标题：AZFP论文：基于滑翔机的浮游动物生物量密度估计：南极半岛北部南极磷虾（Euphausia superba）的渔业案例研究
Abstract
We compare estimates of krill density derived from gliders to those from contemporaneous and previous ship-based surveys. Our comparisons cover several temporal and spatial scales within two strata around the northern Antarctic Peninsula (off Cape Shirreff on the north side of Livingston Island and in the Bransfield Strait). Our objective is to explore the feasibility of using gliders to supplement or replace vessel-based surveys of fishery resources. We deployed two long-duration Slocum G3 gliders manufactured by Teledyne Webb Research (TWR), each equipped with a suite of oceanographic sensors and a three-frequency (38, 67.5, and 125 kHz, each single-beam) Acoustic Zooplankton Fish Profiler. We used the acoustic data collected by these gliders to estimate biomass densities (g·m−2 ) of Antarctic krill (Euphausia superba). The two gliders were, respectively, deployed for 82 and 88 days from midDecember 2018 through mid-March 2019. Off Cape Shirreff, glider-based densities estimated from two repeat small-scale surveys during mid-December and January were 110.6 and 55.7 g·m−2 , respectively. In Bransfield Strait, the glider-based estimate of biomass density was 106.7 g·m−2 during December–January. Contemporaneous ship-based estimates of biomass density, from a multi-ship broad-scale krill survey (Macaulay et al., 2019) restricted to the areas sampled by the gliders, were 84.6 g·m−2 off Cape Shirreff and 79.7 g·m−2 in Bransfield Strait during January. We compared two alternative krill-delineation algorithms (dB differencing and SHAPES); differences
between biomass densities estimated by applying these algorithms were small and ranged between 4 and 7%. Alternative methods of sampling krill length-frequency distributions (LFDs) (nets or predator diets), which are required to convert acoustic energy to biomass density, also influenced the glider-based results. In Bransfield Strait, net-based estimates of biomass density were 6% less than those based on predator diets. Off Cape Shirreff the biomass density of krill estimated from a net-based LFD was 20% greater than that based on predator diets. Development of a variance estimatorfor glider-based biomass surveys is ongoing, but our results demonstrate that fisheries surveys using acoustically-equipped gliders are feasible, can provide density estimates to inform management, and may be conducted at lower cost than ship surveys in some cases.
Keywords: gliders, Antarctic krill, fisheries surveys, fisheries acoustics, zooplankton
摘要：
我们将滑翔机得出的磷虾密度估计值与同期和以前的船基调查结果进行了比较。我们的比较涵盖了南极半岛北部两个地层内的几个时间和空间尺度（利文斯顿岛北侧的希勒夫角和布兰斯菲尔德海峡）。我们的目标是探索使用滑翔机补充或取代基于船只的渔业资源调查的可行性。我们部署了两架由Teledyne Webb Research（TWR）制造的长时间Slocum G3滑翔机，每架都配备了一套海洋传感器和一个三频（38、67.5和125 kHz，每个单波束）声学浮游动物鱼类剖面仪。我们使用这些滑翔机收集的声学数据来估算南极磷虾（Euphausia superba）的生物量密度（g·m−2）。这两架滑翔机分别从2018年12月中旬到2019年3月中旬部署了82天和88天。在Shirreff角附近，12月中旬和1月两次重复的小规模调查估计的滑翔机密度分别为110.6和55.7 g·m−2。在布兰斯菲尔德海峡，12月至1月期间，基于滑翔机的生物量密度估计为106.7 g·m−2。根据多船大规模磷虾调查（Macaulay等人，2019）对滑翔机采样区域的同期船基生物量密度估计值为1月份Shirreff角84.6 g·m−2，布兰斯菲尔德海峡79.7 g·m-2。我们比较了两种替代的磷虾描绘算法（dB差分和SHAPES）；应用这些算法估算的生物量密度差异很小，在4%到7%之间。将声能转化为生物量密度所需的磷虾长度频率分布（LFD）采样的替代方法（网或捕食者饮食）也影响了基于滑翔机的结果。在布兰斯菲尔德海峡，基于净生物量密度的估计值比基于捕食者饮食的估计值低6%。在舍里夫角附近，根据基于网的LFD估计的磷虾生物量密度比基于捕食者饮食的生物量密度高20%。基于滑翔机的生物量调查的方差估计正在开发中，但我们的结果表明，使用配备声学设备的滑翔机进行渔业调查是可行的，可以提供密度估计以告知管理层，并且在某些情况下可能比船舶调查成本更低。
关键词：Glider 滑翔机、南极磷虾、渔业调查、渔业声学、浮游动物，AZFP 鱼类浮游动物声学剖面仪
