RESEARCH ARTICLE Catch and trade bans for seahorses can be negated by non-selective fisheries Tanvi Vaidyanathan 1 | Xiong Zhang 1 | Ramkumar Balakrishnan 2 | Amanda Vincent 1 1 Project Seahorse, Institute for the Oceans and Fisheries, The University of British Columbia, Vancouver, British Columbia, Canada 2 Department of Marine and Coastal Studies, Madurai Kamaraj University, Madurai, India Correspondence Tanvi Vaidyanathan, Project Seahorse, Institute for the Oceans and Fisheries, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada. Email: t.vaidyanathan@oceans.ubc.ca; uep27504uep_t.vaidyanathan@oceans.ubc.ca Funding information International Development Research Centre; Ocean Park Conservation Foundation, Hong Kong; Guylian Belgian Chocolate Abstract 1. All seahorse species (genus Hippocampus) are listed under Schedule I of India's Wild Life Protection Act, making all capture and trade of seahorses illegal. In the more than 15 years since the ban, little work has been done to assess its effects on seahorse conservation. 2. Between 2015 and 2017, fisheries and trade surveys were conducted along the south-east coast of India, in the state of Tamil Nadu, historically known to be a hub for seahorse catches and trade. 3. Seahorses were primarily landed as bycatch, although in greater quantities by traditional drag nets than as trawl bycatch. Total annual catches were estimated between 4.98 million and 13.64 million seahorses, 87% of which were caught by active non-selective gear. 4. Generalized additive models revealed that seahorse catch per unit effort had non-linear relations with depth and latitude, and were higher in biogenic habitats, with active, bottom-used, and non-selective gears (e.g. trawls). 5. The illegal nature of the trade in seahorses hampered an understanding of trade routes and trade volumes. Catch estimates indicated that 11.21–30.31 tonnes of seahorses probably entered trade, yet interviews with traders only documented trade of about 1.6 tonnes. 6. Fishers reported a decreasing availability of seahorses. Since most seahorses come from bycatch in persistent fisheries that are not directly affected by the ban on seahorse capture, this decline is likely to represent a population decline. 7. A fishery and trade ban for incidentally caught species, particularly in a poorly regulated fishery, appears to add little conservation value. There needs to be a shift in the management approach, moving from a ban towards spatial and temporal restrictions, and toward enforcing existing fishery regulations. KEYWORDS bycatch, coastal, conservation, Hippocampus spp., legislation, trawling 1 | INTRODUCTION Concerns about excessive exploitation of wildlife have tended to focus on the need to ban exploitation (Lotze, 2010; Tolotti et al., 2015) or regulate the trade (Kuo, Laksanawimol, Aylesworth, Foster, & Vincent, 2018; Rosen & Smith, 2010) of threatened species. The global wildlife trade involves millions of plant and animal species, and estimates place legal wildlife trade values at USD 332.5 billion annually (Engler, 2008). Wildlife trade often can cause declines in wildlife populations, species extirpations, and ultimately disrupt Received: 12 September 2019 Revised: 27 April 2020 Accepted: 10 June 2020 DOI: 10.1002/aqc.3419 Aquatic Conserv: Mar Freshw Ecosyst. 2020;1–17. wileyonlinelibrary.com/journal/aqc © 2020 John Wiley & Sons, Ltd. 1