Understanding Scallop Biology and Lifecycle for Farming Success

Introduction

  • Scallop farming has become an increasingly popular form of aquaculture in recent years.
  • People like scallops for their tasty part, which is the scallop “meat” we eat.
  • Although places catch scallops in the wild, too many people are catching them, causing a decline in their numbers.
  • Scallop farming ensures a steady supply of scallops in an environmentally friendly manner.
  • We will provide an overview of simple ways for small-scale farmers or aquaculturists to raise scallops.

Scallop Biology and Life Cycle

  • Scallops belong to the Pectinidae family and have two shells.
  • They live on the sea bottom with two shells connected by a band.
  • Scallops are filter feeders that pump large volumes of water through their gills to capture plankton and organic particles for food.
  • They possess adductor muscles that quickly close their shells if disturbed.

Reproduction

  • Scallops are either male or female, releasing sperm or eggs into the water column for external fertilization.
  • After a larval stage lasting 2-4 weeks, scallop larvae settle onto a substrate and metamorphose into tiny spat.
  • The time for scallops to reach market size varies from 9-24 months depending on species and growing conditions.

Selecting a Scallop Species

  • Important species for aquaculture include the Bay Scallop, Sea Scallop, Peruvian Scallop, and Japanese Scallop.
  • Scallop farmers should choose a species suitable for their growing area and market demand.
  • Hybrid scallops that combine fast growth and large size have also been developed.

Obtaining Scallop Seeds

  • Hatchery-raised baby scallops are safe from illnesses but cost more.
  • Collecting baby scallops from the wild is less expensive but comes with a higher risk of them getting sick or not surviving.
  • Before placing the baby scallops into the growing area, they should be kept separately and checked for illnesses.

Setting Up a Scallop Farm

  • Tidal flow helps bring food and oxygen while carrying away waste.
  • To maintain the scallops’ health, it’s important to have clean water that moves well and prevent things from sticking to their environment.
  • Farm sites should be protected from severe storms and predators.
  • Tanks allow the raising of scallops in areas lacking suitable coastal sites.

Tank and Water Requirements

  • Flow-through systems work best to remove waste.
  • Seawater is ideal, but freshwater systems can work if salinity is stabilized around 20-35 ppt by adding salt.
  • Maintain water temperature between 15-20°C for optimal growth. Use filters and UV sterilizers to control diseases.

Feeding and Nutrition

  • Scallops are filter feeders that eat phytoplankton and other microalgae.
  • In tanks, cultivated algae, algae pastes, or commercial shellfish diets can be used.
  • Ensure food density and quality are high enough to support growth.

Monitoring Growth and Health

  • By regularly checking and testing the scallops, farmers can assess their growth rate and decide how many can be kept in one place.
  • The target is to grow scallops to 40-50 mm shell height at 9-15 months.
  • Inspect the scallop shells for any damage, tiny creatures living on them, or things sticking to them.
  • Monitor mortality closely for signs of disease.
  • Water testing helps identify any environmental issues.
  • Good record-keeping is key to improving production.

Predators and Pests

  • Major scallop predators include sea stars, crabs, sharks, and rays.
  • Pests like sponges, tunicates, or hydroids can foul shells and compete for food.
  • Using special cages and nets can keep away animals that might harm the scallops. Keep an eye on anything that sticks to the tanks or equipment, and clean them regularly.
  • Choosing the right location, having good water movement, and using certain substances can help control unwanted growth on the equipment.

Harvesting Market-Sized Scallops

  • Scallops reach market size of 40-80 mm shell height depending on species at around 12-24 months.
  • Farmers can occasionally remove the largest scallops, allowing the smaller ones to keep growing.
  • Handle scallops carefully to avoid damaging the adductor muscle or shells.
  • Well-timed harvests ensure the best scallop quality and profits.

Processing and Marketing Scallops

  • After harvest, processors remove the viscera, roe, and any fouling or parasites from the shells.
  • The edible scallop meat is the adductor muscle.
  • Scallop are packed and then supply  to market for selling.

Conclusion

  • Fish farming for raising scallops provides a steady and environmentally friendly source of scallops.
  • Small-scale farmers can profit from scallop farming using basic setups such as hanging them in the water or using tanks.
  • By choosing the right location, maintaining good water quality, feeding scallops well, keeping them healthy, and collecting them carefully, scallop farming can be a lucrative endeavor.
  • The growing demand for scallops should provide marketing opportunities for farmed scallops.

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