Distribution characteristics of Liza haematocheila and its relationship with environmental factors in Furongdao artificial reef zones, Laizhou Bay, China

Abundance of Liza haematocheila has declined rapidly since the 1980 s in Bohai Sea, due to the increasing fishing pressure caused by the change of fishery methods. Furongdao artificial reefs (ARs), located in Laizhou Bay, has provided a good habitat for L. haematocheila, making it one of the major fish resources in the AR area. In order to explore the response of L. haematocheila to environmental factors, the effect of environmental factors, artificial reefs, food abundance on CPUE and mean standard length of L. haematocheila were analyzed using GAM model. L. haematocheila were collected by trammels survey of Furongdao ARs during 2014-2017. The results showed that there was no significant difference between average CPUE values of artificial reef area and natural area in spring (P = 0.362), however, the CPUE in AR area is 3.53 times CPUE in the control area in the autumn. Three-way ANOVA showed that CPUE is significantly affected by year, month, artificial reefs and interaction effect of year and month (P < 0.01). Average length was affected by year (P < 0.01). Results of Delta GAM showed that the probability that L. haematocheila occurs was significantly influenced by temperature and whether the site is in the AR area. The probability of presence is higher in AR area than in the natural area. As temperature increases, probability of presence decreases. CPUE increases when temperature is below 8 °C and then decreases. Mean standard length of L. haematocheila is influenced by abundance of Bacillariophyta and zooplankton. When abundance of Bacillariophyta is smaller than 3×10⁵ cells/m³, mean standard length decreases with the increase of the abundance of Bacillariophyta, and then tends to stabilize change. Mean standard length decreases with abundance of zooplankton rises. In conclusion, L. haematocheila is mainly distributed in the AR area at low temperature, and large fish is mainly distributed in the area with low abundance of Bacillariophyta and zooplankton.