A Study On Fishery Biology Of The Orangeback Flying Squid In The Eastern Central Atlantic Ocean

This paper analyzed the basic biological data of the 682 orangeback flying squid（Sthenoteuthis pteropus）samples collected by Chinese squid jigging vessels in May,2020 in the Eastern Central Atlantic Ocean.The age and growth of the samples were studied by observing the microstructure of statolith.The results showed that the mantle length of the samples was 124～580mm and that of the dominant group was 200～399mm;the body weight of the samples was 80～6365g and that of the dominant group was 501～1000g.The age of the samples ranged from 105 to 365 days,and that of the dominant group ranged from 100 to 249 days,accounting for about 80.20%of the total.According to the calculation of the age of statoliths and the date of fishing,the mantle length of the first sexual maturity of orangeback flying squid was 404mm and the incubation date of the samples was from May 2019 to February 2020 with the peak period from November to January,mainly for autumn and winter populations.The mantle length growth of the samples conforms to the Logistic model.The average IGR and AGR of the mantle length were 0.45%·d^-1 and 0.778)8)·d^-1,and the average IGR and AGR of the body weight were 1.21%·d^-1 and 13.932)·d^-1.Based on the hard tissues and muscles in the stomach contents of the pterosaur,gastric content analysis and DNA barcoding were used to identify the prey organisms ingested by the pterosaur.Among them,a total of 37 species of fish and 4 species of cephalopods were identified by gastric content analysis,among which lanternfishes,megamouth fishes and cephalopods were the main ones.A total of 19 species were identified by DNA barcoding,of which 7 species of fish and 6 species of cephalopods could be identified as species,and the remaining 5 species of fish and 1 species of cephalopods were identified to the genus level.By measuring theδδ¹³CC andδδ¹⁵NN of the pterosaur muscle,the averageδδ¹³CC andδδ¹⁵NN were-16.60±0.41 and 14.40±2.53;the deviation of carcass length toδδ¹³CC was 29%,the interpretation rate of the deviation of carcass length toδδ¹⁵NN is 31%.The 224-324mm and 324-424mm carcass length groups had moderate niche overlap rates（0.47）,and other niche overlap rates were low（<0.29）.The potential fecundity of pterosaurs is 637.01×10³-12621.00×10³ cells,with an average value of（4535.83±3017.38）×10³ cells;the relative fecundity of individuals is 508.08-3918.45 cell·g^-1,with an average value of（2034.59±688.65）cell g^-1;the number of mature eggs in the fallopian tube is（86.74×103-2031.69）×10³ cell;the number of spawning batches is 5-9 times,and the average spawning batch is（6.71±1.23）times;ovarian oocyte length The range is 0.02-1.21mm.The length and diameter of ovarian oocytes in stage II gradually decrease in a step-by-step manner,mainly distributed in the range of 0-0.3mm.The length and diameter of ovarian oocytes in stage III are unimodal distribution,with a peak interval.The range is 0-0.4mm.When the gonadal maturity is stage IV,the distribution of the length and diameter of ovarian oocytes has a double peak.The first peak appears at 0.2-0.5mm,and the second peak interval ranges from 0.7-0.8mm.Studies have shown that the individual fecundity of the Middle Eastern Atlantic pterosaur is positively correlated with individual development,and the spawning mode is intermittent spawning.The study has preliminarily mastered the basic biological characteristics of the population,age,growth and sexual maturity of the pterosaur,and provided basic data for the rational development of the pterosaur resources in this sea area in my country.