Last updated on 4 October 2018
Previously considered as Octopus vulgaris, the species was singled as O. mimus in 2000 by the management entity, considering morphologic evidences (Cortez et al. 1998) and genetic tests (Perez-Losada et al. 2002)(Warnke et al. 2000) (Sernapesca's statistic reports available here). Later, in 2007, management split records of O. mimus from those in southern Chile, of Patagonian giant octopus Enteroctopus megalocyathus (Subpesca 2018), and separated with it the access to the northern and southern octopus fisheries (Subpesca 2013). Therefore, there have been two different sources of uncertainty with information, one considering it to be a different species making management not count with appropriate tools to present measures for the resource; the second is the combination of landings' volumes from the two different species, which later has been resolved by looking at the origin of captures, since both species apparently do not share locations (Subpesca 2018).
There have been three studies specifically on the Chango octopus, all three of them between 1998 and 1999, two focused on biological parameters (Araya et al. 1999)(Cortez et al. 1998) and one evaluated the fishery, but did not perform a stock assessment (Gonzalez et al. 1998). Later, two more reports have taken O. mimus into consideration on sustainability strategies for benthic fisheries (Pizarro et al. 2009) and molecular characterization and connectivity of benthic resources (Galleguillos et al. 2010). This resource does not count with current stock assessments.
Since 2013 there is a monitoring program (developed by the Fisheries Development Institute, IFOP) for benthic resources that produces annual reports and performs monthly samplings on the main harbors in terms of landings. Records characterize the activity, collect data on individual parameters and volumes. It was recently pointed out that there are major differences in landings' records from this program and records from the surveillance and enforcement entity, Sernapesca, bringing uncertainty to both records (Barahona et al. 2016).
Last updated on 4 October 2018
The misidentification of the species brought a major consequence to management since the minimum capture weight was set according to the common octopus' biological parameters in 1985. At least since 1998 it was published that this species was in fact O. mimus and had a different biology, noting that weights at first maturation were higher than 1 kilogram: 1,439 g in the I region, 1,524 g in the II region and finally 1,910 g in the III region (Cortez et al. 1998). Therefore, the 1000 g minimum weight measure is an underestimation and foments the capture of juvenile individuals. Several reports find the occurrence of individuals under the minimum legal weight, with low (around 3-4% (Barahona et al. 2014)), or higher occurrence (from 20 to 60% depending on the sex and the year (Barahona et al. 2016)(Galleguillos et al. 2010)(Gonzalez et al. 1998)).
The predominant fishing gear consists on a hook at the end of a stick, that allows the diver to reach caves and crevices where the octopuses might be (Barahona et al. 2014). This situation, where fishermen do not see the individuals most of the time, does not allow the selection of sex or even size of octopus (Barahona et al. 2016) and has been described for another resource (E. megalocyathus) to produce great damage to underweighted individuals and that fishermen might extract nesting females, leaving postures unattended and vulnerable (Chong et al. 2001).
As well as for the southern octopus, conflicts with temporal closures have been brought up, and new legislation was created for the chango octopus. However, it was pointed out that when the closure ends, on February 28th, there are still many nesting females, that are easily harvested since they do not leave the eggs unattended until they hatch. The end of the closure is therefore proposed to be delayed until March 15th (Pizarro et al. 2009).
Since the habitat conditions are variable, it is not expected of this resource to have a strict reproductive cycle, and reproductive females are found throughout the entire year (Cortez et al. 1995); and growing in changing conditions implies that growth rates might change considerably among sub-cohorts (Cortez et al. 1999). It is because of this that the resource is considered to be unpredictable and fluctuant (Barahona et al. 2016)(Subpesca 2010), generating uncertainty on the presence of the resource and its relation to environmental conditions (Subpesca 2010). This is why precautionary measurements are proposed for the stock (Barahona et al. 2016)(Subpesca 2010), and as long as there is not a better source of information and assessment, precautionary reference points should be generated (Barahona et al. 2016).
Finally, it is important to consider populations’ connectivity which, in the case of octopus is generated by the larval stage, that in turn has as a source the southern populations and as a sink the northern ones (Galleguillos et al. 2010). This generates larger populations in the northern areas (Galleguillos et al. 2010), which could relate to the higher fishing activity in regions I and II (Araya et al. 1999)(Barahona et al. 2016)(Galleguillos et al. 2010)(Subpesca 2010). These characteristics are therefore of major importance to the assessment and to the management of the species in Chile.
Last updated on 4 October 2018
There is no stock assessment being conducted. According to the description of the fishery from 2005 to 2015, and considering the maturation weight identified by (Cortez T et al. 1998), the fishery has been sustained by the catch of juveniles, with up to 83% in regions I and III, and up to 94% in region II, leading to a growth overexploitation situation (Barahona et al. 2016). It has actually been mentioned that the stock is either overexploited or severely affected (Pizarro et al. 2009). Besides, there is a clear decrease, yet fluctuant, in landings since the late 90s (Subpesca 2010)(Subpesca 2018).