Maturity of Hairtail Varies with Latitude and Environment in the East China Sea

Abstract

Early maturity of economically important fish has become a global issue, which might affect the reproductive potential of fish stocks. We used the samples that were collected in a fisheries-independent survey in the East China Sea annually around the end of August from 2002 to 2017 to investigate the maturation progress of female Hairtail Trichiurus japonicus in response to (1) spatial variation, (2) environmental variation, and (3) CPUE. The preliminary analysis indicated that the gonads of Hairtail in the southern area and the northern area began to develop at similar anal length (around 140-150 mm), but the development was faster in the southern area than in the northern area. The proportion of matured fish was significantly higher in the southern area than in the northern area in the group of fish with 170-210 mm anal length. Based on generalized additive models, we found that temperature and CPUE could affect the maturation schedules of female Hairtail in the East China Sea. The relationship between sea surface temperature and the probability of maturity was close to an s-curve, while the stock density had an approximately negative effect on the degree of precocious puberty.

Identifying Priority Conservation Areas of Largehead Hairtail (Trichiurus japonicus) Nursery Grounds in the East China Sea

“…Juveniles were considered individuals that had finished their larval phase but still had not reached first sexual maturity (Criscoli et al, 2017). However, the transition between larval and juvenile development remains ill defined, Colloca et al (2015) assumed that the first separable modal component of the age group 0 as recruits, we operationally defined juveniles as within the smallest size at sexual maturity in anal length (AL 123 mm) followed Jin et al (2020), the corresponding age is about 3-5 months according to early growth (Sun et al, 2020a). Sex identification for partial juveniles was difficult, so we pooled all the juveniles together regardless of gender for each site.…”

Integrating fish nursery ground conservation with sustainable resource use: The case of Trichiurus japonicus in the East China Sea

“…The results of this study indicated that a bottom water temperature higher than 14°C was suitable for T. japonicus recruits (Figure 5). Several other studies have shown that juvenile T. japonicus prefer warmer water over cold water (Wang et al, 2011; Jin et al, 2020). Recently, otolith microstructure analyses suggested that daily growth of juvenile T. japonicus was affected by water temperature and the optimal temperature range for maximum growth was 18°C–21°C (Sun et al, 2020).…”

“…Several other studies have shown that juvenile T. japonicus prefer warmer water over cold water (Wang et al, 2011;Jin et al, 2020).…”

“…Individuals that had finished their larval phase but had not reached first sexual maturity were considered as juveniles (Criscoli et al, 2017). In the present study, T. japonicus individuals with anal lengths smaller than 120 mm were sampled, based on the latest report that the smallest anal length at sexual maturity of T. japonicus in the ECS was 123 mm (Jin et al, 2020).…”

Acoustic Characteristics of Largehead Hairtail (Trichiurus japonicus) Using Multi-Frequency Detection in the Southern Sea, South Korea

“…The difference in PL between the two stations was statistically significant (t-test, p < 0.05). Based on the PL, the hairtails caught at St. 1 were juveniles, and those at St. 2 were immature [23][24][25].…”