Trends in shore-based angling effort determined from aerial surveys: a case study from KwaZulu-Natal, South Africa
Trends in shore-based angling effort determined from aerial surveys: a case study from KwaZulu-Natal, South Africa
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通过航空调查确定的岸基钓鱼工作趋势：南非夸祖鲁-纳塔尔省的案例研究
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发表时间：
2020
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通讯作者：
J. Mann
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作者：
B. Mann;J. Mann
了解努力的时空特征是管理渔业的关键组成部分。休闲垂钓是钓鱼场最大的部分，也是南非夸祖鲁-纳塔尔(KZN)海岸开展的主要娱乐活动之一。这项研究的目的是对KZN目前的岸基垂钓努力总量做出可靠的估计，并检查努力的空间和时间分布。为了做到这一点，2018年1月至12月期间，在整个KZN海岸线上进行了随机的月度飞行，以“瞬时”的方式计算岸上垂钓者的数量，然后与1994/95年度和2007/08年度进行的类似航空调查进行了比较。共进行了44次飞行，其中在南北海岸分别进行了21次和23次飞行。地面实况显示，岸上垂钓者的空中计数准确率为89%。在周末和天气好的日子，垂钓者的努力明显更高。岸上垂钓努力的季节性表明，最大的努力发生在冬季(6月至9月)，与受欢迎的垂钓物种的季节性供应相吻合。KZN海岸更发达的部分，人口密度更高，更容易进入海滩，垂钓努力最高。据计算，每年的钓鱼量为785538个垂钓日，比1994/95年的估计数减少22.9%，比2007/08年的估计数减少6.9%。2007/08年度和2018年岸上捕捞活动的空间分布非常相似，主要区别是圣卢西亚和马普兰的捕捞活动减少，而2018年“上”(北部)南海岸的捕捞活动略有增加。根据这项研究的结果，关于改善KZN近岸渔业管理的建议包括：(1)利用独立的巡回调查采取后续行动；(2)改进沿海执法；(3)实施钓鱼观察员方案；(4)每10年重复一次航空调查。
Understanding the spatiotemporal characteristics of effort is a critical component of managing fisheries. Recreational shore-angling is the largest sector of the linefishery and one of the primary recreational activities undertaken along the coast of KwaZulu-Natal (KZN), South Africa. The aim of this study was to make a reliable estimate of current total shore-based angling effort in KZN and to examine the spatial and temporal distribution of the effort. To do this, randomised monthly flights to count shore-anglers in an ‘instantaneous’ manner were conducted along the entire KZN coastline between January and December 2018, and then compared with similar aerial surveys conducted in 1994/95 and 2007/08. A total of 44 flights were undertaken, with 21 and 23 flights conducted along the north and south coasts, respectively. Ground-truthing revealed that the aerial counts of shore-anglers were 89% accurate. Angler effort was significantly higher over weekends and during good-weather days. Seasonality of shore-based angling effort showed that greatest effort occurred during the winter months (June to September), coinciding with the seasonal availability of popular angling species. More-developed stretches of the KZN coast with higher population densities and easier beach-access had the highest angling effort. Total annual angler effort was calculated to be 785 538 angler-days y–1, which represents a 22.9% decline from the estimate made in 1994/95 and a 6.9% decline from the estimate made in 2007/08. Spatial distribution of shore-based fishing effort was very similar in 2007/08 and 2018, with the major differences being a decrease in fishing effort at St Lucia and Maphelane, and a slight increase in effort on the ‘upper’ (northern) south coast during 2018. Based on the results of this study, recommendations for improved management of the KZN shore fishery include: (i) follow-up using an independent roving-creel survey; (ii) improvement of coastal law enforcement; (iii) implementation of a linefish observer programme; and (iv) a repeat of the aerial survey every 10 years.