Mackerel Handling and Processing
Mackerel is a slim caudal peduncle with forward pointed nose with thick and firm muscled. It has two large dorsal fins dark steel greenish blue with blue black head.
They grow 14-22 inches long weigh from 1-4 pounds. The swift moving fish move in dense schools of thousands of fish in mackerel schools. They live in open sea with temperatures 10C to 20C.
Importance of mackerel fish
Mackerel is a delicious fish eaten worldwide for its good taste and nutritional properties. Highly perishable they have good economic value in the fisheries industry.
A most valuable fish in commercial fishing it is valued among species like haddock, rosefish and cod. The billion dollar commercial fishing industry involves large vessels, hooks, lines, floating traps, weirs, pound nets.
What they eat
Mackerel eat marine crustaceans, small fish larva and small copepods. Other food sources is plankton, shrimps, Mollusca, annelid worms, small fish. More are sea worms, pelagic fish eggs, small herring, and bottom feeders.
What Mackerel Eat
- Small fish larva
- Small copepods
- Annelid worms
- Small fish
- Sea worms
- Pelagic fish eggs
- Small herring
- Bottom feeders
Enemies include predaceous sea animals like dogfish, sharks, tuna, and bluefish. Others are threshers, striped bass, bonito and squids. They are susceptible to parasitic worms or die in extreme cold conditions.
- Mackerel sharks
- Striped bass
- parasitic worms
Mackerels spawn off the coast of America around continental shelf from Cape Cod. Other locations are south New England, Chesapeake Bay, Gulf of st Lawrence.
They spawn in spring or early summer in warm 46 f water, egg production commences in 48f-56f. Females lay about 450,000 eggs that are 0.97 to 1.38 mm. in diameter and newly hatched larvae are 3.1 to 3.3 mm. long.
Mackerel Handling and Processing
Mackerels are highly perishable therefore freezing is deployed to extend shelf life. Other processing involves salting, canning or smoking. Scomber scombrus is found in warm waters have different species. They are migratory fish and swim vast distances for food and spawning.
Chilling and Freezing
The fatty fish requires immediate chilling or freezing for longer shelf life. This is because they will spoil within 74 hours without refrigeration. Chilling methods include use of ice, refrigerated, salted or smoked. In polythene package and freezing the shelf life is extended for 360 days
Smoking is a common method practiced in third world countries. Smoked fish are ready to eat or used in many culinary applications. The fish has good fat content, oil.to smoke the fish is gutted with fillets removed and salting applied.
Ways of smoking includes grills, smokers, oven drying. Another method is brined whole fish hung by tail over rods then smoked.
Canning smoked mackerel
Mackerel fillets are smoked by first soaking in saturated brine for 6 minutes. They are then packed in 200g cans, steamed for 10 minutes, drained of residual liquid and filled with sauce. Different sauces used are cider, port, sweet/sour/ sauce then heat is applied for 60 minutes at 115C.
To can mackerel whole fish head is removed and gutted with black skin removed from belly wall. The fish is cut into steaks 6-7cm long for 220g cylindrical can.
They are packed vertically in the can with 3g salt added then closed and heat treated at 115C for 90 minutes. Additives like tomato sauce, mackerel oil, vegetable oil before sealing the can. Finished can is labeled, stored or distributed to wholesalers.
Apart from freezing salting is a short term method of fish preservation. Salting involves splitting the fish along the back, blood washed away and fish soaked for 2 hours.
Then it is rinsed, drained and dipped in dry salt. If they are processed for export then they are packed in circular barrels.
How to Identify Spoilt Mackerel
Signs of spoilt fish are nasty smell, sunken eyes, discoloration. Others are washed out appearance, dark brown/reddish gills, ammonia smell