With demand rising globally, octopus farming is developing apace – but, mindful of both the animals’ welfare and concerns around sustainability, should we be scaling it up at all?
Although it’s been a controversial subject of late, there’s no doubt that growing demand for octopus, combined with improved farming techniques, is making cephalopod farming increasingly attractive from an economic perspective.
For those living in the Mediterranean and across Asia, octopus has been a regular feature on their seafood menu for many years. More recently, it has gained popularity in other parts of the world – so much so that demand has at times outstripped supply.
Generally, octopuses grow fast, die after a few years, produce lots of offspring in the middle and fetch a good price on the market. For an aquaculturalist, it seems like an ideal species, and it is perhaps of no surprise that in countries such as Spain, where cephalopod consumption stands at around 3.2kg per capita compared to the global average of 0.51kg per capita, studies into octopus aquaculture started back in the 1980s. However, there have been – and continue to be – many challenges, ranging from barriers to breeding octopus to difficulties in ensuring they survive to adulthood.
Currently most octopus production involves growing wild-caught juvenile octopus in cages where they are fed until they reach marketable size. However, octopus ranching is labour intensive and, together with high variability in initial octopus catches from one season to the next, it is unsurprising that this form of farming hasn’t reached any sizable scale. Nevertheless, research into full life-cycle octopus aquaculture has continued steadily – and seen a number of successes in recent years.
After hatching from their eggs, most octopus species live in the water column, away from the seabed, in what is known as the paralarval phase of their life. At first, octopus rely on their own energy reserves but once these are depleted, paralarvae switch to zooplankton. Historically, ensuring survival past this life stage was a major bottleneck, with feed-related issues being a major factor behind the high rates of mortality. In some respects, this was resolved almost 20 years ago when researchers at the Spanish Institute of Oceanography (IEO) successfully reared octopus past the paralarval stage. There is a catch – the feed consists of living crustacean larvae and brine shrimp, which may become increasingly difficult to obtain in sufficient quantities for commercial production as demand grows. To solve this problem, researchers are now working on developing optimal feed for paralarvae. In fact, suitable feed for the entire life cycle of octopus remains one of the biggest bottlenecks for commercial-scale production.
...follow the link to read the article in full on The Fish Site...