A multidisciplinary approach to identify priority areas for the monitoring of a vulnerable family of fishes in Spanish Marine National Parks

Abstract

Background Syngnathid fishes (Actinopterygii, Syngnathidae) are flagship species strongly associated with seaweed and seagrass habitats. Seahorses and pipefishes are highly vulnerable to anthropogenic and environmental disturbances, but most species are currently Data Deficient according to the IUCN (2019), requiring more biological and ecological research. This study provides the first insights into syngnathid populations in the two marine Spanish National Parks (PNIA—Atlantic- and PNAC—Mediterranean). Fishes were collected periodically, marked, morphologically identified, analysed for size, weight, sex and sexual maturity, and sampled for stable isotope and genetic identification. Due the scarcity of previous information, habitat characteristics were also assessed in PNIA. Results Syngnathid diversity and abundance were low, with two species identified in PNIA (Hippocampus guttulatus and Syngnathus acus) and four in PNAC (S. abaster, S. acus, S. typhle and Nerophis maculatus). Syngnathids from both National Parks (NP) differed isotopically, with much lower δ15N in PNAC than in PNIA. The dominant species were S. abaster in PNAC and S. acus in PNIA. Syngnathids preferred less exposed sites in macroalgal assemblages in PNIA and Cymodocea meadows in PNAC. The occurrence of very large specimens, the absence of small-medium sizes and the isotopic comparison with a nearby population suggest that the population of Syngnathus acus (the dominant syngnathid in PNIA) mainly comprised breeders that migrate seasonally. Mitochondrial cytochrome b sequence variants were detected for H. guttulatus, S. acus, and S. abaster, and a novel 16S rDNA haplotype was obtained in N. maculatus. Our data suggest the presence of a cryptic divergent mitochondrial lineage of Syngnathus abaster species in PNAC. Conclusions This is the first multidisciplinary approach to the study of syngnathids in Spanish marine NPs. Habitat preferences and population characteristics in both NPs differed. Further studies are needed to assess the occurrence of a species complex for S. abaster, discarding potential misidentifications of genus Syngnathus in PNAC, and evaluate migratory events in PNIA. We propose several preferential sites in both NPs for future monitoring of syngnathid populations and some recommendations for their conservation.

Structure and Trophic Niches in Mobile Epifauna Assemblages Associated With Seaweeds and Habitats of Syngnathid Fishes in Cíes Archipelago (Atlantic Islands Marine National Park, North West Iberia)

“…The Family Syngnathidae includes small and cryptic fishes (e.g., seahorses, pipefishes, and seadragons), generally associated with marine flora or other complex benthic habitats (Kuiter, 2009;Ahnesjö and Craig, 2011). In Europe, seahorses (Hippocampus) and pipefishes (e.g., Syngnathus, Nerophis, Entelurus) are members of the ichthyofauna inhabiting temperate sheltered and semi-sheltered coastal habitats dominated by seaweeds and seagrasses (Franzoi et al, 1993;Curtis and Vincent, 2005;Gristina et al, 2014;Correia et al, 2018;Scapin et al, 2018;Ape et al, 2019;Castro-Fernández et al, 2020;Planas et al, 2021a). Unlike many pipefishes, most seahorse species are characterized by limited home ranges and reduced mobility (Foster and Vincent, 2004) due to their morphology and body characteristics.…”

“…Speciesspecific studies of pipefish species (i.e., S. acus, S. typhle, S. abaster, N. ophidion, and N. maculatus) inhabiting diverse coastal areas in southern Europe revealed the importance of harpacticoid copepods, gammarids, carideans, isopods, and mysidaceans in their diet (Franzoi et al, 1993;Vizzini and Mazzola, 2004;Oliveira et al, 2007;Gürkan and Taskavak, 2019;Castro-Fernández et al, 2020;Planas et al, 2020a). However, habitat type and seasonal fluctuations in the composition and availability of food sources may govern variations in the dietary composition (Roelke and Sogard, 1993;Nenciu et al, 2018;Ape et al, 2019;Manning et al, 2019;Planas et al, 2021a). Other factors such as fish size, gender, reproductive status, or spatial changes may also drive prey preferences (Steffe et al, 1989;Woods, 2002;Curtis and Vincent, 2005;Oliveira et al, 2007;Valladares et al, 2017).…”

“…Habitat preferences, feeding behavior and prey availability in syngnathids have been widely studied in many regions worldwide (Kuiter, 2009;Ahnesjö and Craig, 2011;Scapin et al, 2018;Manning et al, 2019). However, studies on the Iberian Peninsula are scarce and mostly focused on specific topics for a few species, habitats and coastal areas Vincent, 2005, 2006;Correia et al, 2015Correia et al, , 2018Valladares et al, 2017;Woodall et al, 2017;Planas et al, 2020aPlanas et al, , 2021a. In this regard, marine protected areas (MPA) might play an important role in contributing to the knowledge and conservation of those flagship fishes in Iberian coastal areas.…”

“…In this regard, marine protected areas (MPA) might play an important role in contributing to the knowledge and conservation of those flagship fishes in Iberian coastal areas. A recent study (Planas et al, 2021a) assessed the distribution and abundance of syngnathids (Hippocampus guttulatus and Syngnathus acus) in Cíes Archipelago (Atlantic Islands National Park, North West Spain) (Fernández et al, 2020). Most specimens inhabited vegetated rocky habitats and, less frequently, mixed sand and rock environments dominated by canopy-forming seaweeds such as Codium spp.…”

A State-of-the-Art Review of Marine Ecosystem Services in the Rías Baixas Natura 2000 Network (Galicia, NW Spain)

“…Our area of study comprises two areas within this marine space: (1) the Cíes Islands (SCI, SAC, and SPAB) in the Ría de Vigo, and (2) the Island of Ons (SCI, SAC, and SPAB) in the Ría de Pontevedra, including the Ons-O Grove Complex (SCI and SAC). Both the Cíes Islands and the Island of Ons belong to the Maritime-Terrestrial National Park (MTNP) of the Atlantic Islands of Galicia, considered one of the best conserved native ecosystems of the Spanish Atlantic coasts, including rocky reefs and other sea beds (for example, Villegas-Ríos et al, 2013;Guerra et al, 2015Guerra et al, , 2016Piñeiro-Corbeira et al, 2020;Planas et al, 2021). These islands have just been included in the UNESCO Tentative List 1 and the Council of Ministers has authorized its inclusion in the Ramsar List of Wetlands of International Importance 2 .…”