“Knuckles” is one of those inherently playful, entertaining words. So it’s hard to resist when you see lobster knuckles listed on the appetizer menu at Brooklyn Fish Camp – the new Park Slope outpost of the West Village’s popular Mary’s Fish Camp. Technically speaking, of course, lobsters don’t have knuckles, which makes the dish seem all the more novel and fun. What lobsters do have are knobby exoskeletal joints that attach the claws to the body, and a pile of these is what’s served at Brooklyn Fish Camp, along with a small bowl of melted butter and a nutcracker. It’s a clever concept.

But here’s the thing: Extracting the small morsels of meat from lobster knuckles is a major pain. After all, when you order a whole lobster, do you start with the knuckles? Of course not. The knuckles are what you save for last, and you might not even bother with them if you’re feeling stuffed after the tail and claws. So why would you want a whole pile of them?

This basic equation – fun concepts whose executions don’t always quite work – is a recurring problem at Brooklyn Fish Camp. Even the name “Fish Camp,” which evokes the informal fried-fish emporia of the rural Deep South, turns out to be a misnomer, because most of the food served here would have Southerners scratching their heads. Who ever heard of a fish camp that didn’t serve catfish? But if you’re a fan of the original Mary’s Fish Camp (which was founded in 2000 by Pearl Oyster Bar partner Mary Redding), the good news is that the Brooklyn menu is pretty much the same as the one in the West Village. The bad news is that the prices are the same, too, which is nothing short of scandalous. Yes, Park Slope rents have gotten way out of hand, but there’s no way they’re as high as in the Village. If you’re going to charge $23 for a lobster roll, $20 for three scallops, and $6 for a side of fries – not to mention $12 for an appetizer serving of lobster knuckles – you’d better be serving some life-altering seafood.

Unfortunately, not enough of the Fish Camp’s fare falls into that category, although there are a few standouts and, if you choose carefully, even some good values. Steamers – imported from Canada due to the red tide that’s ruined this season’s New England clam harvest – initially seem a bit pricey at $14 for an appetizer, but the serving turns out to be big enough to share. The big clam bellies are plump, juicy, and perfectly steamed.

By contrast, a $12 appetizer of New Zealand cockles is, like the lobster knuckles, too much work for too little payoff. These tiny mollusks are great on a pizza or in a salad, but on their own, they’re so small that you need to pick four or five of them out of their shells just to assemble something worth chewing. The accompanying lemon garlic broth is excellent – so why isn’t there any bread to sop it up with?

Then there are the fried skate wings ($18), which are utterly characterless – no oceanic flavor to the meat, no herbs or spices evident in the breading, and lots of unpleasantly chewy, cartilage-like bits throughout. As one person at my table put it, “This is just mediocre fish and chips.”

In happier news, if you enjoy tucking into an entire fish, there’s a rotating selection of daily specials, available grilled or fried ($23) – I can vouch for the grilled tilapia, which was juicy and flavorful. But if, like me, you find the prospect of tackling an entire fish a bit daunting, especially during the heat of summer, there’s a great option lurking in the appetizer listing: a whole fried rouget, a small, sweet fish that lets you have the fun of eating head to tail without the commitment of one of the larger fish species. The rouget is meaty, delicious, and, at only $10, the best value on the menu. Although listed as an appetizer, it makes a great light entree.

The pan-seared scallops are pretty light, too, but that’s because there’s only three of them – no virtue when you’re paying $20. The kitchen, perhaps sensitive to this problem, has paired the scallops with some fine yucca cakes, which are agreeably starchy and add some much-needed heft to the proceedings. It all works, and the scallops are beautifully browned on the outside and juicy inside, but the dish still feels a bit skimpy.

The excellent bouillabaisse offers better bang for your 20 bucks. Packed with cherrystone and razor clams, mussels, shrimp, hake, and an artfully positioned lobster claw, all swimming in a saffron broth with a slow, peppery afterburn, it’s a full-fledged seafood party in a bowl.

Also living up to its price tag is the lobster roll ($23). This is the most celebrated offering at Mary’s, and they also appear to be selling a lot of them in Brooklyn. It’s easy to see why: The big, succulent hunks of lobster (none of which came from the knuckles, you can be sure) are so voluminous that the poor little grilled bun at the bottom of the pile doesn’t stand a chance – this is knife-and-fork territory. So what you’ve really got here is a lobster salad, and a darn good one.

Interestingly, the Fish Camp’s lunch menu also serves an excellent fried clam roll, which is a relative bargain at $14. This is one of several $14 sandwiches that are only available at lunch, including a meaty mako shark BLT and splendidly fishy panfried cod with onions and tomato. Served with a small mountain of Old Bay shoestring fries (so-so) or spicy onion rings flecked with red pepper (excellent), they’re big enough to share but good enough to keep for yourself. These sandwiches are all included on the dinner menu at Mary’s in Manhattan; here’s hoping they achieve dinner status in Brooklyn, too.

As is so often the case with seafood restaurants, desserts seem like an afterthought. The best of them is a nicely tart steamed lemon pudding ($7). Mixed-berry shortcake ($7) would benefit from sweetened whipped cream instead of unsweetened, as would the pedestrian ice cream sundae (ridiculously overpriced at $10).

The Fish Camp folks may think their Manhattan pedigree justifies their price structure, or maybe they just have a lot of chutzpah. Either way, they may soon find that it isn’t that simple. Better seafood for less money is already available right now in brownstone Brooklyn, at Cobble Hill’s Blue Star. And a more formidable challenge to the Fish Camp may be on the horizon: Black Pearl, the East Village seafood operation that has a very Fish Camp-esque menu but cheaper prices has been running a Craig list ad soliciting staff applicants for a new Park Slope outlet.

But hey, competition is healthy, right? Let the fish and chips fall where they may.

Brooklyn Fish Camp, 162 Fifth Ave., Brooklyn; 718-783-3264.