Paralytic Shellfish Toxin Congener Profiles in Three Species of Bivalve Molluscs from Resurrection Bay, Alaska, 2021 and 2022

This study assessed PST concentrations and congener profiles in three bivalve species, blue mussels (Mytilus trossulus), softshell clams (Mya arenaria), and cockles (Clinocardium nuttallii), collected from Afognak Beach in Resurrection Bay, Alaska, an important subsistence and recreational harvest site. From spring through fall of 2021 and 2022 bi-weekly sampling events of blue mussels (n = 32), softshell clams (n = 32), and cockles (n = 25) were collected and analyzed using high-performance liquid chromatography post-column oxidation to quantify PST congener profiles and assess potential risks to harvesters. Results showed measurable toxin concentrations in 50% blue mussel samples, 8.3% softshell clam samples, and 0% cockle samples. Across the full study period, the median PST concentration in blue mussels (1.98 µg STX-eq 100 g⁻¹) was significantly higher than in soft-shell clams and cockles (both medians were below the method detection limit). PST profiles were dominated by GTX4 and GTX5, although blue mussels exhibited an interannual shift characterized by increased GTX1 contribution in 2022. All samples tested below the FDA regulatory limit of 80 µg STX-eq 100 g-1. These findings establish a baseline for PST risk in Resurrection Bay and highlight the importance of ongoing monitoring to ensure safe shellfish harvests in a changing climate.本研究针对采集自阿拉斯加州复活湾阿福戈纳克海滩（当地重要的自给性与休闲贝类捕捞场所）的3种双壳类动物，即蓝贻贝（Mytilus trossulus）、软壳蛤（Mya arenaria）与鸟尾蛤（Clinocardium nuttallii），开展了麻痹性贝类毒素（Paralytic Shellfish Toxins, PST）浓度与同系物谱的检测分析。于2021年与2022年的春季至秋季期间，每两周开展1次采样工作：共采集蓝贻贝样本32份、软壳蛤样本32份、鸟尾蛤样本25份，并采用柱后氧化高效液相色谱法（high-performance liquid chromatography post-column oxidation）对PST同系物谱进行定量分析，以评估贝类捕捞者面临的潜在健康风险。结果显示，50%的蓝贻贝样本、8.3%的软壳蛤样本可检出可量化的毒素浓度，而鸟尾蛤样本未检出任何毒素。整个研究周期内，蓝贻贝的PST中位浓度为1.98 µg STX-eq（石房蛤毒素当量, Saxitoxin Equivalent, STX-eq）/100g，显著高于软壳蛤与鸟尾蛤——后两者的中位浓度均低于方法检出限。PST同系物谱以膝沟藻毒素4（Gonyautoxin 4, GTX4）与膝沟藻毒素5（Gonyautoxin 5, GTX5）为主，但蓝贻贝样本呈现出年际变化特征：2022年膝沟藻毒素1（Gonyautoxin 1, GTX1）的贡献占比有所提升。所有样本的毒素含量均低于美国食品药品监督管理局（Food and Drug Administration, FDA）规定的80 µg STX-eq/100g的监管限值。本研究结果为复活湾地区的PST风险建立了基准数据集，并凸显了在气候变化背景下开展持续监测以保障贝类捕捞安全的重要性。