NEW YORK — McDonald’s says it is offering its first new Happy Meal entree in a decade: Fish McBites.

The world’s biggest hamburger chain said the Fish McBites will be widely available at U.S. restaurants starting this week through March, to coincide with Lent. The Happy Meals will come with seven pieces of Fish McBites, French fries, apple slices and a drink.

The company had already announced last month that the Fish McBites would be sold on the standard menu in three sizes — snack (10 pieces), regular (15 pieces) and shareable (30 pieces).

Fish McBites, which are fried pieces of fish, will use the same Alaska Pollock used in the fast-food chain’s Filet-O-Fish.

The launch marks the start of what McDonald’s says is a bigger pipeline of new limited-time offers for the year ahead. By adding more variety to its menu, the company is hoping it can fend off intensifying competition and tempt customers to eat out more at a time when many are being more careful about their spending.

Brian Irwin, director of marketing for McDonald’s USA, said the Fish McBites are a twist on the popular Chicken McBites that were introduced as a limited-time offer last year. He said the company thought they’d work well in Happy Meals because there’s a “fun, poppable” aspect to them. That’s why McDonald’s sells more Happy Meals with Chicken McNuggets than hamburgers or cheeseburgers, he said — there’s something about the dipping that kids like.

Additionally, Irwin said the company’s internal research showed that moms wanted more seafood options on the menu.

Although the Fish McBites will be offered temporarily, Irwin said the company might bring them back periodically if they perform well.

Depending on which drink is selected, McDonald’s says the Happy Meals with Fish McBites have between 385 calories and 415 calories.

McDonald’s, often a target for health advocacy groups that say Happy Meals encourage kids to eat junk food, in 2011 began adding apple slices and reduced the portion of French fries in the meal boxes.

For adults, the Fish McBites will come with tartar sauce and be served in cartons that make them easy to share or eat as a snack on the go, which Irwin said is an important attraction for customers.

“It fits in your cup holder in the car,” he said.

The big question is whether they can boost sales in the months ahead. In the last quarter of 2012, McDonald’s managed to eke out a higher profit in part by touting its Dollar Menu and urging franchisees to stay open on Christmas. But for January, the company warned that a key sales figure is expected to fall again. That would follow a drop in October, which was the first decline in the monthly figure after nearly a decade.