Developing hatchery technology for the European Spiny Lobster, Palinurus elephas
by Dr David Fletcher, RAS Aquaculture Research Ltd, UK
Lobsters are among the most popular premium seafood species on the global market. Wild harvests are approximately 232 thousand tonnes-per-annum with about 66 percent of the trade comprising Homarus and Nephrops species.
The Palinurid spiny lobsters account for about 32 percent of wild production (FAO 2017). The wild harvest of lobsters has reached maximum sustainable yield and, in some cases, exceeded it, based on the progressively declining harvest of some species (Sibeni & Calderini 2012).
The American lobster, H. americanus, accounts for about 60 percent of world lobster landings and the average unit value is US $20 per kg, compared to around $10 per kg for shrimp and below $5 per kg for finfish. World trade in lobster was over 170,000 tonnes in 2014 valued at $3.3 billion, almost double that of 13 years earlier (FAO, 2017).
Chinese lobster imports grew strongly between 2009 to 2014, from 3,600 tonnes to almost 18,000 tonnes, respectively with the US and Canada accounting for about 60 percent of total Chinese imports of H. americanus.
The lobster imported into China mainly enters the domestic market, especially its upscale segment. 72 percent of total supply to China in 2017 was Homarus – 28 percent live spiny lobster species.
Global landings of spiny lobster (Panulirus spp.) species are about 73,000 tonnes (FAO, 2017) and in general demand much higher prices in the Chinese and European markets. Again China is a focus for all lobster exporters from Australia and New Zealand (Ong & Mulvany, 2015) and while export volumes for rock lobster to China were increasing in the decade to 2015 prices were not significantly affected and the price trend continued to increase (Western Australian Department of Fisheries / Economic Research Associates Pty Ltd, 2015).
Unitary prices paid in China for spiny lobster species were well above the world average; spiny lobster from New Zealand fetching almost $90/kg, and from Mexico and South Africa, an average of $40/kg (FAO 2017).
Annual landings of European lobster, Homarus gammarus, have averaged 3,000 tonnes over the last decade. With the main producers being the UK, Ireland and France. Depending on season, live H. gammarus costs up to twice as much as the closely related American species, H. americanus, whose catches had been increasing annually until 2017 when the globally important Maine fishery saw a 17 percent decline in landings.
There is significant concern about the future of this fishery with climate change believed to be the main factor responsible for a range of problems from increased disease of adults to failed juvenile recruitment (Groner et al., 2018; Waller et al., 2017).
Indeed, numerous and varied impacts of climate change have already been described negatively impacting a broad range of lobster species (Briones-Fourza´n & Lozano-A´lvarez, 2015) including palinurid lobsters.
As with seafood in general, global demand at the luxury end of the market, which includes lobsters, continues to increase, and it is likely to rapidly accelerate as demand from the growing middle classes in Asia increases (Hart 2009).
With future demand expected to dramatically increase over the coming years, there is increasing interest in developing a sustainable supply of lobsters uncoupled from the harvest of wild populations through aquaculture production technologies (Phillips & Matsuda 2011).
The clawed lobsters of the Nephropoidea are generally aggressive in nature and not readily amenable to production in high-density grow-out systems. In contrast, the clawless lobsters of the Palinuroidea are naturally communal in behaviour.
In captivity, these lobsters can be held at higher population densities and hence possess some of the characteristics suitable for farming (Phillips & Matsuda 2011) in recirculation aquaculture systems (RAS).
The European spiny lobster, Palinurus elephas, has several attractive qualities as a potential culture species. On a unitary basis it is among the highest priced seafood species in the EU and international markets.
Demand far outstrips supply with market prices of EU €65–70 per kg in Europe and up to €140 per kg for P. elephas on export to Asia. The Chinese market has an insatiable appetite for several spiny lobster species and as such the first pilot commercial hatchery for a tropical spiny lobster species, Panulirus ornatus, is under construction in Australia.
From an EU perspective H. gammarus has few attractive qualities for commercial farming. It is slow growing and aggressive but more importantly the wild fishery is amenable to effective management and recovery where stocks decline. Consequently, any farmed H. gammarus product would always compete with prices from the wild fishery.
In contrast, Palinurid lobsters like P. elephas are far more susceptible to overfishing and population recovery can be slow to non-existent for several decades without strictly enforced protection over large areas of coastal waters. This observation is likely due to the far more complex and extended planktonic cycle of P. elephas, limited suitable habitat and ease of capture by divers and tangle nets.
Lobster aquaculture based on the capture and on-growing of wild pueruli or juveniles in floating cages was initiated in Vietnam as a high risk, high return venture based on the tropical rock lobster Panulirus ornatus (Williams 2009). The industry peaked in 2006 with approximately 2000 metric tonnes of production before rapidly declining to a low of 720 metric tonnes in 2008, primarily due to disease outbreaks (Hung & Tuan 2009; Sibeni & Calderini 2012).
Lobster ongrowing in Vietnam is associated with significant environmental damage from organic pollution generated from use of 'trash' fish feeds with poor FCRs (30-35:1), use of antibiotic cocktails at up to 5kg per tonne lobster produced (Hedberg et al., 2018), coastal bays littered with discarded plastic lobster cages and the illegal importation of wild juvenile lobsters smuggled into the country from Indonesia.
The whole fishery in Vietnam is entirely dependent on wild juveniles with the Indonesian strain of P. ornatus particularly favoured over native supplies. While similar cage farming ventures have been initiated in several countries all remain dependent on wild juveniles (Sibeni & Calderini 2012).
The EU range of the valuable European spiny lobster, Palinurus elephas, includes the western English Channel, Ireland, Brittany, Spain and Portugal. Weak management has resulted in the EU fishery declining to an all-time low and has been described as 'residual' (ICES, 2006). It was once one of the most important financial contributors to the inshore fishery sector. In Portugal, Spain, Ireland and UK, the P. elephas fishery has declined between 85-95 percent in the last 70 years. Catches in Wales fell by 92 percent between 1980 – 1997, while Irish exports reduced from 270t in 1959 to 20t (Tully 2011) and French Atlantic fisheries declined from 1000t in the 1950s, to 25t in 2010 (Laurans et al., 2011). These trends reflect a catastrophic population crash in the Atlantic, where some fisheries, like those in Wales, are now commercially extinct.
In addition to its economic value, P. elephas is a key component of biodiversity on Annex I reef Habitat, essential for favourable conservation and good environmental status of these habitats. Recovery of the P. elephas population is considered vitally important in gaining Good Environmental Status (GES) under the EU Marine Strategy Framework Directive (Leslie & Shelmerdine, 2012).
Unlike H. gammarus, the land-based farming of P. elephas using RAS technology could be an attractive proposition not only due to its very high market value, but several key biological characteristics important in commercial farming. Commercial P. elephas hatcheries could also support the restoration of depleted Atlantic fisheries to benefit inshore small-scale fisheries (SSF) where employment has declined 20-30 percent in the EU regional economy and 30-50 percent in terms of income in the decade to 2010 (Macfadyen et al., 2011).
However, development of the hatchery technology for spiny lobster culture is extremely challenging. Following the successful hatchery development of juvenile P. ornatus lobster production in 2016 the achievement was described by Professor Greg Smith, University of Tasmania,'….as one of the holy grails of aquaculture because it is such a long and difficult larval cycle.'
In 2013, with grant support from the Wales Government and European Fisheries Fund (EFF) RAS Aquaculture Research Ltd (RASAR) established a pilot R&D project to assess the not insignificant challenge of culturing P. elephas.
Successful juvenile spiny lobster culture requires application of key hatchery disciplines. These include strict control over water quality management using RAS technology, control of phyllosoma disease, design of specific culture tanks for successive phyllosoma stages and development of a feed regime that evolves with the progression of the phyllosoma stages towards the pre-juvenile puerulus stage. This latter requirement is perhaps the most challenging. As the phyllosoma develop through successive stages they must store enough nutrient reserves to enable the subsequent pueruli to metamorphose successfully over a 16 – 18-day period into a juvenile lobster. During this transition period the pueruli do not feed and depend entirely on nutrient reserves stored during the late phyllosoma stages.
For P. elephas, RASAR established a purpose-designed water treatment system enabling very precise control over water quality. A range of larval tank designs followed, together with identification of a feeding strategy to optimise survival and development at each phyllosoma stage.
During the 2019 season RASAR succeeded in producing all P. elephas phyllosoma stages and a small number of juvenile lobsters. This is the first time that P. elephas has been cultured in Europe and could eventually lead to commercial scale production of this high value species using RAS technology. Equally, the techniques being developed could also have application to a more sustainable farming of tropical spiny lobster species in SE Asia.
The complex and protracted P. elephas larval cycle of eight-to-nine months observed in the wild was reduced to about 2.5 months under laboratory conditions. The very high mortality reported for P. elephas phyllosoma stages I – IV (Kittaka et al, 2001) has been resolved with >50% survival to stage VIII being secured without using antibiotics. One important observation is that the juvenile P. elephas have shown no aggressive behaviour when held under communal conditions or even towards newly moulted individuals or defenceless pueruli. A prototype phyllosoma feed is under development. It is planned to repeat the phyllosoma trials at a larger scale during the 2020 season and subsequently evaluate the growth rates of the P. elephas juveniles.
For further information and details please contact David Fletcher.