Cephalopod is a kind of invertebrate marine animals distributed in every corner of the world’s ocean (Jereb and Roper, 2005, 2010; Jereb et al., 2014). It also plays an important role in marine ecosystems (Navarro et al., 2013). As some of the species tend to gather as an assemblage, the different cephalopod species assemblage known as cephalopod community showed significant spatial distribution variations in the global ocean (Rosa et al., 2008a; Pissarra, 2017). The diversity of cephalopod community is more abundant in neritic waters than that in oceanic waters due to the difference in oceanographic conditions (Rosa et al., 2008b, 2019). Northwest Pacific Ocean, especially the East China Sea (ECS), has the most abundant cephalopod species in the world (Pissarra, 2017; Rosa et al., 2019). With the high fishing intensity and climate variability in recent three decades, the Chinese coastal cephalopods have undergone overexploitation and the catch and species composition have significantly fluctuated (Pang et al., 2018; Kang et al., 2021).
The oceanographic environment is one of the fundamental factors in the survival of cephalopods and each marine animal has its own specific habitat condition (Leporati et al., 2007; Aceves-Medina et al., 2017). Abiotic environments affect the distribution of cephalopod individuals or population (Pierce et al., 2008; Robin et al., 2014). Fishery scientists endeavor to explore the relationship between the distribution of cephalopods and the environment by establishing suitable models (Xavier et al., 2016; Yu et al., 2016; Alabia et al., 2020). Currently, the habitat suitability index (HSI) model proposed by United States Fish and Wildlife Service (USFWS) in early 1980s is the most widely used evaluation model of wildlife habitats (Brooks, 1997). As an evaluation system integrating animal abundance with environment features, HSI model has been widely used in fishing forecast, ecological ecosystem restoration and the conservation and management of aquatic animals as a popular evaluation model (Agnew et al., 2002; Brambilla et al., 2009; Tian et al., 2009; Guerra et al., 2016).
Cephalopod is a typical short-lived marine organism with approximately one-year lifetime (Lipiński, 1998). This characteristic enables it to passively experience different kinds of environment and makes it sensitive to the environment change during its life history (Robin et al., 2014). The cephalopod habitat distribution can be changed by some exceptional environment events (Puerta et al., 2015; Keller et al., 2016). In the early life stage, cephalopod has limited movement ability and usually stay on the surface (Rodhouse et al., 1992). Thus, the sea surface temperature (SST) is one of most important oceanographic factors that influence the early life stage of cephalopod and play a vital role in the spatial distribution (Rosa et al., 2011; Yu et al., 2016, 2018). Meanwhile, cephalopod distributions are also related to the food availability, which can be also reflected by chlorophyll-a (Chl-a) in the corresponding area (Puerta et al., 2014; Mohamed et al., 2018). In addition, sea surface height anomaly (SSHA) may also affect the distribution of some cephalopod species due to their diel vertical migration (Alabia et al., 2016; Yu et al., 2019; Jin et al., 2020; Jereb and Roper, 2006, 2010).
The habitat distribution and related environment characteristics of oceanic cephalopod species in most open waters have been already investigated (Xu et al., 2016; Igarashi et al., 2018; Yu et al., 2016, 2019; Wang et al., 2020; Mohamed et al., 2018; Xavier et al., 2016). The distribution of abundant neritic cephalopod species is also influenced by different kinds of oceanographic environments (Jin et al., 2020). Sanchez et al. (2008) analyzed the habitat distribution of Loligo vulgaris in Northwest Mediterranean Sea based on SST, Chl-a, SSHA and photosynthetically active radiation (PAR). Moreno et al. (2014) suggested that there was a close relationship between bottom salinity, river runoff and habitat distribution of Octopus vulgaris in the coast of Portugal. Puerta et al. (2015) indicated that Chl-a concentration had the positive relationship with the habitat distribution of Eledone cirrhosa and Illex coindetii. Chl-a concentration is also the key factor that influences the cephalopod distribution in Yellow Sea (Jin et al., 2020).
In general, the cephalopod habitat distribution in the neritic area of China was seldom explored (Jin et al., 2020). The most abundant taxa of cephalopod are Loliginidae, which habit in the pelagic area, and Octopodidae, Sepiidae, Sepiolida, which prefer to live in the benthic water (Jin et al., 2020). Previous studies mainly discussed the species composition, the number of individuals, and characteristics of spatial agglomeration (Yu et al., 2009; Qin et al., 2011; Zhu et al., 2014; Song et al., 1999; Li et al., 2006; Xu et al., 2008). These studies only focused on the importance of each environmental factor, but the relationship between habitat distribution and environment characteristics was rarely explored. Therefore, the cephalopod habitat in the ECS is not obscure. In addition, most of the current studies focused on the area of offshore ECS and ignored the inshore area, the main spawning ground of neritic cephalopod (Zheng et al., 1999). In order to develop a suitable conservation and restoration approach of cephalopod habitat, it is urgently necessary to explore the cephalopod habitat change and oceanographic environment response (Kang et al., 2021).
In this study, the integrated HSI model was used to simulate the potential habitat distribution pattern of neritic cephalopod taxa (Loliginidae, Octopodidae, Sepiidae, Sepiolidae) based on important environmental factors in the coast of Zhejiang Province. In addition, the different types of the habitat distributions were evaluated so as to explain the variations of cephalopod habitats with seasons and taxa. The study provides the scientific evidence for the sustainable development and coastal ecological protection of neritic cephalopods.