanal mariculture, habitat damage from illegal fishing and reserve design.

Conservation and management of seahorses and other Syngnathidae

“…The size class most affected by fishing will also depend on spatial segregation: for example, breath‐hold fishers in the Philippines tend to fish outside the Sargassum spp. habitats where more of the smaller, juvenile seahorses are found (Morgan & Vincent, 2007). Again, localized habitat damage may cause size‐biased effects on species where size classes are somewhat segregated in space.…”

“…If the juvenile phase was identified as the most vulnerable, then conservation efforts would need to prioritize the macroalgae that the young inhabit (Morgan & Vincent, 2007). On the other hand, should the adult stage be most vulnerable, then the priority would be protection in areas of great habitat richness, where large reproducing adults are found (Morgan & Vincent, 2007). Among the many global initiatives to support marine habitats, Save Our Seahorses (founded in 2004) is distinctive in focusing on syngnathid habitat and monitoring; this non‐profit group is committed to saving seahorses and pipefishes in the Pulai Estuary in Malaysia, partly by surveying seagrass beds (http://www.sosmalaysia.org).…”

Habitat Preference and Population Structure of Two Data Deficient Seahorse (Syngnathidae) Species

“…Other fisheries studies also show that intervening size classes between small juveniles and adults of several marine fish including two species of seahorses (H. guttulatus and H. hippocampus) are rarely seen in benthic surveys and plankton tows (Pérez-Ruzafa et al, 2004;Curtis & Vincent, 2005). While smaller seahorses may have been missed due to the sampling methodology they may be utilizing a different habitats has been observed in H. comes in the Philippines (Perante, 2002;Morgan & Vincent, 2007).…”

Early development of marine catfishes (Ariidae): from mouth brooding to the release of juveniles in nursery habitats

“…Ontogenetic studies of fishes are important tools for evaluating behavioural and ecological traits that are associated with different patterns of development among teleosts (Fukuhara, ; Koumoundouros et al ., ). Usual switches in behaviour, feeding, ecological requirements and habitat are observed in different developmental stages, and these events are closely related to changes in body shape and the formation of specific structures, such as otoliths and fins (Galis et al ., ; Pinder & Gozlan, ; Morgan & Vincent, ). Allometric growth of selected body regions ( e .…”