In partially protected marine areas, such as recreational fishing havens (RFHs), fishery‐independent surveys and recreational angler surveys represent two of the few available methods of collecting length‐frequency data to monitor population responses to protection from commercial fishing and the impacts of ongoing recreational fishing. Although length data plays an important role in facilitating stock assessment and monitoring within RFHs, little is known about the relative magnitude and direction of size‐selective biases introduced by fishery‐independent surveys and angler surveys. This study quantitatively compared length data derived from the two methods for three exploited species or taxa (bream species complex of Acanthopagrus spp. [hybrid complex of Black Bream A. butcheri × Yellowfin Bream A. australis], Dusky Flathead Platycephalus fuscus, and Sand Whiting Sillago ciliata) sampled from two estuarine RFHs in Australia. When all lengths sampled by each method were compared, the species‐specific length frequencies derived from angler surveys and fishery‐independent surveys differed significantly in all cases but for Dusky Flathead from one RFH. Following standardization for minimum‐legal‐length restrictions, the angler survey method captured a more representative spectrum of lengths for Acanthopagrus spp. For Dusky Flathead, angler surveys and fishery‐independent surveys performed equally in terms of the lengths captured. Although length frequencies for Sand Whiting above minimum legal length differed significantly between the methods in both RFHs, spatial inconsistencies precluded a clear conclusion for this species. The fact that neither method consistently outperformed the other across all species supports the idea that using both angler surveys and fishery‐independent surveys in a complimentary manner may enable a clearer understanding of size compositions across multiple species for monitoring and stock assessment purposes and thereby facilitate an ecosystem‐based approach to fishery assessment and management.

中文翻译：

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监测部分受保护的海洋区域内的种群：休闲垂钓者调查和渔业独立调查得出的长度数据比较

在部分受保护的海洋区域中，例如休闲钓鱼港（RFH），独立于渔业的调查和休闲钓鱼者调查是收集长度频率数据以监测人口对商业捕鱼保护的反应以及正在进行的影响的几种可用方法中的两种休闲钓鱼。尽管长度数据在促进RFH内种群评估和监测方面起着重要作用，但对渔业独立调查和垂钓者调查引入的尺寸选择性偏差的相对大小和方向知之甚少。这项研究定量比较了两种方法对三种被开发物种或类群（黑棘A的bre种复合物[黑BreA.butcheri的杂种复合物）的长度数据 ×黄鳍鲷A.芦苇]，暗淡的平头宽头鯒，与沙鳕鱼鳞薷）从澳大利亚2个河口RFHs采样。当比较每种方法采样的所有长度时，除钓鱼者独立调查和渔业独立调查得出的特定物种的长度频率外，所有情况都不同，除了来自一个RFH的Dusky Flathead。在对最小合法长度限制进行标准化之后，垂钓者调查方法捕获了棘突棘的更具有代表性的长度谱spp。对于Dusky Flathead，垂钓者调查和独立于渔业的调查在捕获的长度方面表现均等。尽管两种RFH中两种方法在高于最小法定长度的沙白晶的长度频率上都存在显着差异，但是由于空间不一致，因此无法对该物种做出明确的结论。两种方法都无法始终胜过另一种方法这一事实支持以下观点：以互补的方式同时使用垂钓调查和独立于渔业的调查可能会更清楚地了解多个物种的大小组成，以进行监测和种群评估，从而促进基于生态系统的渔业评估和管理方法。