Abundance, distribution and habitat preference of Hippocampus guttulatus and Hippocampus hippocampus in a semi‐enclosed central Mediterranean marine area

Abstract

Population abundance, distribution and habitat preference of the Mediterranean sympatric seahorses Hippocampus guttulatus and Hippocampus hippocampus were investigated in a semi‐enclosed sea system (Apulian coast, Ionian Sea). A total of 242 individuals of seahorses were sighted in the 11 transects surveyed in summer 2011. Hippocampus guttulatus (n = 225) were 14 times more abundant than H. hippocampus (17). The mean abundance of H. guttulatus for all the pooled sites was 0.018 m−2 (SE ± 0.003) ranging from a maximum of 0.035 (SE ± 0.007) to a minimum of 0.008 (SE ± 0.002). The size structure of long‐snouted seahorse shows a population ranging from 7 to 14 cm (SL) with a peak at 10 cm (TL). Juveniles (96.0 ± 8.0 mm) represent a significant fraction of the population, accounting more than 21% of the sighted individuals. In Mar Piccolo, H. guttulatus is able to shelter both in monotonous habitats, including the algal beds, and diversified ones, such as the rich filter‐feeder communities that colonize hard substrates. By contrast, H. hippocampus is mainly associated with habitats of low complexity. Today, the Mar Piccolo di Taranto is among the most heavily polluted water bodies in South Italy, with trace metals, hydrocarbons, pesticides and organic wastes affecting both biotic and abiotic matrices. However, despite the high level of degradation, the presence of a large mussel farm has avoided the impact of towed fishing gears, and eutrophication of water bodies has ensured a high trophic level that supports large crustacean populations, potential prey for seahorses.

A conspicuous population of the long-snouted seahorse, Hippocampus guttulatus (Actinopterygii: Syngnathiformes: Syngnathidae), in a highly polluted Mediterranean coastal lagoon

“…Other researchers (Foster and Vincent 2004, Curtis and Vincent 2005, 2006, Vincent et al 2011 reported that H. guttulatus inhabited seagrass-or algal beds. The presently reported study is also in partial disagreement with the recent work of Gristina et al (2014), who also studied the Mar Piccolo of Taranto. The above-mentioned authors described H. guttulatus with no habitat preference between algal beds and hard substrates.…”

“…(Results of another study on this population were only recently published by Gristina et al 2014). We would like to emphasize the importance of this lagoon as an important naturalistic area and a refuge for this vulnerable species.…”

Caracterización de las poblaciones de caballitos de mar en diferentes zonas de la costa norte de las regiones occidental y central de Cuba

“…Las aguas eutrofizadas han favorecido también la presencia de caballitos de mar en el mar Piccolo di Taranto, en Italia, debido al incremento de las poblaciones de crustáceos, presas potenciales de estos peces, según sugieren Gristina et al (2015). Rosa et al (2007) encontraron que la disponibilidad de hábitats parece influir en la abundancia y distribución espacial de la especie H. reidi, sugerida por el uso de briozoos y macroalgas abundantes en las estaciones de la costa sur de Brasil, mientras que las raíces de mangle lo fueron en las estaciones de la costa norte.…”

Seafloor integrity of the Mar Piccolo Basin (Southern Italy): quantifying anthropogenic impact

“…Where algae are absent, large numbers of sabellids, mollusks and ceriantharia have colonized the soft bottom (Gristina et al, 2013). The macrozoobenthic community is unique and characterized by very rich assemblages of filter feeders (mainly consisting of sponges, hydrozoans, polychaetes, bryozoans, mollusks, crinoids and tuinicates) that colonize all types of hard substrates forming pluristratified assemblages (Gristina et al, 2013).…”

“…Others have focused on the accumulation of dangerous compounds in the Mar Piccolo Basin waters and sediments (Buccolieri et al, 2006;Calace et al, 2005;Cardellicchio et al, 2007;Petronio et al, 2012). Nevertheless, the area hosts several species protected by the Barcelona convention (Cardone, Corriero, & Gaino, 2010;Cerruti, 1938;Gristina et al, 2013;Parenzan, 1969;Matarrese et al, 2004) and received several conservation designations: Site of Community Importance (SCI; IT9130004 -EU Habitats Directive 92/43/CEE) and a Regional Reserve ('Palude La Vela' EUAP1189) along the eastern coast (Figure 1).…”