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

Abstract

Seagrass meadow degradation and loss is one of the major threats to fish biodiversity in coastal marine and lagoon ecosystems in the Mediterranean. Pipefishes and seahorses (family Syngnathidae) are particularly affected by loss of seagrass meadows and other structured habitats, on which they rely for survival and reproduction. Despite their charismatic appearance and peculiar behaviour, their habitat ecology is still poorly understood in Mediterranean coastal waters. This study focuses on syngnathid assemblage composition and diversity in the shallow waters of the Venice lagoon (Italy), aiming at highlighting habitat preferences and providing insights into the conservation of biodiversity in these ecosystems. Generalized Additive Models were used in order to disentangle the potential effect of habitat typologies and different architectures of seagrass meadows from that of other environmental parameters. Most abundant taxa and whole syngnathid assemblage indicators were positively associated with seagrass meadows. Only few species, however, were seagrass specialists in shallow waters, and preferred meadows with taller canopies. Despite that, other structured habitats including short‐leaved seagrass meadows and macroalgal beds were important for some species and overall assemblage diversity. Managers in Mediterranean coastal lagoons should thus limit human pressures that lead to the depletion of seagrass meadows, with particular attention to long‐ and broad‐leaved species in less confined areas. Nevertheless, syngnathid assemblages would benefit from the preservation and restoration of the overall habitat diversity characterizing shallow waters in coastal lagoon. Future studies should aim at investigating the potential role of habitats at greater depths in supporting syngnathids.

Feeding ecology of pipefish species inhabiting Mediterranean seagrasses

“…ation between the pipefish species shown in the present study were also described by Scapin et al (2018), who highlighted a more generalist behavior in habitat choice of S. abaster, mostly found in association to algal beds and low-density seagrass meadows, compared with S. typhle, which appear to be dense-seagrass specialists. N. ophidion was also expected to be a dense-seagrass specialist (Scapin et al, 2018), but it was mainly found in C. nodosa during our study. Pipefish exhibit a high degree of trophic specialization compared to other epibenthic marine teleosts (Gürkan, 2008).…”

Local Habitat and Seascape Structure Influence Seagrass Fish Assemblages in the Venice Lagoon: The Importance of Conservation at Multiple Spatial Scales

“…In particular, N. ophidion and S. typhle show a greater response to extent and spatial arrangement of seagrass meadows in the seascape, as well as a positive response to larger mosaic patches. This emphasises their role as seagrass specialists that could be employed as indicators of seagrass habitat status, as already pointed out for the Venice lagoon (Scapin et al 2016;Scapin et al 2018).…”

“…Syngnathids exhibit preferences for different canopy heights in seagrass meadows at the site scale in the Venice lagoon (Malavasi et al 2007;Scapin et al 2018). This paper emphasises that species of this family show a different response to canopy height also at the mosaic scale.…”

Predicting the response of nekton assemblages to seagrass transplantations in the Venice lagoon: An approach to assess ecological restoration

“…Similarly, presence/absence of S. pavo , Hippolytidae and Z. ophiocephalus were predicted with high accuracy; hence, the inclusion of such species in the reference assemblages can be inferred due to their relatively high probability of presence. S. typhle and N. ophidion are highly specialized pipefish that have developed morphological and behavioural adaptations to thrive in dense, highly structured seagrass meadows (Franzoi et al, ; Malavasi et al, ; Scapin, Cavraro, et al, ). The peacock blenny ( S. pavo ), grass goby ( Z. ophiocephalus ) and hippolytid shrimps are other common species of seagrass habitats in Mediterranean coastal lagoons (d'Udekem d'Acoz, ; Franzoi et al, ; Scapin et al, ).…”

“…Nekton in transitional water ecosystems play a key role in mediating ecological processes and supporting ecosystem functions and services (Elliott & Hemingway, ; Kneib, ; McLusky & Elliott, ; Pérez‐Ruzafa, Marcos, & Pérez‐Ruzafa, ). Abundant and diverse nekton assemblages in estuaries and coastal lagoons are supported by seagrass meadows, which feature large proportions of habitat specialists as well as endangered and iconic species that utilize seagrass habitats for shelter, food and reproduction (Browne, Baker, & Connolly, ; Franco et al, ; Franzoi, Franco, & Torricelli, ; Scapin et al, ; Shokri, Gladstone, & Jelbart, ; Vincent, Foster, & Koldewey, ). In addition, juveniles of many commercially important species are known to exploit seagrass beds in estuaries and coastal lagoons as nursery areas (Blandon & Zu Ermgassen, ; Pihl et al, ; Whitfield, ).…”