Chilean mussel hatchery has social aims
Chinquihue Foundation is the only facility producing mussel seed in Chile, and it comes with a socially oriented goal: to help low-income fishermen and mussel farmers make a living wage.
Chinquihue Foundation, a Chilean non-profit NGO founded in 1989 with support from the Chilean Government and the Japan International Cooperation Agency (JICA), has operated a hatchery in Puerto Montt since 1996. Its aim is to produce seeds and seedlings from different resources and thus promote small-scale aquaculture, helping artisanal fishermen become farmers.
Located along the coastline in Chincui Bay -12km south of Puerto Montt - this production unit specializes in benthic invertebrates as well as microalgae and macroalgae. In the beginning it was focused on Northern scallop (Argopecten purpuratus) and Pacific oyster (Crassostrea gigas), but many other species have also been reared here over the past two decades. This includes such species as red abalone (Haliotis rufescens), green abalone (Haliotis discus hannai), Chilean sea urchin (Loxechinus albus), clam (Venus antiqua), Pacific clam (Gari solida), Sea asparagus (Ensis macha), Chilean abalone (Concholepas concholepas), Chilean mussel (Mytilus chilensis), Magellan mussel (Aulacomya ater), Choro mussel (Choromytilus chorus), Gracilaria seaweed (Gracilaria spp.) and Giantkelp (Macrocystis spp.).
Currently, there are only mussels in the facility along with the auxiliary cultivation of microalgae to feed those mussels. These are primarily diatomeous and flagellates such as Isochrysis galbana, Nannochloris atomus, Tetraselmis suecica, Chaetoceros calcitrans and Chaetoceros neogracilis.
Pilot level facility
The hatchery operates at pilot level and is located beside the port terminal belonging to Chinquihue Foundation. It is composed of two laboratories, one of 300m2 intended for mollusks and echinoderms and another one of 150m2 for macro-algae. There is also a 315m2 greenhouse for mollusks and echinoderms within these premises.
All rooms have the proper equipment and infrastructure systems required for seawater adduction, aeration, heating and thermal isolation. The facility includes 10 large farming tanks (three of 3,000 liters and seven of 2,500 liters) combined with 100 tanks of 200 liters each.
There are three types of mechanical filters: Prefilters are at the seawater suction pump and in hoses that bring water into the facility. Then, once in accumulation tanks, water is depurated in bag filters and finally passed through a UV system.
Regarding staff size, there were up to 12 workers in this hatchery during the original five-year project funded by JICA. However, this number has been reduced to just five now, who are exclusively employed to work with mussel species.
“In terms of installed capacity, we could produce batches of 30 million pre-metamorphic larvae every two months,” says Viviana Videla, manager of this hatchery.
Although there are three different mussel species native to Chile (Magellan mussel, Choro mussel and Chilean mussel), only the last one is of large commercial interest and represents 100% of the farmed animals and products exported by the local mussel sector.
With harvest volumes that range between 270,000 and 290,000 tonnes per year, this is the second largest aquaculture industry in Chile, with about 70,000 exported tonnes and US$ 200 million in revenues annually. In geographical terms, this is an industry that operates exclusively in the region of Los Lagos, providing about 17,000 workplaces in the area.
Viviana Videla noted that the Chilean mussel is a native species which has a good range of tolerance to changes in temperature, drying and salinity. “It is quite a pliable and resistant species,” she said, adding that this is a blue mussel, very similar to the Galician mussel (Mytilus galloprovincialis) in terms of size, meat color, texture, flavor, etc.
In the wild, this species fertilizes its spat in natural beds, floating within the plankton until they attach themselves to a solid substrate to grow. The production cycle of this bivalve lasts for about 21 months from spat to harvest.
Operation and objectives
This facility’s operation is mainly oriented to detection and identification of Chilean mussel larvae in plankton using epiflourescence microscopy. This is intended to generate useful information for small farmers dedicated to mussel seed collection.
“If we inform them that there is natural spawning in a specific area, they can place collectors and catch seed. Before, they planned this process in connection with certain dates or season,” Videla explained.
In addition, the hatchery has been working on the production of mussel seeds and developing technologies to farm mussels in land-based facilities.
“This is technologically feasible,” she added, “but we need to develop and refine our model, since production costs are still a problem. It is difficult to compete with the costs of seed collection in the wild. The challenge is to produce at competitive costs or to change the paradigm, producing adults instead of just seeds and reducing the number of production stages, for example, and thereby cutting costs.”
Start with the breeders
Mussel seed production starts with the selection of breeders, usually from farming sites; then comes the conditioning of breeding animals, aimed at achieving the maturation of the gonad. Once breeders mature, they are induced (with temperature and UV irradiation) to expel gametes.
A process of cleaning and selection of embryos is performed after fertilization. This lasts for two days and leads to the first larval stage, straight-hinge veliger, commonly known as 'D larva', because of its shape like the capital letter D. This animal is about 80 microns long and continues growing until after about seven days (depending on the temperature) it enters the umbonate larvae stage, at which point the hinge is no longer straight but rounded, which is commonly known as 'umbonate larva'. This stage lasts for 10-12 more days.
When the statocyst becomes visible, it is the first sign that larva (also called ‘eyed larva’) are close to settling, metamorphosing, and fixing through the byssus. Then, the 'foot' appears and starts walking, adheres to a substrate, loses the cilia and stops swimming. At this point it generates the byssus and, when the mollusk is fixed to a substrate, its shell begins to calcify and take color. This stage is usually known as 'post larva'.
“When the mussel reaches 10mm long we call it seed, although it is a juvenile, which continues to grow until it becomes an adult (˜7cm). In this species, the first sexual maturity (with functional gonad) occurs when the specimen reaches about 3.5 cm in height,” Videla explained.
She also described some advantages of producing seed in a hatchery: Specifically she noted that mussel seeds can be produced at any time of the year and makes it possible to select breeders according to desired phenotypic characteristics, for example, growth rate or faster detoxification of toxins such as PSP. Another advantage was de-seasonalizing production in order to maintain processing plants in operation more months every year.
Most of the species reared in this facility over the past 21 years were investigated and produced through governmental-funded projects.
“In general, if the seed market does not exist and the production of adults is not massive, once the project is finished you do not have enough funds to continue. Although our hatchery is not so small, it is not of commercial scale either. It is intended for research at pilot level. Therefore, production is always more oriented to applied research,” she said.
March 5, 2018 By Christian Pérez Mallea
Print this page