RESTAURANT REVIEW SEAFOOD PARLOR & SALOON : Lot of Mystery : The parking area at this establishment always seems to be full. The question is, ‘Why?’

Are there eating places you pass by frequently where the parking lot is always full of cars, but you don’t know anyone who’s ever eaten there? Do you think to yourself: “They must be doing something right, I should try it . . . someday”?

Out on the highway to El Rio, on Vineyard Avenue east of Oxnard, is a place called the Seafood Parlor & Saloon that has a parking lot like that. Whether it’s lunchtime or evening, the front and back lots always seem to be full of cars.

So I headed into the restaurant to see what was bringing in the customers. I quickly discovered that although the fish at the Seafood Parlor is not bad and not too expensive, and the waitresses are fast and certainly cordial enough, there’s little else to get you to turn in to that parking lot.

The monkfish--sometimes described as “poor man’s lobster”--was mesquite-broiled. It had the firm, almost chewy texture similar to a California lobster and, to the restaurant’s credit, was not overcooked. Ditto for the catfish, which seemed to be from a freshwater farm and was served, as the menu notes, “moist and mild.”

One potato side dish, potatoes Romano, wasn’t bad, sort of mashed potatoes with Romano cheese mixed in. Then there was the dish called fajita fries. I don’t know what it was supposed to be, but what I got was something mushy underneath a crust of oil and spices.

The first thing I actually ate at the Seafood Parlor--after doing such meticulous research on the parking situation--was a chowder. I’ve tried both the Boston and the Manhattan versions. Both are pretty bad. Watery might be the best description. And while the spicy sauce for the shrimp cocktail was decent, the shrimp seemed as though they had recently been in the freezer and hadn’t quite finished the thawing process.

Judging from its position on the menu, the bouillabaisse is the house special. Lord knows why. My portion had two clams and two pieces of crab and had been cooked so long that it had an almost metallic flavor.

On one visit, I obeyed a sign, which points to the bar and urges the customer to try the restaurant’s beer and barbecue. The barbecue is not an improvement over the bouillabaisse. The ribs are served dry, and someone has splotched on a gob or two of salty, cloying barbecue sauce. Barbecue is definitely not the way to go here.

People aren’t coming in for the dim atmosphere, with the usual captain’s chairs and some overhead fans. Or the variety of mediocre cheesecakes the place offers for desserts. So would someone, please, let me know just why that parking lot is frequently so full?

* WHERE AND WHEN

Seafood Parlor & Saloon, 3280 Vineyard Ave., Oxnard, 983-6663. Open 11:30 a.m to 10 p.m. Mondays through Thursdays, 11:30 a.m. to 11 p.m. Fridays, 4 to 11 p.m. Saturdays, 4 to 9 p.m. Sundays. Major credit cards accepted, reservations accepted, full bar. Lunch for two: $20-$30; dinner for two: $24-$52. Recommended dishes: catfish, $10.95 dinner; monkfish, $12.45 dinner.