Habitat use in juvenile and adult life stages of the sedentary fish Hippocampus guttulatus

Abstract

Understanding of the spatial distribution and habitat use in different stages of a life cycle represents the essential aspect of threatened species management and conservation. In the present paper, the spatial and temporal patterns of habitat use in juvenile and adult life stages of the long-snouted seahorse Hippocampus guttulatus in the Mar Piccolo of Taranto (Apulia—Italy) (40°28′N, 17°16′W) were examined. From October 2012 to January 2014, monthly visual censuses were conducted in six coastal habitats of a focal area (Buffoluto site). Of a total of 317 individuals of the long-snouted seahorse that were sighted, 148 were juveniles, 82 adult females and 87 adult males. Our results showed significant differences in the habitat use between adult and juvenile life stages of H. guttulatus. Adult individuals were mainly concentrated within Cladophora prolifera beds and the wood poles of a mussel farm at 2–4 m of depth, while juvenile individuals were mainly present in shallower water (0.4–1 m) on artificial hard substrates covered by a brown algae turf. Assessing and describing the habitat use within different life stages of H. guttulatus represent a useful tool to support species conservation by protecting the habitats it uses

Distribution and habitat preferences of Hippocampus species along the Apulian coast

“…Of the five lagoons investigated, seahorses were found only in Taranto Mar Piccolo, where the presence of large populations of both species was reported in previous studies (Gristina et al, , ). According to Gristina et al (, ) the high seahorse abundance might be explained by several factors, such as the presence of shelters, substrate complexity, and food availability. Additionally, there are many mussel farms, which prevent any impact of towed fishing gear, while providing a number of artificial substrates used as holdfasts by seahorses.…”

“…Additionally, there are many mussel farms, which prevent any impact of towed fishing gear, while providing a number of artificial substrates used as holdfasts by seahorses. Taranto Mar Piccolo, as well as the Thau Lagoon (Southern France), hosts the largest seahorse populations known in the Mediterranean Sea (De Casabianca, Laugier, & Marinho‐Soriano, ; Gristina et al, , ; Louisy, ). Interestingly, both lagoons contain large mussel farms, thus suggesting their role in enhancing seahorse conservation on a large geographical scale by providing food resources and holdfasts, as well as a complex substratum.…”

“…The Hippocampus species in temperate Atlantic regions are usually associated with seagrass habitats (Foster & Vincent, ), although some observations suggest that they can also exploit uncovered substrates and sandy bottoms with few potential holdfasts and hiding places (Bell, Lockyear, McPherson, Marsden, & Vincent, ; Garrick‐Maidment & Jones, ). Various publications (Correia, Koldewey, Andrade, & Palma, ; Curtis & Vincent, ; Gristina et al, ; Woodall, ) suggest that H. guttulatus prefers seagrass beds and artificial substrates, whereas H. hippocampus can be found more frequently on soft bottoms among rocks and algae, but also on artificial substrates.…”

Linking pipefishes and seahorses to seagrass meadows in the Venice lagoon: Implications for conservation

“…Hippocampus guttulatus was not abundant in shallow waters, probably preferring deeper and more stable environments such as subtidal meadows and other hard substrata at greater depths (Gristina et al, ). Despite being relatively uncommon, this species was typically associated with tall and spatially continuous seagrass habitats.…”

“…by monitoring attributes of population structure (Pollom, , ). Hippocampus guttulatus , while being associated with tall and highly structured meadows as well, accounts for a very small proportion of the overall catches of syngnathids in the shallow waters of the Venice lagoon, and conversely could represent a key feature of fish assemblages in other structured habitats at greater depths, as suggested by other studies (Gristina et al, , ). For this reason, despite the obviously charismatic function of this species, it may not be as effective a flagship for shallow water seagrass meadows as S. typhle and N. ophidion .…”