Influence of Spatial-Temporal and Environmental Factors on Larimichthys polyactis, Octopus variabilis, and Species Aggregated Set-Net CPUEs in Haizhou Bay, China

• Published in: Journal of Ocean University of China Vol. 17; no. 4; pp. 973 - 982
• Main Authors: Tang, Yanli, Ma, Shuyang, Liu, Changdong, Wang, Xinmeng, Cheng, Shasha
• Format: Journal Article
• Language: English
• Published: Heidelberg Science Press 01.08.2018; Springer Nature B.V; Fisheries Technology Laboratory, College of Fisheries, Ocean University of China, Qingdao 266000, China
• Subjects: Additives; Catch per unit effort; Cephalopod fisheries; Chlorophyll; Chlorophyll a; Critical point; Earth and Environmental Science; Earth Sciences; Environmental factors; Fish; Fisheries; Fishery production; Fishery resources; Fishing; Fishing gear; Flow velocity; Larimichthys polyactis; Life history; Logbooks; Marine molluscs; Meteorology; Net fishing; Oceanography; Sea surface; Sea surface temperature; generalized additive models; environmental factors; small yellow croaker; octopus; Haizhou Bay; spatial-temporal; set-net
• ISSN: 1672-5182; 1993-5021; 1672-5174
• DOI: 10.1007/s11802-018-3659-7

Set-nets are common alongshore fishing gear used in Haizhou Bay, which rely on flow to catch fish. The catch per unit effort (CPUE) of set-net is affected by spatial-temporal and environmental factors but no research has been conducted on this subject. In this study, we used generalized additive models (GAMs) to explore the influence of spatial-temporal and environmental factors on CPUEs of species aggregated, small yellow croaker ( Larimichthys polyactis ), and octopus ( Octopus variabilis ) based on logbooks investigations conducted at 4 stations in an alongshore area of Haizhou Bay from 2011 to 2012. The results showed that all CPUEs exhibited significant spatial-temporal differences at various scales. Aggregated CPUE was high when the sea surface temperature (SST) was 15–18°C and 20–23°C, which was mainly determined by life history traits of the octopus and small yellow croaker (optimal SSTs 14–17°C and 19–24°C, respectively). Chlorophyll- a concentration had significant influences on the aggregated, small yellow croaker and octopus CPUEs at optimal ranges of 3.8–6.2 mg m −3 , 4.2–4.8 mg m −3 and 4.5–5.5 mg m −3 , respectively. Flow through the net had positive relationships with CPUEs. The approximate logarithmic trends in regression curves had a critical point of 2.5 Mm 3 d −1 , which was the dividing point that differentiated whether the major factor affecting CPUEs was the flow velocity or the fishery resource. Our results from this study will help guide fishery production and improve catch rate of set-net fishing in Haizhou Bay.