Field studies of seahorse population density, structure and habitat use in a semi‐closed north‐eastern Mediterranean marine area (Stratoni, North Aegean Sea)

Abstract

The present study was carried out in the marine area of Stratoni, Greece, where two seahorse species are present (Hippocampus hippocampus and H. guttulatus). Two surveys were conducted (September 2016, May 2019) to gather information regarding seahorse species' abundance, distribution and habitat characteristics. Four different seahorse natural and artificial habitat types were identified. Results revealed that the abundance of H. hippocampus was relatively high, especially at sites with artificial structures, while the presence of H. guttulatus was rare. Data collected can provide baseline information for future population assessments.

Large-Scale Distribution of the European Seahorses (Hippocampus Rafinesque, 1810): A Systematic Review

“…Seagrasses are the preferred habitat of many temperate syngnathid species [ 4 ], probably because they maximize prey density and capture efficiency, and could help fish with low swimming capacities avoid predators [ 4 ]. In confined areas, however, seahorses are also reported on incoherent (sandy or muddy) bottoms and algal beds, supporting site-specific studies [ 7 , 20 , 23 , 37 , 38 ]. Some seahorses have been recorded grasping artificial structures, highlighting their important role in the population dynamics of seahorses [ 18 , 37 ].…”

“…In confined areas, however, seahorses are also reported on incoherent (sandy or muddy) bottoms and algal beds, supporting site-specific studies [ 7 , 20 , 23 , 37 , 38 ]. Some seahorses have been recorded grasping artificial structures, highlighting their important role in the population dynamics of seahorses [ 18 , 37 ]. It is known that artificial structures are a suitable habitat for seahorses, probably because they host rich and diversified fouling communities, which can contribute to the complexity of the system by providing additional microhabitats, food, and hiding places [ 7 , 35 , 39 ].…”

Population structure of the seahorse Hippocampus reidi in two Brazilian estuaries

“…m -2 ) and Schwarz et al, 2021 (0 to 0.32 fish/ m2). Low densities are often found for several other seahorse species, such as Hippocampus hippocampus in Ria Formosa lagoon and on Chalkidiki Peninsula (ranging between 0.05 ind.m -2 and 0.015 ind.m -2 ), in the North Aegean Sea (Correia et al, 2015;Correia et al, 2020). Mean densities of 0.0089 m -2 are observed for Hippocampus capensis in South Africa (Bell et al, 2003).…”

Abundance, Distribution, and Habitat Preference of Syngnathid Species in Sabaudia Lake (Tyrrhenian Sea)

“…These charismatic fish have unique life cycle traits, such as a restricted home range, low mobility, and reduced reproductive output, which make them susceptible to direct and indirect threats; these include the degradation of habitats [9], incidental capture in fishing gear [10], and aquarium trade [11]. Moreover, the use of syngnathids (especially seahorses) in Traditional Chinese Medicine (TCM) is a widespread issue with a more recent emergence in the Mediterranean Sea [12]. Consequently, all syngnathids have been listed in Appendix II of CITES and the IUCN Red List of Threatened Species [13]; according to the latter, most syngnathids in the Mediterranean Sea are classified as data-deficient on a global level [13], indicating an urgent need for further research to fill the information gap and permit adequate conservation of these sensitive fishes.…”

“…Indeed, available data on diversity, distribution, threats, and conservation status in the Mediterranean are mostly fragmented, and an updated overview is required to facilitate the identification of research and conservation priorities. Although syngnathids act as flagship species of the marine conservation effort as well as indicators of the health and diversity of coastal ecosystems [13], most of the research in the Mediterranean Sea has referred to seahorses on a local scale, e.g., [12,[14][15][16][17], while studies on pipefishes are lacking and have been mostly limited to generic biodiversity projects and lifecycle studies [18][19][20]. Only a few studies have specifically focused on evaluating pipefish population dynamics, ecology, and spatial distribution [19,21], but most have referred to Turkey [22,23], Tunisia [24], and Spain [25], with only a few studies on the northern Italian Adriatic coast [19,21,26,27].…”