Growth aspect of squid (Loligo chinensis) from the Banyuasin Coastal Waters, South Sumatra, Indonesia

Abstract

Squid (Loligo chinensis) played an important role in small scale fisheries in Banyuasin Coastal Waters, however, the information and publications were limited. This study aimed to estimate the length at first capture (LC50%), the length at first maturity (Lm), growth pattern and condition factor of L. chinensis from Banyuasin Coastal Waters of South Sumatra. The squids were observed for samples in April 2018 and March 2019 using a stationary lift net. During the observation, the squid measurement was conducted on 1179 individuals. The mantle length ranged was 40-210 mm and their body weight ranged was 2-42 gr. The value of LC50%, Lm and ½L∞ were obtained at 103 mm, 147 mm, and 110.5 mm respectively. The analysis results of the length-weight relationship (W = 0.0145L1.4618, R2 = 0.9265 and P < 0.05) showed that their growth pattern was negative allometric (b < 3). The mean relative condition factor (Kn = 1.01) above the critical value limits (K=0.56) confirmed that the environmental condition of Banyuasin Coastal Waters suitable for the L. chinensis growth. However, should be careful with their length size of the squid catch were not feasible in the capture.

Using LBB Tools to Assess Miter Squid Stock in the Northeastern South China Sea

“…The apparent decrease in the estimated asymptotic length might be attributed to fishing-induced miniaturization. Zhang et al (2008) and Chen (2016) also suggested that there was a tendency for miniaturization of squid in the neSCS, with the average mantle length decreasing from 21.0 cm in the 1970s to 10.4 cm in the 1990s, and the average mantle length was 11.5 cm in 2018-2019 ( Figure 2). In addition to being a clear indication of growth overfishing, this also suggests a genetic selection toward smaller sizes.…”

“…The overfishing has also resulted in the decline of catches. With rapid increases in the number of marine motorized fishing boats and their horsepower in Fujian and Guangdong provinces since the 1980s (Figure 3), the annual yield of the squid increased rapidly to culminated (>5 × 10 4 tons) in 1985 (Figure 4), but it since decreased to about 2.0-2.5 × 10 4 tons by the 2000s (Zhang et al, 2008).…”

“…Before and during the 1980s, they were mainly harvested by fishing boats from the Nan'ao County (Figure 1), and the highest landing reached 5.1 × 10 4 tons in 1985 (Li and Wu, 1988). However, landings have since dropped, and annual landings from this fishing ground were estimated at 2.0-2.5 × 10 4 tons by the 2000s (Zhang et al, 2008). Studies on miter squid in the neSCS ever involved its biology, stock status, and fishery management (Ou, 1981(Ou, , 1983Lan, 1985;Zhang et al, 2008;Chen, 2016), but a few studies focused on its population parameters and stock assessment.…”

“…However, landings have since dropped, and annual landings from this fishing ground were estimated at 2.0-2.5 × 10 4 tons by the 2000s (Zhang et al, 2008). Studies on miter squid in the neSCS ever involved its biology, stock status, and fishery management (Ou, 1981(Ou, , 1983Lan, 1985;Zhang et al, 2008;Chen, 2016), but a few studies focused on its population parameters and stock assessment. Based on length frequency data collected during the periods 1975-1977, 1997-1999, and 2018-2019 in the neSCS, this study estimates the population parameters of the squid and assesses its stock status using the LBB method.…”