Overview of marine ranching in Chile

Reduction of coastal fish resources is common problem in the whole world due to overfishing. Qn the other hand, demand is rising due to health consciousness (less cholesterol), contamination of chicken (influenza), cow (BSE) and pork (HEV).

Marine ranching is the one of solution to recovering coastal fish resources which has operated in Japan more than four decades. The result shows that some fishes are recovered, even increased, and contribute benefits. Chile coast water has higher productivity compare to Japan and the method produce more fishes quickly. It may create new business model which has less energy consumption, no contamination and sustainable production, and create employment at rural area.

1.            What is Marine ranching

1.1.             Idea and activities

General ideas of marine ranching are releasing fish juvenile dismissing species into artificial reef (shelter) which design to protect from predators at reservation. The fish takes natural foods and the fish resources recover then maintained the resource by control fishing sustainably.

Activities of marine ranching are construction of shelters at reservation and releasing hatchery made juveniles in it after natural feeds are grown. Secure the fish growing until market size then harvest fish to maintain fish resources based on biomass monitoring.

1.2.             Advantages and disadvantages

o    Produce fish which is similar to wild one

o    Feeding activity not require (less energy consumption), fish take natural feeds

o    Operation require only artificial juvenile for initial seeding, after that reproduce naturally

o    Shelter produce additional products, other fish, octopus, shellfish, sea urchin and algae

∆        Require shelter and installation cost (durability for 30 years)

×        Low recovery due to diffusion, poaching and predation

×        Require secure security system and operation cost

1.3.             Essential factors

Recovery rate of marine ranching is lower (10 %) than intensive culture like cage culture due to diffusion and predation. Thus, some events are necessary to improve recovery rate.

1.3.1.        Seeds

Broodstock are captured at the releasing area to not contaminate gene pool. Artificial seed quality should be similar to wild one physically (less deiform) and genetically to avoid biodiversity contamination. SISP (Semi Intensive Seed Production) or RESISP (recirculation SISP) method are useful for juvenile production which produce premium seed, less deformity and strong with low cost.

Rockfish like Apañado (Hemilutjanus macrophthalmos), San pedro (Oplegnathus insignis), Cabrilla española (Sebastes capensis), Congrio colorado (Genypterus chilensis), Mulata (Graus nigra) are ideal species for rearing at the bottom shelter which gather after releasing. Cold and warm watered fishes released together, San pedro and Mulata for example, to minimize diffusion loss when water temperature change during El niño.

1.3.2.        Shelter

Shelter for juvenile is designed to protect newly released juveniles from predator which are not adapted wild condition. Particularly, the openings of shelters are good for juvenile size which avoid predator to enter into shelter. Also, a shelter for adult is designed to bigger capacity compare to juvenile one and accommodates large biomass. Both shelters are designed to prefabricated structure, assemble in the sea, and minimize transport cost.

Floating shelter (FAD; fish aggregating device) increase productivity of marine ranching. It is reported that pelagic fish like Dorado (Seriola lalandi) and tuna  gather above bottom shelters.

1.3.3.        Area management

Based on sampling, operator monitor stocks as species, size, number and biomass, in each shelter and harvest depend on the demand. ABC (Allowable biological catch) figure out TAC (Total allowable catch) and maintain biomass and keep sustainability. The area is secured from poaching and predators with security system.

2.            Key factors

2.1.             Poaching control

Poaching is the most possible obstacle which robbed products by poacher in the night. Security system which is integrated infrared camera, thermo sensors, underwater camera, sonar and WiFi.  For the minimum poaching, the members who are involved in marine ranching should share investment and rise productivity.

2.2.             Production enhancement

Feeding in to shelter is one of option to minimize diffusion and enhance productivity without over feeding that contaminates area. Also, operation at low productivity area such as sandy beach extends production area which combine feeding activity.

2.3.             Project model

At primary step of marine ranching operate under government to establish method according to fish species selection, monitoring method, shelter design and management method. After that, fishing company and fisherman association scale up to business base if recovery rate reach to 40 % or it has lots of additional products to make profit.