Threatened Species Nomination 2020 Details of the nominated species or subspecies NAME OF SPECIES (OR SUBSPECIES) Scientific name: Squalus chloroculus Common name(s): Greeneye Spurdog, Greeneye Dogfish TAXONOMY Provide any relevant detail on the species' taxonomy (e.g. authors of taxon or naming authority, year and reference; synonyms; Family and Order). Squalus chloroculus (Last, White and Motomura 2007). Kingdom: Animalia Phylum: Chordata Class: Chondrichthyans Subclass: Elasmobranchii Order: Squaliformes (Bramble, sleeper and dogfish sharks) Family: Squalidae (Dogfish sharks) Genus: Squalus Species: Chloroculus Dogfish species of the Squalus genus are small sharks with slow molecular evolution (Daley-Engel et al. 2018). For this reason they have been generally classified within species complexes. In 1994 the “greeneye spurdog” was classed as conspecific with other dogfish in the ‘mitsukurii’ complex (Last and Stevens 1994). Although comparatively low between-species diversity exists within this genus (Daley-Engel et al. 2018), molecular analysis has since revealed S. chloroculus to be a unique species endemic to south-eastern Australia (Last et al. 2007; Last and Stevens 2009). Distinguishing between similar species is possible morphometrically and from its geographical distribution (see Description), although records from the northern-most part of their range (in New South Wales; NSW) show some range overlap with other Squalus species. Many historical (and some contemporary) records do not make the distinction and care must be taken when referring to these records for population analysis due to previous uncertainty of the Squalus taxonomy. This species is not known to hybridise with others. CONVENTIONALLY ACCEPTED Is the species’ taxonomy conventionally accepted? Yes No If the species is not conventionally accepted please provide the following information required by the EPBC Regulations 2000: • a taxonomic description of the species in a form suitable for publication in conventional scientific literature; OR • evidence that a scientific institution has a specimen of the species, and a written statement signed by a person who is a taxonomist and has relevant expertise (has worked with, or is a published author on, the class of species nominated), that the species is considered to be a new species. n.a. Page 2 of 19 DESCRIPTION Provide a description of the species including where relevant, distinguishing features, size and social structure How distinct is this species in its appearance from other species? How likely is it to be misidentified? Squalus chloroculus is a large deep-water dogfish, attaining around 990mm total length (TL; Figure 1). It has characteristically vivid green eyes (when alive or fresh). Its body is fusiform, relatively elongated and stocky, with a prominently humped nape (Last et al. 2007). It has a relatively broad head, with a moderately elongated snout (Last et al. 2007). It has small nostrils, moderately sized eyes and spiracles, and an almost transverse mouth (Last et al. 2007). Its first dorsal fin is larger than the second, which is located on the tail. It is generally uniformly grey, with black margins on its dorsal fins, and black and white patterning on the caudal fin (although these colorations can vary; Last et al. 2007). The tricuspid flank denticles are very small (Last et al. 2007). Although it shares morphological similarities with other Squalus species, it can be distinguished by several features. Its broad head and the position and size of the dorsal fins are distinctive from S. montalbani (Philippine spurdog; Last et al. 2007). It has different caudal fin coloration to S. mitsukurii (Shortspine spurdog) and a lower vertebral count (Last et al. 2007). Identification may only be problematic in the northern-most part of its range in NSW where these species are partially sympatric. The social structure of S. chloroculus is unknown. DISTRIBUTION Provide a succinct overview of the species’ known or estimated current and past distribution, including international/national distribution. Provide a map if available. Is the species protected within the reserve system (e.g. national parks, Indigenous Protected Areas, or other conservation estates, private land covenants, etc.)? If so, which populations? Which reserves are actively managed for this species? Give details. Squalus chloroculus is one of 11 Australian Squalus species and is endemic to the temperate waters of south-eastern and southern Australia (Last et al. 2007). Its range is restricted to upper and mid-continental slope habitats, from Jervis Bay in New South Wales (ca. to the Great Australian Bight (Eucla, Western Australia; Last et al. 2007; Last et al. 2009). The daily and seasonal movements of S. chloroculus are not well understood. Some Squalus species are known to migrate and have strong diel movement patterns and clear home ranges (Carlson et al. 2014) but this has yet to be investigated in this species. One study found S. chloroculus to have travelled up to 480km from where it had been fitted with an acoustic tag (Daley et al. 2009). There is some evidence for spatial age segregation. Using trawls and lines, Rochowski et al. (2015) caught only mature adults, despite catches of small sharks of other species. This may occur in other Squalus species, for example Campagno et al. (1991) found separate pupping groups in Squalus megalops. Spatial partitioning such as this has implications for how fisheries impact on demographics and how populations might respond to management actions. There are no captive breeding populations or proposed re-introduction plans. This species does not occur in any EPBC listed ecological communities. The < 700m depth exclusion introduced in 2007 for all Commonwealth fishing licenced operators (750m in the Great Australian Bight) may provide some refuge. Deepwater dogfish fishing exclusion areas in NSW (NSW Government Official Notice 29 April 2011), as well as larger marine park designations (for example the South-East Marine Parks network in 2007) that prohibit demersal otter trawls (amongst other methods) are also likely to have some benefit for S. chloroculus (Walker and Rochowski 2019). However only around 19.1 per cent of its range falls within Australian marine parks, and of this, only three per cent overlaps with fishery exclusion zones (Heupel et al. 2018). Further, these protected areas are not managed for this species, and systematic monitoring in place to determine the efficacy of such protection specifically for S. chloroculus. Page 3 of 19 BIOLOGY/ECOLOGY Provide a summary of biological and ecological information. Include information required by the EPBC Regulations 2000 on: • life cycle including age at sexual maturity, life expectancy, natural mortality rates • specific biological characteristics • habitat requirements for the species • for fauna: feeding behaviour and food preference and daily seasonal movement patterns • for flora: pollination and seed dispersal patterns S. chloroculus shows female-biased sexual size dimorphism, and both sexes mature slowly. Females grow to around 990mm TL and have been known to live for 26 years. They reach maturity at 799mm TL at around 9-12 years (Last and Stevens 2009; Rochowski et al. 2015). Males grow to 856mm TL with a 24-year lifespan, reaching maturity at 629mm TL at around 16 years old (Last and Stevens 2009; Rochowski et al. 2015). The generation length is 21 years (determined by female age at maturity and longevity; Walker and Rochowski 2019). Natural mortality rates are unknown. Females have a triennial reproductive cycle (Rochowski et al. 2015), with the longest known gestation period of any species (31 - 34 months; Rochowski et al. 2015). This means that each year, only around one third of females will give birth, contributing to a low overall recruitment rate. The conditions needed for breeding are not known, however the female reproductive cycle is seasonal (births from September to December) and the males are likely to be in breeding condition year round (Rochowski et al. 2015). Pups are born at 250mm and litter sizes range from 4 to 15 embryos (average of 9), with a 1:1 sex ratio (Rochowski et al. 2015). Typical breeding success is not known, however higher fecundity (larger litters) has been found more prevalent in larger maternal females (Rochowski et al. 2015), making the species susceptible to length-selective fishing practices (where larger individuals are more likely to be harvested). Further, the continuous male reproductive cycle may be an indication of low mating probability, typical of species living in deeper waters (see Rochowski et al. 2015). Given its longevity, late onset of maturity, triennial reproduction, long gestation period and relatively low fecundity, the species is considered to have very low biological productivity and this makes it highly vulnerable to population loss. Rochowski et al. (2015) observed that TL at maturity varies before and after severe length-selective fishing mortality (potentially biasing reproductive length estimates), demonstrating that fishing impacts may also have sublethal recruitment impacts. S. chloroculus is a bathydemersal species, occurring on both hard and soft substrate on the upper to mid- continental slope at depths of 216 to 1360m (Last et al. 2009). Its habitat use and diet are not well understood, but some Squalus species prey on benthic and demersal teleosts, crustaceans, cephalopods and molluscs (for example, Braccini et al. 2005; Dunn et al. 2013), and this may