Instituto de Ciencias del Mar y Limnología, Unidad Académica de Sistemas Arrecifales, Universidad Nacional Autónoma de México, Puerto Morelos, Quintana Roo, México.
PeerJ. 2023 Mar 20;11:e15073. doi: 10.7717/peerj.15073. eCollection 2023.
Casitas, low-lying artificial shelters that mimic large crevices, are used in some fisheries for Caribbean spiny lobsters (). These lobsters are highly gregarious and express communal defense of the shelter. Scaled-down casitas have been shown to increase survival, persistence, and foraging ranges of juveniles. Therefore, the use of casitas has been suggested to help enhance local populations of juvenile in Caribbean seagrass habitats, poor in natural crevice shelters, in marine protected areas. Following the emergence of Panulirus argus virus 1 (PaV1), which is lethal to juveniles of , concern was raised about the potential increase in PaV1 transmission with the use of casitas. It was then discovered that lobsters tend to avoid shelters harboring diseased conspecifics, a behavior which, alone or in conjunction with predatory culling of diseased lobsters, has been proposed as a mechanism reducing the spread of PaV1. However, this behavior may depend on the ecological context (i.e., availability of alternative shelter and immediacy of predation risk). We conducted an experiment in a lobster nursery area to examine the effect of the use of casitas on the dynamics of the PaV1 disease. We deployed 10 scaled-down casitas per site on five 1-ha sites over a reef lagoon (casita sites) and left five additional sites with no casitas (control sites). All sites were sampled 10 times every 3-4 months. Within each site, all lobsters found were counted, measured, and examined for clinical signs of the PaV1 disease. Mean density and size of lobsters significantly increased on casita sites relative to control sites, but overall prevalence levels remained similar. There was no relationship between lobster density and disease prevalence. Dispersion parameters ( and of the negative binomial distribution) revealed that lobsters tended to avoid sharing natural crevices, but not casitas, with diseased conspecifics. These results confirm that casitas provide much needed shelter in seagrass habitats and that their large refuge area may allow distancing between healthy and diseased lobsters. On eight additional sampling times over two years, we culled all diseased lobsters observed on casita sites. During this period, disease prevalence did not decrease but rather increased and varied with site, suggesting that other factors (, environmental) may be influencing the disease dynamics. Using scaled-down casitas in shelter-poor habitats may help efforts to enhance juvenile lobsters for conservation purposes, but monitoring PaV1 prevalence at least once a year during the first few years would be advisable.
卡西塔斯是模仿大型裂缝的低矮人工避难所，在一些加勒比刺龙虾渔业中被使用。这些龙虾非常喜欢群居，并且会共同保护庇护所。研究表明，缩小版的卡西塔斯可以提高幼龙虾的存活率、生存时间和觅食范围。因此，在加勒比海海草草甸栖息地中，建议使用卡西塔斯来帮助增加当地的幼龙虾数量，因为这些栖息地天然裂缝庇护所很少，属于海洋保护区。在出现对幼龙虾致命的 Panulirus argus virus 1（PaV1）后，人们对使用卡西塔斯可能会增加 PaV1 传播的担忧加剧。后来发现，龙虾往往会避开有同种病龙虾的庇护所，这种行为，单独或与捕食有病龙虾一起，被提议作为减少 PaV1 传播的一种机制。然而，这种行为可能取决于生态背景（即替代庇护所的可用性和捕食风险的紧迫性）。我们在一个龙虾托儿所区进行了一项实验，以研究使用卡西塔斯对 PaV1 疾病动态的影响。我们在泻湖礁（卡西塔斯地点）的五个 1 公顷的地点上每个地点部署了 10 个缩小版的卡西塔斯，另外留下了五个没有卡西塔斯的地点（对照地点）。所有地点每 3-4 个月采样 10 次。在每个地点内，都对所有发现的龙虾进行计数、测量和检查 PaV1 疾病的临床症状。相对于对照地点，卡西塔斯地点的龙虾密度和大小明显增加，但总体流行率水平相似。龙虾密度与疾病流行率之间没有关系。离散参数（负二项分布的和）表明，龙虾倾向于避免与患病同类共享天然裂缝，但不包括卡西塔斯。这些结果证实，卡西塔斯在海草草甸栖息地提供了急需的庇护所，而且它们的大型避难区可能允许健康和患病龙虾之间保持距离。在两年内的另外八个采样时间，我们清除了卡西塔斯地点上所有观察到的患病龙虾。在此期间，疾病流行率没有下降，反而上升了，而且因地点而异，这表明其他因素（例如环境）可能正在影响疾病动态。在庇护所匮乏的栖息地中使用缩小版的卡西塔斯可能有助于保护目的的幼龙虾增强，但在最初几年内，至少每年监测一次 PaV1 的流行率是明智的。
