Queen conch aquaculture 701


et al., 2017,p. 1), is a strategy to help replenish natural popu- lations. Here we include two categories of culture that could be considered conservation aquaculture: stock en- hancement and restoration aquaculture. We define stock enhancement as releasing cultured individuals to supple- ment the populations of exploited species that face contin- ued high fishing pressure, and restoration aquaculture as releasing cultured individuals to rebuild historically exploited populations of species that are now protected and face minimal fishing pressure. The intentional release of cultured organisms into the


ocean for stock enhancement dates from the early 1800s, with mixed positive and negative impacts on ecosystems, species and economic systems (reviewed by Kitada, 2018). Increasingly rigorous principles for responsible stock en- hancement have been developed (Blankenship & Leber, 1995) and improved (Lorenzen et al., 2010). Guiding princi- ples include grounding practices in basic knowledge of the species and fishery to facilitate realistic enhancement that is evaluated through scientific monitoring and assessment (Lorenzen et al., 2010). However, the global review of Kitada (2018) revealed that stock enhancement remains ex- perimental for the majority of species and ecosystems. Furthermore, empirical assessments are typically missing and when present show a trend towards both ecological and economic failure (Kitada, 2018). For example, integrat- ing stock enhancement with metapopulation modelling to create a self-sustaining reserve network for cultured shell- fish, such as oyster, reveals the challenges of rebuilding an ecosystem, even when enhanced sites show clear demo- graphic benefits within their boundaries (Puckett & Eggleston, 2016). Ecosystem condition is typically more important than aquaculture release (Kitada et al., 2019); thus, rebuilding habitats and effective controls on harvest should be in place prior to restoration aquaculture. Restoration aquaculture aims to improve a damaged or di-


minished ecosystem, and its implementation in marine sys- tems is typically for revitalizing foundational species (e.g. ecosystem engineers) for bottom-up benefits. These efforts are currently being employed on saltmarsh, oyster reefs, sea- grass, mangrove, kelp forest and coral reef habitats (Duarte et al., 2020). Coral restoration efforts blending culture and outplanting approaches have demonstrated some success; for example, outplanted coral populations in Japan have been observed spawning (Zayasu & Shinzato, 2016). In some cases, natural populations have been reduced to


such a lowlevel that restoration aquaculturemay be the only means to prevent extinction (Anders, 1998). Targeted en- hancement of endangered species using conservation aqua- culture remains problematic in marine ecosystems because of constraints on financial and technical resources, and de- graded environments. Therefore, it is typically the action of last resort. For example, following the cessation of fishing in the 1990s, white abalone Haliotis sorenseni were expected to


go extinct within 10 years without intervention (Hobday et al., 2001; NOAA, 2001). A restoration aquaculture pro- gramme took 19 years to rear, release into the wild, and monitor cultured white abalone juveniles (Rogers-Bennett et al., 2016). Likewise, time, money and effort has gone into the culturing of pinto abalone Haliotis kamtschatkana, with only 10% survival one-year post release (Carson et al., 2019; Dimond et al., 2022). Importantly, stock enhancement and restoration aqua-


culture are typically posited as conservation strategies, but both become necessary because of failed management at local and international levels. Therefore, the industrial ap- plication of aquaculture as a fisheries solution has been re- cognized as a distraction from addressing the proximate causes of decline, typically poor management practices and degraded habitats (Meffe, 1992). Before implementation of new aquaculture outplanting programmes, techniques need to be established based on data from studies of long- term survival, functional equivalency, cost-effectiveness, and estimates of the impact on livelihoods and food security (Lorenzen et al., 2010). The uncertainty of success and cost of conservation aquaculture make the protection and man- agement of wild populations critical, ideally before species approach a point at which further drastic intervention strat- egies are needed such as closing fisheries or restricting trade. However, conservation aquaculture still receives consider- able attention and support as a means of repopulation des- pite themany well-documented barriers to successful in situ implementation (Glazer & Delgado, 2003).


Queen conch in decline


The queen conch, Aliger (formerly Lobatus, Eustrombus or Strombus) gigas, is a large herbivorous marine snail that was once common throughout the Caribbean, but populations have been greatly reduced by overharvest (Vaz et al., 2022). Queen conch primarily disperse during a pelagic lar- val phase and can potentially travel great distances (Vaz et al., 2022; reviewed by Stoner et al., 2023). Conch popula- tions exhibit genetic isolation related to oceanic distance; thus, a careful blend of local and regional management is re- quired to ensure connectivity among stocks (Truelove et al., 2017). After settlement, queen conchs spend c. 1 year buried as infauna during the day to avoid predation until they are big enough at c. 2 years of age (10 cm in length) to avoid fish gape limits (Iversen et al., 1986, 1990). Older individuals in- habit a variety of relatively shallow ecosystems, including seagrass, hardbottom and rubble, from where they are typ- ically harvested by hand, using freediving or compressed air diving. Research on complex reproductive (reviewed by Stoner & Appeldoorn, 2022) and benthic recruitment ecol- ogy (reviewed by Stoner, 2003) demonstrates that the spe- cies requires minimum densities to maintain population


Oryx, 2024, 58(6), 700–709 © The Author(s), 2025. Published by Cambridge University Press on behalf of Fauna & Flora International doi:10.1017/S0030605324001443


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84  |  Page 85  |  Page 86  |  Page 87  |  Page 88  |  Page 89  |  Page 90  |  Page 91  |  Page 92  |  Page 93  |  Page 94  |  Page 95  |  Page 96  |  Page 97  |  Page 98  |  Page 99  |  Page 100  |  Page 101  |  Page 102  |  Page 103  |  Page 104  |  Page 105  |  Page 106  |  Page 107  |  Page 108  |  Page 109  |  Page 110  |  Page 111  |  Page 112  |  Page 113  |  Page 114  |  Page 115  |  Page 116  |  Page 117  |  Page 118  |  Page 119  |  Page 120  |  Page 121  |  Page 122  |  Page 123  |  Page 124  |  Page 125  |  Page 126  |  Page 127  |  Page 128  |  Page 129  |  Page 130  |  Page 131  |  Page 132  |  Page 133  |  Page 134  |  Page 135  |  Page 136  |  Page 137  |  Page 138  |  Page 139  |  Page 140