The Fecundity Characteristics and Spawning Strategy of Uroteuthis edulis in the East China Sea

SIMPLE SUMMARY: As one of the important economic fishery resources in the East China Sea, Uroteuthis edulis has attracted extensive attention from scholars around the world, but there is no relevant research on the fecundity characteristics and spawning strategies of U. edulis in the East China Sea. Therefore, this study takes the fecundity as the starting point to explore the fecundity characteristics and spawning strategies of U. edulis. Our study showed that the ovary oocytes of U. edulis mature in batches, after which the eggs are laid in batches. The dorsal mantle length (ML), water temperature at 25 m depth (T(25)) and sea surface height (SSH) are important indicators to measure the fecundity of U. edulis. The results of this study provide important fecundity information for understanding the population dynamics of U. edulis under the changing marine environment, and have important significance for the sustainable development and utilization of fishery resources. ABSTRACT: The fecundity characteristics and spawning strategy of Uroteuthis edulis in the East China Sea were investigated by observing the potential fecundity (PF), relative fecundity by dorsal mantle length (PF(ML)) and relative fecundity by body weight (PF(BW)). The relationship between fecundity and a single biological indicator was measured, and generalized additive models (GAMs) were fit by adding environmental variables to help better understand this comprehensive relationship. The long diameter and short diameter of the ovarian oocytes ranged from 0.72 mm to 4.74 mm and from 0.46 mm to 3.67 mm, respectively. The long and short diameters of oviducal eggs ranged from 0.61 mm to 5.12 mm and from 0.39 mm to 3.81 mm, respectively. The egg diameter had a unimodal distribution. The PF, PF(ML) and PF(BW) ranged from 540 to 13,743 cells, 5 to 86 cells/mm and 6 to 53 cells/g, respectively. Three fecundity indicators were unimodally distributed, and the PF(BW) was more stable than the PF(ML) (δ(2)PF(BW) < δ(2)PF(ML)). The fecundity and single biological indicators were fitted, and it was found that the PF and PF(ML) were positively correlated with dorsal mantle length (ML) and body weight (BW). The generalized additive model (GAM) fitting showed that when considering the interaction between dorsal mantle length and sea surface height (M(13)), the deviation explanation rate of the PF and PF(ML) was the highest. Studies have shown that the ovary oocytes of U. edulis mature in batches, and then the eggs are laid in batches. The dorsal mantle length (ML), water temperature at 25 m depth (T(25)) and sea surface height (SSH) are important indicators to measure the fecundity of U. edulis. These findings allow for a deeper understanding of the U. edulis population dynamics for the future management of this economically and ecologically important species.