Anti-masking strategies and communication ranges of polar seal underwater vocalizations

我的研究调查了极地海豹水下发声的产生、传输和接收。来自圣劳伦斯湾的竖琴海豹和来自南极洲的威德尔海豹的水下叫声将被分析，以确定它们是否已经进化到克服其他海豹叫声的干扰(掩饰)。至少两名学生将在南极洲越冬，以确定监测海豹叫声是否可以索引种群数量，并了解更多关于威德尔海豹发声能力的信息。在最佳条件下，一些水下威德尔海豹的叫声可以在25公里外听到，而另一些则只有100米远。竖琴海豹的叫声频率可以超过每分钟130次，从而产生巨大的背景噪音。*这类似于人类在社交活动中遇到的“鸡尾酒会”效应。*我们将确定威德尔海豹是否像竖琴海豹一样遵循“礼貌规则”叫声，这样它们就不会遮盖邻居的发声。海冰破裂、海浪、船只的工业噪音和水下施工也有可能阻碍海豹的声音交流渠道。水下叫声是用放在海冰下的水听器(水下麦克风)研究的。由于有如此多的叫声重叠，没有自动化分析的可能性，分析磁带录音非常耗时。我们将检查自然和人类噪音的变异性，并确定噪音的精细结构将对海豹叫声行为产生影响的程度。通过将海豹叫声的物理和行为方面的信息与它们的听力和生活史需求联系起来，我们将更好地了解在这些极地海豹中声音交流的重要性。这项研究的一个实际方面是，它将提供必要的信息，以评估北极破冰船只产生的噪音对海豹和其他海洋哺乳动物的潜在环境影响。

My research investigates the production, transmission and reception of underwater vocalizations of polar seals.  Underwater calls of harp seals from the Gulf of St. Lawrence and Weddell seals from Antarctica will be analyzed to determine if they have evolved to overcome jamming (masking) by other seal calls.  Two students will overwinter in Antarctica to determine if monitoring seal calls can index population numbers and find out more about the sound generation abilities of Weddell seals. Under optimal conditions, some underwater Weddell seal calls can be heard up to 25 km away while others would only travel 100 metres.  Harp seal calling rates can exceed 130 calls per minute thus producing loud backkground noises.  This is similar to the "cocktail party" effect encountered by humans at social functions.  We will determine if Weddell seals, like harp seals, follow the "courtesy rule" and call so that they do not mask a neighbour's vocalizations.  Cracking ice, waves, industrial noises of ships and underwater construction also have the potential to block the acoustic communication channel of seals. Underwater calls are studied using hydrophones (underwater microphones) lowered under the sea ice.  Because so many calls overlap, there are no automated analysis possibilities and the analyses of the tape recordings is very time consuming.  We will examine the variability of both natural and human noises and determine the extent to which the fine structure of the noises will impact the seal calling behaviours.  By relating information on the physical and behavioural aspects of seal calls to their hearing abilities and life history needs, we will gain a better understanding of the importance of sound communication in these polar seals.  A practical aspect of this research is that it will provide information which is necessary to assess the potential environmental impacts of noises generated by ice-breaking ships in the Arctic on seals and other marine mammals.