Global extinction risk for seahorses, pipefishes and their near relatives (Syngnathiformes) R ILEY A. POLLOM,GINA M. RALPH C AROLINE M. POLLOCK and A MANDA C.J. VINCENT Abstract Few marine taxa have been comprehensively as- Supplementary material for this article is available at sessed for their conservation status, despite heavy pressures doi.org/./S from fishing, habitat degradation and climate change. Here we report on the first global assessment of extinction risk for species of syngnathiform fishes known as of , using the IUCN Red List criteria. This order of bony teleosts Introduction is dominated by seahorses, pipefishes and seadragons (fam- ily Syngnathidae). It also includes trumpetfishes (Aulosto- ome of the greatest conservation concern for marine life midae), shrimpfishes (Centriscidae), cornetfishes (Fistulari- Sarises among species whose habitat most overlaps with idae) and ghost pipefishes (Solenostomidae). At least %are that of humans: the neritic species that inhabit shallow threatened, but data suggest a mid-point estimate of .% coastal zones facing multiple simultaneous pressures (Lotze and an upper bound of %. Most of the threatened species et al., ;Crainetal.,, ). Anthropogenic impacts are seahorses (Hippocampus spp.: / species, with an on the oceans are often most concentrated here, including additional that are Data Deficient) or freshwater pipe- exploitation through industrial and artisanal fishing, climate fishes of the genus Microphis (/ species, with seven add- change, coastal development, land-based effluents and pol- itional that are Data Deficient). Two species are Near lution, shipping and recreational traffic, habitat destruction Threatened. Nearly one-third of syngnathiformes ( spe- from fishing and aquaculture practices, sea-filling and cies) are Data Deficient and could potentially be threatened, dredging, coastal eutrophication, invasive species and sedi- requiring further field research and evaluation. Most species mentation. Such pressures have direct impacts on habitats (%) were, however, evaluated as Least Concern. Primary such as estuaries (Waltham & Connolly, ), mangroves threats to syngnathids are () overexploitation, primarily by (Polidoro et al., ), coral reefs (Carpenter et al., ), non-selective fisheries, for which most assessments were kelp forests (Krumhansl et al., ), sponges (Harasti et al., determined by criterion A (Hippocampus)and/or()habitat ), and seagrasses (Waycott et al., ; Short et al., loss and degradation, for which assessments were determined ). Unsustainable fishing combined with habitat degra- by criterion B (Microphis and some Hippocampus). Threatened dation and loss have a significant and often synergistic impact species occurred in most regions but more are found in East on fishes, and can lead to local extinctions and increased and South-east Asia and in South African estuaries. Vital con- global risk (Dulvy et al., ;Hutchings&Reynolds,; servation action for syngnathids, including constraining fish- Reynolds et al., ;Crainetal.,; Webb & Mindel, ). eries, particularly non-selective extraction, and habitat protec- The IUCN Red List of Threatened Species is the most tion and rehabilitation, will benefit many other aquatic species. widely used method for assessing the extinction risk of spe- cies. It has been published since , with regular updates, Keywords Aulostomidae, Centriscidae, Fistulariidae, and is used globally by governments, businesses, manage- Indo-West Pacific, pipefish, seahorse, Solenostomidae, ment agencies, international environmental agreements, Syngnathidae and NGOs to inform conservation action. Its quantitative methods, which include explicit analyses of a species’ intrin- sic biological features and the pressures bearing on them, have been used to assess . , species (IUCN, ). RILEY A. POLLOM* (Corresponding author, orcid.org/0000-0001-8260-4614) and AMANDA C.J. VINCENT Project Seahorse, Institute for the Oceans and For each taxon, the first IUCN species assessments serve Fisheries, The University of British Columbia, Vancouver, Canada, and IUCN as baselines against which future reassessments will be com- Species Survival Commission Seahorse, Pipefish and Seadragon Specialist pared. Such comparisons are used to produce the Red List Group. E-mail [email protected] Index, which measures aggregate genuine changes in the GINA M. RALPH IUCN Marine Biodiversity Unit, Department of Biological Sciences, Old Dominion University, Norfolk, USA Red List category of species within a taxonomic group (Butchart et al., , , ; Stuart et al., ). The CAROLINE M. POLLOCK IUCN Red List Unit, Cambridge, UK Red List Index is used to highlight concerns about species *Also at: IUCN SSC Global Center for Species Survival, Indianapolis Zoo, Indianapolis, USA that are declining in status and, conversely, highlight suc- Received December . Revision requested February . cesses where conservation action has improved the status Accepted July . First published online May . of species (Hoffmann et al., , ). This is an Open Access article, distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives licence (http://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is unaltered and is properly cited. The written permission of Cambridge DownloadedUniversity from https://www.cambridge.org/core Press must be obtained for commercial. IP address: re-use 170.106.33.42 or in order to, createon 26 aSep derivative 2021 at work.16:13:29, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/termsOryx, 2021, 55(4), 497–506 ©. https://doi.org/10.1017/S0030605320000782The Author(s), 2021. Published by Cambridge University Press on behalf of Fauna & Flora International doi:10.1017/S0030605320000782 498 R. A. Pollom et al. Taxonomic comprehensiveness of the IUCN Red List (ghost pipefishes), and Syngnathidae (seahorses, pipefishes and improvements in the Red List Index contribute directly and seadragons; Plate ) (Longo et al., ). Our phyloge- to progress on several of the Aichi Biodiversity Targets netic and taxonomic paradigm for the order largely follows (CBD, ) and UN Sustainable Development Goals (Aichi that of Nelson et al. (). We do not include in this assess- Targets and on sustainable fisheries and improving spe- ment the Dactylopteridae (flying gurnards), Callionymidae cies conservation status, and UN Sustainable Development (dragonets), Mullidae (goatfishes) or Pegasidae (seamoths) Goal on conserving the oceans, respectively), and are essen- as evidence for their inclusion within the Syngathiformes is tial for effective species conservation planning and action. mixed (Kawahara et al., ; Wilson & Orr, ; Betancur- Some of the first marine fishes assessed on the IUCN Red R. et al., ; Near et al., ; Song et al., ; Sanciangco List, in , were the iconic seahorses (Hippocampus spp.). et al., ). Longo et al. () consider these groups to Apart from their intrinsic worth, flagship species such as belong to a benthic-associated sister clade that is closely seahorses have been shown to draw attention and finance related to, but not a part of, the order Syngnathiformes. In towards conservation initiatives (Bowen-Jones & Entwistle, addition, we do not include the Gasterosteiformes (stickle- ; Walpole & Leader-Williams, ; Rodrigues & Brooks, backs), a distinct order that formerly included families now ; Shokri et al., ; Caro, ; Bennett et al., ; within the Syngnathiformes (Sanciangco et al., ; Longo Carrizo et al., ; Stiller et al., ). et al., ). Seahorses and their relatives are charismatic fishes that We arrived at a final list of syngnathiform fishes that in- have garnered attention and reverence in human cultures cluded extant species at the time of project completion for many centuries (Scales, ; Lourie, ), and thus (early ; Supplementary Table ). Of these, are largely have the potential to help drive contemporary conservation restricted to marine waters and inhabit brackish and/ efforts for coastal ecosystems (Shokri et al., ; Vincent or freshwater. Considerable taxonomic uncertainty remains et al., ; Stiller et al., ). Seahorses and many pipefishes within the order. We used morphological and/or molecular are much sought after for traditional medicine, aquarium evidence to define valid species, and rejected putative spe- display and curios. A better understanding of the conserva- cies differentiated only by variations in colour pattern. tion status of these flagship animals will allow the mobiliza- During this research several new syngnathid species have tion of conservation action for a diversity of coastal ecosys- been described and their Red List assessments are forth- tems. The Syngnathiformes, as a group, have a circumglobal coming (e.g. Short et al., ). Comprehensive treatments range that spans coasts everywhere except for polar regions. of taxonomy are available for the Aulostomidae (Bowen et al., They live in an array of habitats, including estuaries, man- ) and the Syngnathidae at the generic level (Hamilton groves, seagrasses, coral and rocky reefs, kelp forests, sand et al., ). The most recent reviews of the majority of or mud substrates, streams, lakes and rivers (Dawson, ; pipefish genera (Syngnathidae) were undertaken by Dawson Foster & Vincent, ; Kuiter, ; Lourie, ;De (Poss & Heal, ), and we used his subsequent book on Brauwer et al., ). Effective conservation of syngnathi- the Indo-Pacific