Study On The Variation Regularity And Characteristics Of Feeding Acoustic Signals Of Litopenaeus Vannamei

Litopenaeus vannamei has become one of the main aquaculture varieties of shrimp in China due to its fast growth rate,good meat quality,and low environmental requirements for growth.However,due to the difficulty in directly observing benthic feeding activities in traditional aquaculture,especially excessive manual feeding,which not only leads to feed waste,but also economic losses caused by the deterioration of water bodies and the death of shrimp.Therefore,real-time monitoring of their benthic feeding life status is beneficial for intelligent shrimp farming.Passive acoustic monitoring is a scientific means of studying the application of sound in the environment,which can provide sound behavior information of aquatic organisms without interference and damage.Previous studies have shown that when shrimp feed,the closed jaws collide and rub to produce sound,which can reflect the feeding situation of shrimp.In recent years,passive acoustic technology has been applied to the study of the feeding behavior and vocalization of shrimp.However,the application of automatic feeding systems based on underwater sound still requires in-depth understanding of the feeding acoustic signal characteristics of shrimp.In order to understand whether there are regular changes and differences in the vocal information of different body lengths of Litopenaeus vannamei feeding on pellet feed,this paper studied the differences in vocal signal characteristics of five different body lengths(2～3,4～5,6～7,8～9,9～10 cm)of Litopenaeus vannamei feeding on 1.2mm pellet feed in the laboratory based on passive acoustic technology.In addition,further research was conducted on the differences in vocal signal characteristics of shrimp feeding on different types of feed(shrimp shell,bloodworm,squid).This article provides new information for the sound production of shrimp feeding at different growth stages and feeding on different textures of feed,which is helpful for the research and development of shrimp feeding management,as well as the practical application and development of automatic feeding systems.The specific research results are as follows:(1)The acoustic signals of five species of Litopenaeus vannamei(2～3,4～5,6～7,8～9,9～10 cm)feeding on pellet feed and shrimp shell were collected in the laboratory,and the four acoustic characteristic parameters(minimum frequency,maximum frequency,peak frequency,and duration of single pulse signal)of the acoustic signals of five species of whiteleg shrimp feeding on pellet feed and shrimp shell were compared and analyzed.The results showed that: 1)The peak frequency of the shrimp with different body length eating pellet feed was different,the highest was about 25 k Hz for small shrimp(2～3 cm),and the lowest was about 7 k Hz for large shrimp(9～10 cm),which was consistent with the change of frequency range.The peak frequency decreased with the increase of shrimp body length;The duration of single pulse signal increases with the increase of shrimp body length(about 18 ms for large shrimp and about 7 ms for small shrimp),indicating that the sound signal of shrimp feeding pellet feed is related to its body length and has a linear change rule.2)The duration of single pulse signal of shrimp feeding on shrimp shell with different body length increases with the increase of shrimp body length(about 13 ms for big shrimp and about 6 ms for small shrimp).The peak frequency and frequency range are related to the shrimp body length,but there is no significant linear change rule.The study showed that the characteristics of feeding and acoustic signals of Litopenaeus vannamei with different body length were different,and there was a certain rule with the body length,but the acoustic signals of feeding shrimp shells had no linear change rule.(2)The laboratory collected the acoustic signals of 9～10 cm Litopenaeus vannamei feeding on four different kinds of feed or bait(pellet feed,shrimp shell,bloodworm,squid),and compared and analyzed the acoustic information parameters(frequency range,peak frequency,single pulse signal duration)of the four kinds of feed or bait.The results showed that the lowest peak frequency of pellet feed with soft texture was about6 k Hz,the lowest main peak frequency range was about 5～15 k Hz,and the frequency range was about 5～45 k Hz;The peak frequency of shrimp feeding on bloodworm is about 8 k Hz,the main peak frequency range is about 5～30 k Hz,and the frequency range is about 5～30 k Hz;The peak frequency of shrimp feeding squid is about 10 k Hz,the main peak frequency range is about 5～30 k Hz,and the frequency range is about5～30 k Hz;The maximum peak frequency of shrimp feeding on shrimp shell is about 17 k Hz,and the maximum range of main peak frequency is about 5～45 k Hz.The duration of single pulse signal of shrimp feeding on four kinds of feed or bait is between 10～20ms.The study showed that the characteristics of the acoustic signals of the four different textures of feed or bait ingested by Litopenaeus vannamei were different,and the frequency range of the four kinds of feed ingested was relatively similar.The single pulse signal was between 10～20 ms,and there was a significant difference between the peak frequency and the main peak frequency.By studying the content of feeding and vocalization information of Litopenaeus vannamei mentioned above,it was determined that the variation pattern of feeding and vocalization information and body length of Litopenaeus vannamei,as well as the different acoustic signal characteristics of feeding different feeds,were different.This article provides new underwater sound information for the feeding and vocalization of shrimp at different growth stages,which is helpful for the practical development of automatic feeding systems in shrimp farming.